Care of patients and their families with familial adenomatous polyposis

Hereditary Endocrine Tumors and Associated Syndromes: A Narrative Review for Endocrinologists and Endocrine Surgeons

OBJECTIVE

Hereditary endocrine tumors (HET) were among the first group of tumors where predisposition syndromes were recognized. The utility of genetic awareness is having the capacity to treat at an earlier stage, screen for other manifestations and initiate family cascade testing. The aim of this narrative review is to describe the most common hereditary syndromes associated with frequently encountered endocrine tumors, with an emphasis on screening and surveillance.

METHODS

A MEDLINE search of articles for relevance to endocrine tumors and hereditary syndromes was performed.

RESULTS

The most common hereditary syndromes associated with frequently encountered endocrine tumors are described in terms of prevalence, genotype, phenotype, penetrance of malignancy, surgical management, screening and surveillance.

CONCLUSION

Medical practitioners involved in the care of patients with endocrine tumors, should have an index of suspicion for an underlying hereditary syndrome. Interdisciplinary care is integral to successful, long-term management of these patients and affected family members.

Risk Factors and Genetic Predisposition in Colorectal Cancer: A Study on Young and Old Adults

According to GLOBOCAN 2018 data Colorectal cancer (CRC) represents the third most commonly diagnosed cancer in the world and has the second-highest mortality rate. The incidence of CRC has been rising worldwide, the majority of cases being in developing countries mostly due to the adoption of an unhealthy lifestyle. The main driving factors behind CRC are a sedentary lifestyle, obesity, red meat consumption, alcohol, and tobacco; however, early detection screenings and standardized treatment options have reduced CRC mortality. Better family history and genetic testing can help those with a hereditary predisposition in taking preventative measures.

Upper gastrointestinal neoplasia in familial adenomatous polyposis: prevalence, endoscopic features and management

Background

To evaluate the prevalence of upper gastrointestinal (GI) polyps in familial adenomatous polyposis (FAP), and to discuss current therapeutic recommendations.

Methods

Clinical, endoscopic, histological and treatment data were retrieved from charts of 102 patients [1958-2016]. Duodenal adenomatosis was classified according to Spigelman stages.

Results

this series comprised 59 women (57.8%) and 43 men (42.1%) with a median age of 32.3 years. Patients underwent 184 endoscopic procedures, the first at a median age of 35.9 years (range, 13-75 years). Fundic gastric polyps (n=31; 30.4%) prevailed in the stomach. While only 5 adenomas were found in the stomach, 33 patients (32.4%) presented duodenal ones. Advanced lesions (n=13; 12.7%) were detected in the stomach (n=2) and duodenum (n=11). During follow-up, Spigelman stages improved in 6 (12.2%) patients, remained unchanged in 25 (51.0%) and worsened in 18 (36.7%). Carcinomas were diagnosed in the stomach and duodenum (4 lesions each, 3.9%), at median ages of 50.2 and 55.0 years, respectively. Advanced lesions and carcinomas were managed through local or surgical resections. Severe complications occurred in only 2 patients (one death). Enteroscopy in 21 patients revealed jejunal adenomas in 12, 11 of whom also presented duodenal adenomas.

Conclusions

There is a high prevalence of upper GI adenomas and cancer in FAP. There were diagnosed fundic gastric polyps (30.4%), duodenal (32.4%) and jejunal adenomas (11.8%), respectively. One third of duodenal polyps progressed slowly throughout the study. The rates of advanced gastroduodenal lesions (12.7%) and cancer (7.8%) raise the need for continuous surveillance during follow-up.

Hepatoblastoma in patients with molecularly proven familial adenomatous polyposis: Clinical characteristics and rationale for surveillance screening

Familial adenomatous polyposis (FAP) due to APC mutation is associated with an increased risk of hepatoblastoma. All cases of hepatoblastoma in patients with FAP reported in the literature were reviewed. One hundred and nine patients were identified. Thirty-five patients (of 49 with data) were diagnosed with hepatoblastoma prior to a later diagnosis of FAP (often in association with advanced colorectal carcinoma), emphasizing a need to identify patients earlier with germline APC mutations for early colorectal carcinoma screening. Hepatoblastoma may present at birth, and screening for hepatoblastoma in infancy in families with FAP prior to APC mutation testing results may be warranted.

Current status of prophylactic surgical treatment for familial adenomatous polyposis in Japan

PURPOSE

We conducted this study to clarify the current clinical practice of prophylactic colectomy for patients with familial adenomatous polyposis (FAP) in Japan.

METHODS

This retrospective multi-center cohort study involved 23 specialized institutions for colorectal disease in Japan. We analyzed the records of 147 patients who underwent prophylactic surgical treatment between 2000 and 2012. Patients were divided into Group 1 (2000-2006) and Group 2 (2007-2012) based on their date of surgery.

