Determining the risk of ovarian malignancy in postmenopausal women with abnormal findings in the PLCO screening trial

Reporting on the largest study of its kind today at the Society of Gynecologic Oncologists 37th Annual Meeting on Women's Cancer, researchers presented new criteria for detecting ovarian cancer malignancy in postmenopausal asymptomatic women, 55 to 74 years old.

Utilizing the new criteria, researchers determined that they could accurately predict 93 percent of the advanced ovarian cancers and 87 percent of the early ovarian cancers in asymptomatic women enrolled in an annual screening program and found to have an abnormal screen.

The study, "Determining the Risk of Ovarian Malignancy in Postmenopausal Women with Abnormal Findings in the PLCO Screening Trial: A Guide for Physicians," was led by Edward E. Partridge, M.D., University of Alabama at Birmingham, Birmingham, AL.

"Until we have an accurate screening test to identify ovarian cancer in asymptomatic women, we must have guidelines to help doctors evaluate common test abnormalities and detect the malignancy with as much precision as possible," said, Dr. Partridge. "The results of this study are immediately useful for guiding interpretation of ultrasound and CA-125 abnormalities in asymptomatic postmenopausal women."

Early diagnosis of ovarian cancer is vital to reducing mortality. This is the largest prospective cancer screening study to evaluate the risk of malignancy in an exclusively postmenopausal population, ages 55-74, when there are no symptoms. This study is particularly noteworthy because the described screening tests (ultrasound and CA-125) are immediately available to women today.

"The dilemma we face with screening for a disease with low prevalence, like ovarian cancer, is false positive results," commented Dr. Andrew Berchuck, co-director of the Breast/Ovarian Cancer Program of the Duke University Comprehensive Cancer Center. "This study is important because it provides guidelines to better interpret the ultrasound and CA 125 testing we have available. Accurate interpretation of test results could ultimately help to save the lives of postmenopausal women who do not present with symptoms but have ovarian cancer, as well as save women who receive ambiguous results from invasive surgery when there is no real malignancy."

"These new guidelines are a significant step forward in the fight against women's cancers," explained Dr. Partridge. "We hope this will encourage further efforts to validate and refine these criteria in other populations so more women can be properly diagnosed and treated for ovarian cancer."

Ovarian cancer is the leading cause of death from gynecologic malignancies, according to the American Cancer Society. Annually, over 22,000 women in the U.S. will develop ovarian cancer and more than 16,000 will die from this disease.

Results from the first three years of The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trials were reviewed to establish scoring criteria for distinguishing malignant from benign processes. Women enrolled in the study had annual screening for lung, colorectal and ovarian cancer. Although historically a CA-125 level over 35 has been considered abnormal, the authors found that a CA-125 of greater than 65 was the best predictor of ovarian cancer in a postmenopausal asymptomatic woman with an initial abnormal screen. In follow-up screening the following criteria, applied in a hierarchical manner, appear to be accurate at detecting malignancy:

• CA-125 65;
• Or a CA-125 increase of 40 points;
• Or a CA-125 change of 10 with an ovary/cyst 3 cm:
• Or an ovary/cyst change of 6.5 cm.

Using the above criteria for a single screen, 15 of the 20 cancers in the initial or baseline screening group (T0) would have been detected. The study found that subsequent annual screenings provided the opportunity to compare current CA-125 levels and/or transvaginal ultrasounds (TVU) findings with the previous screen. Utilizing the above criteria for distinguishing benign from malignant masses in women with more than one screen, doctors would have been able to detect all 29, or 100 percent of the women with invasive cancer.

"Determining the Risk of Ovarian Malignancy in Postmenopausal Women with Abnormal Findings in the PLCO Screening Trial: A Guide for Physicians," was conducted by Edward E. Partridge, M.D., University of Alabama at Birmingham, Birmingham, AL; Robert T. Greenlee, Marshfield Clinic Research Foundation, Marshfield, WI; Thomas L. Riley, Information Management Services, Inc., Rockville, MD; Craig Williams, Information Management Services, Inc., Rockville, MD; Lawrence R. Ragard, Westat, Rockville, MD; Jian-Lun Xu, National Cancer Institute, Rockville, MD; Saundra S. Buys, Huntsman Cancer Institute, Salt Lake City, UT; and Philip C. Prorok, National Cancer Institute, Rockville, MD.