system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If you have cancer in a certain organ (like liver cancer) why can't you just remove the infected organ and be cancerfree again?
gpt
(cancer biologist / oncologist here)

* Cancer likes to infiltrate other areas and where this has happened is not always clear.
* Removing the organ might pose too much risk (e.g. you need your lungs) - this is why chemo and radiation often occur prior to any surgical removal

But yeah generally surgical removal is very effective it just depends on what kind of cancer it is, how far advanced it is, how clear the surgical margins would be, etc.

For example, breast cancer is treated rather aggressively with surgical removal of the effective tissue (so much that in some cases like dcis its considered to have an overtreatment problem)