Long-term outcome following neoadjuvant therapy for resectable and borderline resectable pancreatic cancer compared to upfront surgery: a meta-analysis of comparative studies by intention-to-treat analysis.

The aim of the study was to evaluate the effect of neoadjuvant therapy on long-term survival in patients with resectable and borderline resectable pancreatic cancer. A meta-analysis was conducted using the reported randomized, controlled trials and retrospective studies using an intention-to-treat analysis to compare upfront surgery and neoadjuvant therapy in resectable or borderline resectable pancreatic cancer patients. Six comparative studies consisting of two randomized, controlled trials and four retrospective studies were included. The overall pooled hazard ratio was 0.66 (95% confidence interval: 0.50-0.87, P = 0.003), indicating that patients in the neoadjuvant group had better long-term survival than those in the upfront surgery group. However, considerable inter-study heterogeneity was observed (I2 = 62%). This meta-analysis focusing on comparative studies analyzed by intention-to-treat analysis showed that neoadjuvant therapy for resectable and borderline resectable pancreatic cancer tends to improve patients' long-term outcomes. However, the evidence level remains too low for a firm conclusion. The well-designed, randomized, controlled trials now ongoing will provide the definite evidence needed in the future.