Implementing screening for Lynch syndrome among patients with newly diagnosed colorectal cancer: summary of a public health/clinical collaborative meeting

Select biomarkers for tumors of the gastrointestinal tract: present and future

CONTEXT

Advances in molecular biomarkers of the gastrointestinal tract have contributed to a decline in the incidence of and mortality from diseases of the gastrointestinal tract. The discovery and clinical validation of new biomarkers are important to personalized cancer therapy, and numerous clinical trials are currently ongoing to help identify individualized therapy affecting these biomarkers and molecular mechanisms they represent. Distinct molecular pathways leading to cancers of the colorectum, esophagus, stomach, small bowel, and pancreas have been identified. Using biomarkers in these pathways to direct patient care, including selection of proper molecular testing for identification of actionable mutations and reporting the results of these biomarkers to guide clinicians and genetic counselors, is paramount.

OBJECTIVE

To examine and review select clinically actionable biomarkers of the colon, esophagus, stomach, small bowel, and pancreas, including present and future biomarkers with relevant clinical trials.

DATA SOURCES

Extensive literature review and practical and consultation experience of the authors.

CONCLUSIONS

Although numerous biomarkers have been identified and are currently guiding patient therapy, few have shown evidence of clinical utility in the management of patients with gastrointestinal cancers. Inconsistent results and discordant proposed algorithms for testing were identified throughout the literature; however, the potential for biomarkers to improve outcomes for patients with gastrointestinal cancer remains high. Continued advances through high-quality studies are needed.

Applying public health screening criteria: how does universal newborn screening compare to universal tumor screening for Lynch syndrome in adults with colorectal cancer?

Institutions have increasingly begun to adopt universal tumor screening (UTS) programs whereby tumors from all newly diagnosed patients with colorectal cancer (CRC) are screened to identify who should be offered germline testing for Lynch syndrome (the most common cause of hereditary CRC). Given limited information about the impact of universal screening programs to detect hereditary disease in adults, we apply criteria used to evaluate public health screening programs and compare and contrast UTS with universal newborn screening (NBS) for the purpose of examining ethical implications and anticipating potential outcomes of UTS. Both UTS and a core set of NBS conditions clearly meet most of the Wilson and Jungner screening criteria. However, many state NBS panels include additional conditions that do not meet several of these criteria, and there is currently insufficient data to confirm that UTS meets some of these criteria. Comparing UTS and NBS with regard to newer screening criteria raises additional issues that require attention for both UTS and NBS. Comparisons also highlight the importance of evaluating the implementation of genomic tests to ensure or improve their effectiveness at reducing morbidity and mortality while minimizing potential harms.

Comparing universal Lynch syndrome tumor-screening programs to evaluate associations between implementation strategies and patient follow-through

PURPOSE

Universal tumor screening (UTS) for all colorectal cancer patients can improve the identification of Lynch syndrome, the most common cause of hereditary colorectal cancer. This multiple-case study explored how variability in UTS procedures influenced patient follow-through (PF) with germ-line testing after a screen-positive result.

METHODS

Data were obtained through Web-based surveys and telephone interviews with institutional informants. Institutions were categorized as Low-PF (≤10% underwent germ-line testing), Medium-PF (11-40%), or High-PF (>40%). To identify implementation procedures (i.e., conditions) unique to High-PF institutions, qualitative comparative analysis was performed.

RESULTS

Twenty-one informants from 15 institutions completed surveys and/or interviews. Conditions present among all five High-PF institutions included the following: (i) disclosure of screen-positive results to patients by genetic counselors; and (ii) genetic counselors either facilitate physician referrals to genetics professionals or eliminate the need for referrals. Although both of these High-PF conditions were present among two Medium-PF institutions, automatic reflex testing was lacking and difficulty contacting screen-positive patients was a barrier. The three remaining Medium-PF and five Low-PF institutions lacked the conditions found in High-PF institutions.

CONCLUSION

METHODS for streamlining UTS procedures, incorporating a high level of involvement of genetic counselors in tracking and communication of results and in reducing barriers to patient contact, are reviewed within a broader discussion on maximizing the effectiveness and public health impact of UTS.

Creation of a network to promote universal screening for Lynch syndrome: the LynchSyndrome Screening Network

The Evaluation of Genomic Applications in Practice and Prevention Working Group published an evidence-based recommendation stating that every newly diagnosed colorectal cancer (CRC) should undergo tumor screening for Lynch syndrome (LS). In 2011, leading cancer institutions and public health agencies created the Lynch Syndrome Screening Network (LSSN) in order to promote routine LS screening on all newly diagnosed CRCs and endometrial cancers (EC). The LSSN facilitates implementation of appropriate screening via shared resources, protocols and data through network collaboration. The LSSN website contains resources for institutions interested in initiating screening, including materials for program development, implementation and sustainability. The LSSN listserv gives providers access to experts in LS screening and implementation. The LSSN database will allow exploration of key gaps in implementation as a consortia-wide endeavor. To date, the LSSN's membership includes 85 institutions involved in the care of CRC patients and nine official partners such as national and state public health entities and other non-profit institutions. Nearly 80 % of the LSSN's members have already implemented routine or universal CRC and/or EC screening. LSSN serves to further the population health potential of universal LS screening through collaborative efforts and resources.

Genetic predisposition to colorectal cancer: Where we stand and future perspectives

The development of colorectal cancer (CRC) can be influenced by genetic factors in both familial cases and sporadic cases. Familial CRC has been associated with genetic changes in high-, moderate- and low-penetrance susceptibility genes. However, despite the availability of current gene-identification techniques, the genetic causes of a considerable proportion of hereditary cases remain unknown. Genome-wide association studies of CRC have identified a number of common low-penetrance alleles associated with a slightly increased or decreased risk of CRC. The accumulation of low-risk variants may partly explain the familial risk of CRC, and some of these variants may modify the risk of cancer in patients with mutations in high-penetrance genes. Understanding the predisposition to develop CRC will require investigators to address the following challenges: the identification of genes that cause uncharacterized hereditary cases of CRC such as familial CRC type X and serrated polyposis; the classification of variants of unknown significance in known CRC-predisposing genes; and the identification of additional cancer risk modifiers that can be used to perform risk assessments for individual mutation carriers. We performed a comprehensive review of the genetically characterized and uncharacterized hereditary CRC syndromes and of low- and moderate-penetrance loci and variants identified through genome-wide association studies and candidate-gene approaches. Current challenges and future perspectives in the field of CRC predisposition are also discussed.

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.

Direct-to-patient disclosure of results of mismatch repair screening for Lynch syndrome via electronic personal health record: a feasibility study

PURPOSE

The adoption of universal mismatch repair screening of colorectal and endometrial cancers has the potential to improve detection of Lynch syndrome, as well as to improve health outcomes among cancer patients and their family members. Electronic patient health records represent an innovative, resource-efficient route of delivering results directly to patients that could be enhanced by multimedia interventions to improve critical downstream outcomes. The current study examines the feasibility and acceptability of this approach.

METHODS

Patients hospitalized for resection of colorectal or endometrial cancer were recruited to receive their mismatch repair result via institutional electronic patient health record. Baseline and follow-up assessments were conducted.

RESULTS

In all, 74% (49/66) of eligible patients consented, and 81% (29/36) of participants who had a result posted to their electronic patient health record completed follow-up, surpassing feasibility thresholds, with 14% (5/36) receiving an abnormal result. Ratings of the study approach surpassed the acceptability threshold--97% had a mean score of ≥ 4 on a 7-point scale--and were high, regardless of whether the results were normal or abnormal. Ineligibility was more common among non-white patients (P = 0.009) and patients ≥ 65 of age (P = 0.035) due to either low Internet use or access to the Internet.

CONCLUSION

Electronic patient health record-based result disclosure for mismatch repair screening is feasible to study and is acceptable to patients, but minority and elderly patients may experience greater barriers to participation.Genet Med 16 11, 854-861.

Role of the clinical pathology laboratory in the evaluation of endometrial carcinomas for Lynch syndrome

Molecular diagnostic testing of endometrial carcinomas in the pathology laboratory has recently emerged as a key component of the clinical evaluation of Lynch syndrome in many centers. Testing modalities involve immunohistochemical and PCR-based analyses. This article outlines the routine application of these analyses, provides a practical guide for troubleshooting some of the common technical issues related to their performance, and reviews common pitfalls in their interpretation. Discrepancies between tissue testing and genetic testing results are discussed in the context of the current understanding of endometrial cancer biology. The merits of universal versus targeted tissue testing based on clinical patient history and histological tumor appearance are also addressed.

Mismatch repair protein immunohistochemistry: a useful population screening strategy for Lynch syndrome

Lynch syndrome (LS), the most frequent form of hereditary colorectal cancer, shows a highly penetrant, autosomal dominant pattern of inheritance. Distinction of LS colorectal carcinoma instances from the much more common sporadic colorectal carcinoma cases is of paramount importance. Revised Bethesda Guidelines were developed to diagnose LS by evaluating a combination of clinical and pathologic data. The aim of the present study was to evaluate the usefulness of the pathology items included in the Revised Bethesda Guidelines. We have prospectively studied a series of 1624 consecutive colorectal carcinomas with an algorithm including immunohistochemical analysis of mismatch repair proteins and molecular study of microsatellite instability and BRAF c.1799 T > A (p.V600E) gene mutations. Patients with tumors showing LS features were referred for germline mutation analysis. By applying our algorithmic approach, we were able to identify LS features in 89 colorectal cancer patients, of whom only 27 met Revised Bethesda Guidelines pathology criteria. Of the 89 patients, 47 were then studied at the Genetic Counseling Unit, and LS was confirmed in 18, of whom 7 had not been identified by the Revised Bethesda Guidelines. Our study shows that the Revised Bethesda Guidelines failed to detect 70% of patients at risk of LS. Our algorithmic approach is a realistic and effective tool for LS identification. We strongly recommend the implementation of universal population screening for LS among all patients with newly diagnosed colorectal carcinoma.

ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis)

Lynch syndrome, familial adenomatous polyposis, and Mut Y homolog (MYH)-associated polyposis are three major known types of inherited colorectal cancer, which accounts for up to 5% of all colon cancer cases. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 and is inherited in an autosomal dominant manner. Familial adenomatous polyposis is manifested as colonic polyposis caused by mutations in the APC gene and is also inherited in an autosomal dominant manner. Finally, MYH-associated polyposis is caused by mutations in the MUTYH gene and is inherited in an autosomal recessive manner but may or may not be associated with polyps. There are variants of both familial adenomatous polyposis (Gardner syndrome--with extracolonic features--and Turcot syndrome, which features medulloblastoma) and Lynch syndrome (Muir-Torre syndrome features sebaceous skin carcinomas, and Turcot syndrome features glioblastomas). Although a clinical diagnosis of familial adenomatous polyposis can be made using colonoscopy, genetic testing is needed to inform at-risk relatives. Because of the overlapping phenotypes between attenuated familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome, genetic testing is needed to distinguish among these conditions. This distinction is important, especially for women with Lynch syndrome, who are at increased risk for gynecological cancers. Clinical testing for these genes has progressed rapidly in the past few years with advances in technologies and the lower cost of reagents, especially for sequencing. To assist clinical laboratories in developing and validating testing for this group of inherited colorectal cancers, the American College of Medical Genetics and Genomics has developed the following technical standards and guidelines. An algorithm for testing is also proposed.

Relationship between PTEN, DNA mismatch repair, and tumor histotype in endometrial carcinoma: retained positive expression of PTEN preferentially identifies sporadic non-endometrioid carcinomas

