Stereotactic body radiation therapy for prostate cancer: Rational and reasonable.

Stereotactic body radiation therapy (SBRT), a treatment procedure that uses large doses per fraction, is currently being used to treat prostate cancer with external radiation therapy in 4 to 5 treatments. Published series in the clinical use of SBRT in patients with localized prostate cancer demonstrate high efficacy within the available follow-up time periods. Rectal and sexual toxicity profiles have been favorable compared with other radiation techniques and surgery. Urinary toxicity profiles might be more comparable to those observed with brachytherapy, more pronounced in the acute setting. SBRT is technically more challenging, requiring precise geometric targeting with in-room image guidance. The use of large doses per fraction potentially provides unique biological effects on both tumor and normal tissues. Immunologic responses in normal tissues, local stromal microenvironment, and specific antigen-presenting cells induced by such high doses likely contribute to effective tumor kill. Ultimately, SBRT for prostate cancer offers significant logistical advantages, with increased convenience to patients and decreased overall cost to the health care delivery system.