Necrosis as a strong independent prognostic factor required in the implementation of pathological reporting for pancreatic adenocarcinoma resection specimens

Pancreatic ductal adenocarcinoma (PDAC) is a major public health issue with an incidence/mortality ratio reaching 98 %. Only 15-20 % of patients with PDAC can undergo surgery. Following PDAC surgical resection, 80 % of patients will experience local or metastatic recurrence of this disease. pTNM staging is the gold standard for risk stratification but is not sufficient to recapitulate the prognosis. Several prognostic factors are known to impact survival after surgery when uncovered during pathological examination. However, necrosis has been poorly studied in pancreatic adenocarcinoma.We retrieved clinical data and reviewed all tumor slides from patients who had a pancreatic surgery between January 2004 and December 2017, in the Hospices Civils de Lyon, to assess the presence of histopathological prognosis factors associated with poor prognosis.514 patients with complete clinico-pathological description were included. Necrosis was found in 231 PDAC (44.9 %) and had an important impact on overall survival with a double risk of death when present in tumor samples (HR: 1.871, 95 % CI [1.523; 2.299], p < 0.001). When integrated in the multivariate model, necrosis is the only morphological aggressive feature to retain high statistical significance associated with the TNM staging but independently of it. This effect is independent of the preoperative treatment.Despites improvement in treatment of PDAC, mortality rates remain relatively stable amongst the last years. There is a desperate need to better stratify patients. Here, we report the strong and prognostic impact of necrosis in surgical PDAC samples and encourage pathologists to report its presence in the future.