Benefit of Adjuvant Chemotherapy for Resectable Gastric Cancer: A Meta-analysis

Abstract

CONTEXT: Despite potentially curative resection of stomach cancer, 50% to 90% of patients die of disease relapse. Numerous randomized clinical trials (RCTs) have compared surgery alone with adjuvant chemotherapy, but definitive evidence is lacking. OBJECTIVES: To perform an individual patient-level meta-analysis of all RCTs to quantify the potential benefit of chemotherapy after complete resection over surgery alone in terms of overall survival and disease-free survival, and to further study the role of regimens, including monochemotherapy; combined chemotherapy with fluorouracil derivatives, mitomycin C, and other therapies but no anthracyclines; combined chemotherapy with fluorouracil derivatives, mitomycin C, and anthracyclines; and other treatments. DATA SOURCES: Data from all RCTs comparing adjuvant chemotherapy with surgery alone in patients with resectable gastric cancer. We searched MEDLINE (up to 2009), the Cochrane Central Register of Controlled Trials, the National Institutes of Health trial registry, and published proceedings from major oncologic and gastrointestinal cancer meetings. STUDY SELECTION: All RCTs closed to patient recruitment before 2004 were eligible. Trials testing radiotherapy; neoadjuvant, perioperative, or intraperitoneal chemotherapy; or immunotherapy were excluded. Thirty-one eligible trials (6390 patients) were identified. DATA EXTRACTION: As of 2010, individual patient data were available from 17 trials (3838 patients representing 60% of the targeted data) with a median follow-up exceeding 7 years. RESULTS: There were 1000 deaths among 1924 patients assigned to chemotherapy groups and 1067 deaths among 1857 patients assigned to surgery-only groups. Adjuvant chemotherapy was associated with a statistically significant benefit in terms of overall survival (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.76-0.90; P < .001) and disease-free survival (HR, 0.82; 95% CI, 0.75-0.90; P < .001). There was no significant heterogeneity for overall survival across RCTs (P = .52) or the 4 regimen groups (P = .13). Five-year overall survival increased from 49.6% to 55.3% with chemotherapy. CONCLUSION: Among the RCTs included, postoperative adjuvant chemotherapy based on fluorouracil regimens was associated with reduced risk of death in gastric cancer compared with surgery alone.