Comparison of conventional-dose vs high-dose conformal radiation therapy in clinically localized adenocarcinoma of the prostate: A randomized controlled trial

Abstract

Context: Clinically localized prostate cancer is very prevalent among US men, but recurrence after treatment with conventional radiation therapy is common. Objective: To evaluate the hypothesis that increasing the radiation dose delivered to men with clinically localized prostate cancer improves disease outcome. Design, Setting, and Patients: Randomized controlled trial of 393 patients with stage T1b through T2b prostate cancer and prostate-specific antigen (PSA) levels less than 15 ng/mL randomized between January 1996 and December 1999 and treated at 2 US academic institutions. Median age was 67 years and median PSA level was 6.3 ng/mL. Median follow-up was 5.5 (range, 1.2-8.2) years. Intervention: Patients were randomized to receive external beam radiation to a total dose of either 70.2 Gy (conventional dose) or 79.2 Gy (high dose). This was delivered using a combination of conformal photon and proton beams. Main Outcome Measure: Increasing PSA level (ie, biochemical failure) 5 years after treatment. Results: The proportions of men free from biochemical failure at 5 years were 61.4% (95% confidence interval, 54.6%-68.3%) for conventional-dose and 80.4% (95% confidence interval, 74.7%-86.1%) for high-dose therapy (P