RESULTS

Age at the time of prophylactic surgery was 27 and 31 years in Groups 1 and 2, respectively. The proportion of attenuated FAP was significantly lower in Group 2 than in Group 1 (1.0 vs. 13 %, respectively). Pathological examination revealed an increased incidence of malignant polyps in the resected specimens from Group 2 patients (10 vs. 23 %, respectively; P = 0.034). Laparoscopic surgery was more frequent in Group 2 than in Group 1 (61 vs. 40 %, respectively). There was no surgical mortality in either group.

CONCLUSION

Prophylactic surgery for FAP results in good short-term surgical outcomes in Japan. The current surgical approach is characterized by limited surgical indications for patients with attenuated FAP, delayed timing of colectomy, and the increasing standardization of laparoscopic surgery.

The importance of G2677T/A and C3435T polymorphisms of the MDR1 gene in the aetiology of colorectal cancer

Introduction

Colorectal cancer (CRC) is the most common cancer among patients, and its aetiology is still not precisely known. It is believed that 15–30% of colorectal cancers are genetically determined. P-glycoprotein (P-gp) encoded by the MDR1 gene in normal conditions plays an important role in the action of colon epithelial cells. However, the MDR1 polymorphism influences the P-gp expression and can weaken its effect against xenobiotics (procarcinogens) and increase the frequency of CRC.

Aim

To evaluate the correlation between the MDR1 C3435T and G2677T/A polymorphisms and the risk of colorectal cancer.

Material and methods

The study group with colorectal cancer included 47 women and 60 men while the control group consisted of 110 healthy patients. The diagnosis in patients suffering from CRC was confirmed by histopathological report. Genetic analysis was performed using PCR-RFLP method.

Results

We showed only a correlation between the frequency of CT and TT genotypes of C3435T polymorphism and the risk of colorectal cancer in younger age. There was no correlation between the C3435T and G2677T/A polymorphisms of the MDR1 gene and other clinical parameters.

Conclusions

Our findings suggest that T allele carriers of C3435T polymorphism have an increased risk of CRC. However, further studies are needed on a much larger number of patients and genes associated with metabolism and transport of xenobiotics including procarcinogens.

The natural history of familial adenomatous polyposis syndrome: a 24 year review of a single center experience in screening, diagnosis, and outcomes

PURPOSE

Understanding the natural history of Familial Adenomatous Polyposis (FAP) will guide screening and aid clinical management.

METHODS

Patients with FAP, age ≤20years presenting between 1987 and 2011, were reviewed for presentation, diagnosis, extraintestinal manifestations, polyp burden, family history, histology, gene mutation, surgical intervention, and outcome.

RESULTS

One hundred sixty-three FAP patients were identified. Diagnosis was made by colonoscopy (69%) or genetic screening (25%) at mean age of 12.5years. Most children (58%) were asymptomatic and diagnosed via screening due to family history. Rectal bleeding was the most common (37%) symptom prompting evaluation. Colon polyps appeared by mean age of 13.4years with >50 polyps at the time of diagnosis in 60%. Cancer was found in 1 colonoscopy biopsy and 5 colectomy specimens. Family history of FAP was known in 85%. 53% had genetic testing, which confirmed APC mutation in 88%. Extraintestinal manifestations included congenital hypertrophy of the retinal pigment epithelium (11.3%), desmoids (10.6%), osteomas (6.7%), epidermal cysts (5.5%), extranumerary teeth (3.7%), papillary thyroid cancer (3.1%), and hepatoblastoma (2.5%). Six patients died secondary to FAP.

CONCLUSIONS

Clinical presentation and manifestations in pediatric FAP are variable. We suggest an individualized patient-oriented screening algorithm that allows for earlier screening and appropriate management.

Inherited colorectal cancer syndromes

Colorectal cancer is common in the Western world; ~5% of individuals diagnosed with colorectal cancer have an identifiable inherited genetic predisposition to this malignancy. Genetic testing and rational clinical management recommendations currently exist for the management of individuals with a variety of colorectal cancer syndromes, including hereditary nonpolyposis colorectal cancer (HNPCC, also known as Lynch syndrome), familial adenomatous polyposis (FAP), MYH-associated polyposis (MAP), and the hamartomatous polyposis syndromes (Peutz-Jeghers, juvenile polyposis, and Cowden disease). In addition to colorectal neoplasia, these syndromes frequently predispose carriers to a variety of extracolonic cancers. The elucidation of the genetic basis of several colorectal cancer predisposition syndromes over the past two decades has allowed for better management of individuals who are either affected with, or at-risk for inherited colorectal cancer syndromes. Appropriate multidisciplinary management of these individuals includes genetic counseling, genetic testing, clinical screening, and treatment recommendations.

Evaluating causes of death in familial adenomatous polyposis

BACKGROUND

Familial adenomatous polyposis is a genetic syndrome associated with an increased risk of colorectal cancer (CRC) and different extracolonic manifestations.

GOALS

The goal of this study is to evaluate the frequency of death causes.

MATERIAL AND METHODS

Charts from 97 patients treated from 1977 to 2008 were reviewed. Retrieved data and family information allowed us to classify causes of death in those related to CCR to other malignancies or other causes.

