According to a recent article published Proceedings of the National Academy of Sciences of the United States of America, a blood test measuring levels of specific proteins circulating in the blood may provide screening for ovarian cancer in the future.
Ovarian cancer is a malignancy that arises from various different cells within the ovaries. Approximately 25,000 new cases of ovarian cancer are diagnosed in the United States each year. The average lifetime risk for developing ovarian cancer is about 2%. Risk factors that may increase this average include a positive family history of ovarian cancer; age (since most ovarian cancer is diagnosed after menopause); obesity; a history of breast cancer; and hormone replacement therapy. If ovarian cancer is detected early, cure rates can reach 80%-90%. However, ovarian cancer often causes no symptoms until it is far advanced, and there is currently no effective screening for the disease. Because ovarian cancer causes no symptoms and there are no screening measures, less than 20% of patients diagnosed with the disease have early-stage cancer. Once ovarian cancer has spread from the ovary, long-term survival rates remain dismal with current treatment modalities. Thus, ovarian cancer is referred to as the “silent killer”. Researchers continue to evaluate screening “markers” that will allow for the early detection and treatment of ovarian cancer, in the hopes of improving survival for women with this disease.
Researchers from Yale University, George Washington University, and the Nevada Cancer Institute recently conducted a study to determine the accuracy of a screening test for ovarian cancer. This study included 106 healthy females, and 100 patients who had been diagnosed with ovarian cancer. Of the patients diagnosed with cancer, 24 had early-stage ovarian cancer, and 76 had advanced stage ovarian cancer. Blood samples were taken from all women, and were tested for levels of 4 proteins (leptin, prolactin, osteopontin, and insulin-like growth factor-II). These proteins were selected from previous studies that indicated differences in levels of these proteins in circulating blood between women with ovarian cancer and healthy women. Overall, with results from the combination of these 4 proteins, 95% of cancers were accurately detected (sensitivity). In addition, 95% of all patients who tested positive for ovarian cancer according to levels of these 4 proteins actually had ovarian cancer (specificity).
The researchers concluded that a combination of levels of 4 specific proteins from a blood sample can provide great accuracy in screening for ovarian cancer. However, they caution that further research is necessary in order to bring this type of blood test into the clinical setting. Future clinical trials are planned regarding this type of screening for ovarian cancer. Patients who are at a high risk of developing ovarian cancer may wish to speak with their physician regarding the participation in a clinical trial evaluating novel screening measures.
Reference: Mor G, Visintin I, Lai Y, et al. Serum protein markers for early detection of ovarian cancer. National Academy of Sciences of the United States of America. 2005;102:7677-7682.