Stage IV pancreatic ductal adenocarcinoma (PDAC) with synchronous liver metastasis: are there survival benefits in liver resection? A systematic review and meta-analysis

Objective: Metastatic PDAC has a very poor prognosis, and surgery has a limited role. The study aims to evaluate the OS of patients with PDAC and synchronous liver metastasis who undergo surgical therapy (ST) versus nonsurgical therapies (NST). Methods: We performed a random effects meta-analysis. Inclusion criteria were: PDAC histology; studies reporting technically resectable cases with liver metastasis and survival data; absence of extra-hepatic disease. The primary endpoint was to evaluate OS. Results were reported as HR and 95 % CI. We performed a metaregression analysis to identify factors influencing heterogeneity. We analyzed key covariates in order to predict how changes in these factors affect HR. Results: Six studies were included. The OS was significantly better in group ST than NST, with HR = 0.41 (95 % CI: 0.32-0.52). Heterogeneity was high (I2 = 64.50 %). As the rate of patients who underwent postoperative CT in the ST group decreased, the difference between the two groups decreased (beta = -1.28 +/- 0.67; p = 0.003), with almost 87.10 % heterogeneity. The adjusted effect based on meta-regression showed an improved OS in ST group only when both pre- and post-operative systemic CT were administrated (HR 0.18, 95 % CI: 0.08-0.40). Conclusions: In highly selected patients with metastatic PDAC who respond to systemic CT and receive postoperative systemic CT, ST could be associated with improved OS. However, the high heterogeneity and retrospective design of included studies limit the ability to draw definitive conclusions.