Title: Can biopsies be omitted after normal colposcopy in women referred with low-grade
cervical cytology? A prospective cohort study.
Version: 3 Date: 10 Aug 2021
Reviewer:  Robert G. Pretorius
Reviewer's report:
Review of R-1 of Jespersen MM et. al.  Can biopsies be omitted after normal colposcopy in
patients with low-grade cervical cytology?
The revised manuscript has been significantly improved.  I have a few further comments.
Line 29:  Within the manuscript you use three different terms for the population you are studying.
In line 29 you use ‘less than HSIL cytology’.  In lines 39, 198, 201, 251, and 368 you use ‘LSIL/
ASCUS cytology’, and in lines 45 and 101 you use ‘low-grade cytology’.  Use only one term
for the population you are studying (I would use ‘cytology of LSIL or ASC-US’).
Lines 45-49:  You decided not to report that 56.1% of the women were diagnosed with
dysplasia (deleted from lines original manuscript 40-41), but the conclusion states that you
found dysplasia in more than half of the women referred with low grade cytology findings and a
normal colposcopic assessment.  In addition, the Conclusion in the manuscript was changed to
recommending taking four random biopsies in women referred for colposcopic evaluation with
low-grade cytology when colposcopic impression is normal (lines 372-375).  The conclusion
in the Abstract should mirror that in the manuscript (e.g. It might say, “As we found CIN 2+
from random cervical biopsies in 22.0% of women with cytology of ASC-US or LSIL who had
normal colposcopic impressions, we advocate performing four random cervical biopsies at the
squamocolumnar junction in such women.”
Line 85:  While the reference from Pretorius RG et. al. from 2004 concluded that random
biopsies were not recommended from women with low-grade cytology, this conclusion is
not consistent with later manuscripts from this group (see JLGTD 2011;15:180-8, JLGTD
2012;16:333-8, JLGTD 2016;e61-2 doi.10,1097J., and JLGTD 2019;23:241-7) in which random
cervical biopsy was recommended for all women having colposcopy for evaluation of abnormal
cervical screening tests.  The problem with the 2004 manuscript was that the conclusion was
based on a low yield of CIN 2+ from random cervical biopsy.  If the metric is proportion of
CIN 2+ diagnosed by random biopsy, performing random biopsy in women with cytology of
less than HSIL is more beneficial than performing random biopsy in women with cytology of
HSIL or worse (see your cited reference #6).  Citing the 2004 reference in line 85 rather than
one of the four more recent references is somewhat misleading.
Old lines 140-145, new lines 169-174:  I am fine with no power calculation.  You might include
the 95% CI for the two most important findings (line 208 where you state that 22% [95% CI
16.0% to 28.9%] (38/173) of women with cytology of LSIL or ASC-US and normal colposcopic
impressions (this includes 36 women with acetowhite lesions not thought to be dysplasia) had
random cervical biopsy showing CIN 2+ and in line 215 were you state that 16.1% [95% CI
10.4% to 23.3%] (22/137) of women with cytology of LSIL or ASC-US and completely normal
colposcopic impressions (none of these women had any acetowhite lesions) had random cervical
biopsy showing CIN 2+).
Line 215: You conclude, again that 52.6% of women were diagnosed with dysplasia.  Reporting
CIN 1+ was supposed to be deleted.
