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 3 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 1 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 2 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.
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