Epidemiology of familial adenomatous polyposis in Sweden: changes over time and differences in phenotype between males and females

Feasibility of underwater endoscopic mucosal resection for endoscopic management of gastric neoplasms in patients with familial adenomatous polyposis

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) has been developed as an effective endoscopic intervention for colon, rectum, and duodenum neoplasms. However, there are no comprehensive reports regarding the stomach, and its safety and efficacy are unknown. We aimed to examine the feasibility of UEMR for gastric neoplasms in patients with familial adenomatous polyposis (FAP).

METHODS

We retrospectively extracted data of patients with FAP who underwent endoscopic resection (ER) for gastric neoplasms at Osaka International Cancer Institute from February 2009 to December 2018. Elevated gastric neoplasms of ≤ 20 mm in diameter were extracted, and conventional endoscopic mucosal resection (CEMR) and UEMR were compared. Furthermore, outcomes after ER until March 2020 were examined.

RESULTS

91 endoscopically resected gastric neoplasms were extracted from 31 patients with 26 pedigrees, and 12 neoplasms underwent CEMR and 25 neoplasms underwent UEMR was compared. The procedure time was shorter for UEMR than for CEMR. There was no significant difference between en bloc resection and R0 resection rates by EMR methods. CEMR and UEMR showed postoperative hemorrhage rates of 8% and 0%, respectively. Residual/local recurrent neoplasms were identified in four lesions (4%), but additional endoscopic intervention (three UEMR and one cauterization) resulted in a local cure.

CONCLUSION

UEMR was feasible in gastric neoplasms of FAP patients, especially in elevated lesions and those of ≤ 20 mm in diameter.

Colorectal Cancer Epidemiology: Recent Trends and Impact on Outcomes

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer related deaths in the world with an estimated number of 1.8 million new cases and about 881,000 deaths worldwide in 2018. The epidemiology of CRC varies significantly between different regions in the world as well as between different age, gender and racial groups. Multiple factors are involved in this variation, including risk factor exposure, demographic variations in addition to genetic susceptibility and genetic mutations and their effect on the prognosis and treatment response. In this mini-review, we discuss the recent epidemiological trend including the incidence and mortality of colorectal cancer worldwide and the factors affecting these trends.

A unique case of two somatic APC mutations in an early onset cribriform-morular variant of papillary thyroid carcinoma and overview of the literature

We report a case of a 22-year-old female patient who was diagnosed with a cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC). While at early ages this thyroid cancer variant is highly suggestive for familial adenomatous polyposis (FAP), there was no family history of FAP. In the tumor biallelic, inactivating APC variants were identified. The patient tested negative for germline variants based on analysis of genomic DNA from peripheral blood leukocytes. Somatic mosaicism was excluded by subsequent deep sequencing of leukocyte and normal thyroid DNA using next generation sequencing (NGS). This report presents a rare sporadic case of CMV-PTC, and to the best of our knowledge the first featuring two somatic APC mutations underlying the disease, with an overview of CMV-PTC cases with detected APC and CTNNB1 pathogenic variants from the literature.

Colorectal Cancer in Individuals With Familial Adenomatous Polyposis, Based on Analysis of the Danish Polyposis Registry

BACKGROUND & AIMS

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder that increases risk for colorectal cancer (CRC). We assessed changes in the incidence and prevalence of CRC, and survival times, of patients with FAP participating in the Danish follow-up study.

METHODS

We collected data from the Danish Polyposis Registry, a nationwide, complete registry of patients with FAP that includes clinical information, surgical procedures, follow-up findings, and pathology reports. We compared data between the periods of 1990-1999 and 2000-2017. In 2017, the registry contained 226 families with 721 individuals with FAP. Probands were defined as patients diagnosed based on bowel symptoms, without any knowledge of hereditary bowel disease. Call-up patients were defined as those found to have FAP during screening and due to a diagnosis of FAP in first-degree relatives.

