Early screening for ovarian cancer appears ineffective

Thursday April 2, 2009 (foodconsumer.org) --- A recent study conducted by the University of Alabama at Birmingham calls into question the efficacy of available screening tests for ovarian cancer. The study focuses specifically on the combination of ultrasound with blood tests which look for CA-125, a protein that signifies cancer in higher levels. Ovarian cancer is currently the fifth highest cause of cancer death in females.

Researches found that CA-125 is an ineffective tool for identifying ovarian cancer in its early stages. While the protein has proven useful for monitoring ovarian cancer relapses, it has not been useful for early detection. Combination screening has proven ineffective as well, catching 70 percent of cancers in the late stage.

According to a March 11, 2009, article in the New York Times, roughly a quarter of invasive cancers are caught early. Ovarian cancer becomes more difficult to treat in later stages. According to the study, conducted by The Lancet Oncology and cited by the New York Times, about 58 cancers (there were 202,638 participants) were detected on first screening. Twenty-eight of these were detected in the early stage.

According to the University of Alabama study, 1.6 percent per 100 positive results were true positives. This low rate of true positives has led to many false positives. False positives can potentially lead to unnecessary surgery.

The study found that transvaginal ultrasound caused a high proportion of unnecessary surgeries, where no tumor was detected after initial surgery. The practice of removing an ovary is called salpingo-oophorectomy and renders the patient sterile. It is sometimes used as a precaution for patients with a high risk for ovarian cancer.

The New York Times reported that ovarian cancer afflicts 21,650 women each year, 15,520 of which are fatal. Women should be cautioned to be wary of positive results, as they may be false positives. A blood test should be followed up by an ultra-sound, and even then there is a low chance of detecting the cancer in its early stages.

According to a study published by the University of Texas Division of Medicine, CA-125 points out that elevated levels of the protein are associated with a number of unrelated, benign conditions. CA-125 has many applications. The study, written in 1998, suggests that CA-125’s most promising application may be in early detection of epithelial cancer, however as of yet this has proven to be false.

The University of Alabama partnered with the Prostate, Lung, Colorectal and Ovarian Cancer Screening trial at the Huntsman Cancer Institute, Salt Lake City; the University of Colorado Cancer Center, Denver; the Washington University School of Medicine, St. Louis; the University of Pittsburgh Medical Center; the Henry Ford Health System, Detroit; the Pacific Health Research Institute, Honolulu; the University of Minnesota, Minneapolis; and the National Cancer Institute, Bethesda, Maryland. The University of Alabama Comprehensive Cancer Center is a national leader in women’s cancer. Funding came from the National Institutes of Health (Science Daily).

Reported by Will Levine, and edited by Heather Kelley.