title: Long-term outcomes after carbon-ion radiotherapy for oral mucosal malignant melanoma.
abstract: Oral mucosal malignant melanoma (OMM) is extremely rare and has a poor prognosis. Owing to its rarity, it has not yet been possible to establish an optimal treatment modality. The objective of this study was to evaluate the long-term efficacy of carbon-ion radiotherapy (C-ion RT) for OMM. Between 1997 and 2013, 19 patients with OMM were treated with C-ion RT alone. Patient ages ranged from 44 to 84 years (median, 69 years). Nine men and 10 women were included. OMMs were restaged in accordance with the seventh edition of the tumour/node/metastasis (TNM) Staging System of the International Union Against Cancer. Before treatment, 14 patients had T3 disease and 5 had T4a disease. Three patients were classified as having N1 disease. All patients were classified as having M0. The hard palate was the most frequently involved oral subsite. All patients were treated with 57.6 Gy (relative biological effectiveness) in 16 fractions. The median follow-up period was 61 months (range, 8-190 months). The 5-year local control, overall survival and progression-free survival rates were 89.5%, 57.4% and 51.6%, respectively. For local control and overall survival, T classification was found to be a significant prognostic factor. Grade 2 and 3 osteoradionecrosis was observed in three and four patients, respectively. The presence of teeth within the planning target volume was a significant risk factor for developing osteoradionecrosis. C-ion RT was an effective treatment option with acceptable toxicity for OMM.
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.|Department of Oral and Maxillofacial Surgery, Aichi Gakuin University, School of Dentistry, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi 464-8651, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Naganawa
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Koto
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takagi
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Hasegawa
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ikawa
authors.affiliation: Department of Oral and Maxillofacial Surgery, Aichi Gakuin University, School of Dentistry, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi 464-8651, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shimozato
authors.affiliation: National Institute of Radiological Sciences Hospital, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kamada
authors.affiliation: Department of Otolaryngology, Chiba University Graduate School of Medicine, 1-8-1 Inohara, Chuo-ku, Chiba 260-8677, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Okamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D063193:Heavy Ion Radiotherapy; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology / Q000532:radiotherapy*; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology* / Q000528:radiation effects; D009062:Mouth Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors; D016896:Treatment Outcome
keywords: carbon-ion radiotherapy; charged particle therapy; mucosal malignant melanoma; oral melanoma; radiotherapy