Comparison of Conventional-Dose vs High-Dose Conformal Radiation Therapy in Clinically Localized Adenocarcinoma of the Prostate: A Randomized Controlled Trial

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