{Reference Type}: Journal Article {Title}: A Retrospective Multicenter Study of Carbon Ion Radiotherapy for Locally Advanced Olfactory Neuroblastomas. {Author}: Suefuji H;Koto M;Demizu Y;Saitoh JI;Shioyama Y;Tsuji H;Okimoto T;Ohno T;Nemoto K;Nakano T;Kamada T; {Journal}: Anticancer Res {Volume}: 38 {Issue}: 3 {Year}: 03 2018 {Factor}: 2.435 {DOI}: 10.21873/anticanres.12399 {Abstract}: The purpose was to evaluate efficacy and safety of carbon ion radiotherapy (C-ion RT) in patients with locally advanced olfactory neuroblastomas (ONBs). This study was a sub-analysis of the Japan Carbon-Ion Radiation Oncology Study Group Study (1402 HN, UMIN000024473). Clinical data of T4 ONBs treated with C-ion RT at four Institutions between November 2003 and December 2014 were retrospectively reviewed. Twenty-one patients underwent C-ion RT. Seven patients had T4a and 14 had T4b tumours without cervical node metastases. The median follow-up period was 39 (range=5-111) months. The 3-year overall survival and local control rates were 88.4% and 83.0%, respectively. Grade 4 late toxicity was observed in three patients, including ipsilateral optic nerve disorder (n=2) and ipsilateral retinopathy (n=1). C-Ion RT is effective and can be a curative modality for T4 ONBs. Prospective multicenter studies are warranted to confirm these findings.