@article{oai:repo.qst.go.jp:00078221,
 author = {Hagiwara, Yasuhito and Bhattacharyya, Tapesh and Matsufuji, Naruhiro and Isozaki, Yuka and Takiyama, Hirotoshi and Nemoto, Kenji and Tsuji, Hiroshi and Yamada, Shigeru and Yasuhito, Hagiwara and Bhattacharyya, Tapesh and Naruhiro, Matsufuji and Yuka, Isozaki and Hirotoshi, Takiyama and Kenji, Nemoto and Hiroshi, Tsuji and Shigeru, Yamada},
 journal = {Clinical and Translational Radiation Oncology},
 month = {Mar},
 note = {Background and purpose
High linear energy transfer (LET) radiation carbon-ion radiotherapy (C-ion RT) is one of the most promising modalities for treating unresectable primary pancreatic cancers. However, how LET contributes to a therapeutic effect is not clear. To assess whether there is an enhanced effect of high LET radiation on tumour control, we aimed to determine the impact of dose-averaged LET on local control (LC) of primary pancreatic tumours.
Materials and methods
A retrospective analysis of 18 patients with primary pancreatic carcinomas treated with definitive C-ion RT with concurrent chemotherapy in 2013 was conducted. The dose of irradiation was 55.2 Gy (RBE). The relationship between dose-averaged LET and LC of primary tumours was evaluated.
Results
All patients had histologically confirmed adenocarcinoma. The median follow-up duration was 22 months. The actuarial LC and overall survival (OS) at 18 months were 62.5% and 70.1%, respectively. There were no cases of grade ≥3 late toxicities observed. Local recurrences developed in four patients (22%), all of which were infield central recurrences. Although there were no significant differences in gross tumour volume (GTV) dose coverage, patients with higher minimum dose-averaged LET (LETmin) values within the GTV had better LC (dose-averaged LETmin ≥44 keV/microm; 18-months LC 100.0% vs 34.3%; p = 0.0366).
Conclusion
Dose-averaged LETmin within the GTV was significantly associated with LC of primary pancreatic cancers. Our data suggest that outcomes for patients with unresectable primary pancreatic cancers receiving C-ion RT can be improved by modulating the dose-averaged LET within the GTV.},
 pages = {19--24},
 title = {Influence of dose-averaged linear energy transfer on tumor control after carbon-ion radiation therapy for pancreatic cancer},
 volume = {21},
 year = {2020}
}