Development of colorectal tumors in colonoscopic surveillance in Lynch syndrome

A systematic review and economic evaluation of diagnostic strategies for Lynch syndrome

BACKGROUND

Lynch syndrome (LS) is an inherited autosomal dominant disorder characterised by an increased risk of colorectal cancer (CRC) and other cancers, and caused by mutations in the deoxyribonucleic acid (DNA) mismatch repair genes.

OBJECTIVE

To evaluate the accuracy and cost-effectiveness of strategies to identify LS in newly diagnosed early-onset CRC patients (aged < 50 years). Cascade testing of relatives is employed in all strategies for individuals in whom LS is identified.

DATA SOURCES AND METHODS

Systematic reviews were conducted of the test accuracy of microsatellite instability (MSI) testing or immunohistochemistry (IHC) in individuals with CRC at risk of LS, and of economic evidence relating to diagnostic strategies for LS. Reviews were carried out in April 2012 (test accuracy); and in February 2012, repeated in February 2013 (economic evaluations). Databases searched included MEDLINE (1946 to April week 3, 2012), EMBASE (1980 to week 17, 2012) and Web of Science (inception to 30 April 2012), and risk of bias for test accuracy was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) quality appraisal tool. A de novo economic model of diagnostic strategies for LS was developed.

RESULTS

Inconsistencies in study designs precluded pooling of diagnostic test accuracy results from a previous systematic review and nine subsequent primary studies. These were of mixed quality, with significant methodological concerns identified for most. IHC and MSI can both play a part in diagnosing LS but neither is gold standard. No UK studies evaluated the cost-effectiveness of diagnosing and managing LS, although studies from other countries generally found some strategies to be cost-effective compared with no testing. The de novo model demonstrated that all strategies were cost-effective compared with no testing at a threshold of £20,000 per quality-adjusted life-year (QALY), with the most cost-effective strategy utilising MSI and BRAF testing [incremental cost-effectiveness ratio (ICER) = £5491 per QALY]. The maximum health benefit to the population of interest would be obtained using universal germline testing, but this would not be a cost-effective use of NHS resources compared with the next best strategy. When the age limit was raised from 50 to 60 and 70 years, the ICERs compared with no testing increased but remained below £20,000 per QALY (except for universal germline testing with an age limit of 70 years). The total net health benefit increased with the age limit as more individuals with LS were identified. Uncertainty was evaluated through univariate sensitivity analyses, which suggested that the parameters substantially affecting cost-effectiveness: were the risk of CRC for individuals with LS; the average number of relatives identified per index patient; the effectiveness of colonoscopy in preventing metachronous CRC; the cost of colonoscopy; the duration of the psychological impact of genetic testing on health-related quality of life (HRQoL); and the impact of prophylactic hysterectomy and bilateral salpingo-oophorectomy on HRQoL (this had the potential to make all testing strategies more expensive and less effective than no testing).

LIMITATIONS

The absence of high-quality data for the impact of prophylactic gynaecological surgery and the psychological impact of genetic testing on HRQoL is an acknowledged limitation.

CONCLUSIONS

Results suggest that reflex testing for LS in newly diagnosed CRC patients aged < 50 years is cost-effective. Such testing may also be cost-effective in newly diagnosed CRC patients aged < 60 or < 70 years. Results are subject to uncertainty due to a number of parameters, for some of which good estimates were not identified. We recommend future research to estimate the cost-effectiveness of testing for LS in individuals with newly diagnosed endometrial or ovarian cancer, and the inclusion of aspirin chemoprevention. Further research is required to accurately estimate the impact of interventions on HRQoL.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002436.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Screening in GI Cancers: The Role of Genetics

Genetic and epigenetic alterations identified in tumors of different cancer types can provide insights regarding the roles played by different cell signaling pathways in carcinogenesis. Somatic mutation profiles of GI tumors are used to guide choice of chemotherapy and can facilitate identification of individuals whose cancers arise in the setting of genetic predisposition. This review provides a framework for how clinical history, family history of cancer, and tumor genomic phenotype can be used to screen patients with colorectal, gastric, or pancreatic cancer for hereditary cancer syndromes. Early identification of individuals who carry germline mutations can affect clinical care not only for patients with cancer but also for their at-risk relatives.

Hereditary and common familial colorectal cancer: evidence for colorectal screening

Colorectal cancer (CRC) is the fourth most common cancer among men and women. Between 3 and 6% of all CRCs are attributed to well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis and several hamartomatous conditions. Up to 30% of CRC cases exhibit common familial risk, likely related to a combination of inherited factors and environment. Identification of these patients through family history and appropriate genetic testing can provide estimates of cancer risk that inform appropriate cancer screening, surveillance and/or preventative interventions. This article examines the colon cancer syndromes, their genetic basis, clinical management and evidence supporting colorectal screening. It also deals with the category of common (non-syndromic) familial risk including risk determination and screening guidelines.

Impact of chromoscopy on adenoma detection in patients with Lynch syndrome: a prospective, multicenter, blinded, tandem colonoscopy study

OBJECTIVES

In Lynch syndrome, flat and diminutive adenomas are particularly prone to malignant transformation, but they can be missed by standard colonoscopy. It is not known whether chromocolonoscopy is able to detect more adenomas than standard colonoscopy in patients with Lynch syndrome.

