Decrease in mortality in Lynch syndrome families because of surveillance

A two-antibody mismatch repair protein immunohistochemistry screening approach for colorectal carcinomas, skin sebaceous tumors, and gynecologic tract carcinomas

Mismatch repair protein immunohistochemistry is a widely used method for detecting patients at risk for Lynch syndrome. Recent data suggest that a two-antibody panel approach using PMS2 and MSH6 is an effective screening protocol for colorectal carcinoma, but there are limited data concerning this approach for extraintestinal tumors. The purpose of this study was to review the utility of a two-antibody panel approach in colorectal carcinoma and extraintestinal tumors. We evaluated mismatch repair protein expression in two cohorts: (1) a retrospective analysis of intestinal and extraintestinal tumors (n=334) tested for mismatch repair protein immunohistochemistry and (2) a prospectively accrued series of intestinal, gynecologic tract, and skin sebaceous neoplasms (n=98). A total of 432 cases were analyzed, including 323 colorectal, 50 gynecologic tract, 49 skin sebaceous, and 10 other neoplasms. Overall, 102/432 tumors (24%) demonstrated loss of at least one mismatch repair protein. Concurrent loss of MLH1 and PMS2 was the most common pattern of abnormal expression (50/432, 12%) followed by concurrent loss of MSH2 and MSH6 (33/432, 8%). Of 55 cases with abnormal PMS2 expression, 5 (9%) demonstrated isolated loss of PMS2 expression. Of 47 cases with abnormal MSH6 expression, 14 (30%) demonstrated isolated loss of MSH6 expression. Isolated loss of MLH1 or MSH2 was not observed. Colorectal carcinomas more frequently demonstrated abnormal expression of PMS2 (39/59, 66%). Skin sebaceous neoplasms more frequently demonstrated abnormal expression of MSH6 (18/24, 75%, respectively). A total of 65 tumors with abnormal mismatch repair protein expression were tested for microsatellite instability (MSI): 47 (72%) MSI high, 9 (14%) MSI low, and 9 (14%) microsatellite stable (MSS). Abnormal MSH6 expression accounted for 14/18 (78%) cases that were MSS or MSI low. Our findings confirm the utility of a two-antibody approach using PMS2 and MSH6 in colorectal carcinoma and indicate that this approach is effective in extraintestinal neoplasms associated with Lynch syndrome.

[HNPCC (hereditary non-polyposis colorectal cancer) or Lynch syndrome: a syndrome related to a failure of DNA repair system]

The HNPCC syndrome (hereditary non polyposis colon cancer) or Lynch syndrome stands for an autosomic dominant condition leading to the most prevalent hereditary colo-rectal cancers (CCR). MMR (mismatch repair)'s genes are involved in carcinogenesis as they play a role in ADNA mismatch repair. Microsatellite instability (MSI+ phenotype) induced by germline mutations is characteristic of such tumors and is necessary to assert the diagnosis. The HNPCC syndrome is associated with a significant increased risk of CCR altogether with endometrium, upper urinary tract and small bowel carcinomas as well as ovarian, biliary system and gastric cancers although of lesser extent. It is of importance to diagnose HNPCC syndrome prior to the treatment starts because it may influence patient's (as well as her/his relatives) disease management (type of surgery, surveillance and screening exams). New French recommendations, developed in 2009, about prophylactic colo-rectal and gynecologic surgeries and monitoring update latest ones published on 2004.

Sharing genetic risk with next generation: mutation-positive parents' communication with their offspring in Lynch Syndrome

Identification of hereditary predisposition to cancer has limited significance if not followed by efficient cancer prevention. The responsibility of informing offspring about genetic risk often falls to the parents. We systematically investigated how parents with Lynch Syndrome share knowledge of genetic risk with their offspring, challenges in the communication process and wish for professional support. Of all known mutation carriers over age 40 (n = 337) in 102 Finnish Lynch Syndrome families, 86% completed a self-reported questionnaire; 248 of them (86%) had children. Of the 248 parents, 87% reported disclosure and 13% nondisclosure. Reasons for nondisclosure were mainly the young age of offspring, socially distant relationships, or feeling of difficulty in discussing the topic. Men reported significantly more often disclosure with a support person (spouse etc.) (P < 0.001). The most difficult communication aspect was discussing children's cancer risk. Of the 191 firstborn adult children informed, 69% had taken the predictive genetic test. Every third parent suggested that health professionals should be involved in passing on the information and that a family appointment at the genetic clinic should be organized at the time of disclosure. Nearly all parents had informed their adult offspring about the genetic risk and possibility of genetic testing, but almost one-third were unsure of how their offspring had used the information. The challenge is to improve the communication processes, so that all offspring would get the information important for their health care, and parents would get the professional support desired at disclosure.

Testing women with endometrial cancer to detect Lynch syndrome

PURPOSE

Women with endometrial cancer as a result of Lynch syndrome may not be identified as such by Amsterdam II criteria. We estimated the costs and benefits of different testing criteria to identify Lynch syndrome in women with endometrial cancer.

METHODS

We developed a Markov Monte Carlo simulation model to compare six criteria for Lynch syndrome testing for women with endometrial cancer: Amsterdam II criteria; age younger than 50 years with at least one first-degree relative having a Lynch-associated cancer at any age (FDR); immunohistochemistry (IHC) triage if age younger than 50 years; IHC triage if age younger than 60 years; IHC triage at any age if 1 FDR; and IHC triage of all endometrial cancers. Net health benefit was life expectancy, and primary outcome was the incremental cost-effectiveness ratio (ICER). The model estimated the number of new colorectal cancers associated with each strategy.

RESULTS

IHC triage of women with endometrial cancer having at least 1 FDR yielded a favorable ICER of $9,126 per year of life gained. This strategy would subject fewer cases to IHC but identify more mutation carriers than age thresholds of 50 or 60 years. IHC triage of all endometrial cancers could identify the most mutation carriers and prevent the most colorectal cancers but at considerable cost ($648,494 per year of life gained).

CONCLUSION

IHC triage of women with endometrial cancer at any age having at least 1 FDR with a Lynch-associated cancer is a cost-effective strategy for detecting Lynch syndrome.

Prevalence of alterations in DNA mismatch repair genes in patients with young-onset colorectal cancer

BACKGROUND & AIMS

Direct germline analysis could be used to screen high-risk patients for mutations in DNA mismatch repair genes associated with Lynch Syndrome. We examined the prevalence of mutations in MLH1, MSH2, and MSH6 in a population-based sample of patients with young-onset (age <50 years) colorectal cancer (CRC).

METHODS

Young-onset CRC cases were randomly selected from 3 Colon Cancer Family Registry sites. DNA was extracted from peripheral blood leukocytes; MLH1, MSH2, and MSH6 were sequenced, and duplication and deletion analyses was performed for MLH1 and MSH2. Results were reported as deleterious or suspected deleterious, likely neutral, variant of uncertain significance, or no alteration detected. Germline data were compared to Amsterdam II criteria (ACII) and immunohistochemistry results in secondary analyses.

RESULTS

Among 195 subjects, 11 had deleterious/suspected deleterious mutations (5.6%; 95% confidence interval [CI], 2.8%-9.9%), 12 had likely neutral alterations (6.2%; 95% CI, 3.2%-10.5%), 14 had variants of uncertain significance (7.2%; 95% CI, 4.0%-11.8%), 2 had a likely neutral alteration and a variant of uncertain significance (1.0%; 95% CI, 0.1%-3.7%), and 156 had no alteration detected (80.0%; 95% CI, 73.7%-85.4%). Sensitivity, specificity, and positive and negative predictive values for detecting deleterious/suspected deleterious mutations, based on ACII, were 36.4% (4/11), 96.7% (178/184), 40.0% (4/10), and 96.2% (178/185), respectively; based on immunohistochemistry these values were 85.7% (6/7), 91.9% (136/148), 33.3% (6/18), and 99.3% (136/137), respectively.