RESULTS

Although the mean incidence rate of FAP was stable from 1990-1999 (0.19/100,000/year) to 2000-2017 (0.32/100,000/year) (P = .91), the point prevalence increased from 4.86/100,000 in 1999 to 6.11/100,000 by the end of 2017 (P = .005). During 2000-2017, 25 of 72,218 CRC cases were associated with FAP (0.03%)-this was a significant decrease from 1990-1999 (26/30,005 cases; 0.09%) (P = .001). The risk of CRC was significantly higher for probands (n = 191; 61.6%) than call-up cases (n = 5; 1.9%) (P < .001). All CRCs in call-up patients were detected at the diagnosis of FAP (no cases were identified in the follow-up program). The median life expectancy for call-up patients was 72.0 years (95% CI, 63.3-80.7), compared to 55.0 years for probands (95% CI, 51.2-58.8) (P < .001). Therefore, the tracing and follow-up program increased life expectancy by 17.0 years for first-degree family members.

CONCLUSION

The Danish Polyposis Registry enables close monitoring of patients with FAP, reducing risk of CRC and prolonging life.

Optimizing the timing of colorectal surgery in patients with familial adenomatous polyposis in clinical practice

Background: Familial adenomatous polyposis (FAP) is characterized by the development of hundreds of colorectal adenomas in the second decade of life, and prophylactic colectomy is usually performed around age of 20. A common question is the appropriate timing of surgery and which endoscopic findings indicate surgery. Methods: All FAP patients known at Leiden University Medical Centre from 1985 onwards were included. The patients were then subdivided into those diagnosed before or after 2000. Patient information included age at diagnosis, colonic phenotype, age at surgery, pathological findings and the outcome of follow-up colonoscopies in whom surgery was postponed. Results: The 72 FAP patients identified consisted of 33 patients diagnosed before (group A) and 39 after (group B) 2000. The median age at diagnosis for patients with classical FAP was 18 in groups A and B. All patients diagnosed before 2000 underwent colorectal surgery versus 68% of those diagnosed >2000. The median age at surgery for classical FAP patients was 19 and 24 years in groups A and B, respectively. In patients with intact colon, the number of adenomas gradually increased over many years. Although most adenomas remained <5 mm, the proportion of 5-15 mm adenomas slowly increased. Only one patient developed a high-grade adenoma. None of the patients developed CRC. Conclusions: Surgery today in FAP is performed less often and at a more advanced age. Our experience also suggests that surgery can be safely postponed in selected patients. The most important endoscopic indication for surgery is substantial number of large adenomas of >5-10 mm.

A Case Report on Gardner Syndrome With Dental Implant Treatment and a Long-Term Follow-Up

A case of Gardner syndrome (GS) in a 37-year-old woman is presented in which rehabilitation with dental implant treatment was followed for 7 years. The course of diagnostics and treatment is followed through an overview of 45 tissue biopsy and cytology samples during a period of 30 years. The patient was diagnosed with GS after a routine review of an oral panoramic radiograph presenting with multiple osteomas and multiple unerupted supernumerary teeth. Biopsy results and surgical procedures with histopathologic diagnoses from 1986 to 2016 are presented. Histologic analysis of the sampled jawbone showed a picture similar to an osteoid osteoma. The installed implant was functionally stable, with no clinical or radiographic events observed at yearly visits, for 7 years. In 1991, benign tumors appeared; in 2014, multiple adenomas were found in the small intestine and rectum. This case report shows the potential for dental implant treatment in a patient with GS.

Web-Based Model for Predicting Time to Surgery in Young Patients with Familial Adenomatous Polyposis: An Internally Validated Study

INTRODUCTION

The timing of prophylactic colorectal surgery in patients with familial adenomatous polyposis (FAP) is based on the immediacy of the colorectal cancer risk. The ability to predict the need for surgery may help patients and their families plan in the context of life events and CRC risk. We created a model to predict the likelihood of surgery within 2 and 5 years of first colonoscopy at our institution.

METHODS

A single institution hereditary colorectal syndrome (Cologene™) database was interrogated for all patients with FAP having a deleterious APC mutation. Patients with first colonoscopy after age 30 and before year 2000 were excluded. Cox regression analysis was done to assess multiple factors associated with surgery, followed by stepwise Cox regression analysis to select an optimal model. Receiver operator curve (ROC) analysis was performed to assess the model.

