Abstract
Carbon ion radiotherapy （C-ion RT） is a high linear energy transfer radiation, and is associated with higher probability of tumor control compared with photon RT.
Additionally, the physical characteristics of C-ions offer the theoretical benefit of a more localized delivery of the radiation dose than that of photons.
Here, we report the safety and efficacy of C-ion RT for oral malignancies in the single-institutional study and multicenter study.
A single-institutional study was conducted on 77 patients of oral malignancies treated with C-ion RT at the National Institute of Radiological Science between April 1997 and March 2016. Forty-three patients had salivary gland carcinomas, 29 patients had mucosal melanoma, and 5 patients had other carcinomas. The median follow-up was 48 months. The 5-year local control, progression free survival, and overall survival rates of all patients were 79.4％, 34.6％, and 57.4％, respectively. Although 11 patients developed grade 3 osteoradionecrosis after the C-ion RT, all patients maintained their mastication and deglutition functions after sequestrectomy and prosthesis.
A multicenter study was conducted on 83 patients of oral malignancies treated with C-ion RT at the 4 institutions in Japan between November 2003 and December 2014.
Forty-six patients had salivary gland carcinoma; 27 had mucosal malignant melanoma, and 10 had other carcinomas. Median follow-up was 30 months. The 3-year local control, progression free survival, and overall survival were 81.0％, 59.8％ and 73.3％, respectively. Grade 3 or higher late morbidities were observed in 18.
It appears that C-ion RT provides therapeutic effectiveness with acceptable toxicities for oral malignancies, which were mainly salivary gland carcinoma and mucosal melanoma.
