Part B. Neoplastic Diseases

7.  Screening for Breast Cancer

RECOMMENDATION

Routine screening for breast cancer every 1-2 years, with mammography

alone or mammography and annual clinical breast examination (CBE), is

recommended for women aged 50-69. There is insufficient evidence to

recommend for or against routine mammography or CBE for women aged

40-49 or aged 70 and older, although recommendations for high-risk

women aged 40-49 and healthy women aged 70 may be made on other

grounds (see Clinical Intervention). There is insufficient evidence to

recommend for or against the use of screening CBE alone or the teaching

of breast self-examination.

Burden of Suffering

In the U.S. in 1995, there were an estimated 182,000 new cases of breast

cancer diagnosed and 46,000 deaths from this disease in women.1

Approximately 32% of all newly diagnosed cancers in women are cancers

of the breast, the most common cancer diagnosed in women.1 The annual

incidence of breast cancer increased 55% between 1950 and 1991.2 The

incidence in women during the period 1987-1991 was 110/100,000.2 In

1992, the annual age-adjusted mortality from breast cancer was

22/100,000 women.3 The age-adjusted mortality rate from breast cancer

has been relatively stable over the period from 1930 to the present.1,2

For women, the estimated lifetime risk of dying from breast cancer is

3.6%.2 Breast cancer resulted in 2.2 years of potential life lost before age

65 per 1,000 women under age 65 in the U.S. during 1986-1988.4 This rate

was surpassed only by deaths resulting from motor vehicle injury and

infections. Breast cancer is the leading contributor to cancer mortality in

women aged 15-54,1 although 48% of new breast cancer cases and 56% of

breast cancer deaths occur in women age 65 and over.2 As the large

number of women in the "baby boom" generation age, the number of breast

cancer cases and deaths will increase substantially unless age-specific

incidence and mortality rates decline.

Important risk factors for breast cancer include female gender, residence

in North America or northern Europe, and older age.5 In American women,

the annual incidence of breast cancer increases with age: 127

cases/100,000 for women aged 40-44; 229/100,000 for women aged 50-

54; 348/100,000 for women aged 60-64; and 450/100,000 for women

aged 70-74.2 The risk for a woman with a family history of breast cancer

in a first-degree relative is increased about 2-3-fold, and for women

under 50 it is highest when the relative had premenopausally diagnosed

breast cancer.6-9 Women with previous breast cancer or carcinoma in situ

and women with atypical hyperplasia on breast biopsy are also at

significantly increased risk.6,7,10-12 Other factors associated with

increased breast cancer risk include a history of proliferative breast

lesions without atypia on breast biopsy, late age at first pregnancy,

nulliparity, high socioeconomic status, and a history of exposure to high-

dose radiation.6,7,10-12 Associations between breast cancer and oral

contraceptives, long-term estrogen replacement therapy, obesity, and a

diet high in fat have been suggested, but causal relationships have not

been established.6,7,13,14

Accuracy of Screening Tests

The three screening tests usually considered for early detection of breast

cancer are clinical breast examination (CBE), x-ray mammography, and

breast self-examination (BSE). Estimates of the sensitivity and

specificity of these maneuvers depend on a number of factors, including

the size of the lesion, the characteristics of the breast being examined,

the age of the patient, the extent of follow-up to identify false negatives,

the skill and experience of the examiner or radiographic interpreter, and

(in the case of mammography) the quality of the mammogram. Because

multiple clinical trials have demonstrated the effectiveness of screening,

measures of screening test performance (such as sensitivity and

specificity) are primarily helpful in comparing trials, screening programs,

and community practice. Uniform definitions, however, are necessary for

such comparisons. For example, different studies may use similar

definitions of sensitivity, such as the number of screen-detected cancers

compared to the total of screen-detected cancers plus interval cancers,

but one may use a fixed interval (e.g., 12 months)15 and another a variable

interval (e.g., time to next screen),16 making direct comparisons difficult.

