Adjuvant Chemotherapy Versus Adjuvant Chemoradiation (CRT) for Gastric Cancer: 16 Years of Local Experience

Background: There is little consensus for the choice of adjuvant therapy for gastric cancer. This study aimed to compare treatment outcomes and toxicities of adjuvant capecitabine-oxaliplatin (XELOX) with adjuvant chemoradiation (CRT). Methods: Patients with resected gastric cancer stage IIA to IIIC disease treated between January 2004 and July 2018 were analysed retrospectively. Patients were treated with XELOX for eight cycles or CRT. For CRT, 5 cycles of 5-fluorouracil (5FU)/leucovorin with 45 Gy in 25 fractions radiotherapy (RT) concurrent with cycles 2 and 3 were given. Relapse-free survival (RFS) and overall survival (OS) were used to compare the effect of adjuvant chemotherapy and CRT. Acute toxicities and the pattern of relapse were also analysed. Results: 120 patients were included. 52 patients were treated with XELOX, and 68 patients were treated with CRT. Univariate analysis resulted in a five-year OS of 66% for XELOX, as compared with 48% for CRT (HR 0.706, 95% CI 0.413-1.208, p=0.202). The five-year RFS was 58% for XELOX, and 43% for CRT (HR 0.708, 95% CI 0.424-1.183, p= 0.185). On multivariate analysis, both RFS and OS favored XELOX: RFS HR 0.51 (95% CI 0.29-0.87), p=0.014; OS HR 0.45 (95% CI 0.25-0.81), p=0.007 when XELOX was compared with CRT. Patterns of failure were similar in the two groups, with distant metastases being most common. Acute toxicity grade 3/4 was seen in 42% of patients for XELOX, as compared to 65% of patients for CRT (p=0.015). Neutropenia ? grade 3 was more frequent in the CRT group (60% vs 21%; p <0.001).