METHODS

We conducted a prospective, multicenter, randomized trial to compare standard colonoscopy with standard colonoscopy followed by pancolonic chromoscopy with indigo carmine in patients with a proven germline mutation in a mismatch-repair gene related to Lynch syndrome and who were undergoing screening or surveillance colonoscopy. Standard colonoscopy was used first to detect visible lesions. Colonoscopy with chromoscopy was then performed by a second gastroenterologist (blinded to the findings of the first colonoscopy) to detect additional lesions. The primary end point was the number of patients in whom at least one adenoma was detected.

RESULTS

A total of 78 eligible patients (median age, 45 years) were enrolled at 10 centers from July 2008 to August 2009. Significantly more patients with at least one adenoma were identified by chromocolonoscopy (32/78 (41%)) than by standard colonoscopy (18/78 (23%); P<0.001). The percentage of patients in whom at least one additional adenoma was detected during the chromoscopy was 31% (24/78). Overall, chromocolonoscopy plus colonoscopy detected a total of 55 adenomas in 32 patients (mean number of adenomas detected per patient: 0.7 vs. standard colonoscopy alone: 0.3; P<0.001).

CONCLUSION

The results support the proposition that chromocolonoscopy may significantly improve the detection rate of colorectal adenomas in patients undergoing screening or surveillance colonoscopy for Lynch syndrome.

Quality of colonoscopy in Lynch syndrome

Lynch syndrome (LS) accounts for 2 - 4 % of all colorectal cancers. Affected family members have a germline mutation in one of the DNA mismatch repair genes MLH1, PMS2, MSH2, or MSH6, and a lifetime risk for development of colorectal cancer of 25 - 75 %. Current guidelines recommend annual to biannual surveillance colonoscopy in mutation carriers. Several factors may predict failure to prevent interval cancer in LS: more lesions in the right colon; more flat ("non polypoid") and lateral growing polyps; small adenomas may already harbor high grade dysplasia or a high percentage of villous component and become advanced adenomas; there is a short duration of the adenoma - carcinoma sequence; synchronous lesions have high prevalence; patients are younger and less tolerant to colonoscopy (need more sedation); and repeated colonoscopies are needed for lifelong surveillance (patient experience is important for compliance). In order to prevent cancer in LS patients, surveillance colonoscopy should be performed in an endoscopic unit experienced with LS, every 1 - 2 years, starting at age 20 - 25 years, or 10 years younger than the age of first diagnosis in the family (whichever is first), and yearly after the age of 40 years. Colonoscopy in LS patients should be a very meticulous and precise procedure (i. e. taking sufficient withdrawal time, documentation of such warranted), with removal of all of the polyps, special attention to the right colon and alertness to flat lesions. Following quality indicators such as successful cleansing of the colon and removal of every polyp will probably improve prevention of interval cancers. At this moment, none of the new endoscopic techniques have shown convincing superiority over conventional high resolution white light colonoscopy.

The genetic basis of Lynch syndrome and its implications for clinical practice and risk management

Lynch syndrome is the most common cause of hereditary colon cancer, and accounts for as much as 3% of all colon and endometrial cancers. The identification and management of individuals with Lynch syndrome have evolved over the past 20 years, yet the syndrome remains vastly underdiagnosed. It is important for clinicians to recognize individuals and families who are at risk in order to be able to manage them appropriately and reduce their morbidity and mortality from this condition. This review will touch on the history of Lynch syndrome, the current knowledge of genotype–phenotype correlations, the cancers associated with Lynch syndrome, and management of individuals who are gene carriers.

Familial colorectal cancer, beyond Lynch syndrome

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.

Cost sharing and hereditary cancer risk: predictors of willingness-to-pay for genetic testing

Increasing use of predictive genetic testing to gauge hereditary cancer risk has been paralleled by rising cost-sharing practices. Little is known about how demographic and psychosocial factors may influence individuals' willingness-to-pay for genetic testing. The Gastrointestinal Tumor Risk Assessment Program Registry includes individuals presenting for genetic risk assessment based on personal/family cancer history. Participants complete a baseline survey assessing cancer history and psychosocial items. Willingness-to-pay items include intention for: genetic testing only if paid by insurance; testing with self-pay; and amount willing-to-pay ($25-$2,000). Multivariable models examined predictors of willingness-to-pay out-of-pocket (versus only if paid by insurance) and willingness-to-pay a smaller versus larger sum (≤$200 vs. ≥$500). All statistical tests are two-sided (α = 0.05). Of 385 evaluable participants, a minority (42%) had a personal cancer history, while 56% had ≥1 first-degree relative with colorectal cancer. Overall, 21.3% were willing to have testing only if paid by insurance, and 78.7% were willing-to-pay. Predictors of willingness-to-pay were: 1) concern for positive result; 2) confidence to control cancer risk; 3) fewer perceived barriers to colorectal cancer screening; 4) benefit of testing to guide screening (all p < 0.05). Subjects willing-to-pay a higher amount were male, more educated, had greater cancer worry, fewer relatives with colorectal cancer, and more positive attitudes toward genetic testing (all p < 0.05). Individuals seeking risk assessment are willing-to-pay out-of-pocket for genetic testing, and anticipate benefits to reducing cancer risk. Identifying factors associated with willingness-to-pay for genetic services is increasingly important as testing is integrated into routine cancer care.

