Distribution of Residual Disease and Recurrence Patterns in Pathological Responders After Neoadjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma

This study aimed to elucidate the residual disease distribution and recurrence patterns in patients with ESCC responding to NAC.To appropriately plan a prospective trial for the organ preservation approach which includes additional chemoradiotherapy in patients who responded to NAC, the distribution of residual disease needs to be elucidated. Given that the residual tumor is located in the regional field, chemoradiotherapy can be safely added to eliminate the residual disease.Overall, 483 patients with resectable ESCC who received NAC followed by transthoracic esophagectomy at 2 high-volume centers were reviewed. The recurrence-free survival, overall survival (OS), and residual and recurrent tumor patterns were compared among the pathological responses.Compared with nonpathological responders, pathological responders exhibited significantly longer recurrence-free survival [hazard ratio of Grade 1b/2/3 compared with Grade 0; 0.25 ( P < 0.001)/0.17 ( P < 0.001)/0.16 ( P = 0.003)] and OS [hazard ratio of Grade 1b/2/3 compared with Grade 0; 0.26 ( P < 0.001)/0.12 ( P < 0.001)/0.11 ( P = 0.003)]. In terms of the distribution of recurrence, the percentages of solitary recurrence in the regional field out of all recurrence was significantly higher in patients with Grade 1b (60%)/2 (67%)/3 (67%) whereas less than 25% in Grade 0 or 1a.It was found that postoperative recurrence in responders occurred in the regional field mostly as a solitary lesion without the distant failure, indicating that the residual tumor cells can be eliminated by additional chemoradiotherapy.