Loss of PTEN (phosphatase and tensin homolog) expression and microsatellite instability are two of the more common molecular alterations in endometrial carcinoma. From the published literature, it is controversial as to whether there is a relationship between these different molecular mechanisms. Therefore, a cohort of 187 pure endometrioid and non-endometrioid endometrial carcinomas, carefully characterized as to clinical and pathological features, was examined for PTEN sequence abnormalities and the immunohistochemical expression of PTEN and the DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. MLH1 methylation analysis was performed when tumors had loss of MLH1 protein. Mismatch repair protein loss was more frequent in endometrioid carcinomas compared with non-endometrioid carcinomas, a difference primarily attributable to the presence of MLH1 methylation in a greater proportion of endometrioid tumors. Among the non-endometrioid group, mixed endometrioid/non-endometrioid carcinomas were the histotype that most commonly had loss of a mismatch repair protein. In endometrioid tumors, the frequency of PTEN loss measured by immunohistochemistry and mutation did not differ significantly between the mismatch repair protein intact or mismatch repair protein loss groups, suggesting that PTEN loss is independent of mismatch protein repair status in this group. However, in non-endometrioid carcinomas, both intact positive PTEN immunohistochemical expression and PTEN wild type were highly associated with retained positive expression of mismatch repair proteins in the tumor. Relevant to screening endometrial cancers for Lynch Syndrome, an initial PTEN immunohistochemistry determination may be able to replace the use of four mismatch repair immunohistochemical markers in 63% of patients with non-endometrioid endometrial carcinoma. Therefore, PTEN immunohistochemistry, in combination with tumor histotype, is a useful adjunct in the clinical evaluation of endometrial carcinomas for Lynch Syndrome.

Colorectal cancer: Cascade genetic testing in Lynch syndrome: room for improvement

Genetic testing in relatives of individuals with Lynch syndrome is of utmost importance for targeted screening and prevention. A recent systematic review suggests that the uptake of testing in at-risk relatives is inadequate and therefore the cost-effectiveness of Lynch syndrome testing is questionable. The results of this study are discussed here.

Management of genetic syndromes predisposing to gynecologic cancers

Women with personal and family histories consistent with gynecologic cancer-associated hereditary cancer susceptibility disorders should be referred for genetic risk assessment and counseling. Genetic counseling facilitates informed medical decision making regarding genetic testing, screening, and treatment, including chemoprevention and risk-reducing surgery. Because of limitations of ovarian cancer screening, hereditary breast and ovarian cancer-affected women are offered risk-reducing bilateral salpingo-oophorectomy (BSO) between ages 35 and 40 years, or when childbearing is complete. Women with documented Lynch syndrome, associated with mutations in mismatch repair genes, should be screened at a young age and provided prevention options, including consideration of risk-reducing total abdominal hysterectomy and BSO, as well as intensive gastrointestinal screening. Clinicians caring for high-risk women must consider the potential adverse ethical, legal, and social issues associated with hereditary cancer risk assessment and testing. Additionally, at-risk family members should be alerted to their cancer risks, as well as the availability of risk assessment, counseling, and treatment services.

Population-based molecular screening for Lynch syndrome: implications for personalized medicine

PURPOSE

Molecular screening techniques are available to identify hereditary Lynch syndrome in people with newly diagnosed colorectal cancer (CRC). We aimed to determine whether decisions of patients or clinicians reduced detection of Lynch syndrome.

PATIENTS AND METHODS

A prospective cohort of 245 consecutive individuals with mismatch repair-deficient CRC recruited from a population-based molecular screening program of all incident patient cases of CRC in a health care region of 1.2 million inhabitants. All incident CRCs were analyzed for mismatch repair protein loss, supported by BRAF mutation and microsatellite instability testing. Advice regarding referral for germline testing was provided to treating surgeons.

RESULTS

The mean age of patients was 72.5 ± standard deviation of 12 years; 64% were women; 65% had BRAF-mutant cancers. Consent for germline testing was received from 194 patients (79%): 120 with low and 74 with high likelihood of Lynch syndrome based on tumor molecular profile. Of patients who consented, 143 provided samples for germline analysis, with 12 of 143 showing a mutation (8.4%; 95% CI, 4.4% to 14.2%). Among the 102 patients who chose not to provide a sample or did not consent, an estimated 5.3 of 102 had germline mutations (5.2%; 95% CI, 2.0% to 17.5%).

CONCLUSION

A universal screening strategy for Lynch syndrome is potentially effective because the overall estimate of germline mutations was 17.3 of 245 patient cases (7.1%; 95% CI, 2.8% to 18.2%). However, the true value of screening is likely to be greatly limited by the decisions and circumstances of patients in taking up germline testing.

