The AMA is the latest medical organization to come out in favor of women beginning screening mammography at 40. In 2009, the U.S. Preventive Services Task Force (USPSTF) withdrew its previous recommendation that women 40 to 49 years of age be screened routinely; instead, the agency has advised these women to consult with their physicians on whether to undergo screening and recommended biennial screening starting at age 50.

In its new policy update, the AMA did stop short of stating that women "should" get screened at 40, advising instead that women "should be eligible" for screening at that age. It also did not include language suggesting yearly mammograms.

"Mammography is the most reliable breast cancer screening tool for the general population, but it also has limitations," the AMA said in a statement. "As a result, several organizations have recommended various mammography screening guidelines. Today, the AMA has adopted policy that starting at age 40, all women should be eligible for screening mammography. The policy also supports insurance coverage for this screening."

Early detection of breast cancer increases the odds of a patient's survival, and mammography screenings are an important tool in discovering this cancer, said AMA board member Dr. Patrice Harris.

"All patients are different and have varying degrees of cancer risk, and patients should regularly talk with their doctors to determine if mammography screening is right for them," Harris said in AMA's statement.