Sir,

Dr Herbert et al (2014, this issue) suggest that women in England born between 1985 and 1995 have been ‘let down’ by the National Health Service. It is true that most would neither have been vaccinated against HPV types 16 and 18 nor have been invited to screening between age 20–24. However, we reject the notion that they have been let down. We have estimated elsewhere (Landy et al, 2014) that the change in policy (inviting women for screening from age 25 instead of from age 20) will have resulted in about 2800 fewer women per 100 000 being treated for cervical intraepithelial neoplasia and have led to at most 23 extra cancers, of which between 3 and 9 would have been stage 1B or worse. We have seen no new data that would lead us to change these estimates. By way of contrast, we have also estimated that introducing a more sensitive screening test (such as primary HPV testing) in women aged 25–64 could prevent 168 cancers per 100 000 women (even without changing the coverage) (Castanon et al, 2013).

We agree with Dr Herbert et al that 1A1 cancers may sometimes be treated with a knife cone under a general anaesthetic rather than by loop excision under a local anaesthetic, but we suggest that the audit data they present are out of date and not representative of England today. In our audit, 92% (887 of 965) women aged 20–29 with stage 1A cancer diagnosed since April 2007 had a cone excision. It is difficult to believe that it is desirable to treat over 100 women with high-grade cervical intraepithelial neoplasia by a cone excision in order to prevent one case of 1A cervical cancer that will also be treated by cone excision (albeit possibly a more invasive one).

The decision to only invite women for cervical screening from age 25 is clearly emotive, but it is not helpful to refer to it as an unfortunate experiment. It was based on an independent committee’s unanimous view that screening women aged 20–24 was likely to cause more harm than benefit. It was certainly not intended to be an experiment, nor does it constitute a particularly good natural experiment. Taking into account all subsequent evidence, we remain convinced that the combined effect of policies announced in October 2003 (switching from conventional cytology to liquid-based cytology; first invitation at age 25; 3-yearly screening for women aged 25–49 instead of 5-yearly, as was the practice in some parts of England; and 5-yearly screening from age 50 to 64) was for the overall good of women in England.