Radiation therapy uses high energy x-rays to destroy cancer cells and shrink tumors. In general, radiation therapy is not useful for treating kidney cancer. However, it may be used before surgery to shrink cancer tissue, after surgery to try to make sure all cancer cells are destroyed, or as an alternative for people who can not tolerate surgery. Radiation therapy may also be used to ease pain or other symptoms caused by tumors in other areas of the body.

There are different types of radiation therapy, but external beam radiation is used to treat kidney cancer. In external beam radiation therapy, radiation is produced by a machine positioned outside the body. Short bursts of x-rays are directed at the cancer. The radiation oncologist will direct the radiation beam to deliver as much radiation to the tumor as possible with as little damage to healthy tissue as possible.