Cervical cancer: screening and risk with age

Abstract

Two new studies have helped to clarify the role of cervical screening, the age at which it can be reasonably stopped, and the circumstances in which it should be continued. In a population-based case-con trol study , the association between screening in women aged 50–64 years and frequency of cervical cancer in those aged 65–83 years was examined. UK researchers matched 1341 women who were diagnosed with cervical cancer when aged 65–83 years between 2007 and 2012, with 2646 randomly selected age-matched control individuals. They recorded that screening at least every 5·5 years in women aged 50–64 years was associated with a 75% reduction in risk of cervical cancer when aged 65–79 years (odds ratio 0·25, 95% CI 0·21–0·30). The protection off ered by a series of negative test results reduced with time: women were at substantially lower risk of cervical cancer aged 75 years than they were aged 80 years. Coauthor Peter Sasieni (Wolfson Institute of Preventive Medicine, London, UK) recommends ending screening at age 60–69 years for women with a series of negative tests. “Stopping before 60 would appear to be premature, but if you continue testing after 70, you’d have to start questioning whether you’d actually be treating a lot of disease that wouldn’t have caused a problem in the woman’s lifetime”, he said. Meanwhile, researchers in Sweden concluded that women treated for cervical intraepithelial neoplasia grade 3 (CIN3) are at increased risk of cervical or vaginal cancer. In this population-based cohort study, researchers examined the records of 150 883 Swedish women diagnosed with CIN3 between 1958 and 2008. These women were at increased risk of either vaginal or cervical cancer more than 1 year after CIN3 diagnosis (standardised incidence ratio 2·39, 95% CI 2·26–2·53). “We can attribute the increased risk to a very strong extent to the ageing of women, not time since treatment or the age of the woman when she was treated”, explained lead author Bjorn Stranders (University of Gothenburg, Sweden). Therefore, lifelong surveillance will be necessary. Margaret Stanley (University of Cambridge, UK) agreed with the studies’ conclusions. “There is a big burden of epidemiological evidence that human papillomavirus infections in older age groups do not progress to cancer, so screening can stop in your sixties. However, if you have had a previous cervical intraepithelial neoplasia, even if you have had it excised, the risk of recurrence is always there”, she added.