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-naïve 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 24 months. Urinary bother increased transiently first at one month and again at 12 months before returning to pre-treatment scores at two years: 80.2 (baseline); 68.2 (one month); 79.8 (three months); 78.3 (six months); 74.5 (nine months); 71.1 (12 months); 75.8 (18 months); 78.3 (24 months). Bowel bother followed a similar pattern but with a more protracted late-stage decline: 91.4 (baseline); 76.0 (one month); 87.8 (three months); 88.4 (six months); 85.8 (nine months); 85.7 (12 months); 87.8 (18 months); 90.1 (24 months). Sexual bother progressively worsened over two years: 65.9 (baseline); 64.8 (three months); 63.0 (six months); 63.2 (12 months); 59.0 (18 months); 58.4 (24 months). Conclusions: SBRT for clinically localized prostate cancer was well tolerated. Treatment-related bother was comparable to conventionally fractionated radiation therapy and brachytherapy. Transient late increases in urinary and bowel bother were observed at one year. Sexual bother steadily increased during the first two years following treatment.
Predicting Distant Failure in Lung Stereotactic Body Radiation Therapy Using Multiobjective Radiomics Model
