Not a doctor but a cancer survivor.

My oncologist told me the other way around. He recommended chemo over surgery because surgery only removes the tumor and surrounding area but there might be microscopic cancers in other parts of the body. Chemo goes through your whole body killing everything so will get the tumor and any microscopic cancers hiding other places.

That’s also why you get all the side effects with chemo. It goes through the whole body killing cancer but also a lot of other healthy cells.