Tired of facing perennial cuts in reimbursement for Medicare services, Tennessee doctors say they can no longer afford to take on new Medicare patients, especially as the costs of providing services and operating a practice increase. Some are beginning to think about cutting current Medicare patients from their roster. The challenges are acute in Tennessee, which has an above-average number of Medicare patients and a below-average number of doctors who treat them. The ratio of physicians to patients is sure to drop, as further reimbursement cuts are inevitable.