system
Given the following post, respond as if you're commenting on Reddit:
human
What makes a tumor inoperable?

I see people dying of inoperable tumors and it makes me wonder, why are they inoperable?
gpt
Location, location, location. In *very* general, it's because the tumor cannot be cut out entirely. Remember that even a single cancer cell can bring about a whole new tumor, so surgeons must be very sure they can get it all or else they cannot cure surgically. Another reason is that if the tumor has already spread to other parts of the body, removing the primary tumor will not cure the disease. Additionally, there are also occasions where the tumor is in a place that anatomically prohibits removal - this is seen with brain tumors, where an attempt at removal could cause severe brain damage. It can also have to do with being wrapped around important blood supply and surgical removal could result in severe bleeding. 

In short, no tumor is "inoperable" - it's just that a surgeon deems it inoperable when they look at what it is, where it is, and how far along it is and say "I cannot cure this disease by removing the tumor."