The present study indicated that the dose constraints might help minimize brainstem necrosis after carbon-ion radiotherapy.

The safety and efficacy of carbon-ion radiotherapy for advanced non-small cell lung cancer have not been established. We evaluated the clinical outcomes and dose-volume histogram parameters of carbon-ion radiotherapy compared with photon therapy in T2b–4N0M0 non-small cell lung cancer. Twenty-three patients were treated with carbon-ion radiotherapy between May 2011 and December 2015. Seven, 14, and 2 patients had T2b, T3, and T4, respectively. The median age was 78 (range, 53−91) years, with 22 male patients. There were 12 adenocarcinomas, 8 squamous cell carcinomas, 1 non-small cell lung carcinoma, and 2 clinically diagnosed lung cancers. Eleven patients were operable, and 12 patients were inoperable. Most patients (91%) were treated with carbon-ion radiotherapy of 60.0 Gy relative biological effectiveness (RBE) in 4 fractions or 64.0 Gy (RBE) in 16 fractions. Local control and overall survival rates were calculated. Dose-volume histogram parameters of normal lung and tumor coverages were compared between carbon-ion radiotherapy and photon therapies, including three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT). The median follow-up of surviving patients was 25 months. Three patients experienced local recurrence, and the 2-year local control rate was 81%. During follow-up, 5 patients died of lung cancer, and 1 died of intercurrent disease. The 2-year overall survival rate was 70%. Operable patients had a better overall survival rate compared with inoperable patients (100% vs. 43%; P = 0.04). There was no grade ≥2 radiation pneumonitis. In dose-volume histogram analysis, carbon-ion radiotherapy had a significantly lower dose to normal lung and greater tumor coverage compared with photon therapies. Carbon-ion radiotherapy was effectively and safely performed for T2b–4N0M0 non-small cell lung cancer, and the dose distribution was superior compared with those for photon therapies. A Japanese multi-institutional study is ongoing to prospectively evaluate these patients and establish the use of carbon-ion radiotherapy.

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 fourOlfactory neuroblastoma (ONB) of the head and neck is a rare malignant tumour that arises from the olfactory neuroepithelium in the upper nasal cavity with extension into the skull base, into the orbit and to the intracranial space (1, 2). Surgery is considered a curative treatment for localized ONB, while postoperative radiotherapy (RT) is necessary for advanced ONBs. Definitive RT alone is considered insufficient therapy for ONBs (3). In advanced cases, intracranial extension may pose a surgical challenge (4). Surgical resection followed by postoperative RT is associated with reduced local recurrence (5).Although ONB has been traditionally regarded as a radioresistant tumour, RT has widely been used as part of the treatment algorithm in adjuvant and definitive settings.Compared to photons, carbon ions (C-ions) offer a higher linear energy transfer and greater relative biological effectiveness (RBE) and therefore provide a higher probability of tumour control. The physical characteristics of C-ions, such as their Bragg peak and small lateral scattering, are theoretically superior to those of photons in that C-ions can allow a more localized delivery of the radiation dose.This study is the first report for ONBs treated by C-ion RT. C-Ion RT for various head and neck radioresistant malignancies has shown excellent results. Jingu et al. reported clinical results of 37 patients with malignant melanoma of the head and neck who received C-ion RT with concurrent chemotherapy. The 3-year local control (LC) and overall survival (OS) rates were 81.1% and 65.3%, respectively (6). Koto et al. reported 3-year LC and OS rates of 76.9% and 59.1%, respectively, in 22 patients with locally advanced sinonasal adenocarcinoma + reated with C-ion RT (7). Therefore, C-ion RT might be a useful and potentially curative option for unresectable head and neck tumours, including ONBs.In November 2003, following a clinical trial, the Ministry of Health, Labour and Welfare in Japan approved C-ion RT as a highly advanced medical technology. As of the end of 2014, there were four C-ion facilities functioning in Japan

Background and purpose: Little information is available on the risk factors for nasolacrimal duct obstruction after radiotherapy for head and neck tumors. We investigated the incidence and predictive dosimetric parameters for nasolacrimal duct obstruction following carbon-ion radiotherapy for head and neck tumors. Materials and methods: Twenty-eight patients with head and neck non-squamous cell carcinoma were analyzed in this single-institution prospective study. More than half of the tumors were located in the nasal cavity and maxillary sinus. Carbon-ion radiotherapy consisting of 57.6 or 64.0 Gy(relative biological effectiveness; RBE) in 16 fractions was administered. Nasolacrimal duct obstruction was recorded according to Common Terminology Criteria for Adverse Events version 4.0. Cutoff values were determined using receiver operating characteristic (ROC) curve analysis. VX indicates the volume irradiated with X Gy (RBE). Results: The median follow-up period was 60.3 months. Incidences of Grade 1 and 2 nasolacrimal duct obstructions were 46% (13/28) and 7% (2/28), respectively; no Grade 3 or greater toxicities were recorded. Throughout the dose range, the volumes of the irradiated nasolacrimal ducts were significantly higher in the obstruction-positive patients than in the obstruction-negative patients (p < 0.001 for V10, V20, V30, V40, V50, and V60). Cutoff values determined by the ROC curve analysis classified the obstructionpositive patients with an accuracy of >96% over the entire range of V10-V60. Conclusion: The incidence and predictive dosimetric parameters for nasolacrimal duct obstruction after carbon-ion radiotherapy were demonstrated in a prospective cohort. These data should help optimize carbon-ion radiotherapy treatments for patients with head and neck tumors.