Daisuke Shimizu1, Hideya Yamazaki2, Takuya Nishimura3, Norihiro Aibe2, Haruumi Okabe4. 1. Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan dshimizu@koto.kpu-m.ac.jp. 2. Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan. 3. Department of Radiology, Kyoto first Red Cross Hospital, Kyoto, Japan. 4. Department of Radiology, Ujitakeda Hospital, Uji, Japan.
Abstract
AIM: We report the long-term tumor control and toxicity outcomes of patients undergoing hypofractionated (2.2 Gy) image-guided intensity-modulated radiotherapy (IG-IMRT) using tomotherapy for clinically localized prostate cancer. PATIENTS AND METHODS: We examined the cases of 138 consecutive patients with stage T1-T3 prostate cancer that were treated with IG-IMRT from June 2007 to July 2009. The median follow-up time was 79 months (range=31-96 months). The planning target volume received a dose of 72.6-74.8 Gy in 33-34 fractions (2.2 Gy/fraction). Megavoltage computed tomographic (CT) scans were performed before each treatment and corrected to the registered positions on the planning CT scans using prostate soft-tissue matching. RESULTS: The 5-year biochemical and clinical relapse-free survival rates were 95% for the low-risk group, 92% for the intermediate-risk group, and 77% for the high-risk group. The 5-year incidence rates of grade 2 and 3 late gastrointestinal toxicities were 6.3% and 3.1%, respectively, and those of grade 2 and 3 late genitourinary toxicities were 7.9% and 0%, respectively. Multivariate analysis indicated that T-stage is a prognostic factor for biochemical relapse-free survival rates. CONCLUSION: This report involved the longest followed-up cohort of patients to have received hypofractionated (2.2 Gy) soft tissue-matched IG-IMRT using tomotherapy. The findings of this study indicate that hypofractionated IMRT is well tolerated and is associated with good long-term tumor-control outcomes in patients with localized prostate cancer. Copyright
AIM: We report the long-term tumor control and toxicity outcomes of patients undergoing hypofractionated (2.2 Gy) image-guided intensity-modulated radiotherapy (IG-IMRT) using tomotherapy for clinically localized prostate cancer. PATIENTS AND METHODS: We examined the cases of 138 consecutive patients with stage T1-T3 prostate cancer that were treated with IG-IMRT from June 2007 to July 2009. The median follow-up time was 79 months (range=31-96 months). The planning target volume received a dose of 72.6-74.8 Gy in 33-34 fractions (2.2 Gy/fraction). Megavoltage computed tomographic (CT) scans were performed before each treatment and corrected to the registered positions on the planning CT scans using prostate soft-tissue matching. RESULTS: The 5-year biochemical and clinical relapse-free survival rates were 95% for the low-risk group, 92% for the intermediate-risk group, and 77% for the high-risk group. The 5-year incidence rates of grade 2 and 3 late gastrointestinal toxicities were 6.3% and 3.1%, respectively, and those of grade 2 and 3 late genitourinary toxicities were 7.9% and 0%, respectively. Multivariate analysis indicated that T-stage is a prognostic factor for biochemical relapse-free survival rates. CONCLUSION: This report involved the longest followed-up cohort of patients to have received hypofractionated (2.2 Gy) soft tissue-matched IG-IMRT using tomotherapy. The findings of this study indicate that hypofractionated IMRT is well tolerated and is associated with good long-term tumor-control outcomes in patients with localized prostate cancer. Copyright