History, genetics, and strategies for cancer prevention in Lynch syndrome

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 genes, mainly MLH1 and MSH2 but also MSH6, PMS2, and EPCAM. Although 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.

Colorectal surveillance in Lynch syndrome families

Lynch syndrome (LS) is an autosomal dominant disorder caused by a mutation in one of the mismatch repair genes. Mutation carriers have a life-time risk of developing colorectal cancer (CRC) of between 25 and 75 %. Since the importance of a centralized organization of surveillance was emphasized in the late 1980s, the number of registered LS families with a known mutation has increased enormously worldwide. Large-scale surveillance programs of these families have achieved a 62 % reduction in incidence of CRC and a 65-70 % decrease in mortality. Nevertheless, the risk of CRC is still substantial even when included in a program and the most optimal surveillance interval for gene carriers remains unknown. Hopefully, improvements in high quality colonoscopy and new endoscopic visualization techniques will further reduce CRC risk in those included in a surveillance program.

Quality colonoscopy and risk of interval cancer in Lynch syndrome

PURPOSE

Despite colonoscopic surveillance, Lynch syndrome patients develop colorectal cancer (CRC). Identification of modifiable factors has the potential to improve outcome of surveillance. The aims of this study were to determine (1) characteristics of patients with CRC, (2) endoscopic and histological features of these cancers, and (3) quality of the previous colonoscopy.

METHODS

Approximately 2,200 medical reports from proven and obligate mutation carriers identified at the Dutch Lynch Syndrome Registry and two large hospitals were retrospectively analyzed for the presence of an interval cancer defined as CRC diagnosed within 24 months of previous colonoscopy.

RESULTS

Thirty-one interval cancers were detected in 29 patients (median age of 52 [range 35-73]), after a median time of 17 months. All were MLH1 or MSH2 mutation carriers, and 39 % had a previous CRC. In patients without previous surgery for CRC, 84 % was proximally located. Of all interval cancers, 77 % were at local stage (T1-3N0Mx). In three patients (9 %) with an incomplete previous colonoscopy, CRC was located in the unexamined colon. In six of the nine patients with an adenoma during previous colonoscopy, the cancer was detected in the same colonic segment as the previously removed adenoma.

CONCLUSIONS

Interval cancers were detected in MLH1 and MSH2 mutation carriers, especially in those with a history of previous CRC and between 40 and 60 years. Interval cancer could be related to incompleteness of previous endoscopy and possibly residual adenomatous tissue. Further reduction of the interval cancer risk may be achieved by optimizing endoscopy quality and individualization of surveillance guidelines.

Causes of death of mutation carriers in Finnish Lynch syndrome families

Lynch syndrome (LS) is an autosomal dominant cancer syndrome including increased life-long risk for colorectal (CRC) and endometrial (EC) cancer, but also for cancers of other types. The risk for CRC is up to 70-80 % and for EC up to 50-60 %. Due to screening and early diagnosing the mortality related to CRC and EC seems to be low. In spite of many studies on surveillance of mutation carriers, there is no comprehensive evaluation on causes of death in LS families. The disease history and cause of death of all the deceased, tested mutation carriers and their mutation negative relatives in the Finnish LS families (N = 179) was examined utilizing hospital records and relevant national registries. Out of 1069 mutation carriers 151 had succumbed; 97 (64 %) from cancer. Out of 1146 mutation-negative family 44 members had died; 11 (25 %) of them from cancer. In 12 (7.7 %) of the deceased mutation carriers no cancer had been diagnosed. The mean age of death from cancer was 63.2 years vs. 68.8 years from non-cancer causes. Only 7.9 % of the patients with CRC had died from CRC and 5 % of those with EC, respectively. 61 % of the cancer deaths were related to extra-colonic, extra-endometrial cancers. The cumulative overall and cancer specific death rates were significantly increased in Mut+ compared to Mut- family members. Even surveillance yields decrease in the life-long risk and mortality of the most common cancers CRC and EC in LS, almost all mutation carriers will contract with cancer, and two thirds of the deceased have died from cancer. This should be taken in account in genetic counseling. Mutation carriers should be encouraged to seek help for abnormal symptoms.

Clinical usefulness of microsatellite instability test in Korean young patients with high-risk features associated with adenoma

The aim of this study was to determine the correlation between microsatellite instability (MSI) and young age in patients with advanced colorectal adenomas. We retrospectively analyzed young patients (≤ 40 years of age) with advanced adenomas (n=84) between January 1996 and December 2006. We randomly selected the control group as patients ≥ 50 years of age with advanced adenomas (n=84) during the same time period. Of these patients, the MSI test and MLH1 immunohistochemistry were performed in the available tissue samples from patients with advanced adenomas. The number of patients who had the two tests was 52 in the young group and 49 in the old group. The monomorphic nature of the BAT26 panel for MSI analysis was used without comparison of normal tissue. MSI was detected in three young patients (n=52) and none of the old patients (n=49). There was no statistical difference between the two groups (P=0.243). All three young patients with MSI had a strong family history of colorectal cancer. MSI analysis was not a useful method of screening for HNPCC in young patients with advanced colorectal adenoma, at least in cases without a family history of colorectal cancer.

Interval colon cancer in a Lynch syndrome patient under annual colonoscopic surveillance: a case for advanced imaging techniques?

Background

Lynch syndrome confers increased risk for various malignancies, including colorectal cancer. Colonoscopic surveillance programs have led to reduced incidence of colorectal cancer and reduced mortality from colorectal cancer. Colonoscopy every 1–2 years beginning at age 20–25, or 10 years earlier than the first diagnosis of colorectal cancer in a family, with annual colonoscopy after age 40, is the recommended management for mutation carriers. Screening programs have reduced colon cancer mortality, but interval cancers may occur.

Case presentation

We describe a 48-year-old woman with Lynch syndrome who was found to have an adenoma with invasive colorectal cancer within one year after a normal colonoscopy.

Conclusion

Our patient illustrates two current concepts about Lynch syndrome: 1) adenomas are the cancer precursor and 2) such adenomas may be “aggressive,” in the sense that the adenoma progresses more readily and more rapidly to carcinoma in this setting compared to usual colorectal adenomas. Our patient’s resected tumor invaded only into submucosa and all lymph nodes were negative; in that sense, she represents a success for annual colonoscopic surveillance. Still, this case does raise the question of whether advanced imaging techniques are advisable for surveillance colonoscopy in these high-risk patients.

Clinicopathological features and management of cancers in lynch syndrome

Lynch syndrome (LS) is characterized by an autosomal dominant inheritance of the early onset of colorectal cancer (CRC) and endometrial cancer, as well as increased risk for several other cancers including gastric, urinary tract, ovarian, small bowel, biliary tract, and brain tumors. The syndrome is due to a mutation in one of the four DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, or PMS2. The majority of LS patients and families can now be identified, and the underlying mutation detected using genetic diagnostics. Regular surveillance for CRC and endometrial cancer has proved beneficial for mutation carriers. However, screening for other tumors is also recommended even though experiences in the screening of these tumors is limited. Prophylactic colectomy, prophylactic hysterectomy, and bilateral salpingo-oophorectomy may be reasonable options for selected patients with LS. This paper describes the features and management of LS.

Preoperative diagnosis of Lynch syndrome with DNA mismatch repair immunohistochemistry on a diagnostic biopsy

BACKGROUND

DNA mismatch repair immunohistochemistry on tumor tissue is a simple, readily available, and cost-effective method of identifying patients with Lynch syndrome in the postoperative setting. The aim of the study was to assess whether the mismatch repair status of a colorectal cancer can be confirmed by mismatch repair immunohistochemistry on preoperative biopsy.

DESIGN

Germline positive patients with Lynch syndrome were identified from a prospectively collected Familial Cancer Clinic database. Preoperative colorectal cancer biopsy specimens were obtained from the source pathology provider to generate a cohort of matched preoperative and postoperative specimens. The specimens were sectioned and stained for 4 mismatch repair proteins (MLH1, MSH2, MSH6, PMS2). An age-matched cohort to compare specimens was selected from Bethesda positive but mismatch repair immunohistochemistry negative patients. All slides were reviewed by a single blinded pathologist. The Wilson method was used to calculate a true underlying proportion of patients for whom the preoperative result matched the postoperative test result with a 95% confidence interval.

RESULTS

Of 128 germline positive mutation carriers, 40 patients (mean age 41, SD 11.3) had colorectal resections. Thirty-three preoperative specimens were retrievable and were matched with biopsies from 33 controls. The germline mutations included in the study were 8 MLH1, 19 MSH2, 3 MSH6, and 2 PMS2. In patients where germline positive status was known, sensitivity was 100% (95% CI 89.2-100) and specificity was 100% (95% CI 89.2-100). Identical sensitivity and specificity were observed in 33 age-matched patients. The sensitivity of the endoscopic biopsy in predicting germline status was 94.9% (95% CI 80.4-98.3).

CONCLUSION

The mismatch repair disease status of a colorectal cancer can be reliably confirmed by mismatch repair immunohistochemistry on a diagnostic colorectal cancer biopsy sample before definitive surgery. Ascertaining a diagnosis of Lynch syndrome before definitive surgery can influence surgical planning.

Rapid development of colorectal neoplasia in patients with Lynch syndrome

BACKGROUND & AIMS

Patients with Lynch syndrome have a high risk for colorectal adenomas and carcinomas. We evaluated the development of colorectal neoplasia in these patients.

METHODS

We assessed serial colonoscopy findings from 54 persons from 29 pedigrees with pathogenic mutations in MSH2 or MLH1; we evaluated the development of colorectal neoplasia by age, sex, tumor location, and number (mean follow-up time, 9.3 years; colonoscopy interval, 1.7 ± 1.2 years; 112 adenomas and 31 cancers). Differences in colorectal phenotype were analyzed by genotype, and dwell time was calculated for advanced neoplasias.

