Prognostic Impact of Thoracic Duct Resection in Patients Who Underwent Transthoracic Esophagectomy Following Neoadjuvant Therapy for Esophageal Squamous Cell Carcinoma: Exploratory Analysis of JCOG1109.

Background: Although several studies have investigated whether thoracic duct (TD) resection improves prognosis, the conclusion remains controversial. JCOG1109 is a three-arm randomized phase III trial to confirm the survival advantage of docetaxel, cisplatin, 5-fluorouracil (DCF), and cisplatin plus 5-fluorouracil (CF) combined with radiotherapy (CF-RT) over CF as neoadjuvant treatment. The study aimed to evaluate the survival impact of TD resection and its association with neoadjuvant treatment and pathological response in patients enrolled in JCOG1109.

Patients And Methods: Clinicopathological factors, surgical results, and prognosis were compared between TD preserved and resected groups. The survival impact of TD resection was also evaluated in the subgroups on the basis of combinations of preoperative therapy and pathological response.

Results: Between December 2012 and July 2018, 601 patients were randomized (CF/DCF/CF-RT; 199/202/200) in JCOG1109. Of them, 541 patients underwent esophagectomy (183/181/177), and TD was resected in 265 patients (93/91/81). For the entire cohort, TD resection was not a significant prognostic factor for overall survival in the multivariable analysis (HR 1.20, 95% CI 0.91-1.57). In the subgroup analyses by combinations of neoadjuvant treatment and pathological response, TD resected group had a significantly better overall survival compared with TD preserved group in patients who received DCF and achieved pathological response (HR 0.20, 95% CI 0.07-0.61).

Conclusions: The survival benefit of TD resection was not demonstrated in patients with surgically resectable esophageal squamous cell carcinoma enrolled in JCOG1109. The residual tumor burden after neoadjuvant treatment might be linked to the survival impact of TD resection.