Long-term Results of Definitive Chemoradiotherapy with Elective Nodal Irradiation Using Modern Radiotherapy Technique for Resectable Locally Advanced Esophageal Cancer

Although definitive chemoradiotherapy (CRT) is widely used as an organ preservation strategy for esophageal cancer, utility of elective nodal irradiation (ENI) is still controversial. ENI is tradeoff between regional control and toxicities especially late cardiopulmonary toxicities. In most of previous reports about late toxicities, classical radiotherapy methods such as 2D-RT or opposing portal irradiation are used. The aim of this study is to investigate the efficacy and toxicity of definitive CRT with ENI by modern radiotherapy technique for resectable locally advanced esophageal cancer. We retrospectively reviewed 54 resectable locally advanced esophageal cancer patients treated by concurrent CRT at one institution between 2006 and 2015. Among the stage IV cases, patients with supraclavicular lymph node metastasis were included. There were 45 males and 9 females, and the median age was 70 (range: 52-83). All patients had squamous cell carcinoma. Clinical stages IB/II/III/IV were 10/16/18/10 patients (UICC7th). Fourteen patients were judged medically inoperable by surgeons and 40 patients refused esophagectomy. ENI was administered in all patients. Median total dose was 66 Gy/ 33 fractions (range: 50.4-66 Gy). All patients received platinum and 5FU-based chemotherapy. The Kaplan–Meier method was used to generate actual survival curves. Median follow-up time was 59 months (range: 7-151) for survivors. The 5-year progression free survival and overall survival (OS) rates were 42% and 57%, respectively. The 5-years OS was 72 % in Stage IB-II patients and 44 % in Stage III-IV patients. Among the 24 failures, only one patient suffered subsequent lymph node recurrence within ENI field and 4 of 6 patients with metachronous esophageal cancer salvaged by endoscopic resection. Acute toxicities ≥grade 3 were observed in 40 patients and most common ≥grade 3 acute toxicity was leucopenia. Grade 5 acute toxicities were not observed. Late toxicities ≥ grade 3 were observed in 7 patients (hypothyroidism in 1, radiation pneumonitis in 1, pleural effusion in 4, pericardial effusion in 3, and heart failure in 2 patients) and two patients with heart failure were grade 5. Both of grade 5 patients had heart disease history and one of them was judged medically inoperable. Definitive CRT with ENI for resectable locally advanced esophageal cancer showed favorable treatment results. Our results suggest that ENI by modern radiotherapy technique contribute to reduce subsequent regional node recurrence with acceptable late cardiopulmonary toxicities.