Not necessarily. A medical treatment can be ordinary if it provides a reasonable chance of success with relatively few side effects. I don’t think you can say there are no circumstances where one might be morally obliged to accept treatment.
And furthermore, some have other illnesses which would render such treatment pointless. My grandmother has colon cancer, which we have opted not to treat because her diabetes, heart failure and dementia are so severe that they are sure to kill her before the cancer does anyway.
There is no “straight up” teaching. But that doesn’t mean that there is no situation where you would be morally obliged to accept treatment.
Here’s one:
A 25 year old mother of one gets breast cancer. It’s detected early so she could start treatment with a reasonable chance of success. Do you really think it would be moral of her to refuse treatment?
I think it would be immoral and a refusal to take reasonable actions to look after your health.
Her vocation and age aren’t relevant. The only thing that matters is, is she obligated to accept a particular treatment according to the teachings of the Church.
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