A nationwide validation of the prognostic impact of pathological response and the distribution of recurrence patterns in responders after neoadjuvant chemotherapy for esophageal squamous cell carcinoma

Background: We previously reported that postoperative recurrence in responders occurred in the regional field mostly as a solitary lesion without distant failure. However, further validation is necessary due to the low percentage of pathological responders, especially those with pCR. This study aimed to validate the prognostic impact of pathological response and the distribution of residual tumors in pathological responders using a nationwide database from 85 Japanese esophageal centers. Methods: We retrospectively reviewed patients with esophageal squamous cell carcinoma (ESCC) who underwent subtotal esophagectomy at 85 authorized institutes for esophageal cancer between 2010 and 2015. The recurrence free survival (RFS), overall survival (OS), and recurrent tumor patterns were compared among the pathological responses. Results: Of 4781 patients initially enrolled, 3840 were selected for subsequent analysis, including 237 patients with pathological complete response (pCR, 6%). The RFS and OS were significantly correlated with pathological response. When the recurrence pattern was classified into regional or distant recurrence, the incidence of distant failure was significantly lower in patients with pCR in cT1/2. Three percent of all patients with pCR in cT1/2 encountered postoperative recurrence in distant organs. Conclusion: The prognostic impact of pathological response was reproduced in the nationwide data. pCR in ESCC patients with cT1/2 provides a favorable prognosis with less incidence of distant failure. This finding may contribute to selecting appropriate candidates for an organ preservation approach based on the response to induction therapy.