Introduction

The burden of cancer falls disproportionately

upon the medically underserved, and research

studies are essential to improving health care in

general, including for medically underserved

populations. Clinical trials are used to evaluate

efficacious prevention and treatment

interventions; however, studies often fail to recruit

the planned number of participants.1 Trials often

do not include an adequately diverse population

to ensure broad generalizability of results.2 Recent

studies of patients enrolled in cancer treatment

trials sponsored by the National Cancer Institute

(NCI) have demonstrated that the following

populations are underrepresented in terms of their

participation in cancer treatment trials: the

elderly, those of low socio-economic status, those

living in rural areas and Latino/Hispanic, Asian

/Pacific Islander and American Indian/Alaska

native men and women, as well as AfricanAmerican men.3,4 Since the 1980s cancer

prevention trials have been conducted with

participants at highest risk for disease to reduce

the cancer burden, and as in treatment trials,

adequate representation of underserved

populations in prevention trials is desirable.

Questions remain regarding the appropriate level

of inclusion, i.e., whether it might depend on the

prevalence of the condition/disease studied in the

overall population. This issue has not been

addressed adequately in the literature. Moreover,

there is substantial uncertainty about what are

important barriers and promoters of recruitment

of underrepresented populations, and what

evidence-based interventions would address them.

At the request of and with the financial

support of NCI, AHRQ commissioned a

systematic review of the existing evidence on the

recruitment of underrepresented populations into

cancer clinical trials, to be performed by the Johns

Hopkins University EPC. Specifically, the EPC

investigators were asked to consider six key

questions:

• Key Question 1: What methods (e.g., survey

studies, focus groups) have been used to

study strategies to recruit underrepresented

populations into cancer prevention and

treatment trials? We defined

underrepresented populations as including

the elderly, adolescents, those of low

socioeconomic status, those living in rural

areas, African Americans, Hispanics/Latinos,

Asian Americans, and American Indians.

• Key Question 2: What measures of success

(e.g., proportional representation relative to

the U.S. population; proportional

representation relative to incidence in a

specified population) have been used to

evaluate the efficacy and/or effectiveness of

strategies for recruitment of

underrepresented populations into cancer

prevention and treatment trials? 

• Key Questions 3 and 4: Which recruitment

strategies (e.g., media appeals, incentives,

etc.) have been shown to be efficacious

and/or effective in increasing participation of

Evidence Report/Technology Assessment

Number 122

Knowledge and Access to Information on

Recruitment of Underrepresented Populations to

Cancer Clinical Trials

Summary

Authors: Ford JG, Howerton MW, Bolen S, Gary TL, Lai GY, Tilburt J, Gibbons MC, 

Baffi C, Wilson RF, Feuerstein CJ, Tanpitukpongse P, Powe NR, Bass EB

Agency for Healthcare Research and Quality

Advancing Excellence in Health Care • www.ahrq.gov

Agency for Healthcare Research and Quality Evidence-Based

Practice
2

underrepresented populations in cancer treatment and

prevention trials?

• Key Question 5: What are the documented barriers to

and promoters of participation of underrepresented

populations in cancer prevention and treatment trials?

Examples of potential barriers include access, knowledge,

attitudes, eligibility, fatalism, religiosity/spirituality and

exclusions by design. Examples of potential promoters

include attitudes, altruism, advanced disease, financial

incentives, and no-cost treatment.

• Key Question 5a: Do these barriers and promoters

differ by age, gender, socioeconomic status or

race/ethnicity?

• Key Question 5b: Are these barriers and promoters

modified by cultural factors?

• Key Question 6: What effects do the attitudes and

perceptions of health care providers have on the

efficacy/effectiveness of strategies for recruitment of

underrepresented populations into cancer prevention and

treatment trials? Health care providers were defined as

including any health professional or health care

organization that provides health services to patients.

Methods

We developed a conceptual framework to guide our analysis,

based on the factors leading to the acceptance or refusal of

participation in a cancer clinical trial. This framework was

derived from a conceptual model developed previously by two

members of the EPC team.4 The premise for the framework is

that in order to accept or refuse participation in a clinical trial,

one must first be aware of the availability of the trial, and have

an opportunity to participate in the trial. The opportunity to

participate in a clinical trial may present itself first, encouraging

patients to seek information about the trial. This, in turn, may

lead to the decision to accept or refuse participation in the trial.

There are multiple pathways to successful recruitment to a

clinical trial, including: (1) patients/clients receiving

information about clinical trials in general through health care

providers or their own social ties, and subsequently accepting a

specific opportunity to participate in a trial; and (2) in the

absence of prior awareness about clinical trials, patients/clients

may consider an opportunity to participate in a trial, with the

result of encouraging them to seek or receive information

regarding the trial, thereby increasing trial awareness. Key

questions 5 and 6 of this report address barriers and promoters

of awareness, opportunity, and acceptance/refusal. 

Literature Search Methods

Searching the literature included the steps of identifying

reference sources, formulating a search strategy for each source,

and executing and documenting each search.

Sources

Our comprehensive search plan included electronic and

hand searching. In March 2004, we searched the following

electronic databases: MEDLINE®, the Cochrane CENTRAL

Register of Controlled Trials (Issue 1, 2003), the Cochrane

Database of Methodology Reviews (CDMR), the Cumulative

Index of Nursing and Allied Health Literature (CINAHL®),

the Psychological Abstracts (PsycINFO), and The Campbell

Collaboration’s Social, Psychological, Educational, and

Criminological Trials Register (C2-SPECTR).

Hand searching for possibly relevant citations took several

forms. First, we identified 34 journals by asking our experts

what journals were most likely to contain relevant articles. We

scanned the table of contents of each issue of these journals for

relevant citations from January 2003 through July 2004.

