Obamacare might mean a lot fewer tests for breast cancer for a lot of women—17 million less, one study suggests.
A controversial new recommendation says women in their 40s at average risk for breast cancer might not need to get an annual mammogram. The guidance is based on a belief that mammograms can lead to overdiagnosis and treatment that, on balance, is worse than waiting until women are older to begin more routine screenings.
Read MoreASCO data drop: What to watch
This recommendation may ultimately result in 17 million insured women losing guaranteed screenings without out-of-pocket payments, according to a new analysis by Avalere Health released Wednesday.
The recommendation made April 20 by the U.S. Preventive Services Task Force, if adopted after a public comment period, would give a "C" rating to mammograms for women age 40 to 49 years old.
Only preventive procedures rated "A" or "B" by that task force are required to be covered by insurers at no extra, out-of-pocket cost to a patient under the Affordable Care Act. The comment period on the recommendations ends May 18.
The USPSTF's recommendations contradict those of the American Cancer Society, which recommends that every woman age 40 and over get a mammogram every year. Such screening is currently provided at no out-of-pocket cost for most insured women.
"The USPSTF is working to balance the lifesaving benefits of breast cancer screening against the potential risks for overdiagnosis and unnecessary treatment for lower-risk women," said Caroline Pearson, senior vice president at Avalere Health. "By linking the ACA rules to USPSTF decisions, coverage for preventive services will continue to evolve as new research and evidence becomes available."
Avalere found that most of the women in their 40s who would lose guaranteed coverage of mammograms without cost sharing would be those with employer-provided health insurance: 13.4 million women.
In its draft recommendation, the USPSTF said, "The decision to start screening mammograms ... should be an individual one," and that for women at average risk of breast cancer most of the benefits of mammography come from biennial screening from age 50 to 74.
"Women who place a higher value on the potential benefit than the potential harm may choose to begin biennial screening between the ages of 40 and 49 years," the draft recommendation said.
"All women undergoing regular screening mammography are at risk for the diagnosis and treatment of noninvasive and invasive breast cancer that would otherwise not have become a threat to her health, or even apparent, during her lifetime (known as 'overdiagnosis'). This risk is predicted to be increased when beginning regular mammography before age of 50 years," the recommendation said.
It also said that women with a parent, sibling or child with breast cancer "may benefit more than average-risk women from beginning screening from the ages of 40 and 49."
The USPSTF also recommended that women between the age of 50 and 74 get mammograms only once every two years, giving that frequency a "B" rating.
The task force's recommendations echo its November 2009 recommendation, which also gave a "C" grade to mammograms for women in their 40s.
Read MoreFew people cost Medicaid a bunch
Because of controversy over that recommendation, Congress inserted a workaround in the ACA, which effectively maintained the "B" rating for that age group that predated 2009, and therefore forced insurers to cover annual mammograms without any out-of-pocket copayment or deductible from patients.
A group of more than 60 members of Congress, including two breast cancer survivors, have asked the Obama administration to disregard the new recommendations.
"Years of science and medicine have shown that appropriate screening can lead to early detection and save lives," said a letter from some senators to Health and Human Services Secretary Sylvia Burwell, according to The Hill.