Yuhei Miyasaka1, Noriyuki Okonogi2, Mai Fukahori3, Wataru Furuichi4, Masaru Wakatsuki5, Shingo Kato6, Tatsuya Ohno7, Takashi Nakano8, Hiroshi Tsuji9. 1. QST Hospital, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Japan. 2. QST Hospital, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan. Electronic address: okonogi.noriyuki@qst.go.jp. 3. Department of Nuclear Safety and Security, International Atomic Energy Agency, Vienna International Centre, Vienna, Austria. Electronic address: mai-fukahori@mext.go.jp. 4. Accelerator Engineering Corporation, Chiba, Japan. Electronic address: furuichi.wataru@qst.go.jp. 5. QST Hospital, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan. Electronic address: wakatsuki.masaru@qst.go.jp. 6. Department of Radiation Oncology, Saitama Medical University International Medical Center, Hidaka, Japan. Electronic address: s_kato@saitama-med.ac.jp. 7. Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Japan. Electronic address: tohno@gunma-u.ac.jp. 8. Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan. Electronic address: nakano.takashi2@qst.go.jp. 9. QST Hospital, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan. Electronic address: tsuji.hiroshi@qst.go.jp.
Abstract
BACKGROUND AND PURPOSE: There is growing evidence on the role of carbon-ion radiotherapy (C-ion RT) for gynaecological tumours. Pelvic insufficiency fracture (PIF) decreases the quality of life after photon beam radiotherapy (RT). However, there is little information on PIF after C-ion RT. This study retrospectively assessed incidence of PIF after C-ion RT for uterine carcinomas (UCs) and the associations of clinical and dosimetric parameters with PIF incidence. MATERIAL AND METHODS: We performed a pooled analysis of 102 patients with UCs who underwent definitive C-ion RT alone and were followed up for >6 months without any additional RT in the pelvic region. PIF occurrence was surveyed using magnetic resonance imaging and/or computed tomography. Associations of clinical and dosimetric parameters with PIF incidence were analysed. RESULTS: The 2- and 5-year actuarial incidences of ≥grade 1 PIF in all pelvic regions were 22.3% and 42.4%, respectively. The most frequent site of involvement was the sacrum. Log-rank tests showed that higher volumes receiving >10 Gy (relative biological effectiveness) (V10), V20, V30, and V40, body mass index (BMI) under 18.5, and current smoking were associated with increased incidence of ≥grade 1 PIF in the sacrum. CONCLUSIONS: We clarified the actuarial incidence of PIF after C-ion RT for UCs. Higher V10, V20, V30, V40, D50%, Dmean, current smoking, BMI <18.5, and using the anterior-posterior direction in whole pelvic irradiation were associated with higher incidences of PIF in the sacrum. The present results may lead to further improvement of C-ion RT for UCs.
BACKGROUND AND PURPOSE: There is growing evidence on the role of carbon-ion radiotherapy (C-ion RT) for gynaecological tumours. Pelvic insufficiency fracture (PIF) decreases the quality of life after photon beam radiotherapy (RT). However, there is little information on PIF after C-ion RT. This study retrospectively assessed incidence of PIF after C-ion RT for uterine carcinomas (UCs) and the associations of clinical and dosimetric parameters with PIF incidence. MATERIAL AND METHODS: We performed a pooled analysis of 102 patients with UCs who underwent definitive C-ion RT alone and were followed up for >6 months without any additional RT in the pelvic region. PIF occurrence was surveyed using magnetic resonance imaging and/or computed tomography. Associations of clinical and dosimetric parameters with PIF incidence were analysed. RESULTS: The 2- and 5-year actuarial incidences of ≥grade 1 PIF in all pelvic regions were 22.3% and 42.4%, respectively. The most frequent site of involvement was the sacrum. Log-rank tests showed that higher volumes receiving >10 Gy (relative biological effectiveness) (V10), V20, V30, and V40, body mass index (BMI) under 18.5, and current smoking were associated with increased incidence of ≥grade 1 PIF in the sacrum. CONCLUSIONS: We clarified the actuarial incidence of PIF after C-ion RT for UCs. Higher V10, V20, V30, V40, D50%, Dmean, current smoking, BMI <18.5, and using the anterior-posterior direction in whole pelvic irradiation were associated with higher incidences of PIF in the sacrum. The present results may lead to further improvement of C-ion RT for UCs.