Nationwide multi-institutional retrospective analysis of high-dose-rate brachytherapy combined with external beam radiotherapy for localized prostate cancer: An Asian Prostate HDR-BT Consortium

To report outcomes and risk factors of high-dose-rate (HDR) brachytherapy combined with external beam radiotherapy with or without androgen deprivation therapy (ADT) in prostate cancer patients.

This multi-institutional retrospective analysis comprised 3424 patients with localized prostate cancer at 16 Asian hospitals. One-thirds (27.7%) of patients received only neoadjuvant ADT, whereas almost half (49.5%) of patients received both neoadjuvant and adjuvant ADT. Mean duration of neoadjuvant and adjuvant ADT were 8.6 months and 27.9 months, respectively. Biochemical failure was defined by Phoenix ASTRO consensus. Biochemical control rate, clinical disease-free survival (cDFS), cause-specific survival, and overall survival (OS) were calculated.

Median followup was 66 months. Ten-year biochemical control, cDFS, cause-specific survival, and OS rate were 81.4%, 81.0%, 97.2%, and 85.6%, respectively. Receiving both neoadjuvant and adjuvant ADT was detected as a favorable factor for biochemical control, cDFS, and OS, but pelvic irradiation was detected as an adverse factor for cause-specific survival, and OS. Ten-year cumulative rates of late Grade ≥2 genitourinary and gastrointestinal toxicities were 26.8% and 4.1%, respectively; receiving both neoadjuvant and adjuvant ADT was detected as a favorable factor for preventing both toxicities.

HDR combined with external beam radiotherapy was an effective and safe treatment for localized prostate cancer. Combination of long-term ADT was suggested to be necessary, even for HDR brachytherapy, and was useful in suppressing late toxicities. Meanwhile, pelvic irradiation was suggested to have an adverse effect on OS of our study population.

Brachytherapy. 2017 Feb 17 [Epub ahead of print]

Hiromichi Ishiyama, Nobuhiko Kamitani, Hidemasa Kawamura, Shingo Kato, Manabu Aoki, Shinji Kariya, Taisei Matsumura, Motoki Kaidu, Ken Yoshida, Yaichiro Hashimoto, Yasutaka Noda, Keith H C Lim, Takatsugu Kawase, Takeo Takahashi, Koji Inaba, Motoyasu Kumano, Nobuhiko Yoshikawa, Yasuo Yoshioka, Katsumasa Nakamura, Junichi Hiratsuka, Jun Itami, Kazushige Hayakawa

Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan. Electronic address: ., Department of Radiology, Kawasaki Medical School, Okayama, Japan., Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan., Department of Radiation Oncology, Saitama Medical University International Medical Center, Saitama, Japan., Department of Radiology, The Jikei University School of Medicine, Tokyo, Japan., Department of Diagnostic Radiology and Radiation Oncology, Kochi Medical School, Kochi, Japan., Departments of Radiology, National Hospital Organization, National Kyushu Medical Center, Fukuoka, Japan., Department of Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan., Department of Radiation Oncology, Osaka Medical College, Osaka, Japan., Department of Radiation Oncology, Tokyo Women's Medical University, Tokyo, Japan., Department of Radiation Oncology, Wakayama Medical University, Wakayama, Japan., Department of Radiation Oncology, National University Cancer Institute, Singapore., Department of Radiation Oncology, National Center for Global Health and Medicine, Tokyo, Japan., Department of Radiation Oncology, Saitama Medical Center, Saitama Medical University, Saitama, Japan., Department of Radiation Oncology, National Cancer Center Hospital, Tokyo, Japan., Department of Radiotherapy, Graduate School of Medical Science, Kanazawa University, Ishikawa, Japan., Department of Radiation Oncology, Osaka University School of Medicine, Osaka, Japan., Department of Radiation Oncology, Hamamatsu University School of Medicine, Shizuoka, Japan., Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan.