Purpose: The prognostic significance of portal/superior mesenteric vein (PV/SMV) invasion at the time of pancreatoduodenectomy (PD) for pancreatic adenocarcinoma (PDAC) is contentious. The aim of this meta-analysis was to compare the survival outcomes in patients with histologically proven adventitial (superficial) versus media/intimal (deep) PV/SMV invasion at the time of PD for PDAC.
Methods: A systematic search of the PubMed, MEDLINE and SCOPUS databases were performed in accordance with PRISMA guidelines. All articles reporting outcomes specific to the depth of PDAC invasion into the PV/SMV wall were included. The primary outcome measure was overall survival.
Results: Six studies including 310 patients who underwent pancreatic resection with PV/SMV resection for PDAC were included in this meta-analysis. There was no difference in overall survival comparing superficial vs deep invasion at 12 months (64% vs 58% respectively, risk difference, - 0.09; CI, - 0.21-0.04; P = 0.183), 36 months (22% vs 18% respectively, risk difference, - 0.05; CI, - 0.16-0.19; P = 0.857) and mean overall survival (42.8 months vs 25.7 months respectively, standard mean difference, - 0.27; CI, - 0.58, 0.03; P = 0.078). Although larger tumours were seen in those with confirmed deep vein wall invasion (P < 0.001), no difference was observed between the superficial and deep invasion groups with regard to age (P = 0.298), R1 resection (P = 0.896), nodal metastatic disease (P = 0.120) and perineural invasion (P = 0.609).
Conclusions: This meta-analysis suggests that the depth of PV/SMV wall invasion by PDAC may not impact survival after PD. However, given the limited sample size, further research is warranted with homogenous cohorts and longer follow-up.
Keywords: Pancreatic cancer; Pancreatoduodenectomy; Porto-mesenteric vein; Vein wall invasion.