Incidence of Regional Recurrence Outside of Radiation Fields in Patients with or without Elective Nodal Irradiation for Stage I Middle Thoracic Esophageal Cancer

Abstract

The appropriate field of elective nodal irradiation (ENI) for middle thoracic (Mt) esophageal cancer is still unclear. To evaluate the efficacy of ENI for stage I Mt esophageal cancer treated with radiotherapy (RT), we researched the incidence of recurrence outside of radiation fields in patients with and without ENI. From April 2006 to December 2014, 55 patients with stage I esophageal cancer mainly located at Mt received definitive RT with or without concurrent chemotherapy in our institution. Of these, 52 patients followed up for more than six months were examined in this study (age, 51-89, median 70; male/female = 46/6; chemoradiotherapy/RT alone = 43/9). Because of the change of institutional policy, ENI became to be performed in principle from 2013. Seventeen patients (33%) received ENI to the mediastinum with or without the supraclavicular region and the upper abdomen. Remaining 35 patients received irradiation only to the range where the margin of 3-4 cm was added above and below the gross tumor volumes. The median follow-up time was 51.8 months (2.5 to 126.5 months). A total of 11 patients (21%) relapsed: 4 (8.0%) developed local, 6 (12%) developed regional and 1 (2.0%) developed loco-regional. The regional recurrence outside of radiation fields occurred in two patients with ENI (12%) and in three patients without ENI (9%) (p=0.71). For patients with ENI, sites of regional recurrences were recurrent nerve lymph nodes (#106rec) in one case and lymph nodes along the lesser curvatures (#3) in one. For patients without ENI, sites of regional recurrences were #106rec in two cases, right cardiac lymph nodes (#2) in one, lymph nodes along the celiac artery in one and left cervical lymph nodes in one. Three-year overall survival rates (OS) and progression free survival rates (PFS) for all patients were 83% and 73%, respectively. Three-year OS for patients with and without ENI were 88% and 80%, respectively (p=0.52). Three-year PFS for patients with and without ENI were 77% and 71%, respectively (p=0.32). Incidence of lymph node recurrence outside of radiation fields did not differ significantly between patient with and without ENI for stage I Mt esophageal cancer. In addition, ENI did not improve OS and PFS significantly.