The purpose of the present study was to evaluate retrospectively the efficacy and safety of proton beam therapy for elderly patients (≥80 years of age) with non-small cell lung cancer. Patients diagnosed with T1–4 N0 M0 non-small cell lung cancer and treated with proton beam therapy between January 2009 and 2015 were recruited from our database retrospectively. Toxicity was evaluated using The Common Terminology Criteria for Adverse Events version 4.0. Thirty-five patients, including 25 (71%) with clinically inoperable lung cancer, were administered proton beam therapy. The median age was 82 years (range: 80–87 years), and the median follow-up time was 34 months (range: 10–72 months). The median dose of proton beam therapy was 80.0 Gy relative biological effectiveness (RBE) (range: 60.0–80.0 Gy [RBE]), and all patients completed the treatments. All patients were followed for at least 23 months or until their death. The 3-year overall survival rate was 67.2% (90.0% in patients with operable lung cancer, and 58.2% in those with inoperable lung cancer). The 3-year local control rate was 86.5%. Two patients presented with grade 2 pneumonitis. The occurrence rate of grade 2 pneumonitis was significantly correlated with a high lung V20 (p = 0.030), and a high mean lung dose (p = 0.030), and a low ratio of lung volume spared from 0.05 Gy (RBE) dose (total lung volume minus lung volume irradiated at least 0.05 Gy [RBE]) (p = 0.030). However, there were no cases of grade 3 or higher radiation pneumonitis. This study suggests that the proton beam therapy was feasible for elderly patients with non-small cell lung cancer and can be considered as one of the treatment choices for elderly patients with lung cancer.

This study aimed to evaluate the therapeutic effect and toxicity of proton beam therapy in combination with intra-arterial infusion chemotherapy in patients with squamous cell carcinoma of the maxillary gingiva. Between December 2010 and March 2016, 30 patients with T4 squamous cell carcinoma of the maxillary gingiva were treated with radiotherapy and retrograde intra-arterial infusion chemotherapy using cisplatin (20–40 mg/m², 4–6 times). Radiotherapy was basically administered using boost proton beam therapy for primary tumor and neck lymph node tumors, following 36–40 Gy photon radiation therapy delivered to the prophylactic area, to a total dose of 70.4–74.8 Gy. The median follow-up was 33 months. The 3-year local control and overall survival rates were 69% and 59%, respectively. Major grade 3 or higher acute toxicities included mucositis, neutropenia, and dermatitis in 12 (40%), 5 (17%), and 3 (10%) patients, respectively. No grade 3 or higher late toxicities were observed. These results suggested that proton beam therapy in combination with intra-arterial infusion chemotherapy was not inferior to other treatment protocols and should be considered as a safe and effective option in patients with T4 squamous cell carcinoma of the maxillary gingiva.

To examine the efficacy and toxicity of particle beam therapy (PT) for biliary duct carcinoma (BDC) and compare the outcomes between extrahepatic BDC (eBDC) and intrahepatic BDC (iBDC). We analyzed multi-institutional data from May 2009 to December 2019. The primary endpoint was overall survival (OS), and the secondary endpoints were local control (LC), progression-free survival (PFS) and toxicity. We included 150 patients with unresectable BDC treated with PT using a median prescribed dose of 70.2 GyRBE (range, 44–77 GyRBE) in 25 fractions (range, 10–38 fractions). With a median follow-up of 13.0 months, median survival time (MST) was 21 months, and 2-year OS was 44.8%. For eBDC and iBDC, the MSTs were 20 and 23 months, respectively. Two-year PFS and LC rates were 20.6% and 66.5%, respectively. Vascular invasion, prescribed dose and serum tumor marker level (carcinoembryonic antigen: CEA) were identified as poor prognostic factors for OS. A higher radiation dose EQD2 ≥ 67 Gy showed superior OS, with a hazard ratio of 0.341. The radiation dose of PT is an important predisposing factor for overall survival. The MST for patients with eBDC given a higher radiation dose was 25 months, compared to 15 months for those given the lower dose and 23 months for patients with iBDC (all iBDC given higher doses). iBDC and eBDC duct carcinomas showed equivalent outcomes with PT, especially when treated with a high radiation dose. In detailed analysis, baseline CEA level in iBDC, and radiation dose and GTV in eBDC were statistically significant predicators for OS. Acute and late toxicity grade ≥3 occurred in 2.2% and 2.7% of patients, respectively, including two late grade-5 toxicities. In conclusion, PT showed good efficacy for BDC, both eBDC and iBDC, with a low incidence of severe toxicity.

Proton beam therapy (PBT) with space-making surgery has been used recently; however, its effectiveness for recurrent esophageal cancer (EC) is unclear. We herein report an unusual case of successful PBT with space-making surgery (omental plombage) for recurrent liver metastasis after EC surgery. A 58-year-old Japanese man underwent proximal gastrectomy for esophagogastric (EG) junction cancer seven months before presentation to our hospital. Microscopic findings after the surgery showed that the tumor was adenocarcinoma of the EG junction (pT1N0M0, stage I). Seven months after the proximal gastrectomy, liver metastases in S6 and S8 were revealed by positron emission tomography-computed tomography. Initial PBT was performed for those two liver metastases, and complete response (CR) was obtained for both liver metastases. Recurrence of liver metastasis in S2 was found eight months after the first PBT, and CR was achieved by chemotherapy. However, new liver metastasis recurred in S2. Considering the effects of radiation exposure on the surrounding gastrointestinal organs, we performed space-making surgery to place the omentum around the liver metastasis. We were able to complete the second PBT for the liver metastasis with 72.6 Gy relative biological effectiveness in 22 fractions. After the second PBT, the patient survived for seven years without recurrence. PBT with space-making surgery (omental plombage) for recurrent liver metastasis after EC surgery is considered to be a therapeutic option.

A 79-year-old man underwent proton beam therapy (PBT) for hepatocellular carcinoma. During follow–up, MRI demonstrated stable T2-weighted hyperintensity in the irradiated region without interval enlargement or mass formation. Five years after PBT, a new hepatocellular carcinoma developed elsewhere in the liver. ¹⁸ F–FDG PET showed no apparent abnormal uptake in the irradiated region, whereas ¹⁸ F-fibroblast activation protein inhibitor–74 PET demonstrated persistent uptake. These findings may reflect chronic radiation–induced fibroinflammatory changes and suggest that fibroblast activation protein inhibitor–PET can visualize such changes even years after PBT.