Adequate Lymphadenectomy as a Quality Measure in Esophageal Cancer: Is there an Association with Treatment Approach?

BACKGROUND: The national comprehensive cancer network defines adequate lymphadenectomy as evaluation of ≥ 15 lymph nodes in esophageal cancer. However, varying thresholds have been suggested following neoadjuvant therapy. OBJECTIVES: Our objectives were to (1) explore trends in adequate lymphadenectomy rates over time; (2) evaluate unadjusted lymphadenectomy yield by treatment characteristics; and (3) identify independent factors associated with adequate lymphadenectomy. METHODS: The National Cancer Data Base was used to identify patients who underwent esophagectomy for cancer from 2004 to 2015. Adequate lymphadenectomy trends over time were evaluated using the Cochrane-Armitage test, and lymph node yield by treatment approach was compared using the Mann-Whitney U and Kruskal-Wallis tests. Associations with treatment factors were assessed by multivariable logistic regression. RESULTS: Among 24,413 patients, 9919 (40.6%) had adequate lymphadenectomy. Meeting the nodal threshold increased over time (52.6% in 2015 vs. 26.0% in 2004; p < 0.01). Lymph node yield did not differ based on neoadjuvant therapy (median 12 [interquartile range 7-19] with and without neoadjuvant therapy; p = 0.44). Adequate lymphadenectomy was not associated with neoadjuvant therapy (40.5% vs. 40.8%, odds ratio [OR] 0.94, 95% confidence interval [CI] 0.82-1.07), but was associated with surgical approach (52.7% of laparoscopic cases, OR 1.28, 95% CI 1.06-1.56; 61.2% of robotic cases, OR 1.71, 95% CI 1.34-2.19, vs. 43.5% of open cases), and increasing annual esophagectomy volume (55.6% in the fourth quartile vs. 32.6% in the first quartile; OR 3.57, 95% CI 2.35-5.43). CONCLUSIONS: Despite increases over time, only 50% of patients undergo adequate lymphadenectomy during esophageal cancer resection. Adequate lymphadenectomy was not associated with neoadjuvant therapy. Focusing on surgical approach and esophagectomy volume may further improve adequate lymphadenectomy rates.