CONCLUSIONS

In a population-based sample of young-onset CRC cases, germline mutations in MLH1, MSH, and/or MSH6 were more prevalent than reported for CRC patients overall. Because only about 5% of young-onset CRC cases had confirmed deleterious or suspected deleterious mutations, further comparative effectiveness research is needed to determine the most appropriate screening strategy for Lynch Syndrome in this high-risk group.

Colonoscopy use following mutation detection in Lynch syndrome: exploring a role for cancer screening in adaptation

Lynch syndrome (LS) is the most common inherited form of colorectal cancer. Mutation carriers can reduce the morbidity and mortality associated with colorectal cancer through colonoscopy. Theoretical models suggest that such health-related behaviors might also bring psychological benefits. This study assessed whether colonoscopy following mutation detection was associated with the levels of depressive symptoms. Data were obtained from a prospective family cohort study offering genetic services for LS. Participants completed questionnaires prior to the provision of services and 6 months post-receipt of mutation results. One hundred thirty-four (134) persons were identified to carry a mutation and completed both the questionnaires. Main outcome measures were depressive symptoms 6 months post-receipt of test results. Mutation carriers who did not complete a colonoscopy within the 6 months following receipt of results were six times (p < 0.01; odds ratio = 6.06) more likely to report depressive symptoms at a level of clinical importance post-receipt of test results compared to those who did undergo colonoscopy. Facilitating the expeditious use of colonoscopy following mutation detection may benefit newly identified mutation carriers by addressing the objective risks for cancer and moderating underlying emotional distress responses to genetic risk information. Furthermore, depressive symptoms may interfere with behavioral compliance in some patients, suggesting referral to mental health specialists.

A systematic review of gynecological cancer surveillance in women belonging to hereditary nonpolyposis colorectal cancer (Lynch syndrome) families

OBJECTIVE/DESIGN

We performed a systematic review of studies that evaluate the role of gynecological cancer surveillance in women who carry a hereditary nonpolyposis colorectal cancer (HNPCC) mutation or belong to a family that fulfills the criteria for HNPCC.

METHODS

The PubMed database and a clinical trials database were used to identify relevant studies. We included studies that reported results of gynecological cancer surveillance in women who carry a HNPCC mutation, belong to a family in which a HNPCC mutation was detected or belong to a family fulfilling the Amsterdam II criteria.

MAIN OUTCOME MEASURES

Number and stage of cancers, interval cancers and cancer precursor states detected at screening.

RESULTS

Five studies fulfilled our review criteria. Surveillance modalities for endometrial cancer included transvaginal ultrasound combined with endometrial sampling when indicated, or transvaginal ultrasound with a routine endometrial biopsy, and, in certain studies, the tumor marker CA-125. The highest yield of pathological findings in surveillance visits, from 5 to 6.5%, occurred in studies that included routine endometrial biopsies. Without a routine sampling, 7/14 cancers and 11/18 hyperplasias would have been missed. One case of advanced ovarian cancer was detected at surveillance.

CONCLUSIONS

Currently available published studies on gynecological cancer surveillance in women with HNPCC do not adequately allow for evidence-based clinical decisions. Detection of endometrial cancer or hyperplasia in nonsymptomatic women belonging to an HNPCC family is improved by adding routine endometrial sampling along with transvaginal ultrasound for surveillance visits. No benefit was shown for ovarian cancer surveillance.

Identification of patients at-risk for Lynch syndrome in a hospital-based colorectal surgery clinic

AIM: To determine the prevalence of a family history suggestive of Lynch syndrome (LS) among patients with colorectal cancer (CRC) followed in a coloproctology outpatient clinic in Southern Brazil.

METHODS: A consecutive sample of patients with CRC were interviewed regarding personal and family histories of cancer. Clinical data and pathology features of the tumor were obtained from chart review.

RESULTS: Of the 212 CRC patients recruited, 61 (29%) reported a family history of CRC, 45 (21.2%) were diagnosed under age 50 years and 11 (5.2%) had more than one primary CRC. Family histories consistent with Amsterdam and revised Bethesda criteria for LS were identified in 22 (10.4%) and 100 (47.2%) patients, respectively. Twenty percent of the colorectal tumors had features of the high microsatellite instability phenotype, which was associated with younger age at CRC diagnosis and with Bethesda criteria (P < 0.001). Only 5.3% of the patients above age 50 years had been previously submitted for CRC screening and only 4% of patients with suspected LS were referred for genetic risk assessment.

CONCLUSION: A significant proportion of patients with CRC were at high risk for LS. Education and training of health care professionals are essential to ensure proper management.

Clinical genetics of hereditary colorectal cancer

Colorectal cancer (CRC) is a common disease, and approximately 25% of patients have a familial component. High-penetrance singlegene germline mutations conferring a true hereditary susceptibility account for around 5% to 6% of all cases. Lynch syndrome is the most common hereditary form of colorectal cancer. Much of the hereditary component in the remaining familial cases of CRC is likely polygenic, and many of the genetic changes involved are as yet unidentified. This article addresses the most clinically important CRC genetic syndromes.

The PREMM(1,2,6) model predicts risk of MLH1, MSH2, and MSH6 germline mutations based on cancer history

BACKGROUND & AIMS

We developed and validated a model to estimate the risks of mutations in the mismatch repair (MMR) genes MLH1, MSH2, and MSH6 based on personal and family history of cancer.

METHODS

Data were analyzed from 4539 probands tested for mutations in MLH1, MSH2, and MSH6. A multivariable polytomous logistic regression model (PREMM(1,2,6)) was developed to predict the overall risk of MMR gene mutations and the risk of mutation in each of the 3 genes. The discriminative ability of the model was validated in 1827 population-based colorectal cancer (CRC) cases.

RESULTS

Twelve percent of the original cohort carried pathogenic mutations (204 in MLH1, 250 in MSH2, and 71 in MSH6). The PREMM(1,2,6) model incorporated the following factors from the probands and first- and second-degree relatives (odds ratio; 95% confidence intervals [CIs]): male sex (1.9; 1.5-2.4), a CRC (4.3; 3.3-5.6), multiple CRCs (13.7; 8.5-22), endometrial cancer (6.1; 4.6-8.2), and extracolonic cancers (3.3; 2.4-4.6). The areas under the receiver operating characteristic curves were 0.86 (95% CI, 0.82-0.91) for MLH1 mutation carriers, 0.87 (95% CI, 0.83-0.92) for MSH2, and 0.81 (95% CI, 0.69-0.93) for MSH6; in validation, they were 0.88 for the overall cohort (95% CI, 0.86-0.90) and the population-based cases (95% CI, 0.83-0.92).

CONCLUSIONS

We developed the PREMM(1,2,6) model, which incorporates information on cancer history from probands and their relatives to estimate an individual's risk of mutations in the MMR genes MLH1, MSH2, and MSH6. This Web-based decision making tool can be used to assess risk of hereditary CRC and guide clinical management.

