Abstract
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.
