Determining acceptable duration for chemoradiation of esophageal squamous cell carcinoma

BACKGROUND: Chemoradiotherapy (CRT) remains the standard practice for patients with non-surgical esophageal squamous cell carcinoma (ESCC). However, the impact of radiation duration is poorly understood. We aimed to determine the effect of CRT duration on the prognosis of patients with ESCC. METHODS: We retrospectively analyzed patients with ESCC treated with CRT at the Ditmanson Medical Foundation Chia-Yi Christian Hospital between January 1, 2010 and December 31, 2021. Patients were either treated with continuous CRT or protracted CRT, which was interrupted due to reassessment of disease status. Differences in survival according to the treatment strategy were examined using propensity score matching (PSM). The risk factors for survival and recurrence were analyzed using Cox regression models. RESULTS: A total of 238 patients who underwent CRT were included in our cohort. After 2:1 PSM, the continuous and protracted CRT groups comprised 41 and 82 patients, respectively. Median survival was 12.2 [interquartile range (IQR), 10.0-19.1] months for the protracted CRT group and 11.4 (IQR, 9.9-17.1) months for the continuous CRT group (p=0.395). The multivariable analysis revealed that duration of radiation > 90 days was an independent risk factor for survival [adjusted hazard ratio (HR), 2.14; 95% confidence interval (CI), 1.23-3.70, p=0.006] and progression-free survival (adjusted HR, 1.74; 95% CI, 1.08-2.80, p=0.022). In addition, a neutrophil-to-lymphocyte ratio > 3 was associated with poor prognosis (adjusted HR, 1.83; 95% CI, 1.09-3.05, p=0.02). CONCLUSION: This study demonstrated that continuous CRT and protracted CRT resulted in similar prognoses; however, a radiotherapy duration exceeding 90 days was associated with inferior survival. These findings have implications for treatment planning in patients with ESCC.