MSH6 and MUTYH deficiency is a frequent event in early-onset colorectal cancer

PURPOSE

Early-onset colorectal cancer (CRC) is suggestive of a hereditary predisposition. Lynch syndrome is the most frequent CRC hereditary cause. The MUTYH gene has also been related to hereditary CRC. A systematic characterization of these two diseases has not been reported previously in this population.

EXPERIMENTAL DESIGN

We studied a retrospectively collected series of 140 patients ≤50 years old diagnosed with nonpolyposis CRC. Demographic, clinical, and familial features were obtained. Mismatch repair (MMR) deficiency was determined by microsatellite instability (MSI) analysis, and immunostaining for MLH1, MSH2, MSH6, and PMS2 proteins. Germline MMR mutations were evaluated in all MMR-deficient cases. Tumor samples with loss of MLH1 or MSH2 protein expression were analyzed for somatic methylation. Germline MUTYH mutations were evaluated in all cases. BRAF V600E and KRAS somatic mutational status was also determined.

RESULTS

Fifteen tumors (11.4%) were MSI, and 20 (14.3%) showed loss of protein expression (7 for MLH1/PMS2, 2 for isolated MLH1, 3 for MSH2/MSH6, 7 for isolated MSH6, and 1 for MSH6/PMS2). We identified 11 (7.8%) germline MMR mutations, 4 in MLH1, 1 in MSH2, and 6 in MSH6. Methylation analysis revealed one case with somatic MLH1 methylation. Biallelic MUTYH mutations were detected in four (2.8%) cases. KRAS and BRAF V600E mutations were present in 39 (27.9%) and 5 (3.6%) cases, respectively.

CONCLUSIONS

Loss of MSH6 expression is the predominant cause of MMR deficiency in early-onset CRC. Our findings prompt the inclusion of MSH6 and MUTYH screening as part of the genetic counseling of these patients and their relatives.

Genetic counseling considerations in the evaluation of families for Lynch syndrome--a review

Lynch syndrome is the most common hereditary colorectal cancer syndrome and the most common cause of hereditary endometrial cancer. Identifying and evaluating families for Lynch syndrome is increasing in complexity due to the recognition that: family history-based clinical criteria lack sensitivity and specificity; genetic testing for Lynch syndrome continues to evolve as understanding of the molecular mechanisms underlying it evolves; and the Lynch syndrome phenotype encompasses multiple organ systems and demonstrates overlap with other hereditary cancer syndromes. This document is a summary of considerations when evaluating individuals and families for Lynch syndrome, including information on cancer risks, diagnostic criteria, tumor and genetic testing strategies, and the management of individuals with this condition.

Endoscopic surveillance for hereditary non-polyposis colorectal cancer (HNPCC) family members in a Southern Italian region

BACKGROUND

Surveillance in hereditary non-polyposis colorectal cancer (HNPCC) family members recommends baseline colonoscopy starting at age 20 and then surveillance colonoscopy every 1-2 years.

AIMS

To verify adherence to the guidelines for HNPCC family members enrolled in endoscopic surveillance.

METHODS

Data regarding 11 HNPCC families was retrieved from our database. Excluding 11 probands, 106 family members were evaluated and 40 underwent surveillance.

RESULTS

At baseline colonoscopy, 7 colorectal cancers (CRC), 14 polyps (PO) [1 inflammatory, 2 hyperplastic, 10 adenomas with low grade dysplasia (LGD-AD) and 1 adenoma with high-grade dysplasia (HGD-AD)] were diagnosed in sixteen individuals. Twenty-eight HNPCC family members underwent endoscopic surveillance, with a total of 94 surveillance colonoscopies. Of these, 45 were positive (4 CRC, 3 inflammatory PO, 34 hyperplastic PO, 21 LGD-AD and 5 HGD-AD). Mean time between two consecutive surveillance colonoscopies was 24.6 months (range 4-168). Median time to first positive surveillance colonoscopy was 84 months for HNPCC family members with negative baseline colonoscopy, and 60 months for those with positive baseline colonoscopy (p=0.21).

CONCLUSIONS

Our data suggests that surveillance colonoscopy every 2 years is adequate to diagnose advanced lesions in HNPCC family members, and improves their compliance with surveillance.

Management of high-risk colonoscopy patients

Rapidly evolving knowledge of the pathogenesis and natural history of colorectal cancer (CRC), especially in high-risk groups, is allowing the development of new tools to identify those who will benefit most from preventive measures. Currently, screening for adenomas, dysplasia, and early-stage invasive cancers provides the best opportunity to prevent and improve survival from CRC. Screening of high-risk groups almost always includes colonoscopy. This review discusses what represents quality colonoscopy. Proper risk stratification, understanding the natural history of each disease, proper patient counseling, and optimal techniques all help define quality colonoscopy in high-risk groups.

Selection of patients with germline MLH1 mutated Lynch syndrome by determination of MLH1 methylation and BRAF mutation

Lynch syndrome is one of the most common hereditary colorectal cancer (CRC) syndrome and is caused by germline mutations of MLH1, MSH2 and more rarely MSH6, PMS2, MLH3 genes. Whereas the absence of MSH2 protein is predictive of Lynch syndrome, it is not the case for the absence of MLH1 protein. The purpose of this study was to develop a sensitive and cost effective algorithm to select Lynch syndrome cases among patients with MLH1 immunohistochemical silencing. Eleven sporadic CRC and 16 Lynch syndrome cases with MLH1 protein abnormalities were selected. The BRAF c.1799T> A mutation (p.Val600Glu) was analyzed by direct sequencing after PCR amplification of exon 15. Methylation of MLH1 promoter was determined by Methylation-Sensitive Single-Strand Conformation Analysis. In patients with Lynch syndrome, there was no BRAF mutation and only one case showed MLH1 methylation (6%). In sporadic CRC, all cases were MLH1 methylated (100%) and 8 out of 11 cases carried the above BRAF mutation (73%) whereas only 3 cases were BRAF wild type (27%). We propose the following algorithm: (1) no further molecular analysis should be performed for CRC exhibiting MLH1 methylation and BRAF mutation, and these cases should be considered as sporadic CRC; (2) CRC with unmethylated MLH1 and negative for BRAF mutation should be considered as Lynch syndrome; and (3) only a small fraction of CRC with MLH1 promoter methylation but negative for BRAF mutation should be true Lynch syndrome patients. These potentially Lynch syndrome patients should be offered genetic counselling before searching for MLH1 gene mutations.

Targeting risk groups for screening

Currently colorectal cancer (CRC) screening guidelines are based on age and to some extent on family history of screenees only. Potentially CRC screening could be also customised according to gender, race, ethnicity, smoking habits, presence of obesity, diabetes and metabolic syndrome. The factors that could be individually modified are: choice of screening test, age of initiation of screening and screening intervals. Gender is probably the easiest factor to be included. One of the professional societies has already included the race into guidelines in order to lower the age of starting screening in African-Americans. Targeting persons at higher than average-risk aims at optimising the use of available resources. However, an important drawback of such approach exists; it is the risk of making guidelines too complex and incomprehensible for both eligible screenees and physicians.

One to 2-year surveillance intervals reduce risk of colorectal cancer in families with Lynch syndrome

BACKGROUND & AIMS

Two percent to 4% of all cases of colorectal cancer (CRC) are associated with Lynch syndrome. Dominant clustering of CRC (non-Lynch syndrome) accounts for 1%-3% of the cases. Because carcinogenesis is accelerated in Lynch syndrome, an intensive colonoscopic surveillance program has been recommended since 1995. The aim of the study was to evaluate the effectiveness of this program.

