Adjuvant chemoradiotherapy vs adjuvant chemotherapy in locally advanced Siewert type II/III adenocarcinoma of gastroesophageal junction after D2/R0 resection

BACKGROUND: For Siewert type II/III adenocarcinoma of gastroesophageal junction (AGE), the efficacy of adjuvant chemoradiotherapy (CRT) after D2/R0 resection remains uncertain. AIM: To determine whether CRT was superior to chemotherapy (CT) alone after D2/R0 resection for locally advanced Siewert type II/III AGE. METHODS: We identified 316 locally advanced Siewert type II/III AGE patients who were treated with D2/R0 resection at National Cancer Center from 2011 to 2018. 57 patients received adjuvant CRT and 259 patients received adjuvant CT. We followed patients for overall survival (OS), relapse-free survival, and recurrence pattern. RESULTS: Five-year OS rates of the CRT group and the CT group for all patients were 66.7% and 41.9% (P = 0.010). Five-year OS rates of the CRT group and the CT group for Siewert type III AGE patients were 65.7% and 43.9% (P = 0.006). Among the 195 patients whose recurrence information could be obtained, 18 cases (34.6%) and 61 cases (42.7%) were diagnosed as recurrence in the CRT group and CT group, respectively. The local and regional recurrence rates in the CRT group were lower than that in the CT group (22.2% vs 24.6%, 27.8% vs 39.3%). Multivariable cox regression analysis showed that vascular invasion, nerve invasion, and adjuvant CRT were important prognostic factors for Siewert type III AGE. CONCLUSION: For locally advanced Siewert type III AGE, adjuvant CRT may prolong OS and reduce the regional recurrence rate.