[Show abstract][Hide abstract] ABSTRACT: Background:
Recent guidelines recommend the Lynch Syndrome prediction models MMRPredict, MMRPro, and PREMM1,2,6 for the identification of MMR gene mutation carriers. We compared the predictive performance and clinical usefulness of these prediction models to identify mutation carriers.
Pedigree data from CRC patients in 11 North American, European, and Australian cohorts (6 clinic- and 5 population-based sites) were used to calculate predicted probabilities of pathogenic MLH1, MSH2, or MSH6 gene mutations by each model and gene-specific predictions by MMRPro and PREMM1,2,6. We examined discrimination with area under the receiver operating characteristic curve (AUC), calibration with observed to expected (O/E) ratio, and clinical usefulness using decision curve analysis to select patients for further evaluation. All statistical tests were two-sided.
Mutations were detected in 539 of 2304 (23%) individuals from the clinic-based cohorts (237 MLH1, 251 MSH2, 51 MSH6) and 150 of 3451 (4.4%) individuals from the population-based cohorts (47 MLH1, 71 MSH2, 32 MSH6). Discrimination was similar for clinic- and population-based cohorts: AUCs of 0.76 vs 0.77 for MMRPredict, 0.82 vs 0.85 for MMRPro, and 0.85 vs 0.88 for PREMM1,2,6. For clinic- and population-based cohorts, O/E deviated from 1 for MMRPredict (0.38 and 0.31, respectively) and MMRPro (0.62 and 0.36) but were more satisfactory for PREMM1,2,6 (1.0 and 0.70). MMRPro or PREMM1,2,6 predictions were clinically useful at thresholds of 5% or greater and in particular at greater than 15%.
MMRPro and PREMM1,2,6 can well be used to select CRC patients from genetics clinics or population-based settings for tumor and/or germline testing at a 5% or higher risk. If no MMR deficiency is detected and risk exceeds 15%, we suggest considering additional genetic etiologies for the cause of cancer in the family.
Full-text · Article · Nov 2015 · JNCI Journal of the National Cancer Institute
[Show abstract][Hide abstract] ABSTRACT: Purpose:The aim of this study was to assess whether differences in frequency and phenotype of APC and MUTYH mutations exist among racially/ethnically diverse populations.Methods:We studied 6,169 individuals with a personal and/or family history of colorectal cancer (CRC) and polyps. APC testing involved full sequencing/large rearrangement analysis (FS/LRA); MUTYH involved "panel testing" (for Y165C, G382D mutations) or FS/LRA performed by Myriad Genetics, a commercial laboratory. Subjects were identified as Caucasian, Asian, African American (AA), or other. Statistical tests included χ(2), Fisher's exact test, analysis of variance, and z approximation.Results:Among participants, 17.5% had pathogenic APC mutations and 4.8% were biallelic MUTYH carriers. With regard to race/ethnicity, 18% were non-Caucasian, with >100 adenomas and younger ages at adenoma or CRC diagnosis (P < 0.0001) than Caucasians. The overall APC mutation rate was higher in Asians, AAs, and others as compared with Caucasians (25.2, 30.9, 24, and 15.5%, respectively; P < 0.0001) but was similar in all groups when adjusted for polyp burden. More MUTYH biallelic carriers were Caucasian or other than Asian or AA (5, 7, 2.7, and 0.3%, respectively; P < 0.0001). Among Caucasians, 5% were biallelic carriers identified by panel testing versus 2% identified by sequencing/large rearrangement analysis (LRA) (P = 0.002). Among non-Caucasians, 3% undergoing panel testing were biallelic carriers versus 10% identified by sequencing/LRA (P < 0.0002).Conclusion:Non-Caucasians undergo genetic testing at more advanced stages of polyposis and/or are younger at CRC/polyp diagnosis. Restricted MUTYH analysis may miss significant numbers of biallelic carriers, particularly in non-Caucasians.Genet Med advance online publication 15 January 2015Genetics in Medicine (2015); doi:10.1038/gim.2014.199.
