Adenoid cystic carcinoma (ACC) is a very rare epithelial tumor of the salivary glands. Surgical resection is considered to be a standard therapy. However, the optimal treatment strategy for managing advanced cases has not yet been established. This study evaluated the efficacy and toxicity of proton beam therapy (PBT) combined with selective intra-arterial infusion chemotherapy (IAIC) using weekly cisplatin for locally advanced ACC of the base of the tongue. Between March 2009 and February 2018, 15 patients were treated. The median follow-up duration was 56 (range: 15–116) months. The 5-year local control and overall survival rates were 89% and 76%, respectively. With regard to late toxicities, grade 2 osteoradionecrosis was found in one patient and grade 5 pharyngeal necrosis was observed in one patient. Considering most cases were significantly advanced and inoperable, this therapy was effective in controlling the primary tumor, preserving function and maintaining the quality of life. Although improvements are needed to reduce adverse events, PBT in combination with IAIC can be a treatment option for locally advanced ACC of the base of the tongue.

Objective The purpose of this cross-sectional study was to evaluate the efficacy and safety of proton beam therapy for liver metastatic recurrence in gastric cancer patients. Methods Consecutive patients who underwent proton beam therapy from 2010 to 2015 were isolated from our institutional database. Patients with extrahepatic metastatic lesions were excluded. Seven patients were enrolled. The median diameter of target lesions was 31 mm (13–68 mm). The most frequent dosage was 72.6 Gy equivalent in 22 fractions. The effectiveness was assessed based on the local control, overall survival and progression-free survival rates. The local control, overall survival and progression-free survival rates were calculated using the Kaplan–Meier method. Adverse events were described according to the patients’ medical records. Results The median follow-up period was 41.7 months (20.7–66.3 months). The 3-year local control, overall survival and progression-free survival rates were 85.7, 68.6 and 43%, respectively. All patients completed proton beam therapy without interruption. No grade ≥3 adverse events were observed. Conclusions Proton beam therapy might be a treatment option for patients with liver metastasis of gastric cancer.

Ameloblastic carcinoma (AC) is a very rare malignant odontogenic tumor. Although surgical resection is generally performed, treatment approaches have not been established for recurrent cases. Chemotherapy and radiotherapy are positioned as adjunctive therapies, and few studies investigated definitive non-operative therapy. We present the case of a 71-year-old male with recurrent secondary-type AC arising from the right maxilla, who was treated with proton beam therapy (PBT; 71.4 Gy relative biological effectiveness in 32 fractions) combined with continuous intra-arterial infusion of cisplatin (40 mg/m2) and docetaxel (8 mg/m2). The patient experienced acute grade 3 mucositis, dermatitis and neutropenia, which were resolved within 3 months of treatment. Late adverse events were grade 1 skin atrophy, and grade 2 right optic nerve disorder and retinopathy. After ~8 years of treatment, the patient died from another cause but did not experience any relapse or metastasis during the follow-up period of 94 months. To the best of our knowledge, this is the first report of recurrent AC treated with PBT and intra-arterial infusion chemotherapy without any severe late adverse events. This combination therapy approach may be considered as an effective therapeutic option for inoperable AC.