Dear student
Chemotherapy is the treatment procedure in which chemical is given to patient to destroy cancer cells. While the radiotherapy is the procedure in which radiations like X-rays are used to destroy cancer cells.
Both of these procedures are beneficial and their use depends on the type of cancer. The chemotherapy is mainly given when cancer cells are present in blood, nose, vagina etc, while the radiotherapy is used to treat cancers of head, breasts, neck etc.
Sometimes doctors use both the procedures to have more effective results.
However, radiotherapy is more beneficial as it kills only specific cells.
Regards