No preview · Article · Jan 2015 · Genetics in medicine: official journal of the American College of Medical Genetics
[Show abstract][Hide abstract] ABSTRACT: Although 30% of individuals diagnosed with colorectal cancer (CRC) report a family history of the disease, only 5% to 6% carry germline mutations in genes associated with known hereditary cancer syndromes. The evaluation and management of families affected with CRC can be complicated by variability in disease phenotypes and limited sensitivity of genetic tests. In this review, we examine what is currently known about familial CRC and what we have yet to learn, and explore how novel genomic approaches might be used to identify additional genetic and epigenetic factors implicated in heritable risk for cancer.
[Show abstract][Hide abstract] ABSTRACT: Although 30% of individuals diagnosed with CRC report a family history of the disease, only 5-6% carry germline mutations in genes associated with known hereditary cancer syndromes. The evaluation and management of families affected with CRC can be complicated by variability in disease phenotypes and limited sensitivity of genetic tests. In this review we examine what is currently known about familial CRC and what we have yet to learn, and explore how novel genomic approaches might be used to identify additional genetic and epigenetic factors implicated in heritable risk for cancer.
No preview · Article · Aug 2013 · Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association
[Show abstract][Hide abstract] ABSTRACT: Colorectal cancer (CRC) is the most common gastrointestinal malignancy and the third cause of cancer death in men and women in the United States. The majority of CRC cases diagnosed annually are due to sporadic events but up to 6% are attributed to known monogenic disorders that confer a markedly increased risk for the development of CRC and multiple extracolonic malignancies. Lynch syndrome is the most common inherited CRC syndrome and is associated with mutations in DNA mismatch repair (MMR) genes, mainly MLH1 and MSH2, but also MSH6, PMS2, and EPCAM. While the risk of CRC and endometrial cancer may approach near 75% and 50% respectively in gene mutation carriers, the identification of these individuals and at-risk family members through predictive genetic testing provides opportunities for cancer prevention including specialized cancer screening, intensified surveillance, and/or prophylactic surgeries. This article will provide a review of the major advances in risk assessment, molecular genetics, DNA mutational analyses, and cancer prevention and management made since Lynch Syndrome was first described 100 years ago.
No preview · Article · Jul 2013 · Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association
[Show abstract][Hide abstract] ABSTRACT: Prediction models for the identification of Lynch syndrome have been developed to quantify an individual's risk of carrying a mismatch repair gene mutation and help clinicians decide for whom further risk assessment and genetic testing is necessary. There are diverse clinical settings in which a healthcare provider has the opportunity to assess an individual for Lynch syndrome. Prediction models offer a potentially feasible and useful strategy to systematically identify at-risk individuals, whether they are affected with colorectal cancer or not, and to help with management of the implications of molecular and germline test results. Given the complexity of diagnostic information currently available to clinicians involved in identifying and caring for patients with Lynch syndrome, prediction models provide a useful and complementary aid in medical decision-making. Systematic implementation of prediction models estimates should be considered in routine clinical care and at various stages of cancer risk assessment and prevention. In this manuscript, we review the main prediction models developed for Lynch syndrome, focus on their specific features and performance assessed in several validation studies, compare the models with other clinical and molecular strategies for the diagnosis of Lynch syndrome, and discuss their potential uses in clinical practice.
[Show abstract][Hide abstract] ABSTRACT: PURPOSEProstate cancer has been described as a component tumor of Lynch syndrome (LS), with tumors obtained from mutation carriers demonstrating the DNA mismatch repair deficiency phenotype. Previous studies quantifying prostate cancer risk in LS have provided conflicting results. METHODS
We examined cancer histories of probands and their first- through fourth-degree relatives for 198 independent mutation-positive LS families enrolled in two US familial cancer registries. Modified segregation analysis was used to calculate age-specific cumulative risk or penetrance estimates, with accompanying Wald-type CIs. Cumulative lifetime risks and hazard ratio (HR) estimates for prostate cancer were calculated and compared with those of the general population.ResultsNinety-seven cases of prostate cancer were observed in 4,127 men. Median age at prostate cancer diagnosis was 65 years (range, 38 to 89 years), with 11.53% of affected individuals diagnosed before age 50 years. The cumulative risk of prostate cancer at ages 60 and 80 years was 6.30% (95% CI, 2.47 to 9.96) and 30.0% (95% CI, 16.54 to 41.30), as compared with the population risk of 2.59% and 17.84%, respectively. The overall prostate cancer HR among carriers was 1.99 (95% CI, 1.31 to 3.03). CONCLUSION
The cumulative lifetime risk of prostate cancer in individuals with LS is two-fold higher than in the general population and is slightly higher in carriers diagnosed before age 60 years (HR, 2.48; 95% CI, 1.34 to 4.59). These estimates are clinically valuable to quantify risk for both patients and providers.
