Cervical cytology and the diagnosis of cervical cancer in older women

OBJECTIVES Most non-screen-detected cervical cancers are advanced stage. We assess the potential for cytology to expedite diagnosis when used outside of routine call and recall screening for cervical cancer. METHODS Two cohorts of women with cytology that did not appear to have been taken as part of routine screening, nested within a census of cervical cytology, in England between April 2007 and March 2010 were studied: 93,322 women aged 40-69 at first cytology, and 14,668 women aged ≥70. The diagnostic performance of high grade cervical squamous intraepithelial lesion (HSIL) or worse cytology was estimated. We also estimated case-fatality from stage distribution in women aged ≥66 with and without cytology in the year prior to diagnosis. RESULTS There were 259 cancers diagnosed in women aged 40-69 at first cytology, and 78 in women aged ≥70. The sensitivity of cytology ≥ HSIL for cancer was 89% and 83% respectively, and the number of women needed to test to identify one cancer was 404 (95% confidence interval [CI]: 355-462) and 226 (95% CI: 177-292) respectively. Women aged ≥66 with cytology within a year of diagnosis had earlier stage cancers than those without, corresponding to a 17-22% reduction in case fatality. CONCLUSIONS Cervical cytology is an excellent identifier of cancer among women tested outside routine screening call and recall. Its use as a triage tool, for instance in women with vague gynaecological symptoms, could facilitate earlier stage diagnosis and reduce cervical cancer mortality.