Survival estimates after pancreatoduodenectomy skewed by non-standardized histopathology reports

Abstract

Survival estimates may be biased if quality control on histopathology is insufficient. We evaluated the effects of standardizing histopathology for pancreatoduodenectomy specimens and compared survival estimates based on standardized vs non-standardized histopathological evaluation. Microscopic slides and histopathological reports from 311 consecutive pancreatoduodenectomies (1980-2004) were reviewed, including 104 adenocarcinomas (1980-1997) resected before and 123 adenocarcinomas (1998-2004) resected after standardizing histopathology. Histopathological factors were re-evaluated for all primary adenocarcinomas (n = 227). The most frequent histological types were pancreatobiliary-type (n = 145) and intestinal-type (n = 73). Standardized histopathology was associated with sampling more blocks and nodes (p < 0.001), and with more frequent identification of non-pancreatic tumour origin, nodal and margin involvement, perineural infiltration, and poor differentiation (p < 0.05). Standardized evaluation was necessary to discriminate between prognostic groups with respect to perineural infiltration and tumour size, but not to identify disparate prognostic subgroups with respect to nodal and margin involvement. Nodal involvement (N1 vs N0, p < 0.001) and histological type (pancreatobiliary vs intestinal, p < 0.001) were independent prognostic factors after pancreatoduodenectomy. Histopathological evaluation should be standardized to provide reliable prognostic estimates and to discriminate between prognostic subgroups. Lymph node involvement and histological type are independent prognostic factors after pancreatoduodenectomy for adenocarcinoma.