[655] Peritoneal Elastic Laminal Invasion of Colorectal Cancer: The Diagnostic Utility and Clinicopathological Relationship.

Motohiro Kojima, Kentaro Nakajima, Genichiro Ishii, Norio Saito, Atsushi Ochiai. National Cancer Center Hospital East, Kashiwa, Chiba, Japan

Background: The distinction of pT3 and pT4a especially in the case which the tumor exhibits wide invasion in the vicinity of the peritoneal surface continues to pose some difficulty for pathologists. Anatomical landmark of peritoneal elastic lamina can provide a clue for making an objective diagnosis.
Design: We performed elastica staining in 564 pT3 and pT4a colorectal cancer cases. Associations between peritoneal elastic laminal invasion of the tumor and clinicopathological features were evaluated. Next, morphology of tumor was compared between cases with and those without peritoneal elastic laminal invasion to estimate morphological alteration that occurs when tumor invades beyond the peritoneal elastic lamina. Next, morphology of tumor was determined and compared between cases with and without peritoneal elastic laminal invasion to estimate morphological alteration that occurs when tumor invades beyond the elastic lamina. Furthermore, morphometric analysis of tumor area beyond the peritoneal elastic lamina was performed and compared with other tumor area to elucidate morphological characteristics of the tumor area beyond the elastic lamina.
Results: Clinicopathological analysis revealed that peritoneal elastic laminal invasion was associated with higher tumor stage, palliative resection, deeper tumor invasion, deeper ulceration, over 5mm of muscular layer elevation and peritoneal surface elevation with fibro-inflammation, higher budding grade, high grade of lymphovascular invasion (P < 0.01). Peritoneal elastic laminal invasion associated with recurrence and prognosis in colon cancer and was an independent risk factor for the recurrence of Stage II colon cancer. Furthermore, morphometric analysis revealed that tumor area in subserosal invasive front beyond peritoneal elastic lamina exhibited significantly more prominent fibrosis and tumor budding than other tumor area (P < 0.01).
Conclusions: Peritoneal elastic lamina was useful hallmark to determine the level of tumor invasion, and was powerful indicator to predict prognosis in colon cancer. Tumor area beyond the elastic lamina is characterized by extensive tumor budding and fibrosis.
Category: Gastrointestinal

Monday, February 28, 2011 11:00 AM

Platform Session: Section E, Monday Morning

 

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