RESULTS

There were analyzed data from 46 men (47.4%) and 51 women (52.6%) with an average age of 35.1 years (14 to 82). At diagnosis, 57 patients (58.7%) already had CRC-associated polyposis. There were performed 93 colectomies, one internal diversion, and one partial resection. Two patients were not operated on. Results from 19 deceased patients (19.5%) were analyzed. CRC, other tumors (desmoid tumors, lymphoma, and gastric cancer), and other causes (complication of duodenal cancer surgery, complication after ileorectal anastomosis (IRA), and coronary disease) were responsible for 12 (63.1%), four (21.1%), and three (15.8%) of all deaths, respectively. Death from CRC occurred in the context of either systemic, rectal, or pouch recurrence. Desmoid disease was the second cause of death (10.5% of all causes), leading to a fatal outcome 22% of all patients who developed DT during the study period. Upper digestive carcinomas were responsible for other two death cases.

CONCLUSIONS

(1) CRC is still the most prevalent cause of death; (2) even after curative resections, CRC can cause death through rectal or pouch malignization; (3) long-term survival was also strongly related to the development of extracolonic neoplasia, especially desmoid tumors and gastroduodenal carcinoma; (4) our results raise the need for local improvement in familiar screening and help us to define follow-up strategies and patient-information standards.

TTD consensus document on the diagnosis and management of hereditary colorectal cancer

Colorectal cancer is the first cause of cancer in occidental countries if we consider both male and females tumours. In Spain, 26,000 new cases are diagnosed every year. The possibilities of cure are higher if the tumour is diagnosed early. One of the most important risk factors for colorectal cancer is inheritance. Some hereditary syndromes, such as familial adenomatous polyposis (FAP), increase the risk by almost 100% and at a young age. Other more prevalent syndromes, such Lynch syndrome, increase the risk 10-12 times more than in the general population. This article aims at summarising the most important aspects in hereditary colorectal cancer and to be a useful tool to oncologists who work with these patients and their families.

[Hereditary colorectal cancer]

One of the main challenges in the clinical management of familial colorectal cancer (CRC) remains the overlap of syndromes with different underlying genetic causes and the differentiated risk management of colorectal and associated malignancies. The Lynch syndrome (hereditary non-polyposis colorectal cancer, HNPCC) is characterized by the development of colorectal, endometrial, gastric and other cancers and is caused by a mutation in one of the mismatch repair (MMR) genes. Microsatellite instability (MSI) and/or immunohistochemistry (IHC) are important prognostic factors and may predict the response to chemotherapy. Familial adenomatous polyposis (FAP) may be seen as a counterpart to Lynch syndrome, responsible for <1% of all CRC cases. Recently the MUTYH gene has been identified as a further polyposis gene. The associated disorder has been termed MYH-associated polyposis (MAP) and displays an autosomal recessive pattern of inheritance. For clinical management, distinguishing between Lynch syndrome, attenuated FAP and MAP is important for risk assessment, surveillance recommendations and indication for prophylactic surgery.

The value of MUTYH testing in patients with early onset microsatellite stable colorectal cancer referred for hereditary nonpolyposis colon cancer syndrome testing

MUTYH adenomatous polyposis (MAP) can mimic both the familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC) phenotypes. As a result of MAP's phenotypic overlap with FAP, some DNA diagnostic laboratories perform MUTYH testing in conjunction with APC testing in patients with suspected FAP or attenuated FAP (AFAP). In addition to testing FAP/AFAP samples for MUTYH mutations, we were interested whether there would also be value in testing samples referred for HNPCC testing. To determine this, we tested a consecutive series of 229 samples referred for HNPCC testing for the two most common MUTYH mutations in the Caucasian population. To enrich our study population with MAP cases, we only included samples from patients with early onset colorectal cancer (CRC diagnosed <50 years old) in whom HNPCC had been excluded by microsatellite instability testing (microsatellite stable or low microsatellite instability). Four biallelic (2%) and six monoallelic (3%) MUTYH mutation carriers were identified. No clinical factors predicted MUTYH mutation status. Specifically, a family history of vertical transmission of CRC or having few polyps (<15) did not rule out the possibility of biallelic MUTYH mutations. Thus, MUTYH mutation testing may be a reasonable cascade test in early onset CRC found to have proficient DNA mismatch repair, regardless of pattern of family history or number of polyps.

