When is radiation therapy used in treating cancer and when is chemotherapy used?

Disease tells: What modalities to use. You left out surgery, but with c and rt these are used alone, sequentially or at the same time. Leukemia and lymphoma has very little need for surgery, and increasingly littl for xrt. All are used in lung, breast, colorectal, brain, h&n and most GI cancers. Little role for chemo in early prostate cancer where s and XRT are competitive.

Depends: In general, in advanced stage of cancer, where the cancer has spread to distant organ- chemo would be the primary therapy. Palliative radiation can be used to relieve pain, obstruction, stops bleeding etc. In more localized disease, radiation is used as a single tx or combination with chemo either to cure (if surgery can't be done); or before or after surgery. Please d/w your oncology team.