For the second form of hand searching, we used ProCite®, a

reference management software, to create a database of

reference material identified through an electronic search for

relevant guidelines and reviews, through discussions with

experts, and through the article review process. The principal

investigators reviewed the articles identified as being possible

review articles during the abstract review process. The

references in these review articles were searched to identify any

additional article for consideration. We also used MEDLINE®

to search articles published by selected experts known to have

interests related to our questions. Finally, we examined the

reference lists of eligible articles to identify any potentially

relevant articles (this was completed by the second reviewer as

part of the article review process). 

Study Selection

Articles included in this evidence synthesis were Englishlanguage reports of original data from published studies that

addressed one of the key questions.

Data Extraction

Pairs of reviewers assessed the study quality and abstracted

data for each eligible article. Data were entered into a relational

database. 
Results

Of the 4,436 citations retrieved by the search methods,

1,089 were eligible for abstract review and 218 of those were

eligible for article review. Only 67 of the articles were eligible

after article review. Many articles were excluded because they

did not address underrepresented populations, did not address

cancer treatment or prevention, or did not discuss recruitment

to a controlled trial. Ultimately, the EPC investigators

identified 14 articles on key question 1, 23 articles on key

question 2, five articles on key questions 3 and 4, 45 articles on

key question 5, and 10 articles on key question 6.

Key Question 1: Methods to Study Recruitment Strategies

We analyzed 14 articles to identify methods (e.g., survey

studies, focus groups) that have been used to study strategies to

recruit underrepresented populations into cancer prevention

and treatment trials. 5-18

• All 14 studies were of U.S. origin, primarily based in

community settings, and targeting patients/participants.

• The reported study designs of the 14 studies varied,

including descriptive (n = 4), randomized controlled trials

(n = 3), quasi-experimental (n = 1), comparisons of two or

more interventions (n = 2), survey (n = 1), qualitative (n =

1), case study (n = 1), and other (n = 1).

• There was substantial variability across the studies in the

reporting of demographic variables such as age, gender,

income or education levels of participants; information

regarding the racial or ethnic distributions of the

participants was available for only eight of these studies. 

• The reporting of the studies limited our ability to

accurately categorize age groups (e.g., adolescents, elderly),

socioeconomic status, or residence (urban versus rural). 

Overall, the evidence indicated the need for greater

consistency in the reporting of target population characteristics,

so that key findings may be considered in relation to specific

populations. This would make it feasible, when the sample size

is adequate, to conduct subgroup analyses to assess whether

barriers to recruitment vary by sociodemographic and cultural

factors. 

Key Question 2: Measures of Success

We sought to identify what measures of success (e.g.,

proportional representation relative to the U.S. population, or

proportional representation relative to incidence in a specified

population) have been used to evaluate the efficacy and/or

effectiveness of strategies for recruitment of underrepresented

populations into cancer prevention and treatment trials.

• All studies (n = 23) were from the U.S. and 22 studies

targeted patients/participants for the recruitment

intervention; and over 50 percent of the studies were

based on multi-center cancer clinical trials conducted in

community settings (n = 9) or hospital centers (n = 7). 5-9,

11, 13, 16, 17, 19-32

• Most of the reports were based on retrospective review of

enrollment to a single or multiple cancer trials.

• Only two articles reported having a recruitment goal for

the underrepresented group prior to enrollment in the

study. The majority of studies either defined recruitment

success as equaling the proportion of underrepresented

selected by the researcher (n = 13) for various reasons or as

the disease-specific proportion of underrepresented (n =

9). The rest of the studies defined recruitment success as

equaling the geographic proportion of underrepresented

(n = 2), or the local research institution’s proportion of the

underrepresented (n = 1).

• Very few studies evaluated recruitment success in

underrepresented groups especially those with low

socioeconomic status, Asian/Pacific Islanders, adolescents,

and rural populations (less than three studies in each

group). No study reported recruitment success measures

for American Indians/Alaska Natives.

The evidence reviewed indicated that success in recruitment

of underrepresented populations is defined primarily by the

goal of each study. When reporting on cancer trials,

investigators should give careful thought to success measures for

recruitment of underrepresented populations, avoid setting

such measures arbitrarily, and report recruitment results based

on the recruitment strategies for individual cancer clinical trials. 

Key Questions 3 and 4: Methods to Study Recruitment

Strategies

We sought to identify recruitment strategies (e.g., media

appeals, incentives, etc.) that have been shown to be efficacious

and/or effective in increasing participation of underrepresented

populations in cancer treatment and prevention trials. We

found a total of five eligible articles. 6, 7, 9, 11, 17

The results of the interventions varied from no observed

improvement to an increase in recruitment into cancer clinical

trials. Two studies examined enrollment differences between

two different intervention methods. Two other studies

compared enrollment differences between interventions to a

3
4

control group. These control groups were either no

intervention (usual medical care from physicians) or a standard

recruitment “intervention” of mailed letters and telephone

contact. However, whether various interventions had a true

effect (null, positive, or negative) was somewhat unclear. Some

authors cautioned that their results could be due to factors such

as changes in recruitment strategy during the duration of the

intervention. To give a clearer picture, each of the five studies is

discussed in detail.

Linnan et al. investigated the differences between passive and

active recruitment into a home-based cancer prevention

randomized trial among employees.17 In the passive employee

contact arm, the research team contacted the employees from a

list of employee names and telephone numbers provided by the

company. In the active employee contact arm, employees

actively signed up to participate. While lower enrollment and

higher attrition were observed in the passive recruitment arm,

the passive method enrolled a more diverse group of

participants than did the active recruitment method. 

