Surgery might be a "one-off", but cancer surgery can be brutal. People with cancer who need surgery are often nutritionally depleted and surgery takes a big toll. Recovery time in the hospital could be weeks. Rehab, getting you back to where you can wipe your own ass and feed yourself, can take months.
It's not like you would just fly in, get cut and fly back in a week.
You would have to set up some kind of support system for yourself there, which would be very expensive.
If you need cancer surgery and you want the best you do the opposite-- fly to the US. E.g. MD Anderson has many patients come from all over the world for surgery.