RESULTS

A total of 211 (53% female) patients were included. Forty-five percent underwent surgery after an average of 3.8 years of surveillance. The final model was created based on initial clinical characteristics (age, gender, BMI, family history of desmoids, genotype-phenotype correlation), initial colonoscopic characteristics (number of polyps, polyp size, presence of high-grade dysplasia); and on clinical events (chemoprevention and polypectomy). AUC was 0.87 and 0.84 to predict surgery within 2 and 5 years, respectively. The final model can be accessed at this website: http://app.calculoid.com/#/calculator/29638 .

CONCLUSION

This web-based tool allows clinicians to stratify patients' likelihood of colorectal surgery within 2 and 5 years of their initial examination, based on clinical and endoscopic features, and using the philosophy of care guiding practice at this institution.

Cancer Screening Recommendations and Clinical Management of Inherited Gastrointestinal Cancer Syndromes in Childhood

Hereditary gastrointestinal cancer predisposition syndromes have been well characterized, but management strategies and surveillance remain a major challenge, especially in childhood. In October 2016, the American Association for Cancer Research organized the AACR Childhood Cancer Predisposition Workshop in which international experts in care of children with a hereditary risk of cancer met to define surveillance strategies and management of children with cancer predisposition syndromes. In this article, we review the current literature in polyposis syndromes that can be diagnosed in childhood and may be associated with an increased incidence of gastrointestinal neoplasms and other cancer types. These disorders include adenomatous polyposis syndromes (APC and MUTYH), juvenile polyposis coli (BMPR1A and SMAD4), Peutz-Jeghers Syndrome (STK11/LKB1), and PTEN hamartoma tumor syndrome (PHTS; PTEN), which can present with a more limited juvenile polyposis phenotype. Herein, the panel of experts provides recommendations for clinical diagnosis, approach to genetic testing, and focus on cancer surveillance recommendations when appropriate during the pediatric period. We also review current controversies on genetic evaluation of patients with hepatoblastoma and indications for surveillance for this tumor. Childhood cancer risks and surveillance associated with disorders involving the mismatch repair genes, including Lynch syndrome and constitutional mismatch repair deficiency (CMMRD), are discussed elsewhere in this series. Clin Cancer Res; 23(13); e107-e14. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

Colorectal polyposis and inherited colorectal cancer syndromes

The majority of colorectal cancer (CRC) cases are sporadic, with hereditary factors contributing to approximately 35% of CRC cases. Less than 5% of CRC is associated with a known genetic syndrome. Although adenomatous polyposis syndromes, hamartomatous polyposis syndromes, and those previously classified as non-polyposis CRC syndromes are quite rare, it is important for clinicians to know the characteristics of each syndrome and to understand the differences in cancer risks between the different conditions. This information is very important when treatment and surveillance plans are formulated for each individual patient.

Hereditary Colorectal Polyposis and Cancer Syndromes: A Primer on Diagnosis and Management

Colorectal cancer (CRC) is the fourth most common cancer amongst men and women. Between 3 and 6% of all CRCs are attributed to well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis (FAP), MUTYH-associated polyposis (MAP), and several hamartomatous polyposis conditions. 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 narrative review examines the hereditary colorectal cancer and polyposis syndromes, their genetic basis, clinical management, and evidence supporting cancer screening.

Hereditary Colorectal Cancer Syndromes

Awareness of hereditary colorectal cancer syndromes is important to facilitate their identification because affected patients are at increased risk for early onset, synchronous, and metachronous colorectal malignancies, and certain extracolonic malignancies depending on the syndrome. Identification of an affected individual allows for screening and early interventions for patients and their at-risk kindred. Genetic counseling and testing is important to the care of these patients. As knowledge of the genetic basis of these syndromes grows, unique genotype-phenotype profiles allow clinicians to tailor surveillance and treatment strategies based on individual risk.