The ability to detect interval cancers may also vary and will affect such

estimates.

A review17 of the current clinical trial data, published and unpublished,

summarized screening test performance for mammography using uniform

definitions. Sensitivity of mammography did not dramatically differ

across the trials. Estimates from three Swedish trials using

mammography alone averaged about 75%, while estimates for

mammography combined with CBE ranged from 75% in the Health Insurance

Plan of Greater New York (HIP) to 88% in the Edinburgh trial and the

Canadian National Breast Cancer Screening Study in women aged 50-59

(NBSS 2). Specificity estimates ranged from 98.5% in the HIP trial to 83%

in the Canadian NBSS 2. Sensitivity estimates for mammography alone and

for combined screening with CBE have generally been 10-15% lower for

women aged 40-49 compared with women greater than age 50.15,17-19

Preliminary results from two North American demonstration projects

suggest improved sensitivity of mammography, especially for women in

their forties, with current mammographic techniques.20 Significant

variations in interpreter performance have also been observed.21-23 In

the Canadian trials, agreement was about 50% beyond that attributable to

chance between radiologists at five screening centers and a single

reference radiologist.21

The effectiveness of CBE alone has not been evaluated directly, but

comparisons of the sensitivity and specificity of this maneuver to that of

mammography can be considered. The Canadian NBSS 2 was designed to

assess the incremental value of mammography above a careful, thorough

(5-10 minutes) CBE.24,25 Preliminary results showing no incremental

benefit highlighted the fact that higher sensitivity (88% for mammography

plus CBE vs. 63% for CBE alone)17 may not guarantee improved

effectiveness. Specificity was comparable or slightly better for CBE

alone. Sensitivity of CBE for women aged 40-49 (Canadian NBSS 1) was

about 10% lower at initial screen compared to the estimate for women

aged 50-59 (Canadian NBSS 2).26 Specificity estimates were similarly

lower for younger women.

Data regarding the accuracy of BSE are extremely limited. One report

calculated an upper limit of sensitivity ranging from 12 to 25% by

assuming all interval cases in the clinical trials were detected by BSE.17

Using a similar approach, the overall sensitivity of BSE alone was

estimated to be 26% in women also screened by mammography and CBE in

the Breast Cancer Detection Demonstration Project (BCDDP).27 Estimated

BSE sensitivity decreased with age, from 41% for women aged 35-39 to

21% for women aged 60-74.27 Thus, as currently practiced, BSE appears

to be a less sensitive form of screening than is CBE or mammography, and

its specificity remains uncertain. The sensitivity of BSE can be improved

by training, as measured by the proportion of benign lumps28 detected on

human models and artificial lumps29 on silicone breast models, although

whether this improved detection on models translates into improved

personal BSE performance is unknown.

Adverse effects of screening tests are an important consideration. False-

positive tests, resulting from the effort to maximize disease detection,

may have negative consequences including unnecessary diagnostic tests. In

the Canadian trials there were 7-10% false positives from combined

screening with mammography and CBE among women aged 40-49 and 4.5-

8% among those aged 50-59.24,30 In a study of the yield of a first

mammographic screening among women, half as many cancers per 1,000

first screening mammograms were diagnosed in women aged 40-49

(3/1,000) compared to women aged 50-59 (6/1,000).31 Yet, women aged

40-49 underwent twice as many diagnostic tests per cancer detected

compared to women aged 50-59 (43.9 vs. 21.9). Women aged 60-69 had a

higher yield from screening, with 13 breast cancers diagnosed per 1,000

first screening mammograms and 10.2 diagnostic tests performed per

cancer detected.

