Reviewer's report
Title:Determinants of women's likelihood of vaginal self-sampling for human
papillomavirus to screen for cervical cancer in Taiwan: a cross-sectional study
Version:2Date:6 August 2014
Reviewer: Stephen Morrell
Reviewer's report:
General: This is a well-written paper. The main issues are that the authors
highlighted the issue of cost but not addressed it as a predictor of self-sampling.
In particular, it is highly likely that cost is a highly negative predictor of
self-sampling overall but its effect is likely modified significantly by income level
and perceived risk of cervical cancer. In fact, the cost issue is probably the most
important finding of this study.
The authors in several instances have implied the sample is more reprentative
than it is. Furthermore, as it was a clinic sample there may well have been some
clinical predictors of self-sampling (eg, women attending for cervix-related issues
rather than pregnancy issues may differ significantly).
Particulars:
Line 15: change ‘for HPV’ to ‘for human papillomavirus (HPV)’
Lines 66, 75, 77, 216: change ‘cervical cancer screening’ to ‘cervical screening’
[As the authors correctly point out earlier in the manuscript, the point of cervical
screening primarily is to detect pre-cancer in order to prevent progression to
cancer; as such it’s not ‘cervical cancer screening’ but ‘cervical screening’]
Lines 86-89: The authors should justify excluding from the analysis those who did
not know about HPV, or asking questions about perceived risk of cervical cancer
or self-sampling on this basis. That a respondent does not know about HPV does
not necessarily mean they have no knowledge or opinion of their risk of cervical
cancer; or did not self-sample for HPV. In the latter case they may well have
self-sampled for HPV but knew of the procedure as something more generic (eg,
a ‘woman’s-health sample’) without knowledge of what specifically was being
sought or even that its purpose was to test for the presence of HPV.
Analogously, if questions were being asked of women about Pap testing and a
majority couldn’t explain what the Pap test actually did, one would still ask them
about their perceived risk of cervical cancer and whether they’ve ever had an
gynaecological examination where a cervical sample was taken.
Line 89: Then it is stated that ‘All women were then asked about their willingness
to self-sample for HPV...’. Was it all women, or was it the women remaining after
excluding those who reported no knowledge of HPV? This is unclear.
Line 98: Unlike ‘Previous Pap testing (yes/no)’, how is ‘Heard of HPV (yes/no)’ a
‘related clinical variable’? It isn’t, and is redundant since it’s part of the knowledge
items for HPV, as outlined in lines 90-91 and the Appendix.
Line 121: Conventional wisdom is that condoms are partially effective in
preventing the spread of HPV--mainly because HPV can infect areas not covered
by the condom--and thus they can lower the chances of spreading HPV infection.
That condoms ‘cannot prevent the spread of HPV’ implies that HPV can cross a
latex barrier, and this is not conventional wisdom. Is there evidence for this? In
the discussion the authors acknowledge condoms’ role in partial protection (line
177), and one might not so readily assume women are ignorant of this aspect of
HPV transmission for thinking that condoms can protect against HPV, albeit
partially.
Line 126: change ‘among who’ to ‘among those who’
Line 158: change ’21 times greater odds’ to ’21 times the odds’. If they were 21
times greater the OR would be 22.
Line 159: change ‘p<.000’ to ‘p<.001’ or ‘p<.0001’ [which the latter is likely]
Line 172: change ‘Taiwanese women’ to ‘clinic sample’. As formulated, the
sentence implies a representative sample of Tiawanese women.
Lines 174-75: The authors need to indicate if the comparisons with Kenyan, US
minority, etc, samples are equivalent. Were these other samples also
convenience samples attending a clinic?
Lines 202-03: change ‘not be performed’ to ‘not occur’
Line 203: The authors are generalising to ‘Tiawanese women’ without justification
Line 210: The respondents weren’t simply 500 women living in central Taiwan.
They were a gynaecological clinic sample, of whom we know little. We don’t
know the proportions of these women attending for issues related to pregnancy
or other issues including an existing cervical lesion.
Line 213: change ‘Future research’ to ‘Research’, or ‘Further research’; ‘future’ is
redundant.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests