Factors affecting the completion of concurrent chemotherapy and impact of non-completion on survival in locally advanced esophageal squamous cell carcinoma

Background To investigate whether completion of concurrent chemotherapy (CCT) improves overall survival (OS) of patients with locally advanced esophageal squamous cell carcinoma (ESCC), and to identify predictors of non-completion of CCT. Methods Data of ESCC patients treated with definitive concurrent chemoradiotherapy from January 2012 to December 2017 were retrospectively analyzed. CCT completion was defined as receiving recommended cycles with at most 25% dose reduction. Propensity score matching (PSM) analysis was applied to adjust unbalanced covariates between groups. Multivariate logistic regression model was used to identify factors affecting CCT completion. Results Of the 487 patients in the study, 194 patients (39.8%) had completed CCT. The majority (90.7%) had stage III–IV disease. Three-year OS rate was significantly higher in the completion group than non-completion group (35.4% vs. 30.3%; p = 0.025). Multivariate Cox analysis showed CCT completion was independently associated with longer OS ( p = 0.005). The independent risk factors for CCT non-completion were weekly CCT regimen [odds ratio (OR) = 4.35, 95% CI 2.26–8.37; p < 0.001], clinical target volume (CTV)-elective nodal irradiation (ENI) (OR = 3.86, 95% CI 2.41–6.18; p < 0.001), planning target volume (PTV)/50 cm 3 (OR = 1.09, 95% CI 1.02–1.16; p = 0.017), age (OR = 1.04, 95% CI 1.01–1.07, p = 0.011), and tumor in middle/lower esophagus (OR = 1.59, 95% CI 1.05–2.43, p = 0.030). Conclusion CCT completion can provide superior OS for ESCC patients treated with definitive CCRT. Weekly CCT regimen, CTV-ENI, PTV, older age, and tumor location are independent predictors of non-completion of CCT.