Of course cancer is NOT saving you! Your friend is an idiot, you need to find smarter friends! I have had a number of friends and relatives diagnosed with cancer, sadly some died of it.
My wife was diagnosed with stage 3 Hodgkin's lymphoma in September, 1993. This was followed by nine months of very intensive chemotherapy, and yeah, it was as bad as others say it is. About the only good thing I can say about it is that thanks to her very good oncologist who treated her, I still don't have to speak of her in the past tense 25 years later.