Ten‐year outcomes of high‐dose, intensity‐modulated radiotherapy for localized prostate cancer

BACKGROUND: The authors investigated long-term tumor control and toxicity outcomes after high-dose, intensity-modulated radiation therapy (IMRT) in patients who had clinically localized prostate cancer. METHODS: Between April 1996 and January 1998, 170 patients received 81 gray (Gy) using a 5-field IMRT technique. Patients were classified according to the National Comprehensive Cancer Network-defined risk groups. Toxicity data were scored according to the Common Terminology Criteria for Adverse Events Version 3.0. Freedom from biochemical relapse, distant metastases, and cause-specific survival outcomes were calculated. The median follow-up was 99 months. RESULTS: The 10-year actuarial prostate-specific antigen relapse-free survival rates were 81% for the low-risk group, 78% for the intermediate-risk group, and 62% for the high-risk group; the 10-year distant metastases-free rates were 100%, 94%, and 90%, respectively; and the 10-year cause-specific mortality rates were 0%, 3%, and 14%, respectively. The 10-year likelihood of developing grade 2 and 3 late genitourinary toxicity was 11% and 5%, respectively; and the 10-year likelihood of developing grade 2 and 3 late gastrointestinal toxicity was 2% and 1%, respectively. No grade 4 toxicities were observed. CONCLUSIONS: To the authors' knowledge, this report represents the longest followed cohort of patients who received high-dose radiation levels of 81 Gy using IMRT for localized prostate cancer. The findings indicated that high-dose IMRT is well tolerated and is associated with excellent long-term tumor-control outcomes in patients with localized prostate cancer.