Brewster et al. examined differences in recruitment into

cancer prevention clinical trials between a clinic registry

method and a media campaign targeting Latina women.6 In the

media recruitment strategy, the study was advertised in flyers

placed in local community businesses, and advertised in

community and regional newspapers in English and Spanish.

The odds of presenting to the clinic and of recruitment were

nearly three times more successful via the media campaign than

via the clinic registry.

Paskett et al. examined the effect of an intervention program

aimed at physicians and the community to increase the number

of rural patients with breast cancer or colorectal cancer in

clinical trials.7 The intervention program consisted of the

installation of a rapid tumor-reporting system to improve data

quality and to expedite the receipt of information on cancer

patients from physicians, a nurse facilitator who would notify

physicians of clinical trials, a quarterly newsletter mailed to

physicians about cancer treatment and clinical trials, and a

health educator who trained lay health educators and provided

community-based information about cancer screening,

treatment, and clinical trials. Five counties in North Carolina

received an intervention program while five counties in South

Carolina served as controls where usual medical care was

practiced. The rates of enrollment into clinical treatment trials

did not improve significantly in the intervention communities.

Moinpour et al. reported the results of a randomized trial in

increasing participation of minorities.9 Minority recruitment

strategies were designed and implemented in five pilot sites:

African Americans in four sites and Hispanics in one site.

While each site had a minority recruiter who was given

requirements and a set of tasks, the specific details of the

minority recruitment interventions for each site were not given.

The overall impact was minimal, and it was unclear if, and at

which site the intervention was fully implemented.

Ford et al. examined recruitment differences among African

Americans randomized into either a control group or three

increasingly intensive intervention arms.7 The control group

used a standard method of recruitment such as a standard

recruitment letter, African-American or Caucasian interviewers

for eligibility screening, baseline information collection via

mailed packets, and reminder phone calls and mailings for

completion of the mailed packets (Arm D). The basic

intervention arm (Arm A) attempted to reduce potential

sociocultural and individual barriers through the use of an

enhanced recruitment letter and eligibility screening by AfricanAmerican interviewers. The second more intensive intervention

arm (Arm B) did not use mailed packets for baseline

information collection but telephone interviews to facilitate

ease of participation in addition to the enhanced recruitment

letter. The third, and most intensive, intervention arm (Arm C)

did not use a mailing packet or telephone interview but a

church-based project site to gather baseline information in

addition to the enhanced recruitment letter and eligibility

screening telephone calls by an African American. The authors

reported significantly higher enrollment yield (3.9 percent) in

the most intensive church-based, face-to-face recruitment

intervention arm (Arm C), compared to the other two

intervention arms (2.5 percent [Arm A] and 2.8 percent [Arm

B]) or the control group (2.9 percent [Arm D]) (p < 0.01).

There is only scant evidence in support of specific

interventions to improve recruitment to cancer clinical trials, as

indicated by the small number of studies comparing

interventions.

Key Question 5: Barriers and Promoters of Recruitment

We sought to identify the documented barriers and

promoters of participation for underrepresented populations in

cancer prevention and treatment trials. Our search yielded 45

eligible studies that were conducted in a variety of settings.3,5, 8, 13,

22, 23, 25, 26, 29, 33-63 Among the underrepresented populations, the

available studies targeted African Americans primarily (n = 27),

as well as Latinos/Hispanics (n = 7); American Indian/Alaska

Native (n = 4 ); the elderly (n = 14); adolescents (n = 3);rural

populations (n = 2); and Asian/Pacific Islanders (n = 2). While

a large proportion of the available studies included populations
with low socioeconomic status, only one did so by design.9 The

search strategy yielded 40 U.S.-based studies, and we included

evidence from 5 non-U.S.-based studies that featured relevant

evidence.22

Barriers and promoters of participation in cancer

prevention and treatment trials 

Types of barriers and promoters identified. Overall, the

eligible studies identified 118 distinct barriers to accrual to

cancer clinical trials, including 97 barriers to accrual to

therapeutic trials, 18 barriers to accrual to prevention trials, and

32 barriers to accrual to both therapeutic and prevention trials.

There were more reported barriers to opportunity (n = 80) than

to awareness (n = 7) or acceptance (n = 40) of clinical trials. Of

the 59 distinct promoters of enrollment, most (n = 29) were

promoters of the opportunity to participate in a cancer trial. 

Barriers and promoters of accrual of African Americans to

cancer treatment trials. Overall, there were 19 studies of accrual

of African Americans to cancer therapeutic trials, which

reported 85 barriers to accrual to therapeutic trials, including

barriers to opportunity (n = 56), barriers to acceptance (n =

28), and awareness (n = 6). Of the 28 barriers to acceptance,

the most frequently reported were perceived harms of clinical

trial participation (n = 8), mistrust of research, researchers, and

the medical system (n = 10), and fear (n = 5). Promoters were

predominantly of promoters of awareness (n = 6). Of the

reported 14 promoters of opportunity, the most frequently

reported were culturally relevant education about trials (n = 3),

and providing transportation (n = 2). Of the 14 promoters of

acceptance, the most frequently reported were altruism (n = 3),

perceived benefits of trial participation (n = 5), and incentives

(n = 5).