METHODS

The study included 205 Lynch syndrome families with identified mutations in one of the mismatch repair genes (745 mutation carriers). We also analyzed data from non-Lynch syndrome families (46 families, 344 relatives). Patients were observed from January 1, 1995, until January 1, 2009. End points of the study were CRC or date of the last colonoscopy.

RESULTS

After a mean follow-up of 7.2 years, 33 patients developed CRC under surveillance. The cumulative risk of CRC was 6% after the 10-year follow-up period. The risk of CRC was higher in carriers older than 40 years and in carriers of MLH1 and MSH2 mutations. After a mean follow-up of 7.0 years, 6 cases of CRC were detected among non-Lynch syndrome families. The risk of CRC was significantly higher among families with Lynch syndrome, compared with those without.

CONCLUSIONS

With surveillance intervals of 1-2 years, members of families with Lynch syndrome have a lower risk of developing CRC than with surveillance intervals of 2-3 years. Because of the low risk of CRC in non-Lynch syndrome families, a less intensive surveillance protocol can be recommended.

Decision Model of Segmental Compared With Total Abdominal Colectomy for Colon Cancer in Hereditary Nonpolyposis Colorectal Cancer

Purpose

In choosing the appropriate surgical option for patients with colon cancer and Lynch syndrome, goals of treatment are to maximize life expectancy while preserving quality of life. This study constructs a decision model that encompasses these two related considerations.

Methods

We constructed a state-transition (Markov) model based on assumptions obtained from available data sources and published literature. Two strategies were considered for the treatment of colon cancer in a patient with Lynch syndrome: segmental colectomy (SEG) and total abdominal colectomy (TAC) with ileorectal anastomosis. Quality-adjusted life years (QALYs) were calculated based on utility states for patients based on the colectomy they received. Multiple sensitivity analyses were planned to examine the impact of each assumption on model results.

Results

For young (30-year-old) patients with Lynch syndrome, mean survival was slightly better with TAC than with SEG (34.8 v 35.5 years). When QALYs were considered, the two strategies were approximately equivalent, with QALYs per patient of 21.5 for SEG and 21.2 for TAC. With advancing age, SEG becomes a more favorable strategy. Results of our model were most sensitive to the utility state of TAC (relative to SEG), rates of metachronous occurrence, and stage of cancer at the time of such occurrence.

Conclusion

SEG and TAC are approximately equivalent strategies for patients with colon cancer and Lynch syndrome. The decision regarding which operation is preferable should be made on the basis of patient factors and preferences, with special emphasis on age and the ability of the patient to utilize intensive surveillance.

Efficacy of annual colonoscopic surveillance in individuals with hereditary nonpolyposis colorectal cancer

BACKGROUND & AIMS

Individuals with hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome) have a high risk for developing colorectal cancer (CRC). We evaluated the efficacy of annual surveillance colonoscopies to detect adenomas and CRCs.

METHODS

In a prospective, multicenter cohort study, 1126 individuals underwent 3474 colonoscopies. We considered individuals from 3 groups of HNPCC families: those with a pathogenic germline mutation in a mismatch repair gene (MUT group), those without a mutation but with microsatellite instability (MSI group), and those who fulfilled the Amsterdam criteria without microsatellite instability (MSS group).

RESULTS

Compliance to annual intervals was good, with 81% of colonoscopies completed within 15 months. Ninety-nine CRC events were observed in 90 patients. Seventeen CRCs (17%) were detected through symptoms (8 before baseline colonoscopy, 8 at intervals >15 months to the preceding colonoscopy, and 1 interval cancer). Only 2 of 43 CRCs detected by follow-up colonoscopy were regionally advanced. Tumor stages were significantly lower among CRCs detected by follow-up colonoscopies compared with CRCs detected by symptoms (P = .01). Cumulative CRC risk at the age of 60 years was similar in the MUT and MSI groups (23.0% combined; 95% confidence interval [CI], 14.8%-31.2%) but considerably lower in the MSS group (1.8%; 95% CI, 0.0%-5.1%). Adenomas at baseline colonoscopy predicted an earlier occurrence of subsequent adenoma (hazard ratio, 2.6; 95% CI, 1.7-4.0) and CRC (hazard ratio, 3.9; 95% CI, 1.7-8.5), providing information about interindividual heterogeneity of adenomas and kinetics of CRC formation.

CONCLUSIONS

Annual colonoscopic surveillance is recommended for individuals with HNPCC. Less intense surveillance might be appropriate for MSS families.

Cancer risk in MLH1, MSH2 and MSH6 mutation carriers; different risk profiles may influence clinical management

BACKGROUND

Lynch syndrome (LS) is associated with a high risk for colorectal cancer (CRC) and extracolonic malignancies, such as endometrial carcinoma (EC). The risk is dependent of the affected mismatch repair gene. The aim of the present study was to calculate the cumulative risk of LS related cancers in proven MLH1, MSH2 and MSH6 mutation carriers.

METHODS

The studypopulation consisted out of 67 proven LS families. Clinical information including mutation status and tumour diagnosis was collected. Cumulative risks were calculated and compared using Kaplan Meier survival analysis.

RESULTS

MSH6 mutation carriers, both males and females had the lowest risk for developing CRC at age 70 years, 54% and 30% respectively and the age of onset was delayed by 3-5 years in males. With respect to endometrial carcinoma, female MSH6 mutation carriers had the highest risk at age 70 years (61%) compared to MLH1 (25%) and MSH2 (49%). Also, the age of EC onset was delayed by 5-10 years in comparison with MLH1 and MSH2.

CONCLUSIONS

Although the cumulative lifetime risk of LS related cancer is similar, MLH1, MSH2 and MSH6 mutations seem to cause distinguishable cancer risk profiles. Female MSH6 mutation carriers have a lower CRC risk and a higher risk for developing endometrial carcinoma. As a consequence, surveillance colonoscopy starting at age 30 years instead of 20-25 years is more suitable. Also, prophylactic hysterectomy may be more indicated in female MSH6 mutation carriers compared to MLH1 and MSH2 mutation carriers.

A review on the molecular diagnostics of Lynch syndrome: a central role for the pathology laboratory

Lynch syndrome (LS) is caused by mutations in mismatch repair genes and is characterized by a high cumulative risk for the development of mainly colorectal carcinoma and endometrial carcinoma. Early detection of LS is important since surveillance can reduce morbidity and mortality. However, the diagnosis of LS is complicated by the absence of a pre-morbid phenotype and germline mutation analysis is expensive and time consuming. Therefore it is standard practice to precede germline mutation analysis by a molecular diagnostic work-up of tumours, guided by clinical and pathological criteria, to select patients for germline mutation analysis. In this review we address these molecular analyses, the central role for the pathologist in the selection of patients for germline diagnostics of LS, as well as the molecular basis of LS.

Colorectal cancer due to deficiency in DNA mismatch repair function: a review

Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome attributable to deleterious germline mutations in mismatch repair (MMR) genes. The syndrome is typified by early-onset, frequently right-sided colorectal cancers (CRCs) with characteristic histologic features and tendency for multiplicity and an increased risk for extracolonic tumors at particular sites; it accounts for 1% to 5% of CRC. Deficient mismatch repair (dMMR) function manifests as immunohistochemically detectable absence of one or more MMR proteins and microsatellite instability (MSI). Approximately 15% of sporadic, noninherited CRC are characterized by high-level MSI, nearly always owing to transcriptional silencing of MLH1; these sporadic and LS cases exhibit considerable phenotypic overlap. Identification of CRC with dMMR is desirable to identify LS and because MSI status is prognostic and potentially predictive. This review will discuss the history of LS, the principles of MMR and MSI, the clinicopathologic features of LS-associated and sporadic high-level MSI CRC, the fundamentals of clinical testing for dMMR CRC, and the results of the Columbus-area Lynch syndrome study. We conclude with our approach to population-based LS screening based on institutional experience with nearly 2000 cases.

