Effect of early adjuvant chemotherapy on survival of advanced gastric cancer patients: A propensity-score matched analysis

Abstract

Background: Generally, adjuvant chemotherapy (AC) should be started as soon as possible after surgery to eradicate microscopic cancer cells. In this study, we investigated the effect of early AC on the survival of stage II/III gastric cancer patients. Methods: Between January, 2008 and December, 2014, 460 patients who received AC (S-1 or XELOX) for pathologic stage II/III gastric cancer at Seoul National University Bundang Hospital were included. Patients were divided into two groups: early AC administration (within 4 weeks) and late AC administration (more than 4 weeks). Patients who received AC early (n=174) were matched 1:1 with patients who received AC late (n=174) by propensity scoring to adjust for clinical differences. Three-year disease free survival (DFS) was evaluated according to the timing of AC. Results: Three-year DFS was 98.1% in stage IIA (n=109), 85.0% in stage IIB (n=83), 87.4% in stage IIIA (n=96), 83.5% in stage IIIB (n=91), and 62.5% in stage IIIC (n=81). After propensity-score matching, DFS was similar between early and late AC groups (HR=1.04, 95% CI=0.62–1.74, p=0.889). Pathologic stage and histological type were independent prognostic factors of DFS (HR=2.05, 95% CI=1.06–3.96, p=0.033

HR=2.61, 95% CI=1.42–4.80, p=0.002). Independent factors of late AC administration were old age and postoperative complications [odds ratio (OR)=2.78, 95% CI=1.57–5.13, p<0.001

OR=7.99, 95% CI=3.59-21.33, p<0.001]. Conclusions: Early initiation of AC within 4 weeks does not affect survival rates of stage II/III gastric cancer patients.