RESULTS

Among mutation carriers, the cumulative risk of colorectal neoplasia was 43% by age 40 years and 72% by 80 years. There were no statistically significant associations between time to development of colorectal neoplasia and sex or mutation type. Most female patients had left-sided neoplasms, whereas most male patients developed right-sided lesions. The mean cumulative numbers of neoplastic lesions in patients were 1.3 ± 0.5 by age 30 years and 7.6 ± 6.8 by age 80 years. Polyp dwell time was 33.0 ± 16.2 months and 35.2 ± 22.3 months for advanced adenoma and colorectal cancer, respectively. The 5-year survival rate for patients with colorectal cancer was 96%.

CONCLUSIONS

High percentages of individuals with pathogenic mutations in MSH2 or MLH1 develop colorectal neoplasia by age 40. Left-sided colorectal neoplasias are more frequent in female patients. The development of 3 or more colorectal neoplasms by age 30 years indicates a possible polyposis syndrome rather than Lynch syndrome. Polyp dwell time is short for advanced neoplasias, arguing for annual colonoscopic screening and surveillance.

Health benefits and cost-effectiveness of primary genetic screening for Lynch syndrome in the general population

In current clinical practice, genetic testing to detect Lynch syndrome mutations ideally begins with diagnostic testing of an individual affected with cancer before offering predictive testing to at-risk relatives. An alternative strategy that warrants exploration involves screening unaffected individuals via demographic and family histories, and offering genetic testing to those individuals whose risks for carrying a mutation exceed a selected threshold. Whether this approach would improve health outcomes in a manner that is cost-effective relative to current standards of care has yet to be demonstrated. To do so, we developed a simulation framework that integrated models of colorectal and endometrial cancers with a 5-generation family history model to predict health and economic outcomes of 20 primary screening strategies (at a wide range of compliance levels) aimed at detecting individuals with mismatch repair gene mutations and their at-risk relatives. These strategies were characterized by (i) different screening ages for starting risk assessment and (ii) different risk thresholds above which to implement genetic testing. For each strategy, 100,000 simulated individuals, representative of the U.S. population, were followed from the age of 20, and the outcomes were compared with current practice. Findings indicated that risk assessment starting at ages 25, 30, or 35, followed by genetic testing of those with mutation risks exceeding 5%, reduced colorectal and endometrial cancer incidence in mutation carriers by approximately 12.4% and 8.8%, respectively. For a population of 100,000 individuals containing 392 mutation carriers, this strategy increased quality-adjusted life-years (QALY) by approximately 135 with an average cost-effectiveness ratio of $26,000 per QALY. The cost-effectiveness of screening for mismatch repair gene mutations is comparable to that of accepted cancer screening activities in the general population such as colorectal cancer screening, cervical cancer screening, and breast cancer screening. These results suggest that primary screening of individuals for mismatch repair gene mutations, starting with risk assessment between the ages of 25 and 35, followed by genetic testing of those whose risk exceeds 5%, is a strategy that could improve health outcomes in a cost-effective manner relative to current practice.

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.

Early detection of colorectal cancer with faecal occult blood test screening

BACKGROUND

Faecal occult blood test (FOBT) screening has been shown to decrease the incidence and mortality from colorectal cancer. This study compared the stage profile of patients with colorectal cancer diagnosed at the first FOBT screening round with that of an unscreened control group.

METHODS

Subjects aged 60-64 years were allocated randomly to biennial FOBT screening (52 998 subjects) or a control group (53 002) in a Finnish prospective public health policy in 2004-2006. FOBT was performed with a guaiac test. At the end of 2007 the screened and control populations were linked to the Finnish Cancer Registry database, and the colonoscopic findings in the screen positives were analysed.

RESULTS

Early-stage colorectal cancer was observed in 52 per cent of the FOBT-positive subjects, in 42.2 per cent of the total screened population and in 38 per cent of the control population (P = 0.191 for FOBT positives, P = 0.592 for total screened population). The prevalence of adenomas and colorectal cancer was 31.5 and 8.2 per cent respectively among the 806 subjects with a positive FOBT. Some 27.3 per cent of all colorectal tumours in the screened population were interval cancers. The tumour was located in the right colon in 28.9 per cent of the screened subjects and 22 per cent of controls (P = 0.255).

CONCLUSION

Biennial FOBT screening improves detection of colorectal cancer at the first screening round, but the high percentage of interval cancers is a cause for concern.