Lines 230-232:  What are you concluding from the data in Table 4?  If I understand correctly,
a type 1 TZ is located entirely on the ectocervix, a type 2 TZ involves the endocervical canal
but the squamocolumnar junction (SCJ) is still visible, and a type 3 TZ shows endocervical
involvement without a fully visible SCJ.  Colposcopy is considered inadequate in type 3 TZ,
whereas adequate colposcopical evaluation is feasible in types 1 and 2 TZ. [Luyten A et. al. J
Low Gen Tract Dis 2015;19(3):185-8] So, I might combine the data for type 1 and 2 TZ and
conclude that the yield of CIN 2+ from random biopsy for women with cytology of LSIL or
ASC-US with type 3 TZ (2.1%, 1/47) is lower than for those with type 1 or 2 TZ (29.4%, 37/126,
Chi-Square = 14.8, df=1, p<.001).  As the yield of CIN 2+ from random biopsies is lower for type
3 TZ, what hypotheses might explain this finding?  One possibility is that the random biopsies
performed in women with type 3 TZ do not sample the SCJ as often as those with type 1 or 2 TZ
and hence have a lower chance of detecting CIN 2+.  You touch on this in lines 227 and 228, but
what I would like to know is whether the proportion of biopsies that contain endocervical and
ectocervical tissue is lower for the 47 women with type 3 TZ than for the 126 women with type
1 or 2 TZ.  If you had results for ECC on all women, you might discover that the proportion of
women with a diagnosis of CIN 2+ based solely on an ECC showing CIN 2+ (i.e., cervical biopsy
not CIN 2+ while ECC was CIN 2+) was higher for those with type 3 TZ than for those with type
1 or 2 TZ (again suggesting that CIN 2+ in women with type 3 TZ is within the endocervical
canal and not easily detected by random cervical biopsy).  Rather than exploring why the yield
of CIN 2+ from random cervical biopsy is lower for women with type 3 TZ, you conclude in
lines 339 to 345 that random biopsy should be done for type 3 TZ.  I have no problem with doing
random biopsy for women with type 3 TZ, I just wanted you to try to figure out what is going
on.  If you cannot determine why the yield of random biopsies is lower for women with type 3
TZ, you might end up with a conclusion like, “More study is required to confirm our finding that
the yield of CIN 2+ from random cervical biopsies in women with cytology of LSIL or ASC-
US and normal colposcopic impression is lower with type 3 TZ than for those with type 1 or 2
TZ and to determine why this might occur; our current recommendation is to treat women with
type 3 TZ similar to those with type 1 or 2 TZ .”
Conclusion:  With the minimal changes suggested above, the manuscript could be published.
The Following two comments are for the authors, not to be published:
I have access to a file with 18,537 colposcopies in which all women had ECC and random
cervical biopsy in quadrants without visible lesions was encouraged (the median number of
cervical biopsies was 3).  Of the 18,537 colposcopies, 17,405 had cytology of Lo (LSIL,
ASC-US, or neg with positive hrHPV).  Of the 17,405 with cytology of Lo, 7,296 had
normal colposcopic impressions.  Of the 7,296 with cytology of Lo and normal colposcopic
impressions, 6,105 had adequate colposcopy (the SCJ was seen) while 1,191 had inadequate
colposcopy (the SCJ was not completely seen).  The proportion of colposcopies with cytology
of Lo, normal colposcopic impression, and adequate colposcopy that had a random cervical
biopsy showing CIN 2+ (6.7%, 407/6,105) was higher than for similar women with inadequate
colposcopy (4.1%, 49/1,191, p=.001).  The proportion of colposcopies with cytology of Lo,
normal colposcopic impression, and adequate colposcopy that had a cervical biopsy of not CIN
2+ with a ECC of CIN 2+ (1.2%, 71/6,105) was about half of that for similar women with
inadequate colposcopy (2.4%, 29/1,191, p=.001).  This suggests that part of the reason that
women with type 3 TZ have a lower proportion of random cervical biopsies showing CIN 2+
is that the CIN 2+ is in the endocervical canal.  This is likely not the whole story as inadequate
colposcopy is more common in older women and the relationship between age, diagnosis of CIN
2+ by random biopsy, and diagnosis of CIN 2+ by ECC is complex [see Pretorius RG et. al. J Low
Genit Tract Dis 2015;19(4):278-81 and Chen Q et.al. J Low Genit Tract Dis 2016;20(3):207-12].
Also performing power calculations for paired samples where McNemars was the statistical
test is difficult, but it is not impossible.  In JLGTD 2020;24:243-246 in which a power
calculation was required for paired samples, the authors (actually, it was Raoul Burchette, who
is a statistician) used an iterative method (described in the Study Procedures) to do a power
calculation.  Though I think that this iterative method is reasonable, it has not been submitted nor
reviewed in a statistics journal.  This methodology for determining power is still not applicable
to your manuscript (I do not know how to do a power calculation for your data).
RG Pretorius, MD
Robert.G.Pretorius@kp.org