Extent of Lymphadenectomy and Prognosis After Esophageal Cancer Surgery.

IMPORTANCE: The prognostic role of the extent of lymphadenectomy during surgery for esophageal cancer is uncertain and requires clarification.

OBJECTIVE: To clarify whether the number of removed lymph nodes influences mortality following surgery for esophageal cancer.

DESIGN, SETTING, AND PARTICIPANTS: Conducted from January 1, 2000, to January 31, 2014, this was a cohort study of patients who underwent esophagectomy for cancer in 2000-2012 at a high-volume hospital for esophageal cancer surgery, with follow-up until 2014.

EXPOSURES: The main exposure was the number of resected lymph nodes. Secondary exposures were the number of metastatic lymph nodes and positive to negative lymph node ratio.

MAIN OUTCOMES AND MEASURES: The independent role of the extent of lymphadenectomy in relation to all-cause and disease-specific 5-year mortality was analyzed using Cox proportional hazard regression models, providing hazard ratios (HRs) with 95% CIs. The HRs were adjusted for age, pathological T category, tumor differentiation, margin status, calendar period of surgery, and response to preoperative chemotherapy.

RESULTS: Among 606 included patients, 506 (83.5%) had adenocarcinoma of the esophagus, 323 (53%) died within 5 years of surgery, and 235 (39%) died of tumor recurrence. The extent of lymphadenectomy was not statistically significantly associated with all-cause or disease-specific mortality, independent of the categorization of lymphadenectomy or stratification for T category, calendar period, or chemotherapy. Patients in the fourth quartile of the number of removed nodes (21-52 nodes) did not demonstrate a statistically significant reduction in all-cause 5-year mortality compared with those in the lowest quartile (0-10 nodes) (HR, 0.86; 95% CI, 0.63-1.17), particularly not in the most recent calendar period (HR, 0.98; 95% CI, 0.57-1.66 for years 2007-2012). A greater number of metastatic nodes and a higher positive to negative node ratio was associated with increased mortality rates, and these associations showed dose-response associations.

CONCLUSIONS AND RELEVANCE: This study indicated that the extent of lymphadenectomy during surgery for esophageal cancer might not influence 5-year all-cause or disease-specific survival. These results challenge current clinical guidelines.