The quality of evidence is downgraded by imprecise results (few events).
Do not use CA 125 and ultrasound to screen for ovarian cancer.In an RCT of 78 216 women aged 55 to 74 years, annual screening with CA-125 for 6 years and transvaginal ultrasound for 4 years was offered to the intervention group. The usual care group received their usual medical care. The participants were followed for a median of 12.4 years (range 10.9 - 13.0 years). Ovarian cancer was diagnosed in 212 women (5.7 per 100 00 person-years) in the intervention group, and 176 (4.7 per 10 000 person-years) in the usual care group (rate ratio 1.21, 95% CI 0.99 to 1.48). 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 RR 1.18; 95% CI 0.82 to 1.71). There were 2924 deaths due to causes other than ovarian cancer in the intervention group, and 2914 deaths in the usual care group (RR 1.01, 95% CI 0.96 to 1.06). Of 3285 women with false-positive results, 1080 undervent surgical follow-up: of whom, 163 women experienced at least one serious complication (15 %).
A systematic review including 6 studies on stage related mortality, 4 studies on the accuracy of pelvic examination, 7 case series and 7 screening studies on ultrasound, 17 case series and 3 screening studies on CA 125, and 3 screening studies on the specificity of CA 125 was abstracted in DARE. In addition, there were 2 mathematical models combining information.
Pelvic examination had a limited value in screening for ovarian cancer. Ultrasound had a summary sensitivity of 85% and a summary specificity of 93.8%. Ultrasound had a predictive value of 1% in 50 year old women and 2% for women with a relative with ovarian cancer. Ca 125 had an overall summary sensitivity of 78% and summary specificity of 98.95 (95% CI 98.6% to 99.2%). CA 125 had a sensitivity of 46% in detecting stage I cancer, and 92% sensitivity in detecting stage II cancer.
Another systematic review abstracted in DARE included 25 prospective screening studies. There were no completed randomised trials. About 50% of stage I cancer can be diagnosed in CA-125-based screening studies and about 75% in ultrasound screening studies. Annual screening with ultrasound appears to have a sensitivity of detection rate close to 100%, whereas the sensitivity of annual CA 125 screening is about 80%. The false-positive rate is about 1.2 - 2.5% for women screened by ultrasound scanning and 0.1 - 0.6% for CA 125-based screening. About 3 - 12% of screened women are called for further testing. The low positive predictive value of ovarian screening (3% for surgery and 0.6% for initial recall for annual ultrasound screening; 15% for surgery and 1% for initial recall for annual CA 125 screening) is due to the low prevalence of ovarian cancer.