Maintenance chemotherapy for esophageal squamous cell carcinoma after standard concurrent chemoradiotherapy: a national propensity score matching cohort study

Esophageal squamous cell carcinoma (ESCC) is a common and aggressive cancer, and its standard treatment is concurrent chemoradiotherapy (CCRT). Maintenance chemotherapy is often used to help prevent cancer recurrence, but its efficacy for patients with ESCC receiving CCRT remains unclear. We conducted a large head-to-head propensity score matching cohort study to estimate the effects of maintenance chemotherapy on overall survival and cancer-specific survival in patients with ESCC receiving standard CCRT. After propensity score matching (PSM), we recruited 2724 patients with ESCC (2177 in the maintenance chemotherapy group and 547 in the non-maintenance chemotherapy group). The adjusted hazard ratios (95% confidence intervals) of all-cause mortality and cancer-specific mortality for the maintenance chemotherapy group were 1.15 (1.06-1.26, P = 0.0014) and 1.08 (0.88-1.29, P = 0.1320), respectively, compared with the non-maintenance chemotherapy group. We also found that older age, relatively lower body mass index (BMI), higher American Joint Committee on Cancer clinical stage, and poor response to CCRT as measured using the Response Evaluation Criteria in Solid Tumors were poor independent predictors of all-cause mortality and cancer-specific mortality. Our findings indicated that maintenance chemotherapy may not improve the survival of patients with ESCC who have received CCRT. Additionally, we identified several key prognostic factors for patients with ESCC receiving CCRT, including relatively low BMI and poor response to CCRT. Further research is needed to understand the benefits and risks of maintenance chemotherapy in similar patient populations in order to identify new therapies that could improve treatment responses.