The U.S. is mulling changes to how the Medicare program pays physicians for administering expensive cancer drugs and other medications given in doctors’ offices, according to a memo from the Centers for Medicare and Medicaid Services.

The memo tells Medicare contractors who process payments to set up a system allowing the government to vary by geographic location how much it reimburses doctors for the drugs they administer. The government could then set up a pilot program to test how limiting reimbursement in Medicare Part B, which pays for seniors’ medical services and supplies, affects doctors’ choice of drugs, according to the memo that was posted on the CMS website.