Meta-analysis of Adjuvant Chemotherapy Versus No Adjuvant Chemotherapy for Resected Stage I Pancreatic Cancer

BACKGROUND:To evaluate comparative outcomes of pancreatic cancer resection with or without adjuvant chemotherapy in patients with stage I pancreatic cancer. METHODS:A systematic search of MEDLINE, CENTRAL, and Web of Science and bibliographic reference lists were conducted. All comparative studies reporting outcomes of pancreatic cancer resection for stage I cancer with or without adjuvant chemotherapy were included, and their risk of bias was assessed using the Risk Of Bias In Non-randomized Studies-of Interventions tool. Survival outcomes were analyzed using the hazard ratio and odds ratio for the time-to-event and dichotomous outcomes, respectively. RESULTS:We included 6 comparative studies reporting a total of 6,874 patients with resected stage 1 pancreatic cancer, of whom 3,951 patients had no adjuvant chemotherapy, and the remaining 2,923 patients received adjuvant chemotherapy. The use of adjuvant chemotherapy was associated with significantly higher overall survival (hazard ratio 0.71, 95% confidence interval 0.62-0.82, P < .00001) and 2-year survival (65.1% vs 57.4%, odds ratio 1.99; 95% confidence interval 1.01-1.41, P = .04) compared to no use of adjuvant chemotherapy. However, there was no statistically significant difference in 1-year (86.8% vs 78.4%, odds ratio 1.60; 95% confidence interval 0.72-3.57, P = .25), 3-year (46.0% vs 44.0%, odds ratio 1.07; 95% confidence interval 0.90-1.29, P = .43), or 5-year survival (24.8% vs 23.3%, odds ratio 1.03; 95% confidence interval 0.80-1.33, P = .81) between the 2 groups. CONCLUSION:Meta-analysis of best available evidence (level 2a with low to moderate certainty) demonstrates that adjuvant chemotherapy may confer survival benefits for stage I pancreatic cancer when compared to the use of surgery alone. Randomized control trials are required to escalate the level of evidence and confirm these findings with consideration of contemporary chemotherapy agents and regimens.