Clinical results of proton beam therapy for twenty older patients with esophageal cancer
In an aging society, increasing number of older patients are diagnosed with esophageal cancer. The purpose of this study was to assess the clinical efficacy and safety of proton beam therapy for older patients with esophageal cancer. Older patients (age:≧65 years) newly diagnosed with esophageal cancer between January 2009 and June 2013 were enrolled in this study. All patients underwent either proton beam therapy alone or proton beam therapy and X-ray irradiation. Toxicities were evaluated using Common Terminology Criteria for Adverse Events version 4.0. Twenty older patients were eligible for this study and all completed the treatment. The median age was 78 years (range: 65-89 years) and median follow-up time was 26.5 months (rage: 6-62 months). Seven patients had lymph node metastases and 10 had stage Ⅱ/Ⅲ cancer. The median dose of proton beam therapy was 72.6 Gy relative biological dose effectiveness (RBE) (range: 66.0-74.8 Gy [RBE]) for proton beam therapy alone and 33.0 Gy (RBE) (range: 30.8-39.6 Gy [RBE]; total dose range: 66.8-75.6 Gy [RBE]) for proton beam therapy with initial X-ray irradiation. The 2-year overall survival rate was 81.8% (95% confidence interval [CI]: 62.4-100%), and the 2-year local control rate was 89.4% (95%CI: 75.5-100%). Grade 2 or 3 toxicities occurred in some cases; however, no grade 4 or 5 toxicity was observed. High-dose (66.0-75.6 Gy [RBE]) proton beam therapy without chemotherapy is an efficacious and safe treatment for older patients with esophageal cancer.