Why do doctors prefer to remove tumors rather than treat them with radiation and chemotherapy?

Radiation and chemotherapy can also kill normal, healthy cells.

Radiation treatment utilizes high-energy particles or surges, such as electron beams, or protons, x-rays, gamma rays, to destroy or damage cancer cells. It operates by preventing the cancer cells from multiplying and dividing to make more cells. Because cancer cells normally grow and distribute faster than normal cells, chemotherapy has a larger effect on cancer cells. However, the drugs used for chemotherapy are persuasive, and they can still generate injury to healthy cells.

Firstly it could effect the body it's still, Radiation And Chemotherapy can also Damage or Kill normal healthy cells.