Barriers and promoters of accrual to therapeutic trials in

other underrepresented populations. Latinos/Hispanics. Four

studies reported evidence on barriers to accrual of

Latinos/Hispanics to cancer therapeutic trials. The reported

eight barriers to opportunity were dominated by transportation

(n = 2), age (n = 1), toxicity of treatment (n = 1), comorbid

conditions (n = 1), and disease stage (n = 1). Of the seven

barriers to acceptance, the most frequently reported was

mistrust of research and the medical system (n = 2). Only two

of the eligible studies for this question reported evidence on

promoters of enrollment of Latinos/Hispanics. Brewster and

colleagues found that a media-based strategy was superior to a

clinic based strategy in recruiting Latino-Hispanic women.6

Others have reported the lack of adequate health insurance,

incentives, culturally relevant education about trials and the

perceived benefits of trial participation as additional promoters

of accrual for Latinos/Hispanics.5, 55

American Indians/Alaska Natives. The amount of evidence

available for the American Indians/Alaska Natives population

with regard to accrual to clinical trials, in general, was very

limited. The aggregate number of American Indians/Alaska

Natives in all of the eligible studies for which data on

population subgroups was reported, was 19.35, 41, 43, 55

Asian and Pacific Islanders. We did not find any evidence

regarding barriers or promoters of participation in cancer

prevention or treatment trial for the Asian and Pacific Islander

population.

The elderly. In the 11 available studies, barriers and

promoters of opportunity were predominant in this population.

Of the 22 barriers to opportunity, the most frequently reported

were age (n = 2).

Adolescents. Only two of the available studies yielded

evidence, and reported the lack of available trials as a significant

barrier to enrollment of adolescents. Promoters of participation

for this population included the perceived benefits of trial

participation, including a chance for better treatment, and

altruistic motives.

Rural populations. Only two of the available studies focused

on recruitment of rural populations to cancer clinical trials,

including cross-sectional surveys of physicians,11 and focus

groups. The studies reported numerous barriers to awareness,

opportunity and acceptance of trial participation. They also

reported altruism and incentives (financial and otherwise) as

promoters.43

Barriers and promoters of accrual to prevention trials in

African-American populations. Overall, there were 13 studies

of barriers and promoters of accrual of African Americans to

cancer prevention trials. We did not include studies of accrual

to other types of primary prevention trials (e.g., diet and

exercise) in this systematic review. Among the 41 barriers to

accrual to prevention trials, barriers to opportunity (n = 24)

were predominant, and of the 13 barriers to acceptance,

mistrust of research and the medical system (n = 8), and the

perceived harms of clinical trial participation (n = 4) were the

most frequently reported. Promoters included provision of

transportation (n = 1) and incentives (n = 2).

Chemoprevention trials.9, 37, 56 On average, each of the

chemoprevention trials reported two barriers (range: 1 to 2).

There were no barriers to awareness, two barriers to

opportunity, and three barriers to acceptance with mistrust of

research reported in two studies. In one study, promoters

included preference for the study’s principal investigator to be

5
black, and the perception that it is better to be treated by

research doctors.

Smoking cessation trials.5,56,60 Out of the three smoking

cessation trials in African-American populations, only one trial

reported barriers to accrual, and not being ready to quit may

have been a confounding factor. The reported promoters were

incentives, support, encouragement, prayer, the certainty of

receiving actual medication, and the impact of diagnosis on risk

perception. 

Screening trials.

7 The results of this one study were discussed

in detail under key questions 3 and 4.

Barriers and promoters of accrual to prevention trials

among other underrepresented populations.

Latinos/Hispanics. Overall, there were four studies reporting

primarily barriers to opportunity (n = 7), especially

transportation (n = 2). Mistrust of research and the medical

system (n = 2) and family considerations or issues (n = 2) were

the most frequent barriers to acceptance. 

American Indians/Alaska Natives and Asian and Pacific

Islanders. As discussed in the section on accrual to therapeutic

trials, very little information is available on these two

populations.

The elderly. Overall, there were three studies of barriers and

promoters of enrollment to cancer prevention trials in the

elderly. These studies reported three distinct barriers, age being

the most frequently cited (n = 2). Among the three promoters

of accrual to prevention trials, there were no promoters of

awareness or acceptance. The three reported promoters of

accrual were the entry criteria, age and low-income status.

Rural populations. The available evidence on barriers and

promoters of accrual of rural populations to cancer prevention

and treatment trials is based on two studies that we discussed in

the section on barriers and promoters of accrual to therapeutic

trials.10,43

Key Question 5a: Effects of Demographic Factors

Overall, the available evidence for key question 5 suggested

that accrual to or intention to participate in a trial varied by the

following sociodemographic factors: age (n = 16); gender 

(n = 3); socioeconomic status (n = 4); and race/ethnicity 

(n = 4). These barriers and promoters related most frequently

to study design barriers, including exclusion by age (n = 6),

study duration and visit structure (n = 4), comorbid conditions

(n = 7), and functional status (n = 6). Few trials were available

for adolescents; and as expected, parental influence was

reported as a factor in decision-making only in this population.

However, the available evidence did not suggest age as a factor

that reduced awareness or acceptance of participation.

Key Question 5b: Effects of Cultural Factors

Three of the studies reported that barriers or promoters of

enrollment varied by cultural factors,39,55,60 however, it is not

entirely clear whether such “cultural factors” refer to cultural

norms, values or beliefs. For the elderly population, enrollment

barriers and promoters did not vary by culturally relevant

factors other than race or ethnicity. The heterogeneity of the

available evidence and the definitional overlap among several of

the underrepresented populations limited our ability to

synthesize the evidence regarding whether some barriers or

promoters vary by cultural factors. 

Key Question 6: Role of Provider Attitudes and

Perceptions 

Nine studies presented data on how provider

attitudes/perceptions were barriers to and promoters of accrual

to cancer clinical trials. Four studies found provider atttitudes

as a barrier to enrollment11,23,44,64 while one study found provider

attitudes to be a promoter of patient accrual.23 The studies also

reported that patient age,23,59,65 comorbidity,

23,59 disease stage,23

mistrust of researchers,23,31 and lack of physician awareness

about trials44,52 were factors that prevented providers from

enrolling their patients into clincial trials. Two studies64, 66 found

that provider communication or method of presentation were

barriers to patient enrollment, whereas one study found it to be

a promoter of trial enrollment.41

For studies that targeted minority populations,29,44,52 mistrust

of researchers and lack of provider awareness about trials were

leading provider barriers 44,52 that decreased patient enrollment

in clinical trials. Additionally, concerns about patient noncompliance and a lack of available protocols were reasons cited

for not talking to patients about clinical trials.29 For studies that

targeted the elderly, provider attitudes regarding clinical trials

prevented them from sharing information about trials with

their patients in one study,23 and increased their willingness to

enroll patients in clinical trials in another study.

