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Researchers now have their first real hint that there might be a way to screen women for ovarian cancer.
A study published Thursday shows that a careful formula that combines a blood test with ultrasound scans could reduce deaths from ovarian cancer by 20 percent.
It’s not ready for prime time yet, but a screening test for ovarian cancer could save thousands of women. It's one of the deadliest cancers because it's almost always diagnosed in late stages, after it has spread.
Doctors are cautiously welcoming the results.
“This study shows that you could decrease deaths from a highly lethal cancer. That can’t be underestimated,” said Dr. Karen Lu, director of the High Risk Ovarian Cancer Screening program at MD Anderson Cancer Center in Houston.
“This study shows that you could decrease deaths from a highly lethal cancer."
“These initial results are promising for the ovarian cancer community, but there is much more data analysis needed in the coming months to determine the true impact on the future of early detection testing for ovarian cancer,” added Ovarian Cancer National Alliance CEO Calaneet Balas.
For the study, a team led by Ian Jacobs at University College London enrolled more than 200,000 women aged 50 to 74 and followed them for as long as 14 years. Half the women got no screening. A quarter of the women got an annual ultrasound, and another 50,000 got an annual blood test for CA-125, a compound whose levels rise in women with ovarian cancer.
In the third group, if CA-125 levels went up according to a fairly complicated formula, they got an ultrasound to look for evidence of tumors.
Over the time of the study about 1,200 of the women got ovarian cancer, and they were divided equally among the groups.
The usual mortality rate for ovarian cancer is about 60 percent. But the women who got the blood tests with ultrasound follow-up appeared to have been diagnosed earlier, because they were less likely to die from their cancer than the other women.
Over the whole study period, women who got the blood test and ultrasound screening and who got ovarian cancer were 15 percent less likely to die than the other women. But after seven years, they were 23 percent less likely to die, the team reported in the Lancet medical journal.
Ovarian cancer will be diagnosed in more than 21,000 American women this year and it will kill more than 14,000.
It causes such vague symptoms until it’s progressed that few women know in time.
“We’ve never had anything for early detection of ovarian cancer where we’ve shown you can actually decrease deaths,” Lu, who was not involved in this trial, told NBC News.
“The study investigators say they need about three more years to be absolutely sure.”
More women are likely to be diagnosed with ovarian cancer over more time, Jacobs and colleagues said.
"The results suggested that an unequivocally significant difference in mortality might emerge after longer follow-up," they wrote.
Screening for ovarian cancer is tricky because while CA-125 often does rise as ovarian tumors grow, there’s not a single specific level that can tell a doctor a woman is at risk. Some women with cancer have low levels, and some healthy women can have high levels.
“We’ve never had anything for early detection of ovarian cancer where we’ve shown you can actually decrease deaths."
And, Lu says, the tests vary depending on which one is used. “Even different labs sometimes can give you different values,” she said.
So the British team used a formula called the Risk of Ovarian Cancer Algorithm, which looks for changes in each woman’s own levels of CA-125.
Using this careful combination of the blood test formula in combination with ultrasound seemed to do the trick.
“I call it a strategy rather than a blood test,” said Lu. “You get the CA-125 blood test once a year. That not too burdensome for women.”
Women could get it as part of an annual physical – perhaps using blood drawn for an annual cholesterol test. “It needs to be that simple,” Lu said.
Experts used to recommend yearly screening for prostate cancer using a blood test for prostate specific antigen or PSA. But then studies showed this didn’t really save any lives and caused a lot of unneeded, painful biopsies. The U.S. Preventive Services Task Force now recommends against routine PSA screening.
And the fight is still going on about how or whether mammograms save many lives.
Lu says while these debates may confuse the public, doctors are learning from them.
“I think we learned that there are two sides to cancer screening tests, that there are benefits and is there also potential harm,” she said. “So I feel like we have become smarter after going through the whole PSA story. That’s why I think this study is so significant.”
Researchers said screening might be best at first for women who know they are at high risk of ovarian cancer — like actress Angelina Jolie, who had her breasts and ovaries removed after learning she had several genetic mutations putting her at very high risk.
Women with a family history of ovarian cancer, as do women with endometriosis - an overgrowth of the uterine lining – and women who have never had children.
Another factor: the study was done in Britain, which has a national health system and where it was easy to tightly control when, where and how the women got screening and treatment. A screening program would look much different in the U.S. where women often change insurers, doctors and other providers.
“As we are waiting those three years to find out the final results, we need to be thinking in this country where our health system is different,” Lu said.
“The more thoughtful we are about that, the more likely we are to have women benefit.”
It’s also important to focus on better treatment of such a deadly cancer, she said. A recent study found that just 41 percent of eligible ovarian cancer patients are getting chemotherapy delivered directly to the abdomen, even though the benefits are so strong that the National Cancer Institute has made a rare recommendation for doctors to use it.