Current Lynch syndrome tumor screening practices: a survey of genetic counselors

An electronic survey of the National Society of Genetic Counselors Cancer Special Interest Group was conducted in July 2011 to assess Lynch syndrome tumor screening programs and identify barriers to implementation. Over half of respondents (52.8 %) reported having a routine Lynch syndrome tumor screening protocol for newly diagnosed colon and/or endometrial cancers, and approximately half of these used a universal approach. There was an increase in the number of those screening over time, especially in the past 3 years. Tumor screening methods varied; 34/53 (64.2 %) started with immunohistochemistry, 11/53 (20.8 %) started with microsatellite instability testing and 8/53 (15.1 %) performed both on newly diagnosed colorectal tumors. Just 21.7 % (23/106) of respondents indicated they have a tumor screening program in place for newly diagnosed endometrial cancers. Written consent is rarely obtained (7.1 %) and the method of how results were returned to the patient was variable among respondents. Prevalent barriers to implementation were concern about cost, bringing key players together and convincing medical staff of the necessity. Use of Lynch syndrome tumor screening is in clinical practice, but protocols vary widely. This survey provides a glimpse of current practices and common barriers, and identifies the need for tumor screening algorithms with outcomes data.

Underutilization of Lynch syndrome screening in a multisite study of patients with colorectal cancer

PURPOSE

The aim of this study was to examine Lynch syndrome screening of patients with metastatic colorectal cancer in integrated health-care-delivery organizations.

METHODS

We determined the availability of Lynch syndrome screening criteria and actual Lynch syndrome screening in the medical records of 1,188 patients diagnosed with metastatic colorectal cancer between 2004 and 2009 at seven institutions in the Cancer Research Network.

RESULTS

We found infrequent use of Lynch syndrome screening (41/1,188). Family history was available for 937 of the 1,188 patients (79%). There was sufficient information to assess Lynch syndrome risk using family history-based criteria in 719 of the 937 patients (77%) with family history documentation. In 391 individuals with a family history of a Lynch syndrome-associated cancer, 107 (27%) could not be evaluated due to missing information such as age of cancer onset. Eleven percent of patients who met the Bethesda criteria and 25% of individuals who met the Amsterdam II criteria were screened for Lynch syndrome. Recommended guidelines were adhered to during screening, but no testing method was preferred.

CONCLUSION

The information required for Lynch syndrome screening decisions is routinely collected but seldom used. There is a critical gap between collection of family history and its use to guide Lynch syndrome screening, which may support a case for implementation of universal screening guidelines.

Implementation of routine screening for Lynch syndrome in university and safety-net health system settings: successes and challenges

PURPOSE

Routine screening for evidence of DNA mismatch repair abnormalities can identify colorectal cancer patients with Lynch syndrome, but impact in usual care settings requires study. After implementing routine screening at our university and safety-net health systems as usual practice, our aims were to determine outcomes, including screening process quality.

METHODS

We conducted a retrospective cohort study from 1 May 2010 to 1 May 2011. Screening included reflexive immunohistochemistry to evaluate DNA mismatch repair protein expression for patients with colorectal cancer aged ≤70 years, with a cancer genetics team following up results. Screening outcomes, as well as challenges to a high-quality screening process were evaluated.

RESULTS

We included 129 patients (mean age 56 years, 36% female); 100 had immunohistochemistry screening completed. Twelve patients had abnormal immunohistochemistry: four with definite Lynch syndrome, four with probable Lynch syndrome, and three without Lynch syndrome; one patient had an incomplete work-up. Lynch syndrome was confirmed for 6/13 asymptomatic relatives tested. Screening process quality was optimal for 77.5% of patients. Barriers to optimal quality screening included ensuring reflexive immunohistochemistry completion, complete follow-up of abnormal immunohistochemistry, and timely incorporation of results into clinical decision making.

