Compliance with screening ranged from 85% at the initial round to 73% at the sixth round, while contamination in the usual care group ranged from about 3.0% for CA-125 to 4.6% for TVU. Across the first four screening rounds, 11.1% of women had at least one positive test, 8.1% had at least one positive TVU, and 3.4% had at least one positive CA-125 test. The yields of both tests were similar. Ovarian cancer was diagnosed in 212 women (5.7 per 10,000 person-years) in the intervention group and 176 women (4.7 per 10,000 person-years) in the usual care group (rate ratio, 1.21; 95% CI, 0.99–1.48). The stage distributions were similar by study group, with stage III and IV cancers comprising the majority of cases in both the intervention group (163 cases, 77%) and the usual care group (137 cases, 78%). The cancer case treatment distributions were very similar between groups within each stage. There were 118 deaths caused by ovarian cancer (3.1 per 10,000 person-years) in the intervention group and 100 deaths (2.6 per 10,000 person-years) in the usual care group (mortality rate ratio, 1.18; 95% CI, 0.82–1.71). Of the 3,285 women with false-positive results, 1,080 underwent surgical follow-up. Of the 1,080 women who underwent surgical follow-up,163 women experienced at least one serious complication (15%). A total of 1,771 women in the intervention group (7.7%) and 1,304 in the usual care group (5.8%) reported oophorectomy. There were 2,924 deaths due to other causes (excluding ovarian, colorectal, and lung cancer) (76.6 per 10,000 person-years) in the intervention group and 2,914 such deaths (76.2 per 10,000 person-years) in the usual care group (rate ratio, 1.01; 95% CI, 0.96–1.06).[26,27]
Among women in the general U.S. population, simultaneous screening with CA-125 and TVU did not reduce ovarian cancer mortality when compared with usual care.
In the UKCTOCS, an ongoing randomized controlled clinical trial, a multimodality screening arm, including a two-stage screening with measurement of CA-125 levels as the primary screen and TVS as the secondary screen, is being compared with TVS alone and a control arm (no screening) for the impact on ovarian cancer mortality. Results on ovarian cancer mortality have not yet been reported.
The Shizuoka Cohort Study of Ovarian Cancer Screening randomly assigned women to either a screening group (n = 41,668) or a control group (n = 40,799) between 1985 and 1999 at 212 hospitals in the Shizuoka prefecture of Japan. The screening protocol comprised ultrasound and CA-125 tests annually. Women with abnormal findings were referred to a gynecological oncologist. Ovarian cancer diagnoses were determined by record linkage to the Shizuoka Cancer Registry in 2002. The annual death certificate file in Shizuoka was checked to ascertain vital status. The mean follow-up time was 9.2 years, and the mean number of screens per woman was 5.4. There were 35 ovarian cancers detected in the screening group and 32 in the control group with a nonstatistically significant difference in the stage distribution. Nine percent of regular screening attendees had at least one false-positive result. Mortality results from this trial could not be identified in the literature.