41

Discussion

Research Quality

Since the enactment of the National Institutes of Health

(NIH) Revitalization Act in 1993,67 cancer researchers have put

increased emphasis on recruitment of underrepresented

populations to clinical trials. However, this aspect of the human

research enterprise has received attention primarily in the

secondary analysis of ongoing clinical trials, rather than as an

area of focused scholarship. This reality is clearly reflected in the

quality of studies available for this evidence report. One of the

6
positive aspects of the studies available for our review is that

they have described a number of barriers and promoters of

participation in clinical trials. However, most of the evidence is

not based on rigorous studies, and a large proportion of the

available studies were not driven by any clear hypotheses. A

major weakness of the available evidence is the limited number

of studies that compared two or more interventions, especially

randomized controlled trials. The quality of the evidence

summarized raises some questions about its adequacy to answer

our questions regarding barriers and promoters of participation

in cancer clinical trials. However, because of the consistency

and patterns of occurrence of the identified barriers and

promoters, it does provide important insights into future

research directions. 

Recommendations and Future Research

Key Questions 1 and 2 

• Much of the available body of evidence was developed as

“evidence by convenience” in the context of recruitment

difficulties, or in retrospective analyses of recruitment of

underrepresented populations across multiple clinical

trials. There is a need for well-designed, controlled studies

of strategies to improve accrual to cancer prevention and

treatment trials. These studies should be hypothesisdriven, and include defined measures of success. They

should also meet the usual standards of the NIH peer

review process. 

• Investigators should give careful thought to success

measures for recruitment of underrepresented populations,

and they should avoid setting such measures arbitrarily.

Additionally, researchers should evaluate and report

recruitment results for underrepresented groups more

consistently. 

• More attention should be focused on issues of trial design.

If studies are not designed to address problems that are

relevant to patients in underserved communities, then

even the best recruitment strategies will be ineffective.

Similarly, trials that exclude patients with chronic

conditions will preferentially exclude the elderly, members

of minority groups, and patients with lower

socioeconomic status, because they are more likely to have

chronic conditions. Hence, recruitment efforts must

proceed hand-in-hand with initiatives to design relevant

and pragmatic trials.68

Key Questions 3, 4, 5, and 6

• Because of many underrepresented populations’ mistrust

of researchers and of research institutions, research efforts

to improve participation of underserved populations in

cancer clinical trials should be developed within the

framework of community-based participatory research,

with community involvement through all phases of the

research. 

• The need remains for community-based studies to

understand barriers to accrual in the community,

including attitudes toward clinical trial participation.

Whenever possible, such studies should be linked to the

implementation of cancer clinical trials, and include actual

recruitment as a major outcome. For example, several

studies have suggested culturally relevant education as a

strategy for improving accrual to cancer clinical trials.

There is a need to further investigate the efficacy of

culturally relevant education as a strategy to improve

accrual to cancer prevention trials and cancer treatment

trials. 

• There is an urgent need to understand why participation

of the Asian American/Pacific Islander and American

Indian/Alaska Native populations in cancer clinical trials is

minimal to non-existent. Studies of barriers and promoters

of their participation should be linked to opportunities to

participate. New research initiatives in this area may

require several years before they are fruitful in terms of

trial enrollment results. 

• Similarly, there is a continuing need to better understand

and improve upon strategies for recruitment of AfricanAmerican males and Latinos/Hispanics into cancer clinical

trials. Ideally, such studies should include documentation

of existing barriers within a population as a basis for

tailored interventions across the spectrum of barriers and

promoters, including awareness, opportunity and

decision-making.

• There is a need for further investigation of effective

communication strategies, including investigations on the

best approach to deliver information about clinical trials,

both at the community level and at the point of

interaction with the potential participant.

• In communities lacking established efforts to promote

awareness about clinical trials, sufficient time should be

allowed for relationships to be built with community

members, including community-based providers, before

accrual can begin. The period for building such

7
relationships may take several years, but it would vary

depending on the community and the existing

relationships prior to an intervention. 

• Some interventions (e.g., media-based strategy for

Hispanic women) have been shown to be effective in

increasing accrual to clinical trials. Such interventions

should be replicated, and where appropriate, the results

should be disseminated widely.

• To advance the evidence regarding efficacious strategies for

improving enrollment to cancer clinical trials, intervention

studies will need to be linked to one or more clinical trials,

depending on sample size requirements. The studies

should include collection of baseline information

regarding prevalent risk factors in the study population.

Systematic data collection about barriers and promoters of

trial participation should be linked to concrete plans for

designing interventions to address such barriers. Moreover,

the next generation of studies of barriers and promoters of

accrual should be multidisciplinary, including the

involvement of community-based participatory

researchers, social and behavioral scientists, as well as

health economists. 

• There are many barriers to care, and it is unlikely that

piecemeal strategies to address these barriers will be

effective to promote participation in cancer clinical trials.

