Local control may be the key in improving treatment outcomes of esophageal squamous cell carcinoma undergoing concurrent chemoradiation

Background/Aim: Little is known about the patterns of treatment failure following definitive chemoradiotherapy (CCRT), especially in esophageal squamous cell carcinoma (SCC). We evaluated definitive CCRT failure patterns and determined the predictive factors for treatment response in esophageal SCC. Methods: We evaluated 136 consecutive patients with esophageal SCC treated with definitive CCRT. We evaluated the factors associated with complete remission (CR) after CCRT and analyzed the pattern of treatment failure of recurred patients and incomplete remission patients. The failures were categorized as either within (locoregional failure) or outside the radiation field (out-field failure). Results: Fifty-seven patients achieved CR after CCRT. Consolidation chemotherapy was significantly associated with CR. Only 4 (7.0%) patients had CR after CCRT in patients with M1a node (Celiac or subclavian lymph nodes involvement by 6th AJCC). During follow-up, 74 patients (54.4%) experienced locoregional failure, 26 (19.1%) out-field failure, and 35 (25.7%) no failure. Esophageal obstruction prior to CCRT, residual tumor according to the first follow-up endoscopy, and poor follow-up computed tomography responses were significantly associated with locoregional failure. Conclusion: Approximately 70% of treatment failures were local failures. Future therapeutic strategies need to focus on improving local control to increase treatment outcomes of CCRT.