Mammographic screening may also adversely affect psychological well-

being. Increased anxiety about breast cancer after a false-positive

mammogram has been reported both at short- and long-term follow-up in

studies surveying groups of screened women.32,33 No impact on

compliance in obtaining future screening examinations was observed,

however. Women who underwent a surgical biopsy as a result of a false-

positive screening mammogram were more likely to report their workup

as a stressful experience than were those who did not have a biopsy.32

Excess breast cancers in populations that received doses of ionizing

radiation significantly greater than currently delivered by mammography,

such as survivors from atomic bombing in Japan34 and patients with

benign breast disease,35 have raised concerns about the potential

radiation risk from screening mammograms. There is no direct evidence of

an increased risk of breast cancer from mammographic screening,

however. Assuming a mean breast dose of 0.1 rad from a mammogram and

extrapolating from higher doses of radiation, modeling suggests that in a

group of 100,000 women receiving annual screening from ages 50 to 75,

12.9 years would be lost due to radiogenic cancers but 12,623 years would

be gained through a 20% reduction in breast cancer mortality as a result

of that screening.34

Fewer data are available regarding adverse effects associated with CBE

and BSE. A dramatic increase in false-positives was observed after

instruction in BSE in a nonrandomized controlled trial evaluating

performance on human models,28 although no increase was found in a

randomized controlled trial evaluating performance on silicone breast

models.29 The latter study also assessed the impact of training on

variables other than detection performance on models. Adverse effects,

such as unnecessary physician visits, heightened anxiety levels, or

increased radiographic and surgical procedures, were not observed.29

Effectiveness of Early Detection

Seven randomized controlled trials16,30,36-40 have evaluated the

effectiveness of screening for breast cancer in women by either

mammography alone or combined with CBE compared to no periodic

screening. The age of participants at date of first invitation ranged from

40 to 74. The six trials16,36-40 that included women aged 50 showed a

reduction in breast cancer mortality of 20-30% in the intervention group.

The reduction was statistically significant in the Health Insurance Plan of

Greater New York (HIP),37 the Swedish two-county trials,16 an overview

of the Swedish trials,40 and two meta-analyses of the trials.41,42

The results of these six trials including women aged 50 have

convincingly demonstrated the effectiveness of mammographic screening

(with or without CBE) for breast cancer in women aged 50-69. The HIP

trial screened women aged 40-64 with annual CBE and two-view

mammography.37 For women who were over age 50 at the time of entry

into the study, mortality from breast cancer in the intervention group was

more than 50% lower than in the control group at 5 years, decreasing to a

21% difference after 18 years of follow-up. The Edinburgh trial36

screened women aged 45-64 from 84 general medicine practices with

two-view mammography and CBE on the initial screen followed by annual

CBE and biennial single-view mammography. Preliminary results at seven

years found a relative risk of 0.80 (95% confidence interval [CI], 0.54 to

1.17) for women aged 50 and older at entry. The results from 10-year

follow-up showed little change.17 An overview pooled the data through

1989 from the four Swedish randomized controlled trials of breast cancer

screening with mammography alone.40 All women diagnosed with breast

cancer before randomization were excluded and endpoints were

independently reviewed. Breast cancer mortality was reduced by about

30% for women aged 50-69 at entry using an endpoint of breast cancer as

the underlying cause of death. A meta-analysis that included the most

recently published results of these trials reported a 23% reduction in

breast cancer mortality for women aged 50 and older.42 A meta-analysis

of European case-control studies done within screening mammography

programs also reported significantly reduced breast cancer mortality

among women aged 50 and older.42

There are few data regarding the optimal periodicity of screening in this

age group. Although an annual interval has been recommended by many

groups, an analysis of data from the Swedish two-county study found

little evidence that an annual interval would confer greater benefit than

screening every 2 years for women over the age of 50.19 This trial used

mammography alone, but the reduction in breast cancer mortality was

similar to that seen in the trials combining CBE with mammography.36,37

The similar mortality reductions found in screening trials using

periodicities ranging from 12 to 33 months in women aged 50 suggests

that biennial screening intervals are as effective as annual intervals. In a

meta-analysis of the trials evaluating screening mammography,42 the

estimated reduction in breast cancer mortality was the same (23%) for

screening intervals of 12 months and 18-33 months in women aged 50-74.

