system
Given the following post, respond as if you're commenting on Reddit:
human
[ELI5] why is it that a tumor that is beyond a certain size can't be cut out?
gpt
There are a couple of reasons of why this sometimes happens:


It could cause a lot of bleeding and tissue destruction, the surgery might cause more damage than good, the tumor might invade certain areas of the body which if damaged could put the patients life in immediate danger. 


Thats why sometimes if cancerous tumors are too big it's preferable to use radiotherapy or chemotherapy to shrink the tumor, and then operate on it. 


Another reason of this is because sometimes cancerous tumors have already metastasized in other parts of the body, meaning that its sometimes better to just wait, because even if you operate a tumor there's still metastatic matter all over the body, and eliminating the big tumor alone does not have a very meaningful effect on the patients health.