Sir,

Bretthauer and Hoff1 state that cervical smear screening for cervical cancer has never been investigated in a randomized trial. However, further to a clinical study in New Zealand, where a number of women were conservatively managed for cervical intraepithelial neoplasia 3 (CIN3), McCredie et al reviewed the outcomes of 1063 women diagnosed within that unit, finding that the cumulative incidence of invasive cancer of the cervix in women managed only by biopsy was 31.3%2. This provides the most valid estimate currently available on the progression and its rate from CIN3 to invasive cancer. Furthermore, studies have shown that untreated vulval intraepithelial neoplasia (VIN) also exhibit significant potential to progress to invasive disease within ten years3.

Similarly, the authors suggest that a “watch and wait” approach should be considered for screen detected ductal carcinoma in situ, but the ethical implications of such an option must be discussed.

Yours faithfully,

1. Bretthauer M, Hoff. Compariative effectiveness research in cancer screeeening programmes. BMJ 2012; 344: e2864

2. Margaret RE McCredie, Katrina J Sharples, Charlotte Paul, Judith Baranyai, Gabriele Medley, Ronald W Jones, David CG Skegg. Natural history of cervical neoplasia and risk of invasive cancer in women with cervical intraepithelial neoplasia 3: a retrospective cohort studyThe Lancet Oncology, Volume 9, Issue 5, Pages 425-434

3. Jones, Ronald W; Rowan, Darion M; Stewart, Alistair W. Vulvar Intraepithelial Neoplasia: Aspects of the Natural History and Outcome in 405 Women Obstetrics & Gynecology:
December 2005 - Volume 106 - Issue 6 - pp 1319-1326

Competing interests: None declared