Polipose gastroduodenal em doentes com polipose adenomatosa familiar Pós-Retocolectomia

RACIONAL: As manifestações extracólicas, como os pólipos gastroduodenais e o tumor do duodeno, são fatores que influenciam a morbimortalidade dos doentes com polipose adenomatosa familiar no seguimento pós-retocolectomia total. OBJETIVO: Investigar a freqüência destas alterações em doentes com polipose adenomatosa familiar e verificar a eficácia do rastreamento endoscópico. MÉTODO:No período de 1984 a 2005, 62 doentes com polipose adenomatosa familiar pós-retocolectomia foram estudados retrospectivamente pelo Grupo de Coloproctologia da Faculdade de Ciências Médicas da Universidade Estadual de Campinas, SP. O tempo de seguimento médio pós-operatório foi de 81,9 meses, sendo que em 53 (85,5%) foi possível analisar a ocorrência de pólipos gastroduodenais. RESULTADOS: Dos 53 doentes em seguimento, 27 (50,9%) apresentavam pólipos gastroduodenais. Em 8 (15,4%) os pólipos adenomatosos eram gástricos, 14 (27%) pólipos duodenais e 5 (9,6%) pólipos gástricos e duodenais. Dois doentes (3,8%) desenvolveram adenoma duodenal com displasia de alto grau. E outro (1,9%), adenocarcinoma em papila duodenal. CONCLUSÃO: O rastreamento endoscópico, desta forma, é de grande importância e o objetivo é detectar, o mais precocemente possível, os casos de adenocarcinoma duodenal e pólipos gastroduodenais com displasia de alto grau.

Self-Surveillance for Genetic Predisposition to Cancer: Behaviors and Emotions

PURPOSE/OBJECTIVES

To describe the kinds of self-monitoring activities and the emotional responses associated with those activities in patients with a genetic predisposition to multiple endocrine neoplasia type 2a (MEN2a) or familial adenomatous polyposis (FAP).

RESEARCH APPROACH

Thematic analysis of the transcripts of patient interviews conducted for two previous grounded theory investigations of participation in lifelong surveillance for patients with cancer predisposition syndromes and their family members.

SETTING

In the original studies, participants were recruited through a high-risk gastrointestinal cancer clinic (for FAP) and pediatric and adult endocrinology clinics (for MEN2a) at two eastern U.S. medical centers and by patient referral.

PARTICIPANTS

58 transcripts of interviews with 29 patients; 17 diagnosed with FAP or the variants of Gardner syndrome and attenuated FAP and 12 patients diagnosed with MEN2a.

METHODOLOGIC APPROACH

Informants participated in two hour-long, in-depth interviews and completed a self-administered sociodemographic questionnaire.

MAIN RESEARCH VARIABLES

Types of self-surveillance activities.

FINDINGS

Patients engage in an elaborate set of self-surveillance activities that are grouped into five categories of behavior: Medication Appraisal, Phenotype Tracking, Intake and Output Monitoring, Laboratory and Treatment Recording, and Tracking of Visits. Self-surveillance behaviors are grouped independent of type of syndrome, penetrance, age, or gender of the patient. Each category comprises a variety of behaviors that correspond with treatment recommendations and understanding of the disorder.

CONCLUSIONS

Self-surveillance may be driven by a combination of anticipation and the need for control and understanding.

INTERPRETATION

Findings from the study could be used to create an assessment tool to evaluate the extent to which patients are involved in day-to-day self-monitoring. Clinicians may use the categories to better understand patients' knowledge deficits and the emotional impact of enhanced vigilance. Self-surveillance activities performed by patients with MEN2a and FAP also may be performed by patients with other cancer predisposition syndromes.

Clinical Implications of Our Advancing Knowledge of Colorectal Cancer Genetics: Inherited Syndromes, Prognosis, Prevention, Screening and Therapeutics

Recent genetic advances in our knowledge of colorectal cancer genetics are beginning to pay translational dividends in the management of this common clinical problem. We are now able to accurately screen and counsel individuals at risk of rare inherited cancer syndromes. We have recently introduced two of what are sure to be numerous biologic-based therapies, and have shown that colorectal neoplasia risk can be modestly reduced by various chemopreventative agents. Finally, our advancing knowledge has led to significant inroads into understanding what genetic alterations define prognosis and predict response to specific chemotherapeutic agents, and we are beginning to explore the utility of this knowledge in mass genetic-based clinical screening efforts. Enthusiasm must be tempered, however, by the extraordinary cost that often accompanies relatively modest gains. Finally, although genetic-based therapy often receives the greatest attention, molecular genetics, will likely have the greatest cost-effective impact in primary prevention and early diagnosis.

Cancer genetics and its "different faces of autonomy"

In this article we discuss the development of a practice of screening, preventive treatment, and presymptomatic testing for individuals at risk of Familial Adenomatous Polyposis (FAP), a specific hereditary predisposition for colon cancer. We describe this development as a process of co-evolution, showing how this practice has been gradually taking shape in a new network of actors, routines, rules, institutions and technologies. We further argue that, looking at the emergence and transformation of this practice, we can distinguish two different regimes: a regime of prevention and a regime of self-determination. In each of these regimes the autonomy of patients and individuals at risk is shaped in a different way, that is, through a different complex of ideals, procedures, institutions, technologies, and routines. In our view, the interference between these two regimes is an important characteristic of the emergent new genetics and is reflected in the growing debate about non-directivity in genetic counselling. However, as our argument implies, when facing the challenges of the new genetics we should not restrict the debate to the quality and ethics of counselling, but extend our view to the whole complex of elements and activities which shapes individual autonomy in the context of different regimes.

