Meta-analysis of the impact of neoadjuvant therapy on patterns of recurrence in pancreatic ductal adenocarcinoma

Background: Neoadjuvant therapy may increase the rate of radical tumour resection in patients with pancreatic cancer. Its impact on tumour recurrence has not been investigated fully. This study aimed to assess the impact of neoadjuvant therapy on patterns of recurrence. Methods: A systematic review was performed of articles identified through the PubMed, Scopus, Embase, Ovid and Google Scholar databases that analysed the relationship between neoadjuvant therapy and recurrence published to January 2016. The main endpoint was overall tumour recurrence. Other endpoints included local recurrence, any kind of distant, hepatic, pulmonary or peritoneal metastasis. Results: A total of 4257 citations were reviewed. Twelve observational studies comprising 1365 patients were analysed. Neoadjuvant therapy significantly reduced the risk of overall (risk ratio (RR) 0.82, 95 per cent c.i. 0.74 to 0.90; P < 0.001) and local (RR 0.42, 0.32 to 0.55; P < 0.001) recurrence. Neoadjuvant therapy did not reduce the risk of any kind of distant (RR 1.02, 0.91 to 1.14; P = 0.78), hepatic (RR 0.86, 0.68 to 1.10; P = 0.13), pulmonary (RR 0.99, 0.37 to 2.66; P = 0.98) or peritoneal (RR 0.88, 0.57 to 1.38; P = 0.58) metastasis. Conclusion: Neoadjuvant therapy reduced the risk of local recurrence but not that of distant metastasis.