Will Medicare pay for previously refused treatment?
If my cancer returns after I have refused radiation treatment (medical protocol), will Medicare cover medical costs to treat the returned cancer?
Medicare will cover medically necessary and reasonable care at the time you need it, regardless of whether you have refused the same or similar care, or different care for the same illness, in the past. Every patient has a right to refuse treatment, and it doesn't matter (for purposes of Medicare coverage) that such a choice may turn out not to eliminate the need for treatment in the future.
One issue you may face in the future, however, is exactly what medical care is necessary and reasonable. If your cancer returns, the same treatment that you had before, or the same treatment that you refused before, may no longer be medically appropriate. So, while Medicare will cover treatment for your cancer if it returns, it will not necessarily cover all the possible treatments that you could have had earlier.