CONCLUSION

Usual care implementation of routine screening for Lynch syndrome can result in significant rates of detection, even in a largely safety-net setting. To optimize implementation, challenges to high-quality Lynch syndrome screening, such as ensuring reflexive screening completion and clinically indicated genetic testing and follow-up for abnormal screens, must be identified and addressed.

Impact of age cutoffs on a lynch syndrome screening program

PURPOSE

To determine the impact of applying an age cutoff to tumor-based Lynch syndrome (LS) screening, specifically focusing on changes in relative effectiveness, efficiency, and cost. The project was undertaken to answer questions about implementation of the LS screening program in an integrated health care delivery system.

PATIENTS AND METHODS

Clinical data extracted from an internal cancer registry, previous modeling efforts, published literature, and gray data were used to populate decision models designed to answer questions about the impact of age cutoffs in LS screening. Patients with colorectal cancer (CRC) were stratified at 10-year intervals from ages 50 to 80 years and compared with no age cutoff. Outcomes are reported for a cohort of 325 patients screened and includes total cost to screen, LS cases present in the cutoff category, number of LS cases expected to be identified by screening, cost per LS case detected, and total number and percentage of LS cases missed.

CONCLUSION

Applying an age cutoff to an LS screening program has considerable potential for decreasing total screening costs and increasing efficiency, but at a loss of effectiveness. Imposing an age cutoff of 50 years reduces the cost of the screening program to 16% of a program with no age cutoff, but at the expense of missing more than half of the cases. Failure to identify LS cases is magnified by a cascade effect in family members. The results of this analysis influenced the final policy in our system.

Public health action in genomics is now needed beyond newborn screening

For decades, newborn screening was the only public health program in the US focused on reducing morbidity, mortality and disability in people affected by genetic conditions. The landscape has changed, however, as evidence-based recommendations are now available for several other genomic applications that can save lives now in the US. Many more such applications are expected to emerge in the next decade. An action plan, based on evidence, provides the impetus for a new paradigm for public health practice in genomics across the lifespan using established multilevel processes as a guide. These include policy interventions, education, clinical interventions, and surveillance. Applying what we know today in hereditary breast/ovarian cancer, Lynch syndrome and familial hypercholesterolemia has the potential to affect thousands of people in the US population every year. Enhanced partnerships between genetic and nongenetic providers of clinical medicine and public health are needed to overcome the challenges for implementing genomic medicine applications both now and in the future.

Multilevel research and the challenges of implementing genomic medicine

Advances in genomics and related fields promise a new era of personalized medicine in the cancer care continuum. Nevertheless, there are fundamental challenges in integrating genomic medicine into cancer practice. We explore how multilevel research can contribute to implementation of genomic medicine. We first review the rapidly developing scientific discoveries in this field and the paucity of current applications that are ready for implementation in clinical and public health programs. We then define a multidisciplinary translational research agenda for successful integration of genomic medicine into policy and practice and consider challenges for successful implementation. We illustrate the agenda using the example of Lynch syndrome testing in newly diagnosed cases of colorectal cancer and cascade testing in relatives. We synthesize existing information in a framework for future multilevel research for integrating genomic medicine into the cancer care continuum.

Diagnosing Lynch syndrome: more light at the end of the tunnel

Since the recognition of Lynch syndrome, which confers a high risk of colorectal, uterine, and other cancers, approaches to its diagnosis have included a family history of associated cancers and web-based algorithms. Identification of causative genes now allows a precise diagnosis, thus focusing present efforts on who should have genetic testing. Testing for cancer tissue changes can determine who should have germline genetic testing. Indeed, such tumor testing is now generally recommended for all newly diagnosed colorectal cancer cases. As reported in this issue of the journal by Yurgelun and colleagues (beginning on page 574), large colorectal adenomatous polyps (≥10 mm) from patients with Lynch syndrome exhibit findings similar to those in Lynch syndrome colorectal cancer tissues. This finding indicates that testing larger adenomas in persons at a significant risk for Lynch syndrome can now determine the need for germline genetic testing. Although further study is needed for general application, the present study justifies large polyp testing in high-risk families when cancer tissue is unavailable, albeit negative polyp tissue would not rule out Lynch syndrome, as would negative cancer tissue.