Timing of Adjuvant Chemoradiation in pT1-3N1-2 or pT4aN1 Esophageal Squamous Cell Carcinoma After R0 Esophagectomy

INTRODUCTION: Postoperative adjuvant radiation therapy (RT) and chemotherapy (aCRT) have been supposed to improve prognosis and outcomes in patients with node-positive thoracic esophageal squamous cell carcinoma (TESCC). Our aim was to analyze the impacts of interval between surgery and aCRT on prognosis, determining the optimal time interval. METHODS: We retrospectively reviewed 520 patients with TESCC between 2007 and 2015 treated with aCRT following radical esophagectomy without neoadjuvant chemotherapy and RT. These patients underwent RT (50–60 Gy) combined with 2–6 cycles chemotherapy after surgery. The time intervals were from 17 days to 145 days and divided into three groups: short interval group (≤28 days, S-Int group), medial interval group (≥29 and ≤ 56 days, M-Int group) and long interval group (≥57 days, L-Int group). RESULTS: Median follow-up was 35.6 months and the 3-, 5-year survival rates and median survival were 49.5%, 36.6% and 35.9 months. The duration of postoperative interval was a predictor of survival outcomes. The median survival and 5-year survival rates in S-Int, M-Int and L-Int groups were 23.6 (32.1%), 44.2 (43.3%) and 32.0 (31.5%) months (P=0.007). The difference was statistically significant between the M-Int and S-Int or L-Int group but was not between the S-Int and L-Int group. Besides, toxic reactions including early, late and adverse events (grade ≥3) in M-Int group were significantly less than S-Int and show no significant differences with L-Int group. CONCLUSION: The optimal time interval was from 29 days to 56 days (5–8 weeks) both in terms of survival outcomes and toxic reactions.