There is a need for a cost-effective strategy to address

barriers to care on multiple levels, and in a manner that

can be integrated into the context of the health care

system and of the research team. To facilitate the

integration of recruitment interventions into health care

systems, especially the research team, a study should

compare the efficacy of a recruitment intervention

specialist to that of usual, opportunistic recruitment

practices. The recruitment intervention specialist would be

a professional or paraprofessional staff member who is

appropriately trained to promote awareness about clinical

trials in the community and to help patients overcome

barriers to opportunity. Ideally, the recruitment

intervention specialist would be indigenous to, or at least

have extensive familiarity with, the community targeted by

the recruitment effort. Thus, this role would be analogous

to that of a patient navigator for clinical trials, and its

cost-effectiveness should be investigated. 

• Research to improve enrollment of underrepresented

populations in cancer clinical trials must interface with

other ongoing initiatives designed to address cancer health

disparities through discovery, development, and delivery.

Such efforts must overcome the critical disconnect

between discovery and development on the one hand, and

delivery of cancer care on the other.

• Substantial resources will need to be dedicated to research

efforts to build upon the existing evidence on strategies for

improving enrollment of underrepresented populations in

cancer clinical trials. Many of the initiatives that

contributed to the available evidence were probably not

funded. NCI should dedicate adequate funds for welldesigned studies of barriers and promoters of accrual to

cancer clinical trials.

Further investigation is needed on barriers to recruitment of

all of the underrepresented populations, as defined in this

report, into cancer-related clinical trials. The specific

populations are: African Americans (especially men), Hispanics,

American Indians/Alaska Natives, Asian and Pacific Islanders,

adolescents, the elderly, and rural populations. Future studies

should include the evaluation of culturally tailored strategies to

promote awareness about cancer clinical trials among

underrepresented populations. Different types of intervention

approaches should be considered to promote accrual to cancer

therapeutic trials and cancer prevention trials. Research and

evaluation of recruitment strategies may yield stronger evidence

about ways to improve participation of underrepresented

populations in cancer clinical trials. The principal need is for

hypothesis-driven research, and ultimately randomized

controlled trials, to evaluate the most promising strategies for

recruiting underrepresented populations into cancer treatment

and prevention trials. 

Availability of the Full Report

The full evidence report from which this summary was taken

was prepared for the Agency for Healthcare Research and

Quality (AHRQ) by the Johns Hopkins University Evidencebased Practice Center, under Contract No. 290-02-0018. It is

expected to be available in June 2005. At that time, printed

copies may be obtained free of charge from the AHRQ

Publications Clearinghouse by calling 800-358-9295.

Requesters should ask for Evidence Report/Technology

Assessment No. 122, Knowledge and Access to Information on

Recruitment of Underrepresented Populations to Cancer Clinical

Trials. In addition, Internet users will be able to access the

report and this summary online through AHRQ’s Web site at

www.ahrq.gov.

8
Suggested Citation

Ford JG, Howerton MW, Bolen S, Gary TL, Lai GY, Tilburt

J, Gibbons MC, Baffi C, Wilson RF, Feuerstein CJ,

Tanpitukpongse P, Powe NR, Bass EB. Knowledge and Access

to Information on Recruitment of Underrepresented

Populations to Cancer Clinical Trials. Summary, Evidence

Report/Technology Assessment No. 122. (Prepared by the

Johns Hopkins University Evidence-based Practice Center,

under Contract No. 290-02-0018.) AHRQ Publication No.

05-E019-1. Rockville, MD: Agency for Healthcare Research

and Quality. June 2005.

References

1. Charlson ME, Horwitz RI. Applying results of randomized trials to

clinical practice: impact of losses before randomization. BMJ.

1984;289:1281-4.

2. Swanson GM, Bailar JC. Selection and description of cancer clinical

trials participants—science or happenstance? Cancer. 2002;9(5):950-9.

3. Sateren WB, Trimble EL, Abrams J, et al. How sociodemographics,

presence of oncology specialists, and hospital cancer programs affect

accrual to cancer treatment trials. J Clin Oncol. 2002;20(8):2109-17.

4. Powe NR, Gary TL. Race and Research in Focus: Perspectives on

Minority Participation in Health Studies: Clinical Trials Chapter. In

Bettina M (Ed). 2004, American Public Health Association. 

5. Berman BA, Grosser SC, Gritz ER. Recruitment to a school-based

adult smoking-cessation program: do gender and race/ethnicity make

a difference? J Cancer Educ 1998;13(4):220-5 .

6. Brewster WR, Anton-Culver H, Ziogas A, et al. Recruitment strategies

for cervical cancer prevention study. Gynecol Oncol 2002;85(2):250-

4.

7. Ford M, Havstad S, Davis SD. A randomized trial of recruitment

methods for older African-American Men in the Prostate, Lung,

Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Clinical

Trials. 2004;1:343-51.

8. Kaluzny A, Brawley O, Garson-Angert D, et al. Assuring access to

state-of-the-art care for U.S. minority populations: the first 2 years of

the Minority-Based Community Clinical Oncology Program. J Natl

Cancer Inst. 1993;85(23):1945-50.

9. Moinpour CM, Atkinson JO, Thomas SM, et al. Minority

recruitment in the prostate cancer prevention trial. Ann Epidemiol

2000;10(8 Suppl):S85-91.

10. Paskett ED, Cooper MR, DeGraffinreid CR, et al. Community

clinical oncology program as a recruitment vehicle for cancer control

research. The Southeast Cancer Control Consortium experience. N C

Med J. 1995;56(6):283-6.

11. Paskett ED, Cooper MR, Stark N, et al. Clinical trial enrollment of

rural patients with cancer. Cancer Pract. 2002;10(1):28-35.

12. Sears SR, Stanton AL, Kwan L, et al. Recruitment and retention

challenges in breast cancer survivorship research: results from a multisite, randomized intervention trial in women with early stage breast

cancer. Cancer Epidemiol Biomarkers Prev. 2003;12(10):1087-90.

