Screening Can Detect Early-Stage Ovarian Cancer; Concerns Remain, Study Says

Main Category: Ovarian Cancer
Article Date: 12 Mar 2009 - 4:00 PDT

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Conducting transvaginal ultrasound scans or blood tests followed by scans on post-menopausal women detects nearly half of early-stage ovarian cancers before they spread beyond the pelvis, according to preliminary results from a British study published Wednesday in the journal Lancet Oncology, the New York Times reports (Rabin, New York Times, 3/11). Ovarian cancer causes about 100,000 deaths annually worldwide, and most women are diagnosed after the disease has spread, when there is a maximum 30% survival rate. Among women whose cancers are detected early, nearly 90% survive. Typically, physicians detect about 15% of early-stage ovarian cancers, the AP/Los Angeles Times reports (Cheng, AP/Los Angeles Times, 3/11). Although the results of the study suggest that widespread screening could improve early ovarian cancer detection rates, the researchers cautioned that the benefits from such screenings are still unclear. They noted that the screenings provided many women with false positive results, which led to unnecessary surgeries and complications, particularly among women who received only the ultrasound scan. In addition, there is no evidence that screening reduces the mortality rate from ovarian cancer, the researchers said (New York Times, 3/11). To determine whether screening would improve ovarian cancer survival rates, the researchers must wait until the completion of the study in 2014. The U.K.'s Medical Research Council, Cancer Research U.K. and the U.K. Department of Health provided funding for the study (AP/Los Angeles Times, 3/11).

For the study, the researchers recruited 202,638 British women ages 50 to 74 between 2001 and 2005. The researchers assigned half of the women to a group receiving no ovarian cancer screening and randomly assigned the remaining women to receive annual screenings either by transvaginal ultrasound scans or blood tests. The blood tests were designed to detect the CA125 tumor marker, and if the tests suggested an abnormality, the researchers followed up with an ultrasound scan (New York Times, 3/11). Among the women who first received the blood test, the researchers identified 38 women who had cancer. Among those who received only the ultrasound, the researchers detected 32 cancer cases. They determined that the blood test method detected 89% of ovarian cancer cases, and the ultrasound-only method detected 75% of cases (AP/Los Angeles Times, 3/11). According to the researchers, about 48% of the cancers, or 28 of the 58 total invasive cancers detected, were in the early stages. The researchers found no significant differences between the two screening methods, although they noted that the rates of unnecessary surgery were higher among women who received only the ultrasound.

Ian Jacobs, director of the Institute for Women's Health at University College London and director of the trial, said the study "demonstrated we can pick up the vast majority of women with ovarian cancer earlier than they would have otherwise been detected and before they have symptoms." He added that the researchers found "that a good proportion of those women have earlier stage disease than we would normally expect them to have." However, Jacobs also warned that women considering ovarian cancer screenings should be aware of possible risks. According to Jacobs, early screening could "do more harm than good" by generating false positive results. "We have reason to think it will save lives," Jacobs said, adding that "the question is, will it save enough lives to balance out the harm it does?" (New York Times, 3/11). Robert Smith, director of cancer screening for the American Cancer Society and who was unconnected to the trial, said he was "cautiously optimistic" about the study's results. He said early ovarian cancer screening "may make a difference to saving lives, but we don't know that right now." Smith also added that the types of cancers these tests detect are not always fatal (AP/Los Angeles Times 3/11). According to Smith, researchers are "not even remotely close to knowing how to screen women of average risk with these tests, or even if we should." In addition, medical groups generally have discouraged using the results of a single blood test as the basis for an intervention, the Times reports (New York Times, 3/11). Smith said, "It's a big and expensive jump to decide that (national) screening programs might be beneficial" (AP/Los Angeles Times, 3/11).

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