Underutilization of microsatellite instability analysis in colorectal cancer patients at high risk for Lynch syndrome.
OBJECTIVE
The revised Bethesda Guidelines were published to improve the efficiency of recognizing Lynch syndrome (LS) by identifying LS-related malignancies that should be analyzed for microsatellite instability (MSI). The aim of this study was to evaluate whether MSI analysis was performed in colorectal cancer patients at risk for LS according to the revised Bethesda Guidelines.


METHODS
Patients diagnosed with colorectal cancer in 11 Dutch hospitals in 2005 and 2006 were selected from a regional database. The patients were included in the study if they met any of the following criteria; 1) diagnosed with colorectal cancer <50 years, 2) a second LS-associated tumor prior to the diagnosis of colorectal cancer in 2005/2006, and 3) colorectal cancer <60 years with a tumor displaying mucinous or signet-ring differentiation or medullary growth pattern.


RESULTS
Of 1905 colorectal cancer patients, 169 met at least one of the inclusion criteria. MSI analysis had been performed in 23 (14%) of the 169 tumors. MSI status had been determined in 18 of 80 included patients aged <50 years, in 4 of 70 patients with a second LS-related tumor, and in 3 of 41 patients aged <60 years with high-risk pathology features.


CONCLUSIONS
There is marked underutilization of MSI analysis in patients at risk for LS. As a result LS might be underdiagnosed both in patients with colorectal cancer and in their relatives.
Van Lier
Margot G F
MG
Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. m.g.f.vanlier@erasmusmc.nl
De Wilt
Johannes H W
JH
Wagemakers
Jessie J M F
JJ
Dinjens
Winand N M
WN
Damhuis
Ronald A M
RA
Wagner
Anja
A
Kuipers
Ernst J
EJ
Van Leerdam
Monique E
ME
D000328:Adult; D000367:Age Factors; D000368:Aged; D001707:Biopsy, Needle; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005820:Genetic Testing / Q000706:statistics & numerical data*; D006579:Heterozygote; D006801:Humans; D007150:Immunohistochemistry; D015994:Incidence; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D051719:MutS DNA Mismatch-Binding Protein / Q000235:genetics*; D020380:Needs Assessment; D009367:Neoplasm Staging; D009426:Netherlands; D017410:Practice Guidelines as Topic; D011336:Probability; D011379:Prognosis; D012042:Registries; D012737:Sex Factors
D051719:MutS DNA Mismatch-Binding Protein