There is limited and conflicting evidence regarding the benefit of

screening women aged 70-74. The Swedish two-county trial and BCDDP

time series included women up to age 74 at entry, and each found a

reduction of breast cancer mortality for the intervention group as a

whole.16,44 The Swedish overview, however, reported a relative risk of

0.98 (95% CI, 0.63 to 1.53) at 12-year follow-up for the age subgroup 70-

74.40 The wide confidence interval, due to small numbers in this subgroup

analysis, does not preclude the possibility of a substantial benefit from

screening in this age group. No clinical trials have evaluated screening in

women over 74 years of age at enrollment.

Although all six trials found a benefit of screening among the total group

of enrolled women who were 40-74 years at entry,16,36-40 there is

uncertainty about the effectiveness of screening women between the ages

of 40 and 49. The Canadian NBSS 1 was specifically designed to address

this uncertainty.30 This trial compared combined annual mammography

and CBE to an initial CBE among women aged 40-49 at entry. At 7-year

follow-up, no benefit of annual screening was observed (RR = 1.36; 95% CI,

0.84 to 2.21). This Canadian trial has been the subject of much

criticism.45-47 Possible irregularities with randomization have been

refuted by its investigators.48 An independent review is planned by the

National Cancer Institute of Canada to determine whether the

randomization was compromised. Although mammography quality issues

have also been a concern, there is little evidence to suggest that the

practices were inconsistent with the standards of the other clinical trials

or community practice at the time of the study.48 In addition,

improvement in mammographic quality over the course of the study period

was noted by both inside and outside observers.48 The proportion of

controls receiving mammography, 26%, can be compared to available

estimates of 13% in the two-county trial, 24% in the Malmo trial (35% for

women 45-49), and 24% in the Stockholm trial.38,39,49 This

contamination may nevertheless have reduced the trial's ability to detect

a benefit from the screening intervention. An excess of node-positive

cancers detected in the intervention group raised concerns about subject

randomization.30 While this may have been the result of chance, other

contributing factors suggested by the investigators include under-

ascertainment secondary to lower surgical dissection rates in the control

group and incomplete breast cancer ascertainment at preliminary follow-

up (although these possibilities are unlikely to account for all of the

observed excess).48 Although the effect of these factors should diminish

with long-term follow-up, te results are unlikely to achieve statistical

significance because sample size calculations were based on an estimated

40% reduction in breast cancer mortality, which is greater than the

typical reduction in mortality observed in the other six trials that

included women in this age group.30

Subgroup analyses of the other trials that included women under 50 have

yielded conflicting evidence regarding the benefit of screening women

aged 40-49. No benefit was observed in the Stockholm trial or in one arm

of the two-county trial, while the remaining trials reported

nonsignificant benefits of about 22% or more.17,50 One meta-analysis,

which pooled the results from 7-year follow-up of six published clinical

trials without adjustment for variation in screening method or interval,

found no reduction in breast cancer mortality for women in their forties

(RR = 1.08; 95% CI, 0.85 to 1.39).41 When the Canadian trial was excluded

from the analysis, the estimate changed little (RR= 0.99; 95% CI, 0.74 to

1.32). The overview of the Swedish trials found a nonsignificant 13%

reduction (RR= 0.87; 95% CI, 0.63 to 1.20) only after 8-12 years of follow-

up in this age group.40 More recent meta-analyses of published

mammography trial data reported nonsignificant 8-10% reductions in

breast cancer mortality in women aged 40-49.42,43 One meta-analysis

reported a significant benefit for women in this age group when

unpublished data were included and the Canadian trial was excluded.43

Longer duration of follow-up was associated with a greater reduction in

mortality, although this finding may have been due to chance.42 Thus,

there is conflicting evidence from clinical trials and meta-analyses,

primarily based on subgroup analyses, regarding the benefit of screening

women aged 40-49. An ongoing British trial is evaluating the

effectiveness of annual mammography screening in women enrolled at age

40 or 41.

