1. Predicted probabilities of brain injury after carbon ion radiotherapy for head and neck and skull base tumors in long-term survivors
- Author
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Kyoji Furukawa, Sung Chul Park, Daiki Takahashi, Sunao Tokumaru, Tomoaki Okimoto, Kazuki Terashima, Masaki Suga, Shinichi Tanaka, Mikuni Takeda, Yusuke Demizu, Yoshiro Matsuo, Shingo Taniguchi, Itsumi Maehata, and Nor Shazrina Sulaiman
- Subjects
medicine.medical_specialty ,business.industry ,Heavy Ion Radiotherapy ,Radiotherapy Dosage ,Common Terminology Criteria for Adverse Events ,Hematology ,Logistic regression ,Skull Base Neoplasms ,complex mixtures ,Skull ,Regimen ,medicine.anatomical_structure ,Oncology ,Brain Injuries ,Relative biological effectiveness ,Humans ,Medicine ,Carbon Ion Radiotherapy ,Radiology, Nuclear Medicine and imaging ,Survivors ,Significant risk ,Radiology ,Head and neck ,business ,Probability - Abstract
Background and purpose We aimed to determine the risk factors for radiation-induced brain injury (RIBI 1 ) after carbon ion radiotherapy (CIRT) to predict their probabilities in long-term survivors. Materials and methods We evaluated 104 patients with head, neck, and skull base tumors who underwent CIRT in a regimen of 32 fractions and were followed up for at least 24 months. RIBI was assessed using the Common Terminology Criteria for Adverse Events. Results The median follow-up period was 45.5 months; 19 (18.3 %) patients developed grade ≥2 RIBI. The maximal absolute dose covering 5 mL of the brain (D5ml) was the only significant risk factor for grade ≥2 RIBI in the multivariate logistic regression analysis (p = 0.001). The tolerance doses of D5ml for the 5% and 50% probabilities of developing grade ≥2 RIBI were estimated to be 55.4 Gy (relative biological effectiveness [RBE]) and 68.4 Gy (RBE) by a logistic model, respectively. Conclusion D5ml was most significantly associated with grade ≥2 RIBI and may enable the prediction of its probability.
- Published
- 2021