November 7, 2005 -- A new study from the National Cancer Institute (NCI), part of the National Institutes of Health, shows that currently available screening methods such as transvaginal ultrasound (TVU) and testing for a protein biomarker called CA-125, alone or in combination, can detect ovarian cancer but can also produce many false-positive test results, causing needless surgery. This report, which summarizes preliminary results from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, appears in the November 15, 2005 American Journal of Obstetrics and Gynecology.

These findings, the first published ovarian cancer screening results from NCI's ongoing multicenter PLCO Cancer Screening Trial, are based on an analysis of the trial participants' initial screening tests. CA-125 and TVU have been considered as potential screening techniques, although studies to date have not shown that they can be effective and thus they are not currently recommended. The long-term objective of the PLCO Trial is to determine whether screening with TVU and/or CA-125 decreases ovarian cancer mortality in women age 55 to 74.

Of the 28,816 healthy women who underwent the initial (baseline) screening, 1338 (4.7 percent) had an abnormal TVU and 402 (1.4 percent) had an abnormal CA-125 blood test. Thirty-four women (0.1 percent) had abnormal results in both screening tests. Among the women with abnormal test results, 29 tumors were detected, 20 of which were invasive cancers.
Women who had an abnormal test result in one or both screening tests underwent a variety of diagnostic procedures to determine whether cancer was present, including 570 women who underwent a surgical procedure as follow-up. Thus, 541 women underwent surgery but did not have cancer.

"Ovarian cancer is a disease that is often fatal, and both patients and physicians are anxious to find ways to detect it at an earlier, more curable stage," said first author on the study, Saundra Buys, M.D., University of Utah, Salt Lake City. "However, the results from the initial year of screening show that TVU and CA-125 cannot currently be recommended for widespread use in the general population. Future results from the additional PLCO screenings and subsequent follow-up will be needed before a final assessment of this screening strategy can be made."

Enrollment in the PLCO study began in 1993 and ended in 2001. When they initially enrolled in the study, women in the intervention arm underwent baseline ovarian cancer screening with CA-125 and TVU and received additional annual screenings and follow-up. Women in the control arm of the study were not screened but were observed over time.

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