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Early-onset colorectal cancer patients without family history are "at very low risk" for lynch syndrome.

ABSTRACT: INTRODUCTION: Several studies evaluated the prevalence of Lynch Syndrome (LS) in young onset colorectal cancer (CRC) patients and the results were extremely variable (5%-20%). Immunohistochemistry (IHC) for MMR proteins and/or MSI analysis are screening tests that are done, either by themselves or in conjunction, on colon cancer tissue to identify individuals at risk for LS. The primary aim of our study was to evaluate the prevalence of LS in a large series of early-onset CRC without family history compared with those with family history. The secondary aim was to assess the diagnostic accuracy of IHC and MSI analysis as pre-screening tools for LS. METHODS: Early-onset CRC patients (? 50 years) were prospectively recruited in the study. IHC and MSI analysis were performed in all the patients. Germ-line mutation analysis (GMA) was carried out in all MMR deficient tumors. A logistic regression model was performed to identify clinical features predictive of MSI-H. RESULTS: 117 early onset CRC cases were categorized in three groups (A, B, C) according with family history of CRC. IHC and MSI analysis showed MMR deficiency in 6/70 patients (8.6%) of group A, 24/40 patients (60%) of group B and none of group C. GMA showed a deleterious mutation in 19 (47.5%) patients of group B. MSI analysis had a diagnostic accuracy of 95.7% (CI 92.1-99.4) and IHC of 83.8% (CI 77.1-90.4). The logistic regression model revealed that by using a combination of the two features "No Amsterdam Criteria" and "left sided CRC" to exclude MSI-H, accuracy was 89.7% (84.2-95.2). CONCLUSIONS: Early-onset CRC patients, with left sided CRC and without family history are "at very low risk" for Lynch syndrome. The two simple criteria of family history and CRC site could be used as a pre-screening tool to evaluate whether or not patients should undergo tissue molecular screening. In the few cases of suspected LS (right sided CRC and/or Amsterdam Criteria), a reasonable approach could be to perform MSI analysis first and IHC afterwards only in MSI-H patients.

SUBMITTER: Stigliano V

PROVIDER: S-EPMC3892010 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Early-onset colorectal cancer patients without family history are "at very low risk" for lynch syndrome.

Stigliano Vittoria V Sanchez-Mete Lupe L Martayan Aline A Diodoro Maria M Casini Beatrice B Sperduti Isabella I Anti Marcello M

Journal of experimental & clinical cancer research : CR 20140102

<h4>Introduction</h4>Several studies evaluated the prevalence of Lynch Syndrome (LS) in young onset colorectal cancer (CRC) patients and the results were extremely variable (5%-20%). Immunohistochemistry (IHC) for MMR proteins and/or MSI analysis are screening tests that are done, either by themselves or in conjunction, on colon cancer tissue to identify individuals at risk for LS. The primary aim of our study was to evaluate the prevalence of LS in a large series of early-onset CRC without fami ...[more]

PMID: 24383517

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Project description:ObjectiveAlthough widely recommended, Lynch syndrome (LS) testing with tumor microsatellite instability (MSI) and/or immunohistochemistry (IHC) is infrequently performed in early-onset colorectal cancer (CRC), and CRC generally. Reasons are poorly understood. Hence, we conducted a national survey focusing on gastroenterologists, as they are frequently first to diagnose CRC, assessing testing barriers and which specialist is felt responsible for ordering MSI/IHC. Additionally, we assessed factors influencing timing of MSI/IHC ordering; testing on colonoscopy biopsy, opposed to post-operative surgical specimens, assists decisions on preoperative germline genetic testing and extent of colonic resection (ECR).MethodsA 21-question web-based survey was distributed through an American College of Gastroenterology email listing.ResultsIn total 509 completed the survey. 442 confirmed gastroenterologists were analyzed. Only 33.4% felt gastroenterologists were responsible for MSI/IHC ordering; pathologists were believed most responsible (38.6%). Cost, unfamiliarity interpreting results and unavailable genetic counseling most commonly prevented routine ordering (33.3%, 29.2%, 24.9%, respectively). In multivariable analysis, non-academic and rural settings were associated with cost and genetic counseling barriers. Only 46.1% felt MSI/IHC should always be performed on colonoscopy biopsy. Guideline familiarity predicted whether respondents felt surgical resection should be delayed until results returned given potential effect on ECR decisions.ConclusionInconsistencies in who is felt should order MSI/IHC may lead to diffusion of responsibility, preventing consistent testing, including preoperatively. Assuring institutional universal testing protocols are in place, with focus on timing of testing, can optimize care. Strategies addressing cost barriers and genomic service availability in rural and non-academic settings can enhance testing. Greater emphasis on guideline familiarity is required.

Project description:ObjectivesLynch syndrome increases risks for colorectal and other cancers. Though published Lynch syndrome cancer risk-management guidelines are effective for risk-reduction, the condition remains under-recognized. The Cancer Genetics Program at an academic medical center implemented a population-based cancer family history screening program, Detecting Unaffected Individuals with Lynch syndrome, to aid in identification of individuals with Lynch syndrome.MethodsIn this retrospective cohort study, simple cancer family history screening questionnaires were used to identify those at risk for Lynch syndrome. Program navigators triaged and educated those who screened positive about hereditary cancer, and genetic counseling and testing services, offering genetic counseling if eligible. Genetic counseling was provided primarily via telephone. Genetic counselors performed hereditary cancer risk assessment and offered genetic testing via hereditary cancer panels to those eligible. Remote service delivery models via telephone genetic counseling and at-home saliva testing were used to increase access to medical genetics services.ResultsThis program screened 212,827 individuals, over half of whom were considered underserved, and identified 133 clinically actionable genetic variants associated with hereditary cancer. Of these, 47 (35%) were associated with Lynch syndrome while notably, 70 (53%) were not associated with hereditary colorectal cancer. Of 3,344 patients offered genetic counseling after initial triage, 2,441 (73%) elected to schedule the appointment and 1,775 individuals (73%) completed genetic counseling. Among underserved patients, telephone genetic counseling completion rates were significantly higher than in-person appointment completion rates (P < .05). While remote service delivery improved appointment completion rates, challenges with genetic test completion using at-home saliva sample collection kits were observed, with 242 of 1592 individuals (15%) not completing testing.ConclusionPopulation-based cancer family history screening and navigation can help identify individuals with hereditary cancer syndromes across diverse patient populations, but logistics of certain downstream service delivery models can impact outcomes.

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Early-onset colorectal cancer patients without family history are "at very low risk" for lynch syndrome.

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Early-onset colorectal cancer patients without family history are "at very low risk" for lynch syndrome.

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