Stereotactic body radiation therapy for low-, intermediate- and high-risk prostate cancer: Disease control and quality of life at 9 years.

20 Background: Stereotactic body radiation therapy (SBRT) takes advantage of the prostate’s low α/β ratio to deliver a large radiation dose in a few fractions. This prospective study expands upon prior studies to further evaluate SBRT efficacy and QOL for a large patient population that includes low-, intermediate- and high-risk patients with prostate cancer. Methods: 515 patients with organ-confined prostate cancer (471 T1c and 44 T2a, all N0M0) received robotic SBRT. The median age was 69 years and the median PSA was 6.48 ng/ml. By NCCN criteria, 324 patients were low-risk, 139 were intermediate-risk, and 52 were high-risk. Androgen deprivation therapy was administered to 70 patients for up to one year. 158 patients with Gleason scores < 4+3 received 35 Gy delivered in 5 daily fractions. The remaining patients, from all risk groups, received a total dose of 36.25 Gy in 5 daily fractions. The proximal seminal vesicles were treated except in low-risk cases. Biochemical failure was assessed using the Phoen...