Masaru Takagi1, Yusuke Demizu2, Osamu Fujii3, Kazuki Terashima4, Yasue Niwa5, Takashi Daimon6, Sunao Tokumaru4, Nobukazu Fuwa7, Masato Hareyama8, Tomoaki Okimoto4. 1. Proton Therapy Center, Sapporo Teishinkai Hospital, Sapporo, Hokkaido, Japan; Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan. Electronic address: mtakagidear@gmail.com. 2. Department of Radiation Oncology, Hyogo Ion Beam Medical Center Kobe Proton Center, Kobe, Hyogo, Japan; Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan. 3. Department of Radiation Oncology, Hakodate Goryoukaku Hospital, Hakodate, Hokkaido, Japan. 4. Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan. 5. Department of Radiation Oncology, Tsuyama Chuo Hospital, Tsuyama, Okayama, Japan. 6. Department of Biostatistics, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan. 7. Department of Radiation Oncology, Ise Red Cross Hospital, Ise, Mie, Japan. 8. Proton Therapy Center, Sapporo Teishinkai Hospital, Sapporo, Hokkaido, Japan.
Abstract
PURPOSE: Although proton therapy is controversial, it has been used to treat localized prostate cancer over the past 2 decades. The purpose of this study is to examine the long-term efficacy and toxicity of proton therapy for localized prostate cancer. METHODS AND MATERIALS: This was a retrospective observational study of 2021 patients from 2003 to 2014 at a single institution. Patients were classified using the risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019. Ninety-eight percent of the patients received 74 Gy (relative biological effectiveness) in 37 fractions. Fifty-one and 6% of the patients received neoadjuvant and adjuvant androgen deprivation therapy, respectively. The outcomes were the time of freedom from biochemical relapse and the time to late toxicity by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. The outcomes were estimated using the Kaplan-Meier method and were analyzed using multivariable Cox proportional hazards models. RESULTS: The median follow-up period was 84 months (interquartile range, 60-110). The 5- and 10-year freedom from biochemical relapse rates were 100% and 100%, 99% and 88%, 93% and 86%, 90% and 79%, 88% and 68%, and 76% and 63% for the very low, low, favorable intermediate, unfavorable intermediate, high, and very high-risk groups, respectively. Patients with higher risk experienced biochemical relapse after shorter periods. The 5-year rates of grade 2 or higher late genitourinary and gastrointestinal toxicity were 2.2% and 4.0%, respectively. The results of multivariable analyses indicate that younger patients more often experienced biochemical relapse. CONCLUSIONS: This study demonstrates the favorable biochemical controls of proton therapy even in advanced localized prostate cancer patients with a low incidence of late toxicities, supporting the feasibility of conducting prospective clinical trials. The risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019, are useful to classify patients with localized prostate cancer. Our findings might suggest the necessity to develop a treatment strategy that accounts for the patient's age.
PURPOSE: Although proton therapy is controversial, it has been used to treat localized prostate cancer over the past 2 decades. The purpose of this study is to examine the long-term efficacy and toxicity of proton therapy for localized prostate cancer. METHODS AND MATERIALS: This was a retrospective observational study of 2021 patients from 2003 to 2014 at a single institution. Patients were classified using the risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019. Ninety-eight percent of the patients received 74 Gy (relative biological effectiveness) in 37 fractions. Fifty-one and 6% of the patients received neoadjuvant and adjuvant androgen deprivation therapy, respectively. The outcomes were the time of freedom from biochemical relapse and the time to late toxicity by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. The outcomes were estimated using the Kaplan-Meier method and were analyzed using multivariable Cox proportional hazards models. RESULTS: The median follow-up period was 84 months (interquartile range, 60-110). The 5- and 10-year freedom from biochemical relapse rates were 100% and 100%, 99% and 88%, 93% and 86%, 90% and 79%, 88% and 68%, and 76% and 63% for the very low, low, favorable intermediate, unfavorable intermediate, high, and very high-risk groups, respectively. Patients with higher risk experienced biochemical relapse after shorter periods. The 5-year rates of grade 2 or higher late genitourinary and gastrointestinal toxicity were 2.2% and 4.0%, respectively. The results of multivariable analyses indicate that younger patients more often experienced biochemical relapse. CONCLUSIONS: This study demonstrates the favorable biochemical controls of proton therapy even in advanced localized prostate cancerpatients with a low incidence of late toxicities, supporting the feasibility of conducting prospective clinical trials. The risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019, are useful to classify patients with localized prostate cancer. Our findings might suggest the necessity to develop a treatment strategy that accounts for the patient's age.
Authors: William M Mendenhall; Eric D Brooks; Stephanie Smith; Christopher G Morris; Curtis B Bryant; Randal H Henderson; Romaine C Nichols; Kathy McIntyre; Stuart L Klein; Nancy P Mendenhall Journal: Int J Part Ther Date: 2021-07-27
Authors: Alicia Bao; Andrew R Barsky; Russell Maxwell; Justin E Bekelman; Stefan Both; John P Christodouleas; Curtiland Deville; Penny Fang; Zelig A Tochner; Neha Vapiwala Journal: Int J Part Ther Date: 2021-10-20