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New Ovarian Cancer Screening Test Reduces Mortality
Results from the UK Collaborative Trial for Ovarian Cancer Screening (UKCTOCS), a large prospective randomized controlled study of more than 200,000 initially cancer-free, postmenopausal women 50 to 85 years of age, have been published in The Lancet. The findings demonstrate that screening may reduce ovarian cancer mortality by an estimated 20% after a median follow-up period of 11 years.
Study participants were randomly assigned to a control group (n = 101,299) who received no screening and a screening group (n = 101,247). The screening group was divided into two arms: a multimodal screening (MMS) group (n = 50,624) and an ultrasound screening (USS) group (n = 50,623). Women in the MMS group underwent a blood test to assess levels of cancer antigen 125 (CA-125), and the outcomes of these tests were evaluated with the Risk of Ovarian Cancer Algorithm (ROCA, Abcodia Ltd) to assign a woman’s level of disease risk. If the risk was classified as intermediate or elevated on ROCA, repeat blood tests and/or a transvaginal ultrasound (TVUS) scan of the ovaries was used. Women with an intermediate classification were referred for a repeat CA-125 test in 12 weeks and were administered a TVUS scan if they received three intermediate ROCA scores. Women assessed with advanced risk received a TVUS scan within 6 to 8 weeks without additional blood testing.
Ovarian cancers were diagnosed in 630 (no screening), 338 (MMS), and 314 (USS) women. A Cox statistical analysis indicated mortality reductions over years 0 to 14 of 15% with MMS and 11% with USS, which were not significant. This mortality reduction consisted of 8% and 23% relative reductions during years 0 to 7 and years 7 to 14, respectively, in the analysis of MMS versus no screening (the reduction during years 7 to 14 was statistically significant) and of 2% and 21%, respectively, in the USS group. The median follow-up period was 11.1 years.
An additional statistical analysis was performed after excluding women who had undiagnosed ovarian cancer when they joined the study. This analysis demonstrated that there was a significant reduction in deaths, with an average mortality reduction of 20% overall and 28% in years 7 to 14. There was also a significant reduction in deaths in the MMS group compared with the no screening group using a separate analysis.
The trial results suggested that approximately 15% of ovarian cancer deaths could be prevented for every 10,000 women who attend a screening program that involves annual blood tests for between 7 and 11 years.
The study findings also confirmed previous results showing that, on average, for every three women who underwent surgery as a result of an abnormal screen, one woman had ovarian cancer and two women did not. For those who had surgery, approximately 3% had major complications.
Previous studies have shown that 92% of women diagnosed with stage 1 ovarian cancer survive for 5 or more years, compared with only 18% of women diagnosed with stage 4 disease. Because ovarian cancer often has nonspecific symptoms or no symptoms, women are usually diagnosed with advanced (stage 3 or 4) disease.
Source: PR Newswire; December 17, 2015.