Adenomatous Polyposis Syndromes: Diagnosis and Management

Familial adenomatous polyposis (FAP) syndromes make up fewer than 1% of patients diagnosed with colorectal cancer each year. Patients with familial polyposis syndromes including FAP, attenuated FAP, and MYH-associated polyposis (MAP), are an important group often cared for by colorectal surgeons. Registry and screening programs have been shown to improve survival in patients with adenomatous polyposis, as it allows patients to undergo surgical intervention prior to the development of colorectal cancer. There are several surgical options for the treatment of colorectal polyps in patients with adenomatous polyposis, so it is important to choose the appropriate procedure for each patient after discussing the risk of cancer in the rectal remnant, as well as bowel and sexual function in a predominantly young patient group. Regardless of procedure choice, long-term follow-up is important with yearly endoscopic evaluation of the pouch or remnant rectum, as well as appropriate screening for extracolonic malignancy. Adenomatous polyposis patients require an intense care regimen, but can have a normal lifespan with good quality when cared for appropriately.

Altered T-Cell Balance in Lymphoid Organs of a Mouse Model of Colorectal Cancer

The adenomatous polyposis coli (APC) gene is a known tumor suppressor gene, and mice with mutations in Apc (Apc^Min/+) spontaneously form multiple intestinal neoplasms. In this model of human colorectal cancer (CRC), it has been reported that CD4⁺ T-cell-derived interleukin 17 (IL-17) promotes intestinal tumor development, but it is not known if the Apc mutation actually directly alters T-cell function and subsequently tumor immunosurveillance. To investigate the Apc^Min/+ mutation on T-cell function, flow cytometric, histochemical, and immunofluorescent studies on both wild-type (Apc^+/+) and Apc^Min/+ mice were performed. We identified decreased levels of interferon gamma (IFN-γ⁺)IL-17⁺ double-positive CD4⁺ cells in the mesenteric lymph nodes and Peyer's patches of Apc^Min/+ mice. In addition, altered levels of CD8⁺ cells, and changes in CD8⁺ production of IFN-γ and granzyme B were observed. These T-cell alterations did modify tumor immunosurveillance, as the adoptive transfer of splenocytes from Apc^Min/+ animals into a chemically induced CRC model resulted in the inability to prevent epithelial dysplasia. These results suggest an altered T-cell balance in Apc^Min/+ mice may disrupt intestinal homeostasis, consequently limiting intestinal tumor immunosurveillance.

Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP), caused by a germline mutation in the adenomatous polyposis coli (APC) gene on chromosome 5q21, is an autosomal dominant disorder characterized by hundreds to thousands of adenomas throughout the gastrointestinal tract. A variety of extraintestinal manifestations, including thyroid, soft tissue, and brain tumors, may also be present. These patients inevitably develop colorectal carcinoma by the fourth decade of life. In this review, the pathology, epidemiology, and genetic features of FAP are discussed.

Familial colorectal cancer

Identifying individuals with a genetic predisposition to developing familial colorectal cancer (CRC) is crucial to the management of the affected individual and their family. In order to do so, the physician requires an understanding of the different gene mutations and clinical manifestations of familial CRC. This review summarises the genetics, clinical manifestations and management of the known familial CRC syndromes, specifically Lynch syndrome, familial adenomatous polyposis, MUTYH-associated neoplasia, juvenile polyposis syndrome and Peutz-Jeghers syndrome. An individual suspected of having a familial CRC with an underlying genetic predisposition should be referred to a familial cancer centre to enable pre-test counselling and appropriate follow up.

The role of illness perceptions in adherence to surveillance in patients with familial adenomatous polyposis (FAP)

OBJECTIVE

The aim of the study was to examine patients' beliefs about having familial adenomatous polyposis (FAP), a hereditary colorectal cancer syndrome, and how these beliefs are associated with adherence to endoscopic surveillance.

METHODS

Adult patients diagnosed with FAP on the national Swedish polyposis register who had undergone prophylactic colorectal surgery (n 209, response rate 76%) completed the Illness Perception Questionnaire (IPQ). Logistic regression analysis was used to investigate the relationships between illness perceptions and adherence, when controlling for demographic and clinical factors.

RESULTS

FAP was less distressing in men and those with fewer symptoms, reporting less serious consequences and more coherent understanding of FAP. Non-adherence (14%) to surveillance was associated with being older, having undergone surgery less recently and no history of malignancy. Patients' beliefs about their FAP were able to explain unique variance in non-adherence, in particular those who believed FAP was less distressing.

