Study leader Dr. Cary Gross, associate professor of internal medicine at Yale School of Medicine and director of the Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, said the research team calculated Medicare expenditures for breast cancer screening and treatment in 137,274 female Medicare beneficiaries age 66 and older.
They had not had breast cancer before 2006. They were tracked for two years to observe screening, breast cancer incidence and associated cost.
The study, published in the journal Internal Medicine, found more than $400 million was spent annually on screening older Medicare beneficiaries 75 and older.
The U.S. Preventive Services Task Force, a voluntary medical group, concluded there was insufficient evidence regarding the effectiveness of breast cancer screening for women age 75 and older.
The study also found substantial variations across geographic regions in Medicare spending for breast cancer screening -- ranging from $40 to $110 per female Medicare beneficiary.
The majority of the difference in cost was due to the use of newer, more expensive screening technologies in the higher-cost areas, the study said.
"Although screening costs varied more than two-fold across geographic regions, there was no evidence that higher expenditures were benefiting women living in the high-cost regions," Gross said in a statement.
"Specifically, there was no relation between screening expenditures and the detection of advanced cancers."