News Note: Screening for ovarian cancer shows no reduction in mortality
Simultaneous screening with a blood test for the biomarker CA-125 along with a transvaginal ultrasound (TVU), compared with usual care, did not reduce ovarian cancer mortality in American women. These results, from a National Cancer Institute (NCI) sponsored trial, also show that diagnostic evaluation following a false-positive result was associated with potentially harmful complications. Ovarian cancer confined to the ovary has a 5-year survival rate of 92 percent; however most women with ovarian cancer are diagnosed with advanced stage disease, making the need to find a test that can detect the disease at an early stage a high priority.
This trial, called the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, is randomized and involves 10 screening centers across the U.S. that, starting in 1993, recruited 78,216 women from 55 to 74 years of age. With these results, and the efficacy of these tests being ruled out, investigators will explore other screening possibilities. Some evidence suggests that ovarian tumors need to be found when they are relatively small—considerably smaller than the current threshold used for TVU. Similarly, had a CA- I25 threshold lower than that used in the PLCO been tested, it may have been possible to detect cancers at an earlier stage; however, this would be at the expense of more false-positive results and perhaps over-diagnosis of benign tumors.