Recommendations to improve identification of hereditary and familial colorectal cancer in Europe

Familial colorectal cancer (CRC) accounts for 10-15% of all CRCs. In about 5% of all cases, CRC is associated with a highly penetrant dominant inherited syndrome. The most common inherited form of non-polyposis CRC is the Lynch syndrome which is responsible for about 2-4% of all cases. Surveillance of individuals at high risk for CRC prevents the development of advanced CRC. About 1 million individuals in Western Europe are at risk for Lynch syndrome. We performed a survey to evaluate the strategies currently used to identify individuals at high risk for CRC in 14 Western European countries. Questionnaires were distributed amongst members of a European collaborative group of experts that aims to improve the prognosis of families with hereditary CRC. The survey showed that in all countries obtaining a family history followed by referral to clinical genetics centres of suspected cases was the main strategy to identify familial and hereditary CRC. In five out of seven countries with a (regional or national) CRC population screening program, attention was paid in the program to the detection of familial CRC. In only one country were special campaigns organized to increase the awareness of familial CRC among the general population. In almost all countries, the family history is assessed when a patient visits a general practitioner or hospital. However, the quality of family history taking was felt to be rather poor. Microsatellite instability testing (MSI) or immunohistochemical analysis (IHC) of CRC are usually recommended as tools to select high-risk patients for genetic testing and are performed in most countries in patients suspected of Lynch syndrome. In one country, IHC was recommended in all new cases of CRC. In most countries there are no specific programs on cancer genetics in the teaching curriculum for medical doctors. In conclusion, the outcome of this survey and the discussions within an European expert group may be used to improve the strategies to identify individuals at high risk of CRC. More attention should be given to increasing the awareness of the general population of hereditary CRC. Immunohistochemical analysis or MSI-analysis of all CRCs may be an effective tool for identifying all Lynch syndrome families. The cost-effectiveness of this approach should be further evaluated. All countries with a CRC population screening program should obtain a full family history as part of patient assessment.

Ten years after mutation testing for Lynch syndrome: cancer incidence and outcome in mutation-positive and mutation-negative family members

PURPOSE

Colonoscopies with polypectomies and endometrial biopsies with transvaginal ultrasonography, repeated at 2- to 3-year intervals, are performed for prevention or early detection of cancer in patients with DNA mismatch repair gene mutation causing Lynch syndrome. The long-term effectiveness of surveillance was evaluated in Lynch syndrome family members tested approximately 10 years ago.

MATERIALS AND METHODS

Cancer incidence and survival were determined after an 11.5-year follow-up in 242 mutation-positive and 367 mutation-negative participants. These participants in 57 Lynch syndrome families with 14 different mutations were at 50% risk. The median age was 36 years (range, 18 to 72 years) in mutation carriers and 42 years (range, 18 to 72 years) in mutation-negative participants, and none had had cancer of the Lynch syndrome type.

RESULTS

Compliance was 95.9% for the colonic surveillance and 97.1% for the gynecologic surveillance. Colorectal cancer (CRC) occurred in 30 mutation-positive participants, and 74 participants had adenomas removed. Three patients died of CRC. Endometrial cancer (EC) occurred in 19 of 103 women at risk, and 48 women had prophylactic hysterectomy. Six of 112 women at risk had ovarian cancer. The overall cancer risk ratio (RR) in mutation carriers was 5.80 (95% CI, 3.4 to 9.5). Cancer mortality rate (RR = 2.28; 95% CI, 0.82 to 6.31) and overall death rate (RR = 1.26; 95% CI, 0.65 to 2.46) were not significantly increased.

CONCLUSION

Long-term compliance in surveillance for CRC and EC exceeded 95% in Lynch syndrome. All CRC deaths were not prevented as a result of noncompliance or missed lesions. Still, after 10 years of surveillance, no significant increase in mortality had occurred compared with mutation-negative relatives.

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.

MATERIAL AND 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.

Germ line MLH1 and MSH2 mutations in Taiwanese Lynch syndrome families: characterization of a founder genomic mutation in the MLH1 gene

This multicenter study evaluated the mutation spectrum and frequencies of the MLH1 and MSH2 genes and determined the occurrence of large genomic deletions in 93 unrelated Taiwanese families that fulfilled the Amsterdam criteria II by denaturing high-performance liquid chromatography analysis, DNA sequencing for aberrant chromatograms, and multiplex ligation-dependent probe amplification analysis. In total, 38 pathogenic mutations (10 large deletions and 28 point mutations or small deletion/insertions) in the MSH2 or MLH1 gene were identified in 61 of the 93 families (66%). Three of the 10 large deletions and 14 of the 28 point mutations or small insertions/deletions have not been reported elsewhere. Three mutations in the MLH1 gene, the MLH1c.1846_1848delAAG (5 families), deletion exons 11-15 (4 unrelated families), and MLH1c.793C>T (13 unrelated families), accounted for 35% of all cases with pathogenic mutations. Haplotype analysis indicated that mutant c.793C>T alleles were derived from two distinct common founders that might be inherited from a single ancestor of presumably Chinese origin. As a mutation detection strategy for Taiwanese Lynch syndrome patients, we recommend that diagnosis starts with screening for large genomic deletions and continues by screening for common mutations in exons 10 and 16 of the MLH1 gene prior to searching for small mutations in the remaining exons.

Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications

More than one million patients will manifest colorectal cancer (CRC) this year of which, conservatively, approximately 3% (approximately 30,700 cases) will have Lynch syndrome (LS), the most common hereditary CRC predisposing syndrome. Each case belongs to a family with clinical needs that require genetic counseling, DNA testing for mismatch repair genes (most frequently MLH1 or MSH2) and screening for CRC. Colonoscopy is mandated, given CRC's proximal occurrence (70-80% proximal to the splenic flexure). Due to its early age of onset (average 45 years of age), colonoscopy needs to start by age 25, and because of its accelerated carcinogenesis, it should be repeated every 1 to 2 years through age 40 and then annually thereafter. Should CRC occur, subtotal colectomy may be necessary, given the marked frequency of synchronous and metachronous CRC. Because 40-60% of female patients will manifest endometrial cancer, tailored management is essential. Additional extracolonic cancers include ovary, stomach, small bowel, pancreas, hepatobiliary tract, upper uroepithelial tract, brain (Turcot variant) and sebaceous adenomas/carcinomas (Muir-Torre variant). LS explains only 10-25% of familial CRC.

Development and validation of a colon cancer risk assessment tool for patients undergoing colonoscopy

OBJECTIVES

Diagnostic criteria for hereditary colorectal cancer (CRC) are complex. "Open-access" colonoscopy makes it challenging to identify who needs genetic evaluation, intensive surveillance, and screening for extracolonic tumors. Our aim was to develop a simple, preprocedural risk assessment tool to identify who may be at highest risk for CRC.

METHODS

A total of 631 outpatients undergoing colonoscopy at two academic practices completed a questionnaire assessing personal and family histories of CRC, polyps, and Lynch syndrome (LS)-associated malignancies. Subjects were considered to be high-risk if one of the nine prespecified characteristics of hereditary CRC syndromes was met. Through recursive partitioning analysis, an algorithm of fewest questions needed to capture the most high-risk individuals was developed. The results were validated in 5,335 individuals undergoing colonoscopy at five private endoscopy centers and tested in 285 carriers of mismatch repair mutations associated with LS.