Full-text · Article · Mar 2013 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: Objectives: Rates of suboptimal bowel preparation up to 30% have been reported. Liberalized precolonoscopy diet, split dose purgative, and the use of MiraLAX-based bowel preparation (MBBP) prior to colonoscopy are recently developed measures to improve bowel preparation quality but little is known about the utilization prevalence of these measures. We examined the patterns of utilization of these newer approaches to improve precolonoscopy bowel preparation quality among American gastroenterologists.
Full-text · Article · Jan 2013 · Therapeutic Advances in Gastroenterology
[Show abstract][Hide abstract] ABSTRACT: Purpose
Suboptimal bowel preparation can result in decreased neoplasia detection, shortened surveillance intervals, and increased costs. We assessed bowel preparation recommendations and the relationship to self-reported proportion of suboptimal bowel preparations in practice; and evaluated the impact of suboptimal bowel preparation on colonoscopy surveillance practices. A random sample of a national organization of gastroenterologists in the U.S. was surveyed.
Demographic and practice characteristics, bowel preparation regimens, and proportion of suboptimal bowel preparations in practice were ascertained. Recommended follow-up colonoscopy intervals were evaluated for optimal and suboptimal bowel preparation and select clinical scenarios.
We identified 6,777 physicians, of which 1,354 were randomly selected; 999 were eligible, and 288 completed the survey. Higher proportion of suboptimal bowel preparations/week (≥10 %) was associated with hospital/university practice, teaching hospital affiliation, >25 % Medicaid insured patients, recommendation of PEG alone and sulfate-free. Those reporting >25 % Medicare and privately insured patients, split dose recommendation, and use of MoviPrep® were associated with a <10 % suboptimal bowel preparations/week. Shorter surveillance intervals for three clinical scenarios were reported for suboptimal preparations and were shortest among participants in the Northeast who more often recommended early follow-up for normal findings and small adenomas. Those who recommended 4-l PEG alone more often advised <1 year surveillance interval for a large adenoma.
Our study demonstrates significantly shortened surveillance interval recommendations for suboptimal bowel preparation and that these interval recommendations vary regionally in the United States. Findings suggest an interrelationship between dietary restriction, purgative type, and practice and patient characteristics that warrant additional research.
Full-text · Article · Aug 2012 · International Journal of Colorectal Disease
[Show abstract][Hide abstract] ABSTRACT: Patients with multiple colorectal adenomas may carry germline mutations in the APC or MUTYH genes.
To determine the prevalence of pathogenic APC and MUTYH mutations in patients with multiple colorectal adenomas who had undergone genetic testing and to compare the prevalence and clinical characteristics of APC and MUTYH mutation carriers.
Cross-sectional study conducted among 8676 individuals who had undergone full gene sequencing and large rearrangement analysis of the APC gene and targeted sequence analysis for the 2 most common MUTYH mutations (Y179C and G396D) between 2004 and 2011. Individuals with either mutation underwent full MUTYH gene sequencing. APC and MUTYH mutation prevalence was evaluated by polyp burden; the clinical characteristics associated with a pathogenic mutation were evaluated using logistic regression analyses.
Prevalence of pathogenic mutations in APC and MUTYH genes.
