Description of the Evidence
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.
A randomized pilot trial in the United Kingdom randomly assigned 10,977 women to a control group and 10,958 women to a screened group in 1989. The primary screen was the CA-125 test, followed by ultrasonography when CA-125 levels were elevated. Women were offered three annual screening rounds, and both groups were followed for 7 years. Compliance was 70.7% for all three screenings and 85.5% for at least one screening. There were 20 ovarian cancers in the control group and 16 in the screened group, only six of which were detected by screening. There was a higher proportion of stage I/II cancers in the screened group than in the control group (31.3% vs. 10.0%). There were 18 ovarian cancer deaths in the control group and nine in the screened group (relative risk [RR], 2.0; 95% CI, 0.78–5.13).