RESULTS

About 17.7% and 20.0% of individuals were classified as high-risk in the development and validation cohorts, respectively. Recursive partitioning revealed three questions that were most informative for identifying high-risk patients: (i) "Do you have a first-degree relative with CRC or LS-related cancer diagnosed before age 50?" (ii) "Have you had CRC or polyps diagnosed before age 50?" (iii) "Do you have > or =3 relatives with CRC?" When asked successively, these questions identified 77% of high-risk individuals in both cohorts and 271 of 285 (95%) of mutation carriers.

CONCLUSIONS

Approximately one in five individuals undergoing colonoscopy would benefit from further risk assessment. We developed a simple, three-question CRC Risk Assessment Tool to identify the majority of patients who require additional assessment and possible genetic evaluation.

Management of extracolonic tumours in patients with Lynch syndrome

Hereditary nonpolyposis colorectal cancer, or Lynch syndrome, is responsible for 2-3% of all colorectal cancers. Lynch syndrome is also associated with a high risk of extracolonic cancers, including endometrial, stomach, small bowel, pancreas, biliary tract, ovary, urinary tract, brain, and skin cancer. In this Review, we discuss the risks, surveillance tests, and guidelines for the management of extracolonic tumours associated with Lynch syndrome. For all types of extracolonic cancer, evidence supporting surveillance is scarce. A benefit of surveillance is evident only for endometrial cancer, where transvaginal ultrasound and endometrial sampling detect tumours in early stages. Surveillance is generally recommended for urinary tract and gastric cancer, especially in families with more than one member with these types of cancer. For the other types of cancer, surveillance is typically not recommended. Prophylactic hysterectomy and bilateral salpingo-oophorectomy should be considered for women with Lynch syndrome who are past childbearing age, especially during surgery for colorectal cancer. No data show efficacy of chemopreventive drugs in reducing the risk of extracolonic cancers for patients with Lynch syndrome.

Genetic testing in gastroenterology: Lynch syndrome

Lynch syndrome/Hereditary non-polyposis colorectal cancer is caused by inherited germline mutations in mismatch repair (MMR) genes, and accounts for 2-5% of colorectal cancers (CRC) . It is characterized by young onset CRC and an increased risk for gynaecologic, urinary tract and gastrointestinal cancers. Family history evaluation is crucial in the early identification of individuals at risk for Lynch syndrome. Individuals whose family history includes multiple relatives with cancer, two or more primary cancers, or component tumours diagnosed at a young age, should undergo genetic evaluation for Lynch syndrome. Guidelines recommend initial evaluation of the tumour with immunohistochemistry or microsatellite instability testing followed by germline testing for mutations in MMR genes in those with abnormal results. Genetic test results can guide screening recommendations for patients and their families. However, results are not always conclusive and in such cases recommendations for cancer screening should be individualized on the basis of personal and family history.

Recommendations from the EGAPP Working Group: genetic testing strategies in newly diagnosed individuals with colorectal cancer aimed at reducing morbidity and mortality from Lynch syndrome in relatives

SUMMARY OF RECOMMENDATIONS

The Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found sufficient evidence to recommend offering genetic testing for Lynch syndrome to individuals with newly diagnosed colorectal cancer to reduce morbidity and mortality in relatives. We found insufficient evidence to recommend a specific genetic testing strategy among the several examined.

RATIONALE

Genetic testing to detect Lynch syndrome in individuals with newly diagnosed colorectal cancer (CRC) is proposed as a strategy to reduce CRC morbidity and mortality in their relatives (see Clinical Considerations section for definition of Lynch syndrome). The EGAPP Working Group (EWG) constructed a chain of evidence that linked genetic testing for Lynch syndrome in patients with newly diagnosed CRC with improved health outcomes in their relatives. We found that assessing patients who have newly diagnosed CRC with a series of genetic tests could lead to the identification of Lynch syndrome. Relatives of patients with Lynch syndrome could then be offered genetic testing, and, where indicated, colorectal, and possibly endometrial, cancer surveillance, with the expectation of improved health outcome. The EWG concluded that there is moderate certainty that such a testing strategy would provide moderate population benefit.

ANALYTIC VALIDITY

The EWG found adequate evidence to conclude that the analytic sensitivity and specificity for preliminary and diagnostic tests were high.

CLINICAL VALIDITY

After accounting for the specific technologies and numbers of markers used, the EWG found at least adequate evidence to describe the clinical sensitivity and specificity for three preliminary tests, and for four selected testing strategies. These measures of clinical validity varied with each test and each strategy (see Clinical Considerations section).

CLINICAL UTILITY

The EWG found adequate evidence for testing uptake rates, adherence to recommended surveillance activities, number of relatives approachable, harms associated with additional follow-up, and effectiveness of routine colonoscopy. This chain of evidence supported the use of genetic testing strategies to reduce morbidity/mortality in relatives with Lynch syndrome. Several genetic testing strategies were potentially effective, but none was clearly superior. The evidence for or against effectiveness of identifying mismatch repair (MMR) gene mutations in reducing endometrial cancer morbidity or mortality was inadequate.

CONTEXTUAL ISSUES

CRC is a common disease responsible for an estimated 52,000 deaths in the United States in 2007. In about 3% of newly diagnosed CRC, the underlying cause is a mutation in a MMR gene (Lynch syndrome) that can be reliably identified with existing laboratory tests. Relatives inheriting the mutation have a high (about 45% by age 70) risk of developing CRC. Evidence suggests these relatives will often accept testing and increased surveillance.

Identification in daily practice of patients with Lynch syndrome (hereditary nonpolyposis colorectal cancer): revised Bethesda guidelines-based approach versus molecular screening

BACKGROUND

The identification of individuals who should undergo hereditary nonpolyposis colorectal cancer (HNPCC) genetic testing remains a critical issue. The Bethesda guidelines were developed to preselect patients for microsatellite instability (MSI) testing before germline mutation screening. These criteria have been revised, and a new set of recommendations, the revised Bethesda guidelines, has been proposed.

OBJECTIVE

To evaluate the performance of these revised guidelines for identifying patients with HNPCC in a series of unselected consecutive patients and compare this revised guidelines-based approach with a molecular strategy (MSI testing for all tumors, followed by exclusion of MSI-positive sporadic cases from mutational testing).

PATIENTS AND METHODS

The study included 214 patients with newly diagnosed colorectal cancer. The MSI analysis was performed for all tumors. Germline testing, guided by immunohistochemical staining for mismatch repair proteins, was performed for patients with MSI-positive tumors. Sporadic MSI-positive tumors were identified by screening for BRAF mutation and MLH1 promoter methylation.

RESULTS

Ninety patients (42.1%) met the revised guidelines. Twenty-one patients (9.8%) had MSI-positive tumors. Germline testing identified eight mutations (3.7%) (MSH2 N = 5, MLH1 N = 2, MSH6 N =1). The revised guidelines failed to identify 2 of the 8 probands (aged 67 and 81 yr, both with no family history). In contrast, the molecular strategy identified all patients requiring testing for germline mutation. The percentages of patients selected for germline testing by the revised guidelines and the molecular strategy were 4.2% and 5.1%, respectively.

CONCLUSIONS

The revised Bethesda guidelines did not identify all HNPCC cases in our series. The molecular approach identified all HNPCC patients with MSI-positive tumors, increasing the workload for germline testing only slightly.

