[628] Evaluation of Peritoneal Elastic Lamina Invasion as a Prognostic Marker in Stage II Colonic Carcinoma.

Andrea Grin, David E Messenger, Richard Kirsch. Mount Sinai Hospital, Toronto, ON, Canada

Background: The benefit of adjuvant chemotherapy in stage II colorectal cancer remains unclear and it is usually reserved for patients with adverse prognostic features (including pT4 disease). Distinguishing pT3 from pT4a tumors can be challenging. A recent study demonstrated that peritoneal elastic lamina invasion (ELI) is a predictor of survival in stage II colonic cancer and that survival in pT3N0 cases with peritoneal ELI was comparable to pT4N0 cases (Kojima et al., Am J Surg Pathol. 2010; 34:1351-60). We report our own experience with a Movat stain in determining the prognostic significance of peritoneal ELI.
Design: A total of 141 patients undergoing resection of a stage II colonic tumor (114 pT3; 27 pT4) between 1992 and 2006 were identified. Details regarding lymph node count, histologic grade, tumor budding, perforation, lymphatic and vascular invasion were recorded. Peritoneal ELI was assessed in slides closest to the peritoneum with the use of a Movat stain.
Results: The peritoneal elastic lamina was visualized in 82% (93/114) of pT3 cases (elastic lamina of large vessels served as an internal control). Staining intensity was highly variable with continuous, strong staining identified in only 39% (36/93). ELI was seen in 12 of 93 assessable pT3 cases (13%), but showed no significant difference in 5-year overall survival compared to pT3 ELI negative cases. A high tumor budding count and harvesting less than 12 lymph nodes were independently associated with poor survival outcome (p=0.029 and p=0.013, respectively).
Conclusions: Variability in the detection and continuity of the peritoneal elastic lamina may limit the utility of peritoneal ELI as a prognostic marker in routine practice. The prognostic significance of lymph node harvest and tumor budding in stage II colonic cancer is confirmed.
Category: Gastrointestinal

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 47, Wednesday Morning

 

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