Standardized Prosection Protocol Increases Detection Rate of Positive Circumferential Margins in Whipple Specimens
Danielle H Carpenter, Ilke Nalbantoglu, Elizabeth M Brunt. Washington University in St. Louis, St. Louis, MO
Background: Adenocarcinoma of the pancreas has a dismal prognosis, with high recurrence rates even when surgical margins, including circumferential resection margins (CRM), are reported negative (R0). In the literature, reported rates of microscopically positive margins (R1) vary widely and are often lower than recurrence rates, raising the question of R1 disease being classified as R0 due to sampling error. The traditional protocol (TP) for prosection of pancreatoduodenectomy (Whipple) specimens included an X section through the duodenum, pancreatic duct, and common bile duct for tumor visualization, gross assessment of the margin status, and radial or en face sampling of the CRM based on prosector judgment. A newer standardized protocol (SP) is performed by serially sectioning the entire pancreatic head and peripancreatic fat perpendicular to the opened duodenal segment and completely embedding the sectioned tissue surrounding the tumor for complete radial assessment of the CRM. The aim of this study is to evaluate whether the new SP increases detection of R1 disease.
Design: Whipple cases diagnosed as adenocarcinoma arising in the pancreatic head or ampulla were evaluated; 115 consecutive cases (predominantly since divisional protocol change Oct 2009) were included in the SP group; consecutive Whipple specimens following the TP from the prior year were the comparator group (n=70). Cases with surgically evident positive margins (R2), non-adenocarcinoma cases, and primary common bile duct or small bowel (excluding ampulla) were excluded from both groups. The surgeons for both groups were the same. Positive circumferential margins, defined as carcinoma ≤1mm from inked margins, were tallied by site (posterior, portal vein groove, uncinate) and compared using Fischer's exact test. The total number of blocks submitted for each Whipple specimen was also recorded and the mean number of blocks for SP and TP was calculated and compared using student's t test.
Results: The TP group had 22 cases with at least one CRM positive for tumor (31.4%) while the SP group had 57 cases with at least one CRM positive (49.6%) (p=0.02). On average in the TP group, 23.4 blocks were submitted per Whipple and, in the SP group, 42.8 blocks were submitted (p=0.0001).
Conclusions: Evaluation of entire circumferential resection margins CRM in radial sections increases detection rate of R1 disease in a statistically significant fashion. The radial assessment of all margins increases the number of blocks submitted by nearly two-fold.
Category: Quality Assurance
Monday, March 19, 2012 1:00 PM
Poster Session II # 255, Monday Afternoon