Colorectal adenomas were reported in 7225 individuals; 1457 with classic polyposis (≥100 adenomas) and 3253 with attenuated polyposis (20-99 adenomas). The prevalence of pathogenic APC and biallelic MUTYH mutations was 95 of 119 (80% [95% CI, 71%-87%]) and 2 of 119 (2% [95% CI, 0.2%-6%]), respectively, among individuals with 1000 or more adenomas, 756 of 1338 (56% [95% CI, 54%-59%]) and 94 of 1338 (7% [95% CI, 6%-8%]) among those with 100 to 999 adenomas, 326 of 3253 (10% [95% CI, 9%-11%]) and 233 of 3253 (7% [95% CI, 6%-8%]) among those with 20 to 99 adenomas, and 50 of 970 (5% [95% CI, 4%-7%]) and 37 of 970 (4% [95% CI, 3%-5%]) among those with 10 to 19 adenomas. Adenoma count was strongly associated with a pathogenic mutation in multivariable analyses.
Among patients with multiple colorectal adenomas, pathogenic APC and MUTYH mutation prevalence varied considerably by adenoma count, including within those with a classic polyposis phenotype. APC mutations predominated in patients with classic polyposis, whereas prevalence of APC and MUTYH mutations was similar in attenuated polyposis. These findings require external validation.
No preview · Article · Aug 2012 · JAMA The Journal of the American Medical Association
[Show abstract][Hide abstract] ABSTRACT: Racial and ethnic differences in the risk of premalignant colorectal neoplasia have not been extensively studied.
To measure adenoma prevalence among asymptomatic white, black and Hispanic patients undergoing screening colonoscopy.
In this cross sectional cohort study, data from individuals ≥50 years undergoing first-time colonoscopy since 2006 at a single tertiary-care medical centre were obtained from the electronic medical record. Adenoma prevalence among whites, blacks and Hispanics was calculated; multivariate Poisson and logistic regression were used to identify factors independently associated with adenoma rates and the presence of advanced adenomas.
We identified 5075 eligible subjects: 3542 (70%) whites, 942 (18%) Hispanics and 591 (12%) blacks. The mean age was 62.2 years with 58% women. At least one adenoma was detected in 19%, 22% and 26% of whites, Hispanics and blacks respectively (Hispanics vs. whites P = 0.09; blacks vs. whites P = 0.0001). Isolated proximal adenomas were present in 9% of whites, 11% of Hispanics (P = 0.03) and 11% of blacks (P = 0.03). In multivariate analyses, a higher rate of adenomas was present in Hispanics (RR: 1.37, 95% CI: 1.20-1.57) and blacks (RR: 1.76, 95% CI: 1.52-2.04) than whites. Hispanics and blacks also had an increased risk of advanced adenomas compared to whites (OR(Hispanics) : 2.25, 95% CI: 1.62-3.11; OR(blacks) : 1.91, 95% CI: 1.27-2.86).
Adenoma prevalence was higher in blacks and Hispanics than in whites. Both groups were at greater risk of having proximal adenomas in the absence of any distal pathology than whites, where these lesions would have only been detected by colonoscopy. Efforts to promote screening are necessary among diverse, under-represented populations.
[Show abstract][Hide abstract] ABSTRACT: Poor quality bowel preparation has been reported in almost one third of all colonoscopies. To better understand factors associated with poor bowel preparation, we explored perceived patient barriers to optimal pre-colonoscopy bowel preparation from the perspective of the gastroenterologist. A random sample of physician members of the American College of Gastroenterology was surveyed via the internet and postal mailing. Demographic and practice characteristics and practice-related and perceived patient barriers to optimal bowel preparation were assessed among 288 respondents. Lack of time, no patient education reimbursement, and volume of information were not associated with physician level of suboptimal bowel preparation. Those reporting ≥10 % suboptimal bowel preparations were more likely to believe patients lack understanding of the importance of following instructions, have problems with diet, and experience trouble tolerating the purgative. Bowel preparation instruction communication and unmet patient educational needs contribute to suboptimal bowel preparation. Educational interventions should address both practice and patient-related factors.
Full-text · Article · Apr 2012 · Journal of Cancer Education