Clinical guidelines versus universal molecular testing: are we ready to choose an optimal strategy for Lynch syndrome identification?

Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common form of inherited colorectal cancer (CRC). Affected individuals need to undergo intensive CRC surveillance, screening for associated cancers, and possibly prophylactic surgery. Clinically-based guidelines have been used as the basis for Lynch syndrome screening in CRC patient populations. More recently, it has been argued that the universal molecular testing strategies should be implemented to increase the identification of patients who should get germline testing for Lynch syndrome. In this issue of American Journal of Gastroenterology, Julie et al. compare the performance of clinical guidelines with a molecular strategy based on universal microsatellite instability (MSI) testing for identifying CRC patients who have Lynch syndrome. Although there is insufficient evidence to support universal molecular testing for all CRC patients at the current time, the study highlights the need for a systematic approach to identify patients with Lynch syndrome. Physicians and health care systems need to do a better job of identifying patients and families with early-onset of CRC and/or a consistent cancer family history so that they may undergo appropriate molecular evaluation, genetic counseling, and cancer risk management.

Randomized trial of a decision aid for individuals considering genetic testing for hereditary nonpolyposis colorectal cancer risk

BACKGROUND

Despite the potential benefits of genetic testing for hereditary nonpolyposis colorectal cancer (HNPCC) risk, individuals can find the genetic testing decision-making process complicated and challenging. The goal of the current study was to measure the effectiveness of a tailored decision aid designed specifically to assist individuals to make informed decisions regarding genetic testing for HNPCC risk.

METHODS

In all, 153 individuals were randomized to receive the decision aid or a control pamphlet at the end of their first genetic counseling consultation. Of these, 109 (71.2%) completed the first questionnaire 1 week after consultation, whereas 95 (62.1%) completed the 6-month follow-up questionnaire.

RESULTS

Although the decision aid had no significant effect on postdecisional regret or actual genetic testing decision, the trial results demonstrated that participants who received the decision aid had significantly lower levels of decisional conflict (ie, uncertainty) regarding genetic testing (chi-square(1) = 8.97; P = .003) and were more likely to be classified as having made an informed choice concerning genetic testing (chi-square(1) = 4.37; P = .037) than participants who received a control pamphlet. Also, men who received the decision aid had significantly higher knowledge levels regarding genetic testing compared with men who received the control pamphlet, whereas no such differences were found for women (chi-square(2) = 6.76; P = .034).

CONCLUSIONS

A decision aid for individuals considering genetic testing for HNPCC is an effective intervention to reduce uncertainty and assist individuals to make an informed choice regarding genetic testing for HNPCC after genetic counseling.

Attitudes toward genetic testing for cancer risk after genetic counseling and decision support: a qualitative comparison between hereditary cancer types

This study aimed to qualitatively assess individuals' attitudes toward genetic testing for cancer risk after genetic counseling and decision support. As part of a larger study, 78 women considering genetic testing for hereditary breast/ovarian cancer (HBOC) risk and 22 individuals considering genetic testing for hereditary nonpolyposis colorectal cancer (HNPCC) completed an open-ended table of their perceived pros and cons of genetic testing. The most frequently reported pros were "to help manage my risk of developing cancer," "to help my family," and "to know my cancer risk." With regards to risk management, the HBOC group perceived genetic testing as most helpful in informing their general risk management practices, while the HN-PCC group focused on the potential to clarify their need for bowel cancer screening, suggesting that patients' perceptions of the benefits of genetic testing may differ across cancer syndromes. Individuals in both groups expressed concern about the potential psychological impact of genetic testing. We also found that some affected individuals may not fully comprehend the meaning of their potential test results. Eliciting patients' perceived pros and cons during genetic counseling is likely to be a valuable tool for improving patient care. This data also provides an improved evidence base for the development of patient education tools.

Syndromic colon cancer: lynch syndrome and familial adenomatous polyposis

Colon cancer, the third leading cause of mortality from cancer in the United States, afflicts about 150,000 patients annually. More than 10% of these patients exhibit familial clustering. The most common and well characterized of these familial colon cancer syndromes is hereditary nonpolyposis colon cancer syndrome (Lynch syndrome), which accounts for about 2% to 3% of all cases of colon cancer in the United States. We review the current knowledge of familial cancer syndromes, with an emphasis on Lynch syndrome and familial adenomatous polyposis.

Lynch syndrome: still not a familiar picture

BACKGROUND

Germ line mutations in mismatch repair genes underlie Lynch syndrome and predispose carriers for colorectal carcinoma and malignancies in many other organ systems.

CASE PRESENTATION

A large Lynch syndrome family with 15 affected family members and involvement in 7 organs is reported. It illustrates a lack of awareness and knowledge about this hereditary tumor syndrome among doctors as well as patients. None of the described family members underwent presymptomatic screening on the basis of the family history.

CONCLUSION

Hereditary features, like young age at diagnosis, multiple tumors in multiple organs and a positive family history, should lead to timely referral of suspected cases for genetic counseling and diagnostics. For Lynch syndrome, these features can be found in the Amsterdam and Bethesda criteria. Subsequently, early identification of mutation carriers might have diminished, at least in part, the high and early morbidity and mortality observed in this family.

The impact of predictive genetic testing for hereditary nonpolyposis colorectal cancer: three years after testing

BACKGROUND

To fully assess predictive genetic testing programs, it is important to assess outcomes over periods of time longer than the 1-year follow-up reported in the literature.

METHODS

We conducted a 3-year study of individuals who received predictive genetic test results for previously identified familial mutations in Australian Familial Cancer Clinics. Questionnaires were sent before attendance at the familial cancer clinic and 2 weeks, 4 months, 1 year, and 3 years after receiving test results. Psychological measures were included each time, and preventive behaviors were assessed at baseline and 1 and 3 years. Psychological measures were adjusted for age, gender, and baseline score.

RESULTS

The study included 19 carriers and 54 non-carriers. We previously reported an increase in mean cancer-specific distress in carriers at 2 weeks with a return to baseline levels by 12 months. This level was maintained until 3 years. Non-carriers showed sustained decreases after testing with a significantly lower level at 3 years compared with baseline (P < 0.001). These scores tended to be lower than those for carriers at 3 years (P = 0.09). Mean depression and anxiety scores did not differ between carriers and non-carriers and, at 3 years, were similar to baseline. All carriers and 7% of non-carriers had had a colonoscopy by 3 years, and 69% of 13 female carriers had undergone gynecological screening in the previous 2 years. Prophylactic surgery was rare.

CONCLUSION

This report of long-term data indicates appropriate screening and improved psychological measures for non-carriers with no evidence of undue psychological distress in carriers of hereditary nonpolyposis colorectal cancer mutations.

Câncer ano-reto-cólico: aspectos atuais II - câncer colorretal - fatores de riscos e prevenção

O câncer colorretal é curável e passível de prevenção. A chave para o alcance desses objetivos é relativamente simples e pode ser aplicada em escala populacional. Basta, para tanto, que sejamos capazes de conscientizar os médicos, independente da sua área especial de atuação, e proporcionar às pessoas o mais fácil alcance às informações médicas expressas em termos simples sobre a profilaxia e o diagnóstico precoce dessa neoplasia maligna, sobretudo, destacando os fatores protetores e os de riscos, principalmente os que são suscetíveis de ser modificados.

