Optimal Adjuvant Treatment for Curatively Resected Thoracic Esophageal Squamous Cell Carcinoma: A Radiotherapy Perspective

PURPOSE The purpose of this study was to evaluate the benefits of adjuvant treatment for curatively resected thoracic esophageal squamous cell carcinoma (ESCC) and determine the optimal adjuvant treatments. MATERIALS AND METHODS One hundred ninety-five patients who underwent a curative resection for thoracic ESCC between 1994 and 2014 were reviewed retrospectively. Postoperatively, the patients received no adjuvant treatment (no-adjuvant group, n=68), adjuvant chemotherapy (AC group, n=62), radiotherapy (RT group, n=41), or chemoradiotherapy (CRT group, n=24). Chemotherapy comprised cisplatin and 5-fluorouracil administration every 3 weeks. The median RT dose was 45.0 Gy (range, 34.8 to 59.4 Gy). The overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and distant metastasis (DM) rates were estimated. RESULTS At a median follow-up duration of 42.2 months (range, 6.3 to 215.2 months), the 5-year OS and DFS were 37.6% and 31.4%, respectively. After adjusting for other clinicopathologic variables, the AC and CRT groups had a significantly better OS and DFS compared to the no-adjuvant group (p < 0.05). The LRR rate was significantly lower in the RT and CRT groups than in the no-adjuvant group (p < 0.05), whereas no significant difference was observed in the AC group. In the no-adjuvant and AC groups, 25% of patients received high-dose salvage RT due to LRR. The DM rates were similar. The anastomotic stenosis and leakage were similar in the treatment groups. CONCLUSION Adjuvant treatment might prolong survival after an ESCC resection, and RT contributes to a reduction of the LRR. Overall, the risks and benefits should be weighed properly when selecting the optimal adjuvant treatment.