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 non-surgical 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 meta-regression 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 (β = -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 post-operative 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.