The findings are consistent with guidelines by the US Preventative Services Task Force, which recommend against such screening. Nonetheless, the authors conclude, further results are needed to determine if annual ultrasound and CA 125 screening reduces mortality.
The study included 34,261 women without prior oophorectomy who were invited to undergo four rounds of annual screening as part of the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial. Compliance ranged from 83.1% in the first year to 77.6% in the fourth year.
A positive screen was defined as one with a CA 125 level of 35 units/mL or higher or an abnormality on ultrasound, lead author Dr. Edward Partridge, from the University of Alabama at Birmingham School of Medicine, and colleagues note.
Of the 89 invasive ovarian or peritoneal cancers diagnosed, 60 were screen detected, the report indicates. Seventy-two percent of those detected on screening were either stage III or IV.
Positivity rates with ultrasound fell slightly during the study, whereas no time trend was seen with CA 125. During the four-year period, the positive predictive value of the combination of tests ranged from 1.0% to 1.3% across screening rounds, and the cancer yield per 10,000 women varied from 4.7 to 6.2.
Among screen positives, the biopsy rate fell from 34% in the first year to 15% to 20% in the last three years. Overall, 19.5 surgeries were performed for every screen-detected cancer.
In an accompanying editorial, Dr. David G. Mutch, from Washington School of Medicine, St. Louis, comments that “more research with the development of new and better technologies is needed if we are going to help identify patients with ovarian cancer at an earlier stage.”
Obstet Gynecol 2009;113:772-782.