Pinealoblastoma in a patient with familial adenomatous polyposis: variant of Turcot syndrome type 2? Report of a case and review of the literature

We report a case of a 23-year-old Turcot female patient who was first diagnosed as having a pinealoblastoma. Thyroid papillary carcinoma was diagnosed a few months later, and multiple colonic polyps were detected three years after that. A genetic workup revealed an APC gene mutation in her family. Long-term survival (i.e., >5 years) of pinealoblastoma is considered to be 20 percent. A review of 25 documented Turcot cases determined that the average age at death is 20.3 years, raising the difficult question of whether she should undergo restorative proctocolectomy. Restorative proctocolectomy may itself cause major morbidity but is currently the only way to prevent colon cancer.

Family history assessment to detect increased risk for colorectal cancer: conceptual considerations and a preliminary economic analysis

BACKGROUND

Although the rationale for earlier screening of persons with a family history of colorectal cancer is plausible, there is no direct evidence that earlier assessment is either effective or cost-effective.

OBJECTIVE

To estimate the clinical and economic effect of using family history assessment to identify persons for colorectal cancer screening before age 50.

METHODS

We developed a decision model to compare costs and outcomes for two scenarios: (a) standard population screening starting at age 50; (b) family history assessment at age 40, followed by screening colonoscopy at age 40 for those with a suggestive family history of colorectal cancer. The analysis was conducted using the health insurer perspective.

RESULTS

Using U.S. population estimates, 22 million would be eligible for family history assessment, and one million would be eligible for early colonoscopy; 2,834 invasive cancers would be detected, and 29,331 life years would be gained. The initial program cost would be USD $900 million. The discounted cost per life year gained of family history assessment versus no assessment equals USD $58,228. The results were most sensitive to the life expectancy benefit from earlier screening, the cost of colonoscopy, and the relative risk of colon cancer in those with a family history.

CONCLUSIONS

The cost-effectiveness of family history assessment for colorectal cancer approaches that of other widely accepted technologies; yet, the results are sensitive to several assumptions where better data are needed. Because of the relatively high prevalence of family history in the population, careful analysis and empirical data are needed.

Genetic testing for inherited colon cancer

The genes associated with each of the inherited syndromes of colon cancer have now been identified, and genetic testing is available for diagnosis. These syndromes include familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and, possibly, Cowden's syndrome. Clinical genetic testing approaches have been developed for each of these syndromes and are now a part of accepted clinical care. Disease-causing mutations can be found in the majority of families affected with one of the inherited syndromes, and, most importantly, once a mutation is found in an index case of the family, relatives can be tested for the presence or absence of that mutation with near 100% accuracy. Cancer screening and management in syndrome families is then based on the results of genetic testing. For the physician to order and properly interpret genetic tests, a basic understanding of the types of mutations that lead to inherited disease and the methods for detecting them is vital. These issues will be presented. Additional clinical issues somewhat unique to genetic testing include genetic counseling and informed consent for genetic testing, both of which will also be reviewed. Often the most difficult aspect of genetic testing is deciding which patients and families should undergo the testing. Furthermore, this issue is quite specific for each of the syndromes. Thus, following presentation of general principles of selection for genetic testing, a detailed approach for identifying persons who should undergo testing for each of the individual syndromes will be given, together with relevant descriptions of the syndromes. Finally, the ongoing work to discover new and possibly more common but less penetrant colon cancer susceptibility genes that cause common familial colon cancer will be presented.

Hereditary colorectal cancer syndromes

The purpose of this article is to review the genetic colorectal cancer syndromes including Hereditary Nonpolyposis Colorectal Cancer (HNPCC), Family Polyposis (FAP) and the hamartomatous polyposis syndromes. HNPCC is the most common of the hereditary colorectal cancer syndromes, and is the result of defects in the mismatch repair genes. Individuals with HNPCC have an 80 lifetime risk of colorectal cancer, and in females a 30-50% risk of endometrial cancer, as well as predisposition for a number of other malignancies. Early screening and interval surveillance for colorectal and endometrial cancer are recommended. In FAP, mutations in the Adenomatous Polyposis Coli (APC) tumor suppressor gene give rise to hundreds to thousands of colorectal polyps, some of which will inevitably progress to cancer. Early diagnosis and timely prophylactic colectomy prevent this outcome. Chemoprevention with nonsteroidal anti-inflammatory drugs can reduce adenoma number and size in FAP, but the effect is incomplete. In addtion, surveillance for upper gastrointestinal tract malignancies is necessary. Attenuated forms of FAP may be the result of mutations in the APC gene, or in the recently described MYH gene. Mutations in the MYH gene should be considered in individuals with multiple adenomas whose family history does not reflect an autosomal dominant pattern of inheritance. The hamartomatous polyposis syndromes are uncommon but distinctive disorders in which multiple hamartomatous polyps develop at a young age. Our understanding of the genetic basis of these disorders is improving, and a predisposition for gastrointestinal and other malignancies has recently been recognized. This article summarizes the genetics, clinical manifestations and clinical management of each of these syndromes with an emphasis on genetic testing and prevention.