Review article: Detection and management of hereditary non-polyposis colorectal cancer (Lynch syndrome)

BACKGROUND

The most common hereditary colorectal cancer syndrome is hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome. Diagnosis of this syndrome is difficult, because of lack of specific diagnostic features.

AIM

To discuss the diagnostic criteria and laboratory work up for HNPCC. Furthermore, surveillance programs for HNPCC and treatment of HNPCC associated colorectal cancer are discussed.

RESULTS

Current diagnostic criteria, including the Amsterdam II and Bethesda criteria, are suboptimal for the detection of HNPCC. Molecular screening by microsatellite instability (MSI) and immunohistochemistry (IHC) is useful in the diagnosis of HNPCC. Both techniques have a higher sensitivity compared to the Amsterdam II and Bethesda criteria. A combination of both MSI and IHC provides the most optimal selection for mutation analysis. After identification of a mutation in an affected individual, genetic counselling and presymptomatic mutation analysis should be offered to relatives. Furthermore, colonoscopic surveillance should be performed in proven mutation carriers.

CONCLUSIONS

Identification of HNPCC is a clinical challenge involving many clinicians. Identification of persons at risk can be achieved by a combination of a detailed family history, testing with molecular and mutation analysis.

Review article: The Lynch syndrome (hereditary nonpolyposis colorectal cancer)

BACKGROUND

The most common inherited colorectal cancer syndrome is the Lynch syndrome (HNPCC) which is characterized by the development of colorectal, endometrial, and other cancers and the presence of microsatellite instability (MSI) in tumours. The syndrome is due to a mutation in one of the mismatch repair (MMR) genes: MSH2, MLH1, MSH6 and PMS2.

AIMS

To evaluate the clinical features of the Lynch syndrome and to assess the tools that are available for the identification of families with this syndrome.

METHODS

A systematic literature search using PubMed and reference lists of retrieved articles was performed.

RESULTS

The review provides an update of the clinical phenotype of the Lynch syndrome. Until recently, the Amsterdam criteria were the most important tool for the identification of Lynch syndrome. Nowadays, the Bethesda guidelines are more widely used. These guidelines describe all clinical conditions in which a search for MSI indicated. Both MSI-analysis as well as immunohistochemical analysis of the MMR-proteins are appropriate to identify patients with a high probability of carrying a MMR-gene mutation.

CONCLUSION

All specialists that are involved in the treatment of cancer patients should know the Bethesda criteria in order to identify all families suspected of the Lynch syndrome.

Gene-related cancer spectrum in families with hereditary non-polyposis colorectal cancer (HNPCC)

The family histories of 130 individuals with documented hereditary non-polyposis colorectal cancer (HNPCC) (caused by mutations in mismatch-repair (MMR) genes MSH2 (n = 64), MLH1 (n = 62) or MSH6 (n = 4)) were obtained, and incidence of cancers in those families was compared to that in the general population. There were a total of 982 cancers in 723 individuals. Colorectal cancer (CRC) was the commonest type (64% and 55% in individuals from families with germline MLH1 and MSH2 mutations respectively). Median age at diagnosis of first CRC in MSH6 mutation families was 59 years compared to 45 years in both MLH1 and MSH2 mutation families. The relative risk (RR) of endometrial cancer was 55 in MSH2 mutation families, compared with 27 in MLH1 mutation families, and 37 in MSH6 mutation families; median age at diagnosis 49 years. Even within MSH2 families, endometrial cancer tended to cluster, with 28 of the 58 cases coming from families with three or more cases (P < 0.001). Absolute risk of endometrial cancer in MLH1 families was still greater than any other cancer (other than CRC). 5% of cancers in both MLH1 and MSH2 mutation families were gastric (RR = 12); 53% of these were diagnosed before 50 years. Seven cases of small intestinal cancer occurred in MSH2 and MLH1 mutation families (RR = 26). There were 13 cases of cancer of the ureter; all were in MSH2 families. These cancers tended to cluster within families (P < 0.001); three of seven families with urothelial cancer had such cases in two or more individuals; two others had kidney cancer. Nineteen of 27 ovarian cancers (70%) were in MSH2 mutation families and 70% of these were diagnosed before age 50 years. There were 9 cases of sebaceous skin cancer, 3 in two MLH1 and 6 in four MSH2 mutation families. Of 22 pancreatic cancers, 14 were known to be diagnosed before 60 years. Breast cancer RR was 1.7 overall. The type of mutation (truncating or other type, and site of mutation) showed no obvious correlation with the presence or absence of extra-colonic cancers in families.

Recently identified colon cancer predispositions: MYH and MSH6 mutations

Single-gene germline mutations conferring a high lifetime risk of colorectal cancer (CRC) account for up to 6% of all CRC cases. The most widely studied monogenic colorectal cancer syndromes include familial adenomatous polyposis (FAP) and Lynch syndrome. However, additional syndromes continue to be defined and new predisposition genes are continuing to be identified. Most recently, MYH-associated polyposis (MAP) and an "atypical Lynch syndrome" related to the presence of MSH6 mutations have been linked to an increased risk of CRC. In this review, we summarize basic information related to these newly recognized gene mutations, including the accumulating data on the prevalence and penetrance of deleterious mutations, as well as the management options for identified carriers and their families. Recognizing these heritable syndromes is essential and predictive genetic testing will continue to transform the field of cancer risk assessment by offering the opportunity to focus on more precise risk management and cancer prevention.

Surveillance colonoscopy practice in Lynch syndrome in the Netherlands: A nationwide survey

Lynch syndrome, or hereditary nonpolyposis colorectal cancer (HNPCC), is the most common genetic disorder predisposing to colorectal cancer. As regular colonoscopic surveillance has been shown to reduce the incidence of colorectal cancer, this strategy is recommended worldwide. Recently, several advances in colonoscopic techniques have improved detection rates of neoplasia in Lynch syndrome. In this nationwide survey, we evaluated current surveillance colonoscopy practices for Lynch syndrome in the Netherlands and the extent to which advanced techniques have been adopted in routine clinical practice.

Direct contact in inviting high-risk members of hereditary colon cancer families to genetic counselling and DNA testing

BACKGROUND

Identification of hereditary predisposition to cancer has limited significance if not followed by efficient cancer prevention in the family. Probands are traditionally left to inform their relatives about the increased risk, but distant relatives may remain uninformed. An approach to contacting directly at-risk persons assumed to be unaware of their increased cancer risk was taken. With cancer prevention as the ultimate goal, the study was aimed at investigating attitudes towards and psychosocial consequences of this novel strategy.

METHODS

In families with hereditary non-polyposis colorectal cancer (Lynch syndrome), 286 healthy adult relatives with a 50% risk of a predisposing mutation were contacted by letter. Of these, 112 participated in counselling and predictive testing. Baseline information and information obtained 1 month after the test for 73 respondents were compared with 299 corresponding subjects, approached via the proband (family-mediated approach in our previous study) in these families.

RESULTS

After the contact letter, 51% consented to the study. Of these, 92% approved of the direct contact and 33% had tried to seek information. In 34% of the mutation carriers, neoplasia was identified in the first post-test colonoscopy. Although post-test fear of cancer increased among the mutation carriers and decreased among noncarriers, almost all participants were satisfied with their decision to participate, independently of their test results, parallel to the family-mediated approach.

CONCLUSION

In this large-scale study, relatives in cancer families were actively contacted to inform them of the condition and genetic counselling. Their attitudes were encouraging, and the psychosocial consequences were similar to the family-mediated approach. Our results suggest the appropriateness of direct contact as an alternative method of contact in cases of life-threatening treatable disease.