Examined lymph node count is not associated with prognosis in elderly patients with pN0 thoracic esophageal cancer

The purpose of this study was to determine whether the number of lymph nodes dissected predicts prognosis in surgically treated elderly patients with pN0 thoracic esophageal cancer. We searched the Surveillance, Epidemiology, and End Results database and identified the records of younger (<75 years) and older (≥75 years) patients with pN0 thoracic esophageal cancer between 1998 and 2015. The patient characteristics, tumor data, and postoperative variables were analyzed in this study. The Kaplan-Meier method and a Cox proportional hazard model were used to compare overall and cause-specific survival. Data from 1,792 esophageal cancer patients (older: n = 295; younger: n = 1497) were included. The survival analysis showed that the overall and cause-specific survival in the patients with ≥15 examined lymph nodes (eLNs) was significantly superior to that in the patients with 1 to 14 eLNs (P < .001); however, the difference disappeared in the older patients. After stratification by the tumor location, histology, pT classification, and differentiation between the younger and older cohorts to analyze the association between eLNs and survival, we found that the differences remained significant in most subgroups in the younger cohort. There were no differences in any subgroups of older patients. This study replicated the previously identified finding that long-term survival in patients with extensive lymphadenectomy was significantly superior to that in patients with less extensive lymphadenectomy. However, less extensive lymphadenectomy may be an acceptable treatment modality for elderly patients with pN0 thoracic esophageal cancer.