A clinician's guide to hereditary colon cancer

Approximately 10% of patients diagnosed with colorectal cancer are at risk for a hereditary form of the disease. At-risk patients can be offered genetic counseling and testing to determine whether they carry a detectable mutation for such a syndrome. If so, this information provides the clinician with valuable data about the patient's risk for other cancers, and what further surveillance and risk reduction options should be incorporated into the management plan. Mutation identification within a family also makes it possible for other family members to learn if they are at risk for the same syndrome. There are many hereditary colorectal cancer syndromes, and the clinician must know what essential information should be elicited from a family history and which patients should be referred for genetic counseling and testing.

Hereditary cancer predisposition syndromes

Cancer genetics is increasingly becoming integrated into the practice of modern medical oncology. The ability to distinguish a growing proportion of the 5% to 10% of all cancers that develop in individuals who have inherited a genetic mutation conferring heightened susceptibility to specific cancers may permit targeted efforts in cancer surveillance and prevention. While these individuals comprise a small proportion of the overall burden of cancer, strategies successful in reducing their remarkable cancer risks may be generalizable to the broader population. In this review, we highlight the most common hereditary cancer syndromes, most attributable to genes inherited in an autosomal dominant manner with incomplete penetrance, and a number of rare syndromes in which particular progress has been made. The prevalence, penetrance, tumor spectrum, and underlying genetic defects are discussed and summarized in a large table in which a more comprehensive enumeration of syndromes is provided.

Cancer genetics in primary care

The cloning of two major breast cancer susceptibility genes, BRCA1 and BRCA2, in 1994 and 1995 and the subsequent development of commercial genetic testing has brought hereditary cancer genetics into the public eye. In addition to DNA-based genetic testing, new strategies and treatments have been developed to provide accurate assessment of cancer risk and to reduce the chances of cancer developing in the future. This increasing scientific and public attention has prompted some cancer patients and their families to find out whether they "have the cancer gene" and has placed more responsibility on primary care clinicians to identify people who should be referred for specialized services of hereditary cancer genetics.

Colorectal cancer chemoprevention--an overview of the science

The development and dissemination of sophisticated detection technologies have recently exposed the high prevalence of preinvasive colorectal neoplasia in the adult U.S. population. Although cancer screening and surveillance provide opportunities for risk stratification, they achieve risk reduction only when coupled with effective interventions. This review surveys the lead compounds for colorectal cancer prevention and the measures by which they may be prioritized for clinical testing. Clinical trials remain the rate-limiting step in agent development, and novel trial designs are needed to hasten agent identification and testing for cancer prevention. Innovative research models include the nesting of prevention end points within cancer treatment trials and within trials testing promising preventive compounds intended for nononcologic indications.

Challenging colonic polyposis pedigrees: differential diagnosis, surveillance, and management concerns

Hereditary polyposis syndromes show extensive phenotypic and genotypic heterogeneity within and among families, a situation that may hinder diagnosis. In these settings, germline mutation testing may be the sine qua non for diagnosis if such a mutation is identified in a patient or family. We provide examples of phenotypically differing polyposis pedigrees depicting various challenges in hereditary polyposis syndrome diagnosis. Our purpose is to augment physician understanding of phenotypic variation and thus help identify high-risk presymptomatic family members who could benefit from highly targeted surveillance and management strategies. We describe nine familial polyposis pedigrees displaying anecdotal clinical problems that can confound the differential diagnosis. Emphasis was given to a multidisciplinary approach focusing on pathological confirmation with respect to number, histology, and location of polyps in the gastrointestinal tract; a detailed family history of cancer at all anatomic sites; noncancer phenotypic features of hereditary polyposis syndromes; and appropriate molecular genetic testing in concert with genetic counseling. Improved physician understanding of the clinical natural history features, genetic transmission patterns, and appropriate gene testing will help in diagnosis and, ultimately, surveillance and management for the various hereditary polyposis syndromes.

Familial adenomatous polyposis at the Tel Aviv Medical Center: demographic and clinical features

Familial adenomatous polyposis (FAP) is an uncommon, but widespread genetic disorder that develops multiple colonic adenomatous polyps and, if untreated, can lead to large bowel cancer. Little is known about its occurrence and characteristics in the Israeli population.

AIMS

To evaluate FAP prevalence, phenotypic manifestations and compliance for diagnosis and follow-up in our registry.

METHODS

Since 1993 approximately one-half of FAP patients in Israel have been seen and followed-up by us before and/or after colectomy. They and their families were encouraged to have mutation analysis, genetic and/or endoscopic screening.

RESULTS

37 pedigrees were identified, including 2 non-Jewish. The Jewish ethnic distribution was similar to that of the general population and the point prevalence rate estimated as 28.4/one million Jewish inhabitants. There were 461 first-degree relatives at-risk for FAP. Genetic screening was completed and successful in 28 pedigrees (87.5%), and 73 FAP patients entered the registry. Marked intra- familial phenotypic variations with minimal disease manifestation were noted in 11 patients belonging to 4 pedigrees. Cancer occurred in 15.1% (11 patients), in 10 before FAP diagnosis or during follow- up elsewhere, but one non-compliant patient developed duodenal cancer. One other patient died from a massive, neglected, intra- abdominal desmoid. Compliance for evaluation and follow-up of pedigree members and individual FAP patients was inadequate in 29% and 27%, respectively.

