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.
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.
Authors: João Cortez Pinto; Isadora Rosa; Catarina Martins; Inês Marques; João Pereira da Silva; Ricardo Fonseca; João Freire; António Dias Pereira Journal: J Gastrointest Cancer Date: 2020-03
Authors: Alexander Arnold; Matthias Kloor; Lina Jansen; Jenny Chang-Claude; Hermann Brenner; Moritz von Winterfeld; Michael Hoffmeister; Hendrik Bläker Journal: Virchows Arch Date: 2017-05-23 Impact factor: 4.064
Authors: Teppei Morikawa; Noriko Tanaka; Aya Kuchiba; Katsuhiko Nosho; Mai Yamauchi; Jason L Hornick; Richard S Swanson; Andrew T Chan; Jeffrey A Meyerhardt; Curtis Huttenhower; Deborah Schrag; Charles S Fuchs; Shuji Ogino Journal: Arch Surg Date: 2012-08