Hypofractionated intensity-modulated radiotherapy (70 Gy at 2.5 Gy per fraction) for localized prostate cancer: Cleveland Clinic experience

Abstract

Purpose: To study the outcomes in patients treated for localized prostate cancer with 70 Gy delivered at 2.5-Gy/fraction within 5 weeks.

Methods and materials: The study sample included all 770 consecutive patients with localized prostate cancer treated with hypofractionated intensity-modulated radiotherapy at the Cleveland Clinic between 1998 and 2005. The median follow-up was 45 months (maximum, 86). Both the American Society for Therapeutic Radiology and Oncology (ASTRO) biochemical failure definition and the alternate nadir + 2 ng/mL definition were used.

Results: The overall 5-year ASTRO biochemical relapse-free survival rate was 82% (95% confidence interval, 79-85%), and the 5-year nadir + 2 ng/mL rate was 83% (95% confidence interval, 79-86%). For patients with low-risk, intermediate-risk, and high-risk disease, the 5-year ASTRO rate was 95%, 85%, and 68%, respectively. The 5-year nadir + 2 ng/mL rate for patients with low-, intermediate-, and high-risk disease was 94%, 83%, and 72%, respectively. The Radiation Therapy Oncology Group acute rectal toxicity scores were 0 in 51%, 1 in 40%, and 2 in 9% of patients. The acute urinary toxicity scores were 0 in 33%, 1 in 48%, 2 in 18%, and 3 in 1% of patients. The late rectal toxicity scores were 0 in 89.6%, 1 in 5.9%, 2 in 3.1%, 3 in 1.3%, and 4 in 0.1% (1 patient). The late urinary toxicity scores were 0 in 90.5%, 1 in 4.3%, 2 in 5.1%, and 3 in 0.1% (1 patient).

Conclusion: The outcomes after high-dose hypofractionation were acceptable in the entire cohort of patients treated with the schedule of 70 at 2.5 Gy/fraction.