File talk:Peer review of cervical screening article.pdf

I thank Dr Usha Rani Poli for the comments.

Before arriving at the final outcomes/estimates, the model did take into account that not all screened women would benefit because of factors Dr Poli alludes to. Using data from Botswana, only 85% of women were successfully treated – the model also assumed this proportion of women would benefit if visual inspection with acetic acid was rolled out in South Africa. This 85% proportion was one of the best available contemporary estimates in the literature.

In addition, the model was deliberately conservative like the model by Chigwedere and colleagues so that a minimum irrefutable number of lost benefits could be estimated. Data on the rate of screen positivity was obtained from a randomized controlled trial in a South African setting. The rate of positivity at baseline was 23.1%; however screen positive rates from another study in South Africa were as high as 45% (HIV positive women).

The model also assumed that all women who received a Pap smear benefited (Figure 3) which is certainly not the case. Hence the conservative nature of the model so that the number of cervical cancers and deaths from it that could have been prevented are difficult to dismiss. As highlighted above, Chigwedere et al employed a conservative approach.

Once again, I thank Dr Poli for the insightful comments.