Either High or low Risk: The Acinar Score at the Resection Margin Dichotomizes the Risk Spectrum Of Pancreas-specific Complications After Pancreatoduodenectomy

Background: Pancreatic acinar content has been associated with pancreas-specific complications after pancreatoduodenectomy (PD). The aim of this study was to improve the prediction ability of intraoperative risk stratification by integrating the pancreatic acinar score. Methods: A training and a validation cohort underwent PD with subsequent histologic assessment of pancreatic section margins for acinar content (Ac), fibrosis (Fc), and fat. Intraoperative risk stratification (pancreatic texture, duct diameter) and pancreas-specific complications (postoperative hyperamylasemia [POH], post pancreatectomy acute pancreatitis [PPAP], pancreatic fistula [POPF]) were classified according to ISGPS definitions. Results: In the validation cohort (n= 373), the association of pancreas-specific complications with higher Ac and lower Fc was replicated (all P<0.001). In the entire cohort (n= 761), the ISGPS classification allocated 275 (36%) patients into intermediate-risk classes B (POH 32%/PPAP 3%/POPF 17%) and C (POH 36%/PPAP 9%/POPF 33%). Using the acinar score (Ac ≥60% and/or Fc ≤10%), intermediate-risk patients could be dichotomized into a low- (POH 5%/PPAP 1%/POPF 6%) and a high- (POH 51%/PPAP 9%/POPF 38%) risk group (all P<0.001). The acinar score AUC for POPF prediction was 0.70 in the ISGPS intermediate-risk classes. Overall, 239 (31%) patients were relocated into the high-risk group from lower ISGPS risk classes using the acinar score. Conclusions: The risk of pancreas-specific complications appears to be dichotomous - either high or low - according to the acinar score, a tool to better target the application of mitigation strategies in cases of intermediate macroscopic features.