Early diagnosis of ovarian cancer may reduce mortality

A study published by Jacobs et al in Lancet reports on a new approach for earlier diagnosis of ovarian cancer which is known for its poor prognosis. Their strategy was based on a series of CA125 tests, identifying women to be given ultrasound by a mathematical formula that took into account a woman’s age and the degree of change in CA125 over time, and calculated a risk score. In this randomized controlled trial, postmenopausal women aged 50–74 years from Great Britain were assigned to annual multimodal screening (MMS) with serum CA125, annual trans-vaginal ultrasound screening (USS), or no screening, in a 1:1:2 ratio. The primary outcome was death due to ovarian cancer, comparing MMS and USS separately with no screening. Between June 1, 2001, and Oct 21, 2005, 202 638 women were randomly allocated: 50 640 to MMS, 50 639 to USS, and 101 359 to no screening. Screening ended on Dec 31, 2011, and included 345 570 MMS and 327 775 USS annual screening episodes. At a median follow-up of 11·1 years, ovarian cancer was found in 1282 (0·6%) women: 338 (0·7%) in the MMS group, 314 (0·6%) in the USS group, and 630 (0·6%) in the no screening group. Of these women, 148 (0·29%) women in the MMS group, 154 (0·30%) in the USS group, and 347 (0·34%) in the no screening group had died of ovarian cancer. The primary analysis using a Cox proportional hazards model gave a mortality reduction over years 0–14 of 15% with MMS and 11% with USS. Although the mortality reduction was not significant in the primary analysis, the authors noted a significant mortality reduction with MMS when prevalent cases were excluded. They also noted encouraging evidence of a mortality reduction in years 7–14, but further follow-up is needed before firm conclusions can be reached on the efficacy and cost-effectiveness of ovarian cancer screening as 641 women had to be screened annually for 14 years for each life saved.