Medline ® Abstracts for References 31,32
of 'Lynch syndrome (hereditary nonpolyposis colorectal cancer): Clinical manifestations and diagnosis'
Pathology features in Bethesda guidelines predict colorectal cancer microsatellite instability: a population-based study.
Jenkins MA, Hayashi S, O'Shea AM, Burgart LJ, Smyrk TC, Shimizu D, Waring PM, Ruszkiewicz AR, Pollett AF, Redston M, Barker MA, Baron JA, Casey GR, Dowty JG, Giles GG, Limburg P, Newcomb P, Young JP, Walsh MD, Thibodeau SN, Lindor NM, Lemarchand L, Gallinger S, Haile RW, Potter JD, Hopper JL, Jass JR, Colon Cancer Family Registry
Gastroenterology. 2007;133(1):48. Epub 2007 Apr 25.
BACKGROUND&AIMS: The revised Bethesda guidelines for Lynch syndrome recommend microsatellite instability (MSI) testing all colorectal cancers in patients diagnosed before age 50 years and colorectal cancers diagnosed in patients between ages 50 and 59 years with particular pathology features. Our aim was to identify pathology and other features that independently predict high MSI (MSI-H).
METHODS: Archival tissue from 1098 population-based colorectal cancers diagnosed before age 60 years was tested for MSI. Pathology features, site, and age at diagnosis were obtained. Multiple logistic regression was performed to determine the predictive value of each feature, as measured by an odds ratio (OR), from which a scoring system (MsPath) was developed to estimate the probability a colorectal cancer is MSI-H.
RESULTS: Fifteen percent of tumors (162) were MSI-H. Independent predictors were tumor-infiltrating lymphocytes (OR, 9.1; 95% confidence interval [CI], 5.9-14.1), proximal subsite (OR, 4.7; 95% CI, 3.1-7.3), mucinous histology (OR, 2.8; 95% CI, 1.7-4.8), poor differentiation (OR, 1.9; 95% CI, 1.2-3.1), Crohn's-like reaction (OR, 1.9; 95% CI, 1.2-2.9), and diagnosis before age 50 years (OR, 1.9; 95% CI, 1.3-2.9). MsPath score>or=1.0 had a sensitivity of 93% and a specificity of 55% for MSI-H.
CONCLUSIONS: The probability an individual colorectal cancer is MSI-H is predicted well by the MsPath score. There is little value in testing for DNA mismatch repair loss in tumors, or for germline mismatch repair mutations, for colorectal cancers diagnosed in patients before age 60 years with an MSPath score<1 (approximately 50%). Pathology can identify almost all MSI-H colorectal cancers diagnosed before age 60 years.
Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, University of Melbourne, Parkville, Victoria, Australia. email@example.com<firstname.lastname@example.org>
Validation microsatellite path score in a population-based cohort of patients with colorectal cancer.
Bessa X, Alenda C, Paya A,Álvarez C, Iglesias M, Seoane A, Dedeu JM, AbulíA, Ilzarbe L, Navarro G, Pellise M, Balaguer F, Castellvi-Bel S, Llor X, Castells A, Jover R, Andreu M
J Clin Oncol. 2011;29(25):3374. Epub 2011 Jul 25.
PURPOSE: Bethesda guidelines are used to recognize patients at risk for Lynch syndrome. However, obtaining personal and familial tumor data can sometimes be difficult. The Microsatellite Path Score (MsPath), a pathological score, based on age, tumor location, and pathologic features, has been developed to effectively predict colorectal cancer with DNA mismatch repair (MMR) deficiencies. However, the MsPath model's performance in an unselected, population-based colorectal cancer (CRC) population is unknown.
PATIENTS AND METHODS: We analyzed all patients with CRC regardless of age, personal or family history, and tumor characteristics from the EPICOLON study, an independent, prospective, multicenter, population-based cohort (N = 1,222). All patients underwent tumor microsatellite instability (MSI) analysis and immunostaining for MLH1/MSH2, and those with MMR underwent tumor BRAF mutation analysis and MLH1/MSH2 germline testing. All the pathologic features were centralized and evaluated blinded to the MMR status.
RESULTS: MsPath score for prediction of having MSI high, with the recommended MsPath cutoff score≥1.0, had a sensitivity, specificity, and positive predictive value (PPV) of 92.8% (95% CI, 86.9 to 98.3), 64.1% (95% CI, 61.1 to 66.8), and 15.8% (95% CI, 12.2 to 18.6), respectively. MsPath score had a sensitivity, specificity, and PPV of 81.8% (95% CI, 59.0 to 99.8), 60.6% (95% CI, 57.8 to 63.4), and 1.9% (95% CI, 0.7 to 3.1), respectively, for the identification of MLH1/MSH2 gene carriers. Application of the MsPath score, resulted in two (18%) of 11 mutation carriers being missed, both pathogenic germline MSH2 mutations.
CONCLUSION: In the general nonselected population, the MsPath score accurately predicted the probability of bearing a MSI high CRC, but it was insufficiently accurate to use for the selection of patients warranting MLH1/MSH2 mutation testing in the setting of Lynch syndrome.
Hospital del Mar de Barcelona. Parc de Salut Mar. Passeig Marítim 25-29, 08003-Barcelona, Catalonia, Spain. email@example.com