Outcomes of Definitive Chemoradiotherapy for Stage IVa (T4b vs. N4) Esophageal Squamous Cell Carcinoma Based on the Japanese Classification System: A Retrospective Single-Center Study

SIMPLE SUMMARY: Definitive chemoradiotherapy is a standard treatment for stage IVa esophageal cancer, although it is unclear whether T/N factors affect treatment outcomes and whether we should modify chemoradiotherapy regimens based on T/N factors. This single-center retrospective study aimed to determine whether T/N factors affected progression patterns and overall survival after chemoradiotherapy for stage IVa esophageal squamous cell carcinoma. There were no significant differences between the T/N groups in terms of overall survival, progression-free survival, or progression patterns. Therefore, it may not be useful to modify chemoradiotherapy regimens based on T/N factors for patients with stage IVa squamous cell carcinoma. ABSTRACT: The differences in prognoses or progression patterns between T4b non-N4 and non-T4b N4 esophageal squamous cell carcinoma post chemoradiotherapy (CRT) is unclear. This study compared the outcomes of CRT for stage IVa esophageal squamous cell carcinoma according to T/N factors. We retrospectively identified 66 patients with stage IVa esophageal squamous cell carcinoma who underwent definitive CRT at our center between January 2009 and March 2013. The treatment outcomes, i.e., progression patterns, prognostic factors, and toxicities based on version 5.0 of the National Cancer Institute Common Terminology Criteria for Adverse Events, were studied. The patients (56 men and 10 women) had a median age of 67 (range: 37–87) years. The T/N classifications were T4b non-N4 (28/66), non-T4b N4 (24/66), and T4b N4 (14/66). Objective response was achieved in 57 patients (86.4%, (95% confidence interval, 74.6–94.1%)). There were no significant differences between the T/N groups in terms of overall survival, progression-free survival, and progression pattern. We found no significant differences in prognoses or progression patterns among patients with T4b non-N4, non-T4b N4, and T4b N4 esophageal squamous cell carcinoma. Thus, it seems impractical to modify CRT regimens based on T/N factors.