CONCLUSIONS

Patients who were non-adherent to endoscopic surveillance had more positive perceptions about their FAP and, in particular, were less emotionally affected compared to those who adhered. As non-adherence implies a greater risk of future malignancies, special efforts are required to effectively prevent cancer in all patients with FAP. Those who have lived with the condition for a long time, and are not troubled by gastrointestinal symptoms or worried about their FAP, may be in need of specific information and support. Further prospective research is required to examine emotional predictors and consequences of non-adherence. Copyright © 2015 John Wiley & Sons, Ltd.

The Genetics of Colorectal Cancer

The hereditary colorectal cancer syndromes comprise a heterogeneous group of conditions with varying cancer risks, gastrointestinal polyp types, nonmalignant findings, and inheritance patterns. Although each one is unique in its own right, these syndromes often have overlapping features, making diagnoses difficult in select cases. Obtaining accurate polyp history (histologic type, number, location, and age of onset), cancer history (location, type, and age of onset), and other nonmalignant features is imperative in determining the likely disease diagnosis and thereby the appropriate genetic tests for precise diagnosis in a timely fashion. This process often necessitates collaboration among surgical oncology team members and genetic counselors.

ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes

This guideline presents recommendations for the management of patients with hereditary gastrointestinal cancer syndromes. The initial assessment is the collection of a family history of cancers and premalignant gastrointestinal conditions and should provide enough information to develop a preliminary determination of the risk of a familial predisposition to cancer. Age at diagnosis and lineage (maternal and/or paternal) should be documented for all diagnoses, especially in first- and second-degree relatives. When indicated, genetic testing for a germline mutation should be done on the most informative candidate(s) identified through the family history evaluation and/or tumor analysis to confirm a diagnosis and allow for predictive testing of at-risk relatives. Genetic testing should be conducted in the context of pre- and post-test genetic counseling to ensure the patient's informed decision making. Patients who meet clinical criteria for a syndrome as well as those with identified pathogenic germline mutations should receive appropriate surveillance measures in order to minimize their overall risk of developing syndrome-specific cancers. This guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

Systematic review of the impact of registration and screening on colorectal cancer incidence and mortality in familial adenomatous polyposis and Lynch syndrome

BACKGROUND

The British Society of Gastroenterology recommends that all familial adenomatous polyposis (FAP) and Lynch syndrome (LS) families are screened in the context of a registry. This systematic review was performed to appraise the published evidence for registration and screening in relation to colorectal cancer (CRC) incidence and mortality.

METHODS

Five electronic databases were searched using a combination of medical subject heading terms and free-text keywords. Titles and abstracts were scrutinized by two independent reviewers. Inclusion criteria were English-language studies describing CRC incidence and/or mortality in patients with FAP or LS, with comparison of either: screened and unscreened patients, or time periods before and after establishment of the registry.

RESULTS

Of 4668 abstracts identified, 185 full-text articles were selected; 43 studies fulfilled the inclusion criteria. No randomized clinical trial evidence was identified. For FAP, 33 of 33 studies described a significant reduction of CRC incidence and mortality with registration and screening. For LS, nine of ten studies described a reduction of CRC incidence and mortality with registration and screening. Five studies (FAP, 2; LS, 3) provided evidence for complete prevention of CRC-related deaths during surveillance. Clinical and statistical heterogeneity prevented pooling of data for meta-analysis.

CONCLUSION

Studies consistently report that registration and screening result in a reduction of CRC incidence and mortality in patients with FAP and LS (level 2a evidence, grade B recommendation). Funding and managerial support for hereditary CRC registries should be made available.

Patients with genetic cancer undergoing surveillance at a specialized clinic rate the quality of their care better than patients at non-specialized clinics

OBJECTIVES

To compare ratings of quality of care between patients with genetic cancer who receive specialized care with patients who receive non-specialized care while controlling for socio-demographic and clinical variables;

MATERIAL AND METHODS

All patients in a national cohort of adult patients diagnosed with familial adenomatous polyposis (FAP) who had undergone prophylactic colorectal surgery were assessed (n = 276, response rate 76%). Quality of care was measured with the Quality of Care from the Patient Perspective (QPP). Univariate and multivariate logistic regression analyses were performed;

RESULTS

Patients receiving specialized care were significantly more likely to report the quality of care as better in all three QPP dimensions investigated than those receiving non-specialized care;

CONCLUSIONS

In order to promote and maintain good quality of care for surgically treated patients with FAP, and to minimize the risk of cancer, specialized care, including continuity and easy access of health care professionals, should be provided.

