An annual blood test to screen postmenopausal women for ovarian cancer could reduce deaths from this killer by 20 percent, a large British trial suggests.
Currently, with no reliable screening method, most ovarian cancer is diagnosed at an advanced stage, and 60 percent of patients die within five years, the study authors explained.
Using newly developed software to analyze blood test results, the researchers hope routine testing can find cancer early when it’s curable and significantly reduce deaths.
“This is an important step forward in managing a disease that has a very poor prognosis,” said lead researcher Dr. Ian Jacobs, a professor at University College London.
“This is the first time that there has been evidence of a reduction in deaths from ovarian cancer through early detection by screening,” he said. “It opens up the prospect that, in due course, a national screening program for ovarian cancer could become available alongside breast cancer and cervical cancer screening.”
The study findings were published online Dec. 17 in The Lancet.
The trial enrolled more than 200,000 women aged 50 to 74 between 2001 and 2005. The women were randomly selected to have no screening (50 percent of the women); annual screening of a blood marker (CA125) plus ultrasound (25 percent of the study group); or ultrasound alone (the remaining 25 percent). Screening ended in December 2011.
Instead of a being a one-time blood test, this new approach analyzes a woman’s CA125 pattern over time to detect any significant increase.
Over a follow-up of roughly 11 years, 630 women who had no screening were diagnosed with ovarian cancer, as were 338 women screened with the blood test and 314 screened with ultrasound alone.
At first glance, screening appeared to have no significant life-saving effect. But when the researchers excluded women who had undiagnosed ovarian cancer when they entered the study, an average reduction in deaths of 20 percent appeared.
According to Jacobs, 641 women would have to be screened to prevent one death from ovarian cancer.
Robert Smith, senior director of cancer control at the American Cancer Society, said, “With longer follow-up, the reductions in deaths will grow stronger and the numbers to screen to save a life will get smaller.”
Smith said in breast cancer screening, which is deemed effective, nearly 1,400 women need to be screened to save one life.
“If you can prevent one death by screening 1,000 people, that’s responsible public health,” Smith said.
Among women in the study screened with the blood test, about 14 out of 10,000 underwent unnecessary surgery for what turned out to be normal ovaries. In these women, the major complication rate following surgery was 3 percent, the findings showed.
The study authors are optimistic about the findings.
“We knew from our previous studies conducted over a period of 30 years that screening was acceptable to women, that it had a low false-positive rate, achieved a high detection rate and could detect ovarian cancer at an earlier stage. We now have evidence to suggest that it saves lives,” Jacobs said.
Further follow-up will clarify how great the impact is, and perhaps resolve questions regarding the risk-to-benefit ratio and cost-effectiveness of ovarian cancer screening, he said.
“When all of this information is available, decisions about implementing a national screening service can be made,” Jacobs said. “In the meantime, women who are considering whether or not to undergo ovarian cancer screening and the health professionals who advise them will have more information from this report on which to base their decision.”
Rene Verheijen, from the department of gynecological oncology at the UMC Utrecht Cancer Center in the Netherlands, said screening and early detection could prove to be “an alternative to aggressive and expensive treatments that try but fail to improve survival of patients with ovarian cancer.”
However, Verheijen, co-author of an accompanying journal editorial, said more work is needed. “It remains to be seen whether this would mean that screening of all women would yield the same results,” he said.
The American Cancer Society estimates that more than 21,000 U.S. women will be diagnosed with ovarian cancer in 2015, and more than 14,000 will die from it.
For more on ovarian cancer, visit the American Cancer Society.