About one-quarter of men with prostate cancer choose radiotherapy. Two different approaches to prostate radiotherapy exist, and both produce the same tissue changes in the prostate. In brachytherapy, interstitial radiation is delivered by implanted seeds with a radioisotope (¹³¹I,¹⁹²Ir, or ¹⁹⁸Au). In external beam therapy, an external beam delivers radiation to the whole pelvis with a boost to the prostate.

Serum prostate-specific antigen (PSA) and a rectal examination may suggest whether or not radiotherapy has eradicated all the tumor. [ read more ]