Association Between a High Number of Isolated Lymph Nodes in T1 to T4 N0M0 Colorectal Cancer and the Microsatellite Instability Phenotype

作者：Eveno Clarisse; Nemeth Judith; Soliman Hany; Praz Francoise; de The Hugues; Valleur Patrice; Talbot Ian C; Pocard Marc^*

来源：Archives of Surgery, 2010, 145(1): 12-17.

DOI：10.1001/archsurg.2009.224

Hypothesis: Stage I or II colorectal carcinomas with microsatellite instability (MSI) are characterized by more isolated lymph nodes in the resected specimen than their counterparts with microsatellite stability (MSS).
Design: Prospective study.
Setting: Academic research.
Patients: Using a pentaplex polymerase chain reaction assay, MSI status was determined prospectively for 135 operative patients.
Main Outcome Measures: Mismatch repair defects were investigated by immunohistochemistry on tumors demonstrating MSI.
Results: Among 82 stage I or II colorectal carcinomas, 11 had MSI, and 71 had MSS, with a mean (SD) number of 23.6 (3.1) and 13.7 (1.0) negative lymph nodes, respectively (P = .001). The mean number of lymph nodes for all resected stage I or II colorectal carcinomas analyzed at our hospital was 15. The prevalence of MSI among tumors with more than 15 lymph nodes in the specimen was 25% (9 of 36), and 82% (9 of 11) of MSI tumors belonged to this group.
Conclusions: A high number of isolated lymph nodes in stage I or II colorectal carcinomas was associated with the MSI phenotype. Good prognosis that is usually associated with tumors having a high number of uninvolved lymph nodes might reflect the high prevalence of MSI among these tumors. The number of examined lymph nodes as a quality criterion should be used with caution. For stage I or stage II colorectal carcinomas, restricting MSI phenotyping to tumors with more than the mean number of lymph nodes identifies almost all MSI tumors.

• 出版日期2010-1