Standardized Prosection Protocol for Whipple Specimens Does Not Affect Lymph Node Counts.
Danielle H Carpenter, David C Linehan, Elizabeth M Brunt. Washington University School of Medicine, St. Louis, MO
Background: Increased attention to circumferential resection margins (CRM) of pancreatoduodenectomy (Whipple) specimens has resulted in a new standardized prosection protocol (SP). The traditional protocol (TP) for 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; lymph nodes (LN) were dissected by palpation or direct visual identification and submitted separately. The new 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 including peripancreatic fat with LN. Thus, each slide contains an inked margin for evaluation. The aim of this study is to evaluate whether the new SP is equivalent to the TP with regard to LN count and status. The hypothesis was there would be an increased number of LN and positive LN in the SP compared to the TP.
Design: All Whipple cases since the change in protocol in Oct 2009, were reviewed (n=81). Consecutive Whipple specimens following the TP from the prior year were the comparator group (n=122). Known non-neoplastic cases were excluded from both groups. The surgeons for both groups were the same, as was the spectrum of final diagnoses. The total and positive number of LN dissected from the Whipple specimens were quantified for each case; LN submitted separately by the surgeon were excluded in order to evaluate only differences in the prosection protocols. The mean number of LN for SP and TP was calculated and compared using the t test. For both groups, the number of positive LN per case was calculated, as was the total percent of cases in each group with at least one positive lymph node.
Results: In the TP group, the average number of LN per case was 22.1; in the SP group, the average number of LN per case was 24.5 (p=0.13). The average number of positive LN for the TP and SP groups was 2.2 and 2.3, respectively. Additionally, 51% of cases in the TP group had at least one positive LN, compared to 46% of cases in the SP group.
Conclusions: In spite of serial sectioning of LN by the new SP, the average counts and the number of positive LN per case has not increased in a statistically significant fashion compared to the TP. Thus, the SP provides the benefit of complete margin assessment as well as thorough, but not inflated LN counts.
Category: Quality Assurance
Monday, February 28, 2011 1:00 PM
Poster Session II # 222, Monday Afternoon