13. Thornquist MD, Patrick DL, Omenn GS. Participation and

adherence among older men and women recruited to the BetaCarotene and Retinol Efficacy Trial (CARET). Gerontologist.

1991;31(5):593-97.

14. Zhu K, Hunter S, Bernard LJ, et al. Recruiting elderly AfricanAmerican women in cancer prevention and control studies: a

multifaceted approach and its effectiveness. J Natl Med Assoc.

2000;92(4):169-75.

15. Advani AS, Atkeson B, Brown CL, et al. Barriers to the participation

of African-American patients with cancer in clinical trials: a pilot

study. Cancer. 2003;97(6):1499-506.

16. Maurer LH, Davis T, Hammond S, et al. Clinical trials in a rural

population: professional education aspects. J Cancer Educ.

2001;16(2):89-92.

17. Linnan LA, Emmons KM, Klar N, et al. Challenges to improving the

impact of worksite cancer prevention programs: comparing reach,

enrollment, and attrition using active versus passive recruitment

strategies. Ann Behav Med. 2002;24(2):157-66.

18. Randall-David B, Stark N, Gierisch J, et al. ‘What do they know

about it?’ How the North Carolina public views cancer clinical trials:

implications for primary care doctors. N C Med J. 2001;62(5):281-5.

19. Alexander GA, Chu KC, Ho RC. Representation of Asian Americans

in clinical cancer trials. Ann Epidemiol 2000;10(8 Suppl):S61-67.

20. Benson AB 3rd, Pregler JP, Bean JA, et al. Oncologists’ reluctance to

accrue patients onto clinical trials: an Illinois Cancer Center study. J

Clin Oncol. 1991;9(11):2067-75.

21. Goodwin JS, Hunt WC, Humble CG, et al. Cancer treatment

protocols. Who gets chosen? Arch Intern Med. 1988;148(10):2258-

60.

22. Hunter CP, Frelick RW, Feldman AR, et al. Selection factors in clinical

trials: results from the Community Clinical Oncology Program

Physician’s Patient Log. Cancer Treat Rep 1987;71(6):559-65.

23. Kemeny MM, Peterson BL, Kornblith AB, et al. Barriers to clinical

trial participation by older women with breast cancer. J Clin Oncol

2003;21(12):2268-75.

24. Klabunde CN, Springer BC, Butler B, et al. Factors influencing

enrollment in clinical trials for cancer treatment. South Med J.

1999;92(12):1189-93.

25. Krailo MD, Bernstein L, Sullivan-Halley J, et al. Patterns of

enrollment on cooperative group studies. An analysis of trends from

the Los Angeles County Cancer Surveillance Program. Cancer

1993;71(10 Suppl):3325-30.

26. Lewis JH, Kilgore ML, Goldman DP, et al. Participation of patients

65 years of age or older in cancer clinical trials. J Clin Oncol

2003;21(7):1383-9.

27. Murthy VH, Krumholz HM, Gross CP. Participation in cancer

clinical trials: race-, sex-, and age-based disparities. JAMA.

2004;291(22):2720-6.

28. Schiffman M , Adrianza ME. ASCUS-LSIL Triage Study. Design,

methods and characteristics of trial participants. Acta Cytol

2000;44(5):726-42.

29. Simon MS, Du W, Flaherty L, et al. Factors associated with breast

cancer clinical trials participation and enrollment at a large academic

medical center. J Clin Oncol. 2004;22(11):2046-52.

9
30. Trimble EL, Carter CL, Cain D. Representation of Older Patients in

Cancer Treatment Trials. Cancer. 1994;74(7):2208-14.

31. Yee KW, Pater JL, Pho L, et al. Enrollment of older patients in cancer

treatment trials in Canada: why is age a barrier? J Clin Oncol

2003;21(8):1618-23.

32. Zhu K, Hunter S, Bernard LJ, et al. Recruiting elderly AfricanAmerican women in cancer prevention and control studies: a

multifaceted approach and its effectiveness. J Natl Med Assoc.

2000;92(4):169-75.

33. Adams-Campbell LL, Ahaghotu C, Gaskins M, et al. Enrollment of

African Americans onto clinical treatment trials: study design barriers.

J Clin Oncol 2004;22(4):730-4.

34. Sears SR, Stanton AL, Kwan L, et al. Recruitment and retention

challenges in breast cancer survivorship research: results from a

multisite, randomized intervention trial in women with early stage

breast cancer. Cancer Epidemiol Biomarkers Prev 2003;12(10):1087-

90.

35. Broome ME, Richards DJ. The influence of relationships on children’s

and adolescents’ participation in research. Nurs Res 2003;52(3):191-7.

36. Advani AS, Atkeson B, Brown CL, et al. Barriers to the participation

of African-American patients with cancer in clinical trials: a pilot

study. Cancer 2003;97(6):1499-506.

37. Bieniasz ME, Underwood D, Bailey J, et al. Women’s feedback on a

chemopreventive trial for cervical dysplasia. Appl Nurs Res

2003;16(1):22-8.

37. Comis RL, Miller JD, Aldige CR, et al. Public attitudes toward

participation in cancer clinical trials. J Clin Oncol 2003 ;21(5):830-5.

39. Brown DR, Topcu M. Willingness to participate in clinical treatment

research among older African Americans and whites. Gerontologist

2003;43(1):62-72.

40. Grunfeld E, Zitzelsberger L, Coristine M, et al. Barriers and

facilitators to enrollment in cancer clinical trials: qualitative study of

the perspectives of clinical research associates. Cancer

2002;95(7):1577-83.

41. Kornblith AB, Kemeny M, Peterson BL, et al. Survey of oncologists’

perceptions of barriers to accrual of older patients with breast

carcinoma to clinical trials. Cancer 2002;95(5):989-96.

