Long-term follow-up of the Stockholm screening study on ovarian cancer

Seventy percent of ovarian cancer is diagnosed at advanced stages. Having a method for early diagnosis is a very attractive concept. Several attempts have been made, using monoclonal antibody-based immunoassays, ultrasound, or combinations of both, to identify methods that might prove to be sufficiently sensitive and specific as a screening test. Despite promising results, a mortality study of a large population has yet to be completed due in part to the high cost involved.

One of the first studies aimed at devising a screening strategy for ovarian cancer used the CA 125 immunoassay followed by ultrasound. The study was performed in Stockholm from 1986 through 1988. Ten years now having passed, an analysis has been performed to further evaluate the results of that study.

Screening led to the diagnosis of ovarian cancer in six patients, five of whom have since died of the disease. By searching the Cancer Registry, we were able to identify 20 ovarian cancer patients who developed the disease after the screening period. Of these, 12 died of the disease, 2 are alive with disease, and 6 have no evidence of disease following treatment. The median survival for patients diagnosed by screening was 100 months. Median survival for ovarian cancer patients identified subsequent to screening was 20 months. Although there was no difference in survival between these two groups, median survival was better for women diagnosed by screening (borderline significance, P = 0.059).

These results indicate that a study of a large number of women with a sufficiently long observation time will be required to establish whether or not screening can reduce ovarian cancer mortality. Such a study may also provide insight into the natural history of ovarian cancer.