Current status of radiotherapy for patients with thoracic esophageal cancer in Japan, based on the Comprehensive Registry of Esophageal Cancer in Japan from 2009 to 2011 by the Japan Esophageal Society.

Abstract

Although esophagectomy is the standard treatment for resectable esophageal cancer, chemoradiotherapy or radiotherapy alone is also selected for some cases. However, there have been very few detailed studies conducted on a large scale on the efficacy of these treatments in Japan. Of the patients enrolled in the Comprehensive Registry of Esophageal Cancer in Japan by the Japan Esophageal Society for the 2015-2017 surveys (patients treated between 2009 and 2011), the data of 388 patients treated by definitive radiotherapy alone (RTx) and 1964 patients treated by definitive chemoradiotherapy (CRTx) were analyzed. The median age of the patients was 78years in the RTx group and 69years in the CRTx group; thus, the proportion of elderly patients was significantly higher in the RTx group than in the CRTx group (p < 0.0001). With regard to the rates of treatment by the two modalities according to the depth of invasion, extent of lymph node metastasis, and disease stage, the treatment rate by CRTx increased more significantly than that by RTx as the disease progressed (p < 0.0001). With regard to the distribution of the total irradiation dose, 11.4% and 2.3% of patients in the RTx and CRTx groups, respectively, received a dose of 67Gy or more; thus, the RTx group received significantly higher total irradiation doses (p < 0.0001). In the RTx group, the 5-year overall survival rate was 23.2%, and the rates in patients with cStage 0-I, II, III, and IV disease were 41.8%,18.5%, 9.3%, and 13.9%, respectively. In the patients of the RTx group showing complete response (CR), the 5-year overall survival rate was 46.6% and the rates in patients with cStage 0-I, II, III, and IV disease were 54.8%, 39.6%, 32.4%, and 38.9%, respectively. In the CRTx group, the 5-year overall survival rate was 30.6% and the rates in patients with cStage 0-I, II, III, and IV disease were 57.8%, 47.8%, 23.4%, and 13.0%, respectively. In the patients of the CRTx group showing CR, the 5-year overall survival rate was 59.2% and the rates in patients with cStage 0-I, II, III, and IV disease were 67.9%, 59.5%, 56.5%, and 39.6%, respectively. This study revealed the current status of treatment of esophageal cancer in Japan, and we think that we have been able to establish the grounds for explaining to patients with esophageal cancer and their families the treatment decisions made for them in daily clinical practice.