42. Diener-West M, Hawkins BS, Moy CS, et al., for the Collaborative

Ocular Melanoma Study Group. Sociodemographic and clinical

predictors of participation in two randomized trials: findings from the

Collaborative Ocular Melanoma Study COMS report no. 7. Control

Clin Trials. 2001;22(5):526-37.

43. Randall-David B, Stark N, Gierisch J, et al. “What do they know

about it?” How the North Carolina public views cancer clinical trials:

implications for primary care doctors. N C Med J 2001;62(5):281-5.

44. Pinto HA, McCaskill-Stevens W, Wolfe P, et al. Physician perspectives

on increasing minorities in cancer clinical trials: an Eastern

Cooperative Oncology Group (ECOG) Initiative. Ann Epidemiol

2000;10(8 Suppl):S78-84.

45. Fouad MN, Partridge E, Green BL, et al. Minority recruitment in

clinical trials: a conference at Tuskegee, researchers and the

community. Ann Epidemiol 2000;10(8 Suppl):S35-40.

46. Brown DR, Fouad MN, Basen-Engquist K, et al. Recruitment and

retention of minority women in cancer screening, prevention, and

treatment trials. Ann Epidemiol 2000;10(8 Suppl):S13-21.

47. Fouad MN, Partridge E, Wynn T, et al. Statewide Tuskegee Alliance

for clinical trials. A community coalition to enhance minority

participation in medical research. Cancer 2001;91(1 Suppl):237-41.

48. Outlaw FH, Bourjolly JN, Barg FK. A study on recruitment of black

Americans into clinical trials through a cultural competence lens.

Cancer Nurs 2000;23(6):444-51, quiz 451-2.

49. Chen CI, Skingley P, Meyer RM. A comparison of elderly patients

with aggressive histology lymphoma who were entered or not entered

on to a randomized phase II trial. Leuk Lymphoma 2000;38(3-

4):327-34.

50. Ling J, Rees E, and Hardy J. What influences participation in clinical

trials in palliative care in a cancer centre? Eur J Cancer

2000;36(5):621-6.

51. Lee MM, Chamberlain RM, Catchatourian R, et al. Social factors

affecting interest in participating in a prostate cancer chemoprevention

trial. J Cancer Educ 1999;14(2):88-92.

52. McCaskill-Stevens W, Pinto H, Marcus AC, et al. Recruiting minority

cancer patients into cancer clinical trials: a pilot project involving the

Eastern Cooperative Oncology Group and the National Medical

Association. J Clin Oncol 1999;17(3):1029-39.

53. Twelves CJ, Thomson CS, Young J, et al. Entry into clinical trials in

breast cancer: the importance of specialist teams. Scottish Breast

Cancer Focus Group and Scottish Cancer Therapy Network. Eur J

Cancer 1998;34(7):1004-7.

54. Mouton CP, Harris S, Rovi S, et al. Barriers to black women’s

participation in cancer clinical trials. J Natl Med Assoc 1997

;89(11):721-7.

55. Roberson NL. Clinical trial participation. Viewpoints from

racial/ethnic groups. Cancer 1994;74(9 Suppl):2687-91.

56. Lerman C, Rimer BK, Daly M, et al. Recruiting high risk women into

a breast cancer health promotion trial. Cancer Epidemiol Biomarkers

Prev 1994;3(3):271-6.

57. Millon-Underwood S, Sanders E, Davis M. Determinants of

participation in state-of-the-art cancer prevention, early

detection/screening, and treatment trials among African-Americans.

Cancer Nurs 1993;16(1):25-33.

58. Kemp N, Skinner E, Toms J. Randomized clinical trials of cancer

treatment—a public opinion survey. Clin Oncol 1984;10(2):155-61.

59. Spaight SJ, Nash S, Finison LJ, et al. Medical oncologists’

participation in cancer clinical trials. Prog Clin Biol Res 1984;156:49-

61.

60. Woods MN, Harris KJ, Mayo MS, et al. Participation of African

Americans in a smoking cessation trial: A quantitative and qualitative

study. J Natl Med Assoc 2002;94(7):609-618.

61. Green BL, Partridge EE, Fouad MN, et al. African-American attitudes

regarding cancer clinical trials and research studies: results from focus

group methodology. Ethn Dis 2000;10(1):76-86.

62. Robinson SB, Ashley M, and Haynes MA. Attitude of AfricanAmericans regarding prostate cancer clinical trials. J Community

Health 1996;21(2):77-87.

63. Moore DH. Ovarian cancer in the elderly patient. Oncology

1994;8:21-25.

64. Richardson JL, Myrtle R, Solis JM, et al. Participation of community

medical oncologists in clinical research trials. Prog Clin Biol Res

1986;216:269-80.

10
11

65. Pinto BM, Clark MM, Maruyama NC, et al. Psychological and fitness

changes associated with exercise participation among women with

breast cancer. Psychooncology 2003;12(2):118-26.

66. Fallowfield L, Ratcliffe D, Souhami R. Clinicians’ attitudes to clinical

trials of cancer therapy. Eur J Cancer 1997;33(13):2221-9.

67. National Institutes of Health. 1993. NIH guidelines on the inclusion

of women and minorities as subjects in clinical research. Available at:

http://grants.nih.gov/grants/funding/women_min/guidelines_update.h

tm. Accessed October 1, 2004.

68. Corrie P, Shaw J, Harris R. Rate limiting factors in recruitment of

patients to clinical trilas in cancer research: descriptive study. BMJ

2003;327(7410):320-1. 
www.ahrq.gov

AHRQ Pub. No. 05-E019-1

June 2005

ISSN 1530-440X