After listening to stories from my Canadian friends about how hard it is to just get basic medicine like antibiotics I'd expect this to be caused by a lack of screening/diagnosis rather than actual differences in cancer rates.

Do they live somewhere that requires a float plane to reach a doctor? I've never heard of a fellow Canadian having a hard time getting antibiotics, what a bizarre anecdote.

Nope, just Northern Ontario. I've driven to their houses from the US.