A novel and rapid method of determining the effect of unclassified MLH1 genetic variants on differential allelic expression

Germline mutations in mismatch repair genes predispose patients to Lynch Syndrome and the majority of these mutations have been detected in two key genes, MLH1 and MSH2. In particular, about a third of the missense variants identified in MLH1 are of unknown clinical significance. Using the PeakPicker software program, we have conducted a proof-of-principle study to investigate whether missense variants in MLH1 lead to allelic imbalances. Lymphocyte RNA extracted from patients harboring known MLH1 variants was used to quantify the ratio of variant to wild-type transcript, while patient lymphocyte DNA was used to establish baseline allelic expression levels. Our analysis indicated that the missense variants c.350C>T, c.793C>T, and c.1852_1853AA>GC, as well as the truncating variant c.1528C>T were all associated with significantly unbalanced allelic expression. However, the variants c.55A>T and c.2246T>C did not demonstrate an allelic imbalance. These results illustrate a novel and efficient method to investigate the pathogenicity of unclassified genetic variants discovered in mismatch repair genes, as well as genes implicated in other inherited diseases. In addition, the PeakPicker methodology has the potential to be applied in the diagnostic setting, which, in conjunction with results from other assays, will help increase both the accuracy and efficiency of genetic testing of colorectal cancer, as well as other inherited diseases.

Immune evasion of microsatellite unstable colorectal cancers

Colorectal cancers (CRC) develop through 2 major pathways of genetic instability. In contrast to the majority of CRCs, which are characterized by chromosomal instability, high-level microsatellite unstable (MSI-H) CRCs arise as a consequence of the loss of DNA mismatch repair (MMR) functions and show accumulation of insertion and deletion mutations particularly in microsatellite sequences. MSI-H occurs in about 15% of CRCs, and virtually all CRCs occurring in the context of the hereditary cancer-predisposing Lynch syndrome. These tumors are characterized by a comparably good prognosis and a low frequency of distant metastases. Because of the expression of a defined set of tumor-specific antigens, MSI-H CRCs elicit a strong local and systemic antitumoral immune response of the host and therefore use different strategies to evade the control of the immune system. In this review, we will summarize novel molecular mechanisms that at the same time drive pathogenesis, immunogenicity and immune evasion during the development and progression of MSI-H CRCs. We will focus on the current knowledge about alterations in human leukocyte antigen (HLA) antigen presentation and discuss how immune evasion-while offering protection against local antitumoral immune responses-paradoxically might interfere with the ability of the tumor to form distant organ metastases.

Prevalence and predictors of appropriate colorectal cancer surveillance in Lynch syndrome

OBJECTIVES

Lynch syndrome (LS) is a hereditary cancer syndrome that conveys a high risk of colorectal cancer (CRC). Guidelines recommend colonoscopy every 1 to 2 years. There is limited information about screening compliance in this high-risk group.

METHODS

Data about cancer screening behaviors were obtained from subjects recruited through four US cancer genetics clinics. The main outcome was prevalence of appropriate CRC surveillance for LS.

RESULTS

A total of 181 individuals had a family history that met the Amsterdam criteria for LS (n=154) and/or had an identified mutation in a mismatch repair (MMR) gene (n=105). Of these 181 individuals, 131 (73%) had appropriate LS surveillance with colonoscopies at least every 2 years for their age >25 years. Of those with inadequate surveillance, 26/49 (53%) had colonoscopies at 3- to 5-year intervals. There were no significant differences in health-care setting, perceived risk of CRC, or compliance with screening for other cancers. Rates of appropriate surveillance were higher among individuals who had been referred for genetic evaluation for LS compared with those who had not (109/136 (80%) vs. 23/45 (51%), respectively, P=0.0004). In multivariate analysis, personal history of CRC (odds ratio (OR) 2.81), having a first-degree relative with CRC at age <50 years (OR 2.61), and having undergone a genetic evaluation (OR 4.62) were associated with appropriate CRC surveillance for LS.

CONCLUSIONS

The time between colonoscopic exams in patients with LS is often longer than recommended by current guidelines and may place them at risk for interval cancers. Recognizing clinical features of LS and providing genetic counseling, evaluation, and intensive surveillance may improve cancer prevention for those at the highest risk for CRC.

Pharmacotherapy for inherited colorectal cancer

IMPORTANCE OF THE FIELD

An important recent consideration in the medical management of colorectal cancer risk has been the notion of primary prevention or 'chemoprevention' of adenomas. A number of promising agents, and even combinations of agents, have shown promise in clinical trials. This review is written in the interest of capturing the current state of chemoprevention in familial adenomatous polyposis (FAP). This will take a decidedly clinical perspective.

AREAS COVERED IN THIS REVIEW

This review addresses mainly randomized clinical chemoprevention trials. A search using PubMed from 1980 to present was conducted.

WHAT THE READER WILL GAIN

The reader should gain an appreciation of the role that chemoprevention clinical trials in FAP has had in establishing a basis for clinically oriented use of selected drugs, mainly sulindac and celecoxib, as adjuncts to surgical and endoscopic treatment. In addition, the reader will see how FAP trials can provide a foundation for similar trials in nonfamilial adenomas.

TAKE-HOME MESSAGE

As a proving ground for new, potential chemopreventive agents, trials in FAP involved short-term (3- to 12-month) administration of drug. Endpoints generally involved measures of adenoma regression in the rectal segment retained post-colectomy.

