Reviewer's report
Title:Analysis of 3 strategies to increase screening coverage for cervical cancer
in the general population of women from 60 to 70 years of age: A randomized
controlled trial. The CRICERVA Study
Version: 4Date:10 June 2013
Reviewer: Michael Gardner
Reviewer's report:
BMC Women’s Health manuscript “Analysis of 3 strategies to increase screening
coverage for cervical cancer in the general population of women from 60 to 70
years of age: A randomized controlled trial. The CRICERVA Study.
1) This is an interesting study assessing 3 strategies to increase screening
coverage for cervical cancer. Interventions that encourage women to uptake
cervical screening are an important area of research, highlighted by the
Cochrane collaboration review (Forbes et al 2009).
Major comments overall
2) To improve the readability of the manuscript and to help undertake appropriate
statistical analyses, authors should follow the Consort 2010 statement: extension
to cluster randomized trials (BMJ 2012;345:e5661.
Abstract
Major compulsory revisions
3) What were the primary and secondary outcomes? What was the length of
follow-up? These need to be specified in the Methods subsection of the Abstract.
For primary outcome, the effect size should be given with its precision (95%
Confidence interval).-
Minor essential revisions
4) Need to be consistent with terminology. Inadequately screened is used in
Abstract and Results, but screening for unknown is used in Figure 1. HPV was
accrued in 1376 women in the abstract, yet gynecological screening was detailed
in Figure 1. Coverage increases in the Results subsection of the Abstract don’t
agree with the Results section, or table 2. There is a typo in the Results
subsection of the Abstract- two examples for IG2.
Introduction
Major compulsory revisions
5) Fourth paragraph- authors need to highlight the novelty of this study.
Emphasise what the study adds to the literature, over and above the studies in
the Cochrane collaboration review (Forbes et al 2009)?
6) Why have the four basic health care areas in the Valles Occidental, Barcelona
been chosen for this study? Why have the authors chosen the 3 interventions?
Minor essential revisions
7) 1st paragraph- Discuss why might an increase in the incidence of invasive
squamous cervical cancer be observed in the cohort of women born after
1930-1940. Are the references correct after pre-cancerous lesions (8) [4]? Maybe
change “determination of the HPV” to detection of HPV.
2nd paragraph- Are the references correct after 10 years prior to diagnosis (15)
[6]? Change programmers to programs and sensitization to sensitivity. “Eighty
percent of the cases of cervical cancer in Catalonia have not undergone previous
cytology tests during the 10 years prior to diagnosis”. How does this compare to
the rest of Spain?
4th paragraph- Maybe change the 2nd sentence to “The objective of this study is
to determine which of the three intervention strategies is the most effective at
increasing screening coverage for cervical cancer.”
Methods
Major compulsory revisions
8) 2nd paragraph- Why were the four Basic Health Care Areas (BHCA) chosen?
What were the exclusion criteria? Some of these were included in the results of
the Abstract, but not in the overall Methods section. Need to define the primary
and secondary outcomes. e.g. The primary outcome might be defined as the
difference in the proportion of women who had had a cervical screening by the
end of the follow-up period between the intervention and control group. Authors
state that “The process of randomization, participant selection and sample size
are described in the study protocol”. However, it would be much clearer if these
descriptions were included in the manuscript. i.e. Why was the multicentre
randomized controlled trial chosen and why was the randomization unit BHCA (ie
clustered design) chosen? How was the sample size determined? Was intraclass
correlation coefficient calculated? What were the methods of sequence
generation and allocation concealment?
9) 4th paragraph (Statistical analysis)- Need to specify the statistical methods
used to compare groups for primary and outcomes. Hence, will need to calculate
either Odds Ratios, Risk Ratios or Risk Differences and their respective 95%
Confidence intervals.
Minor essential revisions
10) 1st paragraph- Change “multicentric” to “multicentre”
3rd paragraph (Study arms)- The non-intervention group were receiving usual
care and attended the clinic “opportunistically” rather than “spontaneously”?
Results
Major compulsory revisions
11) Need to comment on the baseline characteristics (Table 1). Why for example
were many more people interviewed for IG3 (1158) than other groups? Does this
indicate selection bias?
12) 6th paragraph (Increase in coverage after the intervention). For primary
outcome will need effect size and its precision (95% Confidence Interval). E.g.
post-intervention risk difference (RD) in cervical cancer screening between
intervention and control (and 95% CI).
Minor essential revisions
13) 1st paragraph- typo- “Error! Reference source not found”. Change
spontaneously to opportunistically.
2nd paragraph Mean age was 66.2±SD?
6th paragraph- typo-“Error! Reference source not found”.
Table 1- No SD given for Age.
Discussion
Major compulsory revisions
14) Need to include a section on strengths and limitations. Discuss sources of
potential bias including selection bias and comment on any baseline imbalances.
Minor essential revisions
15) 1st paragraph- change “phone call hardly improved” to “phone call did not
improve”. “Our adherence was greater than that referred in other countries
introducing a particular type of intervention”. Need to elaborate this sentence to
make the comparison clearer.
2nd paragraph- Discuss the findings of the study in comparison with the
Cochrane collaboration review (Forbes et al 2009). Also make reference to other
literature, e.g. Sabatino et al 2012 “Effectiveness of interventions to increase
screening for breast, cervical and colorectal cancers” (Am J Prev Med
2012;43:97-118).
4th paragraph- “Our intervention”- be specific here. Typo- should be “Thus, these
data although based on a small number”.
5th paragraph- Following sentence should read “Once follow up of these women
is completed we might be able to indicate that the HPV strategy is better than
cytology as a primary screening tool”.
6th paragraph- Aren’t you saving the system 1,376-19 cytologies ie 1,357?
7th paragraph- change “correct” to “appropriate” screening.
Conclusion- Change last word “feasible” to “most effective”?