Bother following stereotactic body radiation therapy for clinically localized prostate cancer.

195 Background: Stereotactic body radiation therapy (SBRT) delivers high doses of radiation while minimizing radiation to adjacent normal tissues. Large fraction sizes may increase the risk of functional decrements. However, treatment-related bother may be more important to a patient than treatment-related dysfunction. Methods: Between August 2007 and July 2011, 228 hormone-naive patients with clinically localized prostate cancer were treated with 35-36.25 Gy SBRT delivered using the CyberKnife Radiosurgical System (Accuray) in five fractions. Patients completed the validated Expanded Prostate Cancer Index Composite (EPIC)-26 questionnaire at baseline, one month post-treatment, every three months the first year, then every six months. EPIC scores for bother range from 0 to 100 with lower values representing increased interference or annoyance caused by limitations in function. Results: Two hundred twenty eight patients at a median age of 69 (range, age 44 to 90) received SBRT with a minimum follow-up of 2...