At the University of Texas M.D
At the University of Texas M.D. Anderson Cancer Center (MDACC), the surgeon and pathologist evaluate each specimen first by frozen-section examination of the common bile duct transection margin and the pancreatic transection margin. The retroperitoneal margin is defined as the soft-tissue margin directly adjacent to the proximal 3 to 4 cm of the superior mesenteric artery (SMA) (Fig. 32.4-1) (Figure Not Available) , and is evaluated by permanent-section examination of a 2- to 3-mm full-face (en-face) section of the margin. The retroperitoneal margin must be taken at the time of tumor resection by the pathologist and surgeon. Identification of this margin of resection is not possible once the gross examination of the specimen has been completed. A positive bile duct or pancreatic transection margin is treated with re-resection; this is not possible in the retroperitoneum, where the aorta and SMA origin limit the extent of surgical resection. Samples of multiple areas of each tumor, including the interface between tumor and adjacent uninvolved tissue, are submitted for paraffin-embedded histologic examination (5 to 10 blocks). Sections 4 mum thick are cut and stained with hematoxylin and eosin. Final pathologic evaluation of permanent sections includes a description of tumor histology and differentiation; gross and microscopic evaluation of the tissue of origin (pancreas, bile duct, ampulla of Vater (or duodenum); and assessments of maximal transverse tumor diameter, lymph node status, and the presence or absence of perineural, lymphatic, and vascular invasion (Table 32.4-6) (Table Not Available) . When segmental resection of the superior mesenteric vein (SMV) is required, the area of presumed tumor invasion of the vein wall is serially sectioned and examined in an attempt to discriminate benign fibrous attachment from direct tumor invasion. In patients who received preoperative chemoradiation, the grade of treatment effect is assessed on permanent sections using the grading schema developed by Cleary and reported by Evans and coworkers.
The method for classifying subsets of regional lymph nodes in pancreaticoduodenectomy specimens is based on the work of Cubilla and colleagues. The soft fibrofatty tissue containing regional lymph nodes is divided into six regions as outlined on the anatomic pathology dissection board (Fig. 32.4-2) (Figure Not Available) . If lymph nodes are not identified, fat or other potentially neoplastic tissue is submitted for microscopic examination. Staley and colleagues have demonstrated that the number of lymph nodes identified in the surgical specimen is increased by the use of a standardized system of specimen analysis. The dissection board illustrated in Figure 32.4-2 (Figure Not Available) provides a simple means of improving lymph node identification and documenting the location of histologically confirmed lymph node metastases. In contrast, the Japanese staging system, which involves extremely detailed analysis of margins and lymph node groups, is not a practical system for widespread application.
As the use of multimodality treatment strategies for pancreatic cancer becomes more common, it will be even more important to standardize pathologic assessment of tumor specimens.