Advantageous factors of R0 curative conversion esophagectomy and the optimal extent of lymphadenectomy after induction therapy for cT4b thoracic esophageal cancer.

Aim: This study aimed to clarify the prognostic factors, the advantageous factors of R0 curative resection, and optimal extents of lymph node dissection for conversion esophagectomy after induction therapy. Methods: Among 1903 patients with esophageal cancer at Toranomon Hospital between January 2006 to May 2020, 151 patients with locally advanced T4b thoracic esophageal cancer were divided into two groups according to treatment: conversion surgery group (n = 54) and non‐surgical treatment group (n = 97) for comparison. Results: The patients who underwent R0 curative resection showed preferable survival comparable to the survival rate of patients with cCR in the non‐surgical treatment group (1‐, 3‐ and 5‐year survival: 96.9%, 82.1% and 76.7% vs 94.1%, 86.3%, and 86.3%; P = 0.770). Multivariate analysis revealed that the T4b tumor invasion by primary site (odds ratio (OR) = 6.100; 95% CI, 1.439‐25.865: P = 0.014) and time to conversion surgery from start of induction therapy within four months (OR = 5.229; 95% CI, 1.296‐21.102: P = 0.020) were all independent advantageous factors of R0 curative resection. Actuarial 1‐, 3‐ and 5‐year survival rates in patients who underwent conversion surgery with D2‐3 lymphadenectomy were 90.9%, 48.6%, and 40.8%, respectively. Conclusions: R0 resection led to improved prognosis in conversion esophagectomy for cT4b esophageal cancer. The T4b tumor invasion by primary site and time to conversion surgery from start of induction therapy within 4 months were independent advantageous factors of R0 curative resection. In addition, standard radical esophagectomy including prophylactic D2‐/3‐ lymphadenectomy should be performed if it is possible, while taking adequate care regarding the increased risk after induction therapy. [ABSTRACT FROM AUTHOR]