Impact of the radiological morphology of the mesopancreas on the outcome after pancreatoduodenectomy for pancreatic ductal adenocarcinoma: retrospective study.

Background: The most frequently invaded margins on pancreatoduodenectomy specimens for pancreatic ductal adenocarcinoma are vascular margins, particularly the superior mesenteric artery (or mesopancreatic) margin. Due to limited exploration of the radiological aspect of the mesopancreas, the aim of this study was to evaluate mesopancreatic infiltration through imaging of patients with pancreatic ductal adenocarcinoma who underwent pancreatoduodenectomy, to correlate these findings with histopathology and evaluate their impact on survival.

Methods: Data for all patients who underwent pancreatoduodenectomy for pancreatic ductal adenocarcinoma from 2015 to 2021 were reviewed, including review of surgical margin histopathology and blinded review of preoperative diagnostic imaging. According to qualitative radiological assessment, the mesopancreas was characterized as having normal fat, fat stranding, or solid infiltration. Survival data were analysed using Cox regression.

Results: A total of 149 patients were included. At baseline imaging, mesopancreatic fat stranding or solid infiltration was present in 47 patients (31.5%) and 20 patients (13.4%) respectively. Median overall survival and disease-free survival were significantly lower with mesopancreatic solid infiltration (17 and 8 months) compared with normal fat (30 and 14 months) and fat stranding (29 and 16 months) (P = 0.017 and 0.028 respectively). In multivariable analysis, pathological tumour size was an independent prognostic factor for overall survival, and tumour location in the uncinate process and pathological tumour size were independent prognostic factors for disease-free survival.

Conclusion: At diagnostic imaging, solid infiltration (but not fat stranding) of the mesopancreas is associated with a poor prognosis for pancreatic ductal adenocarcinoma patients who undergo pancreatoduodenectomy. Pathological tumour size significantly influences the prediction of overall survival, and tumour location in the uncinate process and pathological tumour size significantly influence the prediction of disease-free survival, suggesting further exploration of underlying mechanisms related to retroperitoneal tumoral invasion of vascular margins and the mesopancreas.