CONCLUSIONS

FAP occurs in the Israeli Jewish population at the expected rate, but is inadequately recognized in non-Jews. The inadequate compliance for screening and post-surgical follow-up needs to be addressed by educating the public, health care workers and Health Insurers.

Preventive surgery for colon cancer in familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer syndrome

BACKGROUND

A better understanding of the molecular basis of hereditary colorectal cancer syndromes such as hereditary nonpolyposis colorectal cancer syndrome (HNPCC) and familial adenomatous polyposis (FAP) has profound consequences for both the diagnosis and (prophylactic) treatment of (pre)malignant neoplastic lesions.

DISCUSSION

Sequence analysis of the underlying genes for these conditions and the detection of disease-causing genetic alterations in an index patient enable predictive testing for individuals at risk within an affected family. However, the clinical implications of predictive molecular testing depend on the overall penetrance and variability in the expression of pathogenic mutations. The extent of these parameters differs considerably among the various known hereditary colorectal cancer syndromes. Hence the integration of genetic information into the daily surgical practice remains challenging.

CONCLUSIONS

This review provides an update on the indications for family assessment, purpose and limitations of the genetic testing and resulting recommendations for prophylactic surgery in FAP and HNPCC.

Heritable colorectal cancer syndromes: recognition and preventive management

Familial CRC syndromes account for a small yet important portion of colorectal malignancies. HNPCC, FAP, JPS, and Peutz-Jeghers syndrome are the four major conditions to r to consider if an hereditary condition is suspected in an individual with CRC. A multidisciplinary team comprised of a medical geneticist, gastroenterologist, pathologist, radiologist, and colorectal surgeon with expertise in recognizing and establishing the diagnosis of a specific familial cancer condition is crucial to implementing the proper management and prevention strategies unique to each of these syndromes. Genetic testing for each of these coniditions is available and useful for presymptomatic diagnosis and for indicated surveillance regimens. Vigilant endoscopic surveillance and careful timing of surgery are the mainstays of prevention for gastrointestinal malignancies. But with the advancement of genetic evaluation, improved cancer surveillance for intestinal as well as extraintestinal cancer, and chemopreventive strategies, the management of patients with a familial CRC syndrome will continue to evolve and, hopefully, significantly reduce their cancer burden.

Different types of epithelial cadherin alterations play different roles in human carcinogenesis

Epithelial cadherin (E-cadherin) gene and protein alterations are implicated in the existence of two clearly distinct types of tumors in the stomach (isolated cell and glandular carcinomas), breast (lobular and ductal carcinomas), and thyroid (papillary and follicular carcinomas), as well as in the occurrence of poorly differentiated foci in colorectal and prostate adenocarcinomas. A thorough correlation between clinicopathologic features and molecular data, and the study of early lesions from familial cases provide clues for the understanding of the role played by E-cadherin in these settings.

The role of sigmoidoscopy and colonoscopy in the diagnosis and management of lower gastrointestinal disorders: technique, indications, and contraindications

Flexible sigmoidoscopy and colonoscopy have revolutionized the clinical management of colonic diseases. Colonoscopy has a broad range of indications, including evaluating lower GI symptoms such as lower GI bleeding, evaluating abnormal radiographic findings, and screening and surveillance for colon cancer. Colonoscopy is increasingly being used therapeutically. Patient evaluation, patient instructions, and colonic preparation before colonoscopy are essential for safe and efficient colonoscopy. Intravenous sedation reduces patient pain and anxiety during colonoscopy, but requires monitoring by pulse oximetry and automated measurements of vital signs. An experienced colonoscopist can complete colonoscopy in 90% or more of cases, using maneuvers to maintain the colonic lumen in view, straighten the colonoscope, and avoid looping during colonic intubation.

Gastrointestinal polyps and polyposis syndromes in children

Gastrointestinal polyps are common during childhood and most often present with painless rectal bleeding. Most polyps occur as isolated colonic lesions and are not harbingers of an underlying genetic disorder, nor do they bestow a risk of gastrointestinal cancer. The astute pediatrician must be aware, however, that occasionally polyps may occur in the context of a genetic polyposis disorder characterized by an increase in the life-time risk of cancer in the gastrointestinal tract and other organ systems. This review outlines the major polyposis syndromes affecting children and highlights associated findings that might clue the alert physician to an underlying diagnosis. Recent developments in the understanding of the genetics of each disorder are emphasized.