A recent analysis of data by tumor size, nodal status, and stage from the

BCDDP, a U.S. screening project using annual two-view mammography and

CBE, suggests comparable 14-year survival rates for women 40-49 and

women 50-59.51 A similar analysis of breast cancers detected in the

Swedish two-county trial confirms this finding.52 Based on these data,

time series comparisons of survival, frequency of interval cancers in the

two-county trial, and subgroup analysis of available clinical trial data,

some experts have suggested that annual screening intervals may be

necessary to achieve a reduction in breast cancer mortality from

screening for women aged 40-49.19,20,52 In a meta-analysis of published

trial results, however, the estimated mortality reduction from screening

women in this age group was similar for 12- and 18-33-month screening

intervals (1% and 12%, respectively).42

There is no direct evidence that assesses the effectiveness of CBE alone

compared to no screening. Modeling studies of the HIP trial estimated that

two thirds of the effectiveness of the combined screening may have been a

result of CBE.53-56 The Canadian NBSS 2 was designed to test the

incremental value of annual mammography over a careful annual CBE

among women aged 50-59 at study entry.24 At 7-year follow-up, there

was no difference in breast cancer mortality for the group receiving

combined screening compared to CBE alone (RR = 0.97; 95% CI, 0.62 to

1.52). This result suggests that thorough CBE may be as effective as

mammography for screening in this age group. The confidence interval is

wide, however, and substantial benefit or harm from screening is not

excluded by the preliminary data. Concerns regarding the early quality of

mammography of Canadian NBSS 1 also apply to this trial.48 Long-term

follow-up and additional studies are needed to confirm this apparent lack

of an incremental benefit of mammography above a careful, thorough

annual CBE. It is also unclear whether CBE adds benefit to screening with

mammography. A meta-analysis of mammography trial results reported

similar reductions in breast cancer mortality with and without the

addition of CBE.42

Evidence for effectiveness of BSE alone is also limited. In the United

Kingdom Trial of Early Detection of Breast Cancer, a nonrandomized

community trial, 40-50% of women living in two districts participated in

BSE instruction that included a short film and a lecture by a specially

trained health provider.57 At 7-year follow-up, there was no reduction in

breast cancer mortality in the BSE communities compared with the

control districts. Baseline comparability of intervention and control

districts, treatment variation by community, and contamination by other

screening modalities were not assessed, however. A World Health

Organization (WHO) population-based randomized controlled trial in

Leningrad comparing formal BSE instruction to no intervention in women

aged 40-64 has reported increases in physician visits, referrals for

further screening tests, and excisional biopsies in the intervention group

at 5-year follow-up.58 Breast cancer patients in the two groups did not

differ in number, size, or nodal status of their tumors. Completeness of

endpoint assessment is a concern in this study, given the lack of a

national tumor registry. Follow-up through 1999 is planned for reporting

mortality results. In a case-control study of women who had been

diagnosed with advanced stage (TNM III or IV) breast cancer, there was no

association between disease status and self-reported BSE.59 Proficiency

in practicing BSE, however, was reported as poor by both cases and

controls. For the small group of women reporting thorough BSE compared

to all others, the relative risk was 0.54 (95% CI, 0.30 to 0.98). A meta-

analysis of pooled data from 12 descriptive studies found that women who

practiced BSE before their illness were less likely to have a tumor of 2.0

cm or more in diameter or to have evidence of extension to lymph nodes.60

The studies from which these data were obtained, however, suffer from

important design limitations and provide little information on clinical

outcome (i.e., breast cancer mortality). Retrospective studies of he

effectiveness of BSE have produced mixed results.27,61-63

Recommendations of Other Groups

The American Cancer Society (ACS),64 American College of Radiology,65

American Medical Association,66 American College of Obstetricians and

Gynecologists (ACOG),67 and a number of other organizations65

recommend screening with mammography every 1-2 years and annual CBE

beginning at the age of 40, and annual mammography and CBE beginning at

age 50.

