Study Finds Ovarian Screening Tests Don't Improve Survival
Blood test, ultrasound found to make little difference, lead to false positives, complications
SATURDAY, June 4, 2011 (HealthDay News) -- New research finds that the only two tests available to screen for ovarian cancer don't reduce the average woman's risk of dying from this "silent killer."
Screening with a blood test and then a transvaginal ultrasound might even cause harm, the University of Utah study suggests, since there was a huge number of worrisome false-positive results, subsequent biopsies and resulting complications.
"I am neither surprised nor disappointed. We kind of knew that, but it's nice to have the final results of the study," said Dr. Karen Lu, a professor of gynecologic oncology at The University of Texas M.D. Anderson Cancer Center in Houston.
"This actually confirms what we've always known," added Dr. Mark Wakabayashi, chief of gynecologic oncology at City of Hope Cancer Center in Duarte, Calif.
The bottom line: there are currently no good screening techniques to detect ovarian cancer early in women who are otherwise healthy, Lu said. Unfortunately, that means that many women are diagnosed at a later stage of the illness, when it is less treatable.
"Most of these cancers are detected late, even in screening trials," Wakabayashi confirmed.
The researchers were slated to present their findings Saturday at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago. The findings are also being published simultaneously online in the Journal of the American Medical Association.
Scientists have long been investigating a blood test for a marker called CA-125, as well as transvaginal ultrasound (TVA).
To test its effectiveness, the Utah authors randomized almost 80,000 women, aged 55 to 74, to either undergo an annual CA-125 screen for six years plus TVA annually for four years, or to "usual care."
After a follow-up of up to 13 years, the researchers found no differences in ovarian cancer diagnoses or mortality rates between the two groups. There were 212 cases of ovarian cancer in the screening group, compared to 176 in the usual care group, and 118 deaths in the screening group compared to 100 in the usual care group.
Moreover, almost 3,300 women received false positive results from the screens. Almost 1,100 of these women went on to undergo surgical biopsies and 163 had some kind of serious complication, the study found.
Other screening techniques for ovarian cancer are being studied, including a trial led by Lu that looks at whether changes in CA-125 levels over time could pick up malignancies.
However, for the time being, successful screening for ovarian cancer remains elusive.
"This doesn't change anything in terms of standard of care," Lu said. "There is still no successful current effective method to screen for ovarian cancer."
"There's really nothing that's good at this point [for women at average risk]," Wakabayashi said. But, she pointed out that women at high risk for ovarian cancer, such as those carrying the malignancy-linked BRCA gene mutation, should still have their CA-125 checked and undergo ultrasounds.
The U.S. National Cancer Institute has more on ovarian cancer.