Survival benefits of adjuvant chemotherapy for patients with residual pathological disease after neoadjuvant chemotherapy and surgery for locally advanced esophageal squamous cell carcinoma

Background and purpose Although preoperative neoadjuvant chemotherapy (NACT) or chemoradiation is the current standard of care for esophageal cancer in China, the impact of subsequent adjuvant therapy on patient prognosis remains unknown. This study aims to analyze the effect of adjuvant chemotherapy (ACT) on the survival rates of patients who have achieved a non-pathological complete response (non-pCR) after NACT and subsequent surgery. Methods We reviewed the data of 2193 patients with locally advanced thoracic esophageal squamous cell carcinoma (ESCC) who underwent radical surgery between January 2006 and January 2016. Of these patients, 46 received NACT and ACT, while 109 received NACT only. Propensity score matching was used to compare 86 patients, with 43 patients in the NACT+ACT group and 43 patients in the NACT group.Univariate analysis was performed using the Kaplan-Meier method and Log-rank test, while Cox regression analysis was used for multivariate analysis. Results Multivariate analysis revealed that pathological lymph node status (positive vs. negative) (P<0.001) and treatment modalities (NACT+ACT vs. NACT) (P=0.005) were independent prognostic factors. There was a significant difference in long-term survival rates between the NACT+ACT and NACT groups, with 5-year survival rates of 55.8% vs. 39.5%, respectively (c2=4.270, P=0.039). In patients with ypN+ status, the 5-year survival rate was 31.8% for those who received ACT after NACT and surgery, compared to 10.0% for those who did not receive additional ACT (c2=6.101, P=0.014). The corresponding percentages in patients with ypN- were 81.0% and 65.2%, respectively (c2=1.993, P=0.158). Conclusion Adjuvant chemotherapy should be recommended for locally advanced ESCC patients with residual cancer after NACT and surgery, especially for patients with nodal metastases after NACT.