Current hypotheses on how microsatellite instability leads to enhanced survival of Lynch Syndrome patients

High levels of microsatellite instability (MSI-high) are a cardinal feature of colorectal tumors from patients with Lynch Syndrome. Other key characteristics of Lynch Syndrome are that these patients experience fewer metastases and have enhanced survival when compared to patients diagnosed with microsatellite stable (MSS) colorectal cancer. Many of the characteristics associated with Lynch Syndrome including enhanced survival are also observed in patients with sporadic MSI-high colorectal cancer. In this review we will present the current state of knowledge regarding the mechanisms that are utilized by the host to control colorectal cancer in Lynch Syndrome and why these same mechanisms fail in MSS colorectal cancers.

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.

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.

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.

[Colorectal cancer: from diagnosis to screening]

Colorectal cancer fulfils the conditions required for mass screening. Data from controlled studies indicate that it is possible to reduce colorectal cancer mortality at a population level using faecal occult blood testing. Screenings rely on biennial testing in between 50 and 74average risk subjects. Compliance must be over 50%. Colorectal cancer mortality decrease in this case between 15 and 18% in the general population, 33 and 39% among participants to screening. The European Commission, on the basis of available data recommended to organise colorectal cancer screening in the European Union. Generalisation of screening has become a reality in France. Epidemiological studies allow us to define subjects at very high risk (genetic origin) and high risk for colorectal cancer. Colonoscopy screening is recommended in first degree relatives of patients with colorectal cancer or large adenoma diagnosed before 60years or with two affected first-degree relatives, in subjects with an extended inflammatory bowel disease, or with a personal history of large bowel cancer or large adenoma. Promising research strategies are arising: immunochemical tests in the short term, stool-based DNA tests in stools and proteome-based approach in the long term.

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.

Genetic counselling and genetic testing in hereditary gastrointestinal cancer syndromes

Up to 10% of cancers are caused by inherited mutations in single genes. The process of genetic counselling and genetic testing allows for identification of these high-risk individuals and their at risk family members and enrolment into appropriate screening protocols. The medical impact of genetic testing is evidenced by reduced morbidity and mortality, however, the impact on a personal or psychosocial level has been more difficult to evaluate. We present a review of the current literature regarding the role of genetic counselling and testing in the setting of gastrointestinal cancers and explore several related issues including risk perception and risk communication, family communication, psychosocial factors and decision making, and family planning. We also provide guidelines for referral to cancer genetics clinics and for promoting discussions about genetic counselling and genetic testing.

MUTYH-associated polyposis

MUTYH-associated polyposis (MAP) is an autosomal recessive disorder characterised by adenomatous polyps of the colorectum and a very high risk of colorectal cancer. It appears to be at least as prevalent as autosomal dominant familial adenomatous polyposis (that is caused by truncating mutations in the APC gene) with which it shares important gastroenterological features. It was first recognised as recently as 2002 and its full phenotype and natural history are still being characterised. Key extracolonic manifestations include a predisposition to duodenal adenomas and cancer and a modest increase in risk for several extraintestinal tumours. Testing for mutations in the MUTYH gene is indicated in patients who have multiple colorectal adenomas or a family history suggestive of autosomal recessive colorectal cancer and for the siblings and spouses of patients with MAP in order to inform surveillance and treatment for patients and their families.

Missed adenomas during colonoscopic surveillance in individuals with Lynch Syndrome (hereditary nonpolyposis colorectal cancer)

BACKGROUND AND AIMS

Lynch syndrome (also known as hereditary nonpolyposis colon cancer) is associated with an increased risk for colorectal cancer, which can arise despite frequent colonoscopic exams. We evaluated the adenoma miss rate of conventional colonoscopy in patients with Lynch syndrome, and compared the sensitivity of chromoendoscopy versus intensive inspection for detecting polyps missed by conventional colonoscopy.

METHODS

Fifty-four subjects with Lynch syndrome underwent tandem colonoscopies at four centers of the Great Lakes-New England Clinical Epidemiology and Validation Center of the Early Detection Research Network. All participants first had a conventional colonoscopy with removal of all visualized polyps. The second endoscopy was randomly assigned as either pancolonic indigo carmine chromoendoscopy or standard colonoscopy with intensive inspection lasting >20 minutes. Size, histology, and number of polyps detected on each exam were recorded.

RESULTS

After undergoing standard colonoscopy, 28 individuals were randomized to a second exam with chromoendoscopy and 26 underwent intensive inspection. The mean interval since last colonoscopy was 17.5 months. Seventeen polyps (10 adenomas and 7 hyperplastic polyps) were identified on the first standard colonoscopies. Twenty-three additional polyps (12 adenomas and 11 hyperplastic polyps) were found on the second exams, yielding an adenoma miss rate of 55%. Fifteen polyps (5 adenomas and 10 hyperplastic polyps) were found in subjects who had chromoendoscopy and 8 polyps (7 adenomas and 1 hyperplastic polyp) in those who had intensive inspection. Chromoendoscopy was associated with more normal tissue biopsies (11 versus 5) and longer procedure times compared with intensive inspection (29.8 +/- 9.5 versus 25.3 +/- 5.8 minutes; P = 0.04). Controlling for age, number of previous colonoscopies, procedure time, and prior colonic resection, chromoendoscopy detected more polyps (P = 0.04), but adenoma detection was not significantly different compared with intensive inspection (P = 0.27).

