Dose-volume histogram analysis of brainstem necrosis in head and neck tumors treated using carbon-ion radiotherapy

作者：Shirai Katsuyuki^*; Fukata Kyohei; Adachi Akiko; Saitoh Jun ichi; Musha Atsushi; Abe Takanori; Kanai Tatsuaki; Kobayashi Daijiro; Shigeta Yuka; Yokoo Satoshi; Chikamatsu Kazuaki; Ohno Tatsuya; Nakano Takashi

来源：Radiotherapy and Oncology, 2017, 125(1): 36-40.

DOI：10.1016/j.radonc.2017.08.014

• Brainstem necrosis
• Carbon-ion radiotherapy
• Head and neck tumors
• Non-squamous cell carcinoma
• Dose-volume histogram

Background and purpose: We aimed to evaluate the relationship between brainstem necrosis and dose volume histograms in patients with head and neck tumors after carbon-ion radiotherapy.
Material and methods: We evaluated 85 patients with head and neck tumors who underwent carbon-ion radiotherapy and were followed-up for >= 12 months. Brainstem necrosis was evaluated using the Common Terminology Criteria for Adverse Events (version 4.0).
Results: The median follow-up was 24 months, and four patients developed grade 1 brainstem necrosis, with 2-year and 3-year cumulative rates of 2.8% and 6.5%, respectively. Receiver operating characteristic curve analysis revealed the following significant cut-off values: a maximum brainstem dose of 48 Gy (relative biological effectiveness [RBE]), D1 cm(3) of 27 Gy (RBE), V40 Gy (RBE) of 0.1 cm(3), V30 Gy (RBE) of 0.7 cm(3), and V20 Gy (RBE) of 1.4 cm(3). Multivariate analysis revealed that V30 Gy (RBE) was most significantly associated with brainstem necrosis. The 2-year cumulative rates were 33% and 0% for V30 Gy (RBE) of >= 0.7 cm(3) and <0.7 cm(3), respectively (p < 0.001).
Conclusions: The present study indicated that the dose constraints might help minimize brainstem necrosis after carbon-ion radiotherapy.

• 出版日期2017-10