Colorectal cancer screening

During the past decade we have seen dramatic advances in colon cancer screening. Reduction in mortality in average risk screening for colorectal cancer has now been shown in multiple trials. Efforts to increase public awareness and compliance with evidence-based screening guidelines are underway. Recent guidelines have incorporated family history, as it has been identified as a common risk factor. The genes responsible for the inherited syndromes of colon cancer have been identified and genetic testing is available. Currently, screening the average risk population over the age of 50 would reduce mortality from colon cancer by 50%. Future advances will likely include improved screening tests, and the development of familial genetic testing.

Colon cancer screening strategies

Screening has been shown to reduce morbidity and mortality related to colorectal cancer. However, the optimal strategy for population screening for colorectal cancer has been a topic of heated debate. Recent studies have challenged the efficacy and cost-effectiveness of current population screening practices. Novel approaches to improve the assessment of an individual's colorectal cancer risk and advances in technology are changing our approach to colorectal screening. This review covers current guidelines for screening for colorectal cancer, recent advances in cancer risk assessment, and the role of endoscopy, virtual colonoscopy, and fecal DNA testing in colorectal cancer screening.

Secondary prevention: screening and surveillance of persons at average and high risk for colorectal cancer

Secondary prevention of colorectal cancer with FOBT and endoscopy with polypectomy decreases cancer deaths. Other available modalities include genetic tests and imaging studies, but outcomes data are not yet available. Issues remain concerning the most appropriate test, the optimal intervals, and cost-efficacy. Patients may be stratified by personal and family risk, and specific strategies may be used. Newer developments in genetic tests and imaging, including virtual colonoscopy, hold promise for the future. The most important issue at present is to have people screened or surveilled by any of the recommended modalities.

Early gastric cancer in young, asymptomatic carriers of germ-line E-cadherin mutations

BACKGROUND

Germ-line truncating mutations in the E-cadherin (CDH1) gene have been found in families with hereditary diffuse gastric cancer. These families are characterized by a highly penetrant susceptibility to diffuse gastric cancer with an autosomal dominant pattern of inheritance, predominantly in young persons. We describe genetic screening, surgical management, and pathological findings in young persons with truncating mutations in CDH1 from two unrelated families with hereditary diffuse gastric cancer.

METHODS

Mutation-specific predictive genetic testing was performed by polymerase-chain-reaction amplification, followed by restriction-enzyme digestion and DNA sequencing in Family 1 and by heteroduplex analysis in Family 2. A total gastrectomy was performed prophylactically in five carriers of mutations who were between 22 and 40 years old. In each case, the entire mucosa of the stomach was extensively sampled for microscopical analysis.

RESULTS

Superficial infiltrates of malignant signet-ring cells were identified in the surgical samples from all five persons who underwent gastrectomy. These early diffuse gastric cancers were multifocal in three of the five cases, and in one person infiltrates of malignant signet-ring cells were present in 65 of the 140 tissue blocks analyzed, representing in aggregate less than 2 percent of the gastric mucosa.

CONCLUSIONS

We recommend genetic counseling and consideration of prophylactic gastrectomy in young, asymptomatic carriers of germ-line truncating CDH1 mutations who belong to families with highly penetrant hereditary diffuse gastric cancer.

Genetic testing for cancer predisposition

Clinical cancer genetics is becoming an integral part of the care of cancer patients. This review describes the clinical aspects, genetics, and clinical genetic management of most of the major hereditary cancer susceptibility syndromes. Multiple endocrine neoplasia type 2, von Hippel-Lindau disease, and familial adenomatous polyposis are examples of syndromes for which genetic testing to identify at-risk family members is considered the standard of care. Genetic testing for these syndromes is sensitive and affordable, and it will change medical management. Cancer genetic counseling and testing is probably beneficial in other syndromes, such as the hereditary breast cancer syndromes, hereditary nonpolyposis colorectal cancer syndrome, Peutz-Jeghers syndrome, and juvenile polyposis. There are also hereditary cancer syndromes for which testing is not yet available and/or is unlikely to change medical management, including Li-Fraumeni syndrome and hereditary malignant melanoma. Thorough medical care requires the identification of families likely to have a hereditary cancer susceptibility syndrome for referral to cancer genetics professionals.

Hereditary colorectal cancer: risk assessment and management

There are at least nine major cancer susceptibility syndromes that infer an increased risk for colorectal cancer and/or colorectal polyposis; hereditary nonpolyposis colorectal cancer syndrome, Muir-Torre syndrome, Turcot syndrome, the I1307K polymorphism of the APC gene, familial adenomatous polyposis, attenuated familial adenomatous polyposis, Peutz Jeghers syndrome, juvenile polyposis, and the PTEN hamartoma tumor syndrome. As a result, the differential diagnosis of hereditary colorectal cancer can be complex. In addition, there has been a dramatic increase in the knowledge available regarding risk assessment and management of hereditary colorectal cancer syndromes. The literature was reviewed to develop this concise review of the hereditary colorectal cancer syndromes to facilitate the accurate diagnosis of each syndrome and the appropriate medical care for individuals with these diagnoses. Referral to a qualified Clinical Cancer Genetics program is appropriate if any of these syndromes is suspected and they will ensure the most up-to-date information is available to the patient, their family, and their health care professionals.