The American Academy of Family Physicians (AAFP) recommends CBE

every 1-3 years for women aged 30-39 and annually for those aged 40 and

older, and mammography annually beginning at age 50;68 these

recommendations are currently under review. The American College of

Physicians (ACP) recommends screening mammography every 2 years for

women aged 50-74 and recommends against mammograms for women

under 50 or over 75 years and baseline mammograms.69 The ACP makes

the same recommendations for high-risk women, unless the woman

expresses great anxiety about breast cancer or insists on more intensive

screening. The Canadian Task Force on the Periodic Health Examination

recommends annual CBE and mammography for women aged 50-69 and

recommends against mammograms in women under 50.70 The National

Cancer Institute states there is a general consensus among experts that

routine mammography and CBE every 1-2 years in women aged 50 and over

can reduce breast cancer mortality, and that randomized clinical trials

have not shown a statistically significant reduction in mortality for

women under the age of 50.71

Organizations that presently recommend routine teaching of BSE include

the AAFP,68 ACOG,67 and ACS.64 The recommendations of the AAFP are

currently under review.

Discussion

At this time, there is little doubt that breast cancer screening by

mammography with or without CBE has the potential of reducing mortality

from breast cancer for women aged 50 through about 70. The benefit

derived from biennial screening appears to be quite similar to the benefit

derived from annual screening. Given this similarity in effectiveness,

biennial screening is likely to have the added benefit of increased cost-

effectiveness. The incremental value of CBE above mammography or vice

versa is uncertain, although the Canadian NBSS 224 suggests that careful

CBE may be as effective as mammography.

Evidence does not establish a clear benefit from screening in women aged

40-49. Only the Canadian NBSS 130 was designed to test the effectiveness

of screening in this age group, however, and none of the trials had

adequate power for subgroup analysis. If screening is in fact ineffective

in younger women, one possible explanation is a lower sensitivity of

mammography in younger women (see Accuracy of Screening Tests). Other

possibilities include suboptimal screening intervals, differential (less

aggressive) treatment offered to women with mammographically detected

cancer, and varying biologic characteristics of breast tumors.52,72 The

Swedish overview,40 HIP,37 and Edinburgh36 trials suggest some benefit

in women aged 40-49 after 8-12 years of follow-up, but it is possible

that the delayed benefit is due to screening women in their fifties who

entered the trials in their middle to late forties.72a The final results of

the Canadian NBSS 1 may provide important information. An ongoing

British trial and a proposed trial in Europe which will enroll women only

in their early forties and compare mammography to no screening could

also clarify this issue.73 Until further information is available, it is

unclear whether any potential improvement in breast cancer mortality

achieved by screening women aged 40-49 is of sufficient magnitude to

justify the potential adverse effects that may occur as a result of

widespread screening.

Because breast cancer incidence increases with age, the burden of

suffering due to breast cancer in elderly women is substantial. In

addition, there is no evidence (as there is in younger women) that

sensitivity of mammography in older women is not comparable to that in

women aged 50-69. This is an age group, moreover, in which

underutilization of breast cancer screening is common.74-76 In a decision

analysis of the utility of screening women over 65 for breast cancer,

screening saved lives at all ages, but the savings decreased substantially

with increasing age and comorbidities.77 In the oldest women, those aged

85, short-term morbidity such as anxiety or discomfort from the

screening may have outweighed the small benefits. Until more definitive

data become available for elderly women, it is reasonable to concentrate

the large effort and expense associated with screening mammography on

women in the age group for which benefit has been most clearly

demonstrated: those aged 50-69. Screening women aged 70 and older

might be considered on an individual basis, depending on general health

and other considerations (e.g., personal preference of the patient).

