system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Can you live with cancer and never detect it?

My grandpa passed away some months ago on his sleep, an otherwise healthy 98 y.o. When we spoke to the doctor he told us that he found significant evidence for prostate cancer, it had probably went unnoticed for decades. Can you live your whole life with some form of cancer without ever even noticing it?
According to this Doctor he says that if one looks closely enough we all develop cancer at some point of our lives.
gpt
Yeah, you've actually brought up a good example. Prostate cancer is one of those cancers that can be detected in up to 80% of elderly men after they die but never actually cause any problems when they are alive to affect them meaningfully. Or, sometimes cancers can be detected quite late and never cause any big issues, but then one day it hits a vital artery or organ and you suddenly deteriorate. There's also cancers that can spontaneously regress as your body fights them since cancers can make the immune system attack them.