Hypofractionated intensity-modulated radiotherapy (70 GY at 2.5 GY per fraction) for localized prostate cancer: Long-term outcomes

Purpose: To analyze the long-term relapse-free survival and toxicity rates in patients treated with hypofractionated intensity-modulated radiotherapy. Methods and Materials: The study sample includes the first 100 consecutive localized prostate cancer patients treated to 70.0 Gy at 2.5 Gy per fraction. The median follow-up was 66 months (range, 3 to 75 months). Biochemical failure was the study endpoint, using both the ASTRO definition (A-bRFS) and the alternate "nadir + 2 ng/mL" definition (N-bRFS). RTOG scores were used to assess toxicity. Results: The 5-year A-bRFS and N-bRFS rates were 85 % (95 % CI, 78 -93 %) and 88 % (95 % CI, 82-95 %) for all cases, respectively. For low, intermediate and high-risk disease, the 5-year A-bRFS rates were 97%, 88%, and 70%. The corresponding 5-year N-bRFS rates were 97%, 93%, and 75%, respectively. The acute rectal toxicity scores were 0 in 20, 1 in 61, and 2 in 19 patients. The acute urinary toxicity scores were 0 in 9, 1 in 76, and 2 in 15 patients. The late rectal toxicity scores were 0 in 71, 1 in 19, 2 in 7, and 3 in 3 patients. The actuarial late Grade 3 rectal toxicity rate at 5 years was 3%. A number of the toxicities observed either resolved spontaneously or were corrected. At last follow-up, the rate of combined Grades 2 and 3 late rectal toxicity at 5 years was only 5%. The late urinary toxicity scores were 0 in 75, 1 in 13, 2 in 11, and 3 in 1 patients. The actuarial late Grade 3 urinary toxicity rate at 5 years was 1%. Conclusion: With a median follow-up of 66 months, the long-term results after high-dose hypofractionation are excellent. Late toxicity, urinary and rectal, has been limited. High-dose hypofractionation is an alternative dose escalation method in the treatment of localized prostate cancer. (c) 2005 Elsevier Inc.