CONCLUSIONS

Small adenomas are frequently missed in patients with Lynch syndrome. Although chromoendoscopy did not detect more missed adenomas than intensive inspection in this pilot study, larger trials are needed to determine optimal surveillance techniques in this high-risk population.

Surveillance colonoscopy improves survival in a cohort of subjects with a single mismatch repair gene mutation

OBJECTIVE

Previous studies have shown a benefit for surveillance colonoscopy in heterogeneous groups of subjects with suspected or proven hereditary nonpolyposis colon cancer. The aim of this study was to investigate whether surveillance colonoscopy improves the survival in subjects who all carry a single mismatch repair gene defect.

METHOD

This is a prospective cohort study of 178 subjects who carry a mutation of the MLH1 gene in exon 13 (C1528T). They were offered surveillance colonoscopy between 1988 and 2006, and were followed up until September 2007.

RESULTS

One hundred and twenty-nine subjects underwent surveillance colonoscopy, and 49 declined. After a median follow up of 5 years, colorectal cancer was diagnosed in 14/129 (11%) subjects in the surveillance group and 13/49 (27%) in the nonsurveillance group (P = 0.019). Cancers in the surveillance group were at an earlier stage than in the nonsurveillance group (P = 0.032). Death from colorectal cancer occurred in three of 129 (2%) subjects in the surveillance group, and six of 49 (12%) in the nonsurveillance group (P = 0.021). The Kaplan-Meyer estimates for median survival from birth were 78 years in the surveillance group, and 55 years in the nonsurveillance group (P = 0.024). The Kaplan-Meyer estimates for median colorectal cancer-free survival from birth were 73 years in the surveillance group and 47 years in the nonsurveillance group (P = 0.0089).

CONCLUSION

Surveillance colonoscopy was associated with improved overall and colorectal cancer-related survival in subjects carrying a single mismatch repair gene mutation.

Mechanisms of pathogenicity in human MSH2 missense mutants

The human mismatch repair (MMR) gene MSH2 is the second most frequently mutated hereditary nonpolyposis colorectal cancer (HNPCC) susceptibility locus. Given that missense mutations account for 17% of all identified alterations in this gene, the study of their pathogenicity is of increasing importance. Previously, we showed that pathogenic MSH2 missense mutations typically impaired the repair activity of the protein. In this study, we took advantage of its crystal structure and attempted to correlate the mismatch binding and ATP-catalyzed mismatch release activities with the location of 18 nontruncating MSH2 mutations. We observed that the MMR-deficient mutations situated in the amino-terminal connector and lever domains of MSH2 (V161D, G162R, G164R, L173P, L187P, C333Y, and D603N) affected protein stability, whereas mutations in the ATPase domain (A636P, G674A, C697F, I745_I746del, and E749 K) mainly caused defects in mismatch binding or release. Of the MMR-proficient variants, four (T33P, A272 V, G322D, and V923E) showed slightly reduced mismatch binding and/or release efficiencies compared to wild-type (WT) protein, while two variants (N127S and A834 T) showed no defects in the assays. Similar to our biochemical data, the mutations that affected protein stability were associated with an absence of the protein in tumors in immunohistochemical (IHC) analyses. In contrast, the protein with the mutation E749 K, which abrogates MMR but not protein stability, is well expressed in tumors. In conclusion, pathogenic missense mutations in MSH2 may interfere with different mechanisms that tend to cluster in separate protein domains with varying effects on protein stability, which could be taken into account when interpreting IHC data.

Adenoma-infiltrating lymphocytes (AILs) are a potential marker of hereditary nonpolyposis colorectal cancer

Patients with hereditary nonpolyposis colorectal cancer syndrome (HNPCC) develop microsatellite-unstable colorectal cancers that tend to be more proximally located and are histologically more likely to show high numbers of tumor-infiltrating lymphocytes, a lack of dirty necrosis, mucinous or poor differentiation, and a Crohn-like host immune response, when compared with microsatellite-stable cancers. However, histologic features that are characteristic of and can perhaps distinguish colorectal adenomas in HNPCC patients from those occurring in the general population have not been previously reported. We compared 16 adenomas endoscopically removed from patients with genetically proven HNPCC to 32 control adenomas, group-matched for patient age and sex, along with endoscopic size, shape, anatomic location, and presence of high-grade dysplasia. Adenomas from HNPCC patients were more likely to contain high numbers of adenoma-infiltrating lymphocytes (AILs) with 12 of 16 (75%) adenomas having >or=5 AILs per high-power field (HPF) as opposed to 4 of 32 (12%) adenomas in the control group (P=0.00003). HNPCC adenomas were also less likely to contain increased numbers of apoptotic bodies: 7 of 16 (44%) contained >or=5 apoptoses per HPF, compared with 27 of 36 (84%) control adenomas (P=0.006). The presence of necrosis or serrated architecture, percent villous component, and numbers of mitotic figures per HPF did not differ significantly between the 2 groups. Therefore, increased numbers of AILs and decreased numbers of apoptoses in colorectal adenomas are simple and inexpensive markers that raise the possibility of HNPCC.