The value of lymphadenectomy in esophageal cancer after neoadjuvant chemoradiation.

79 Background: There are conflicting reports on the value of the extent of post neoadjuvant chemoradiation (NCRT) lymphadenectomy (LND) in locally advanced esophageal adenocarcinoma (E-ADC) and squamous cell carcinoma (E-SCC). We sought to study the impact of LND variables [positive and total lymph node (LN) number and LN ratio (LNR)] on oncological outcomes in these patients. Methods: The National Cancer Data Base 2004-2014 was queried for patients with NCRT followed by esophagectomy. The median examined LN number was used to divide the patients into a higher (> 12) and lower (≤ 12) LND groups. The primary outcome was overall survival (OS) and secondary outcomes were 30- and 90-day postoperative mortality. Results: A total 4708 patients were included. The median of positive, negative LN, and LNR were and (0, 11, 0%). The median and 5-year OS for higher LND group were higher than the lower LND group (39 vs. 32 months, 38% vs. 34%), p < 0.0001. OS was not significantly different among E-SCC subset or among those who achieved pathological complete response (pCR). The higher LND group had better 30- and 90-day postoperative mortality rates (61/2335 = 2.6%, 141/2308 = 6.1%) than lower LND group (86/2262 = 3.8%, 184/2251 = 8.2%), p = 0.01 and 0.001, respectively . In multivariate Cox regression analysis, higher LND group (HR 0.88, 95% CI 0.81-0.96, p = 0.004) and LNR (per 10% increase: 1.11, 95% CI 1.09-1.13, p < 0.0001) were significant predictor of OS. Conclusions: The LND (> 12 examined LN) remains as a crucial treatment goal after NCRT with potential survival benefit, especially among E-ADC and those did not achieve pCR.