The age range of 50-69 years, for which mammography has been proven

effective, is to a large extent based on artificial cutpoints chosen for

study purposes rather than on biologic cutpoints above or below which the

ratio of benefits to risks sharply decreases. Both the incidence of breast

cancer and the sensitivity of mammography increase with age. Thus, it is

logical that women in their seventies, for whom only limited clinical trial

experience is available, benefit from breast cancer screening. For women

aged <50 years, evidence has been insufficient to establish a clear benefit

from breast cancer screening. This age cutpoint may be a marker for

biologic changes that occur with age, especially menopause. It is

therefore plausible that women in their late forties, particularly

postmenopausal women, might derive some intermediate benefit from

screening. The risks and benefits of mammography and CBE may be best

considered as changing on an age continuum rather than at a specific

chronologic age. Guidelines for breast cancer screening should be

interpreted with this in mind.

No large study has quantitated the effectiveness of breast cancer

screening by either CBE or mammography for women who are at higher risk

of developing breast cancer than the general population. The increased

incidence of disease in high-risk women increases the positive predictive

value (PPV) of screening tests used in this group. For example, in a

community screening program, the PPV of mammography was increased 2-

3-fold for women with a family history of breast cancer.31 This is an

especially important consideration for women under 50, in whom the

benefit of screening has not been established for the general population.

There may be a benefit from screening younger women in high-risk groups,

but studies confirming this effect are lacking. Nevertheless, given their

increased burden of suffering, screening high-risk women under age 50

may be considered on an individual basis for women who express a strong

preference for such screening.

Data regarding the effectiveness of BSE are extremely limited, and the

accuracy of BSE as currently practiced appears to be considerably inferior

to that of CBE and mammography. False-positive BSE, especially among

younger women in whom breast cancer is uncommon, could lead to

unnecessary anxiety and diagnostic evaluation, although a small

randomized clinical trial29 did not find such adverse effects. A point also

worth consideration is that time devoted to teaching BSE may reduce time

available for prevention efforts with proven effectiveness. Given the

present state of knowledge and the potential adverse effects and

opportunity cost, a recommendation for or against inclusion of teaching

BSE during the periodic health examination cannot be made.

CLINICAL INTERVENTION

Screening for breast cancer every 1-2 years, with mammography alone or

mammography and annual clinical breast examination (CBE), is

recommended for women aged 50-69 ("A" recommendation). Clinicians

should refer patients to mammographers who use low-dose equipment and

adhere to high standards of quality control. Such standards have recently

been established by the Mammography Quality Standards Act, a federal law

mandating that all mammography sites in the U.S. be accredited through a

process approved by the Department of Health and Human Services.78

There is insufficient evidence to recommend annual CBE alone for women

aged 50-69 ("C" recommendation). For women aged 40-49, there is

conflicting evidence of fair to good quality regarding clinical benefit from

mammography with or without CBE, and insufficient evidence regarding

benefit from CBE alone; therefore, recommendations for or against routine

mammography or CBE cannot be made based on the current evidence ("C"

recommendation). There is no evidence specifically evaluating

mammography or CBE in high-risk women under age 50; recommendations

for screening such women may be made on other grounds, including patient

preference, high burden of suffering, and the higher PPV of screening,

which would lead to fewer false positives than are likely to occur from

screening women of average risk in this age group. There is limited and

conflicting evidence regarding clinical benefit of mammography or CBE for

women aged 70-74 and no evidence regarding benefit for women over age

75; however, recommendations for screening women aged 70 and over who

have a reasonable life expectancy may be made based on other grounds,

such as the high burden of suffering in this age group and the lack of

evidence of differences in mammogram test characteristics in older

women versus those aged 50-69 ("C" recommendation). There is

insufficient evidence to recommend for or against teaching BSE in the

periodic health examination ("C" recommendation).

The draft update of this chapter was prepared for the U.S. Preventive

Services Task Force by Marisa Moore, MD, MPH, and Carolyn DiGuiseppi, MD,

MPH.

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