Colorectal carcinoma: Pathologic aspects

Colorectal carcinoma is one of the most common cancers and one of the leading causes of cancer-related death in the United States. Pathologic examination of biopsy, polypectomy and resection specimens is crucial to appropriate patient managemnt, prognosis assessment and family counseling. Molecular testing plays an increasingly important role in the era of personalized medicine. This review article focuses on the histopathology and molecular pathology of colorectal carcinoma and its precursor lesions, with an emphasis on their clinical relevance.

Colorectal carcinoma: Pathologic aspects

Colorectal carcinoma is one of the most common cancers and one of the leading causes of cancer-related death in the United States. Pathologic examination of biopsy, polypectomy and resection specimens is crucial to appropriate patient managemnt, prognosis assessment and family counseling. Molecular testing plays an increasingly important role in the era of personalized medicine. This review article focuses on the histopathology and molecular pathology of colorectal carcinoma and its precursor lesions, with an emphasis on their clinical relevance.

Patients' views of surgery and surveillance for familial adenomatous polyposis

BACKGROUND

Familial adenomatous polyposis (FAP) is an inherited condition that requires prophylactic surgery (colectomy) followed by a lifetime program of endoscopic surveillance to prevent colorectal cancer. Patients are normally free of symptoms before surgery but a majority report problems related to bowel function postoperatively.

OBJECTIVE

The aim of the study was to gain a deeper understanding of how FAP affects life by exploring patients' view of what it is like living with the illness and being committed to a lifelong screening program.

METHODS

Three focus group interviews were conducted, and data were analyzed using descriptive qualitative content analysis.

RESULTS

The analysis resulted in two categories related to the participants' view of living with FAP. The first category was associated with concerns related to the hereditary and lifelong nature of the disease as well as to the prophylactic surgery and the second category was related to patients' ways of managing life.

CONCLUSION

Most participants expressed unmet needs, such as lack of healthcare providers with good knowledge about FAP, practical and psychosocial support, FAP educational programs, and organized meetings with other persons with the condition.

IMPLICATIONS FOR PRACTICE

One important aspect of living with FAP shared by the participants concerned ways of managing life concerns, something that healthcare providers caring for patients with FAP should identify and support. Furthermore, continuity of care by health care providers with good knowledge about FAP can be an important way of reducing patient concerns.

Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72

Background

Familial adenomatous polyposis (FAP) is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations.

Methods

Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations.

Results

10 novel APC gene mutations were identified in 11 families. A broad spectrum of extracolonic manifestations was identified in most of these individuals. Two sisters with an insertion in codon 528 (c.1582_1583insGC) both showed severe phenotypes with classical polyposis, upper gastrointestinal polyps and thyroid cancer. A woman with a 3'APC mutation (c.5030_5031insAA) developed colon cancer at age 72 as the first manifestation of attenuated FAP.

Conclusion

With an increasing number of FAP families diagnosed, a broad and variable tumor spectrum and a high frequency of extracolonic manifestations are gradually recognized. We report novel APC mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.

The prevalence of gastrointestinal diseases in Israeli adolescents and its association with body mass index, gender, and Jewish ethnicity

OBJECTIVE

The objectives of this study were to describe gastrointestinal (GI) disease prevalence in Israeli adolescents, and possible associations between prevalence and body mass index (BMI), sex and Jewish ethnicity.

DESIGN

A retrospective analysis of screening for GI disease performed by the Israeli Defense Forces recruiting office between 1998 and 2003.

SETTING

Screening was performed at the recruiting office, and included detailed history and physical examination performed by a general practitioner. Further testing was performed as needed and the final diagnosis was established by a gastroenterologist at the recruiting office.

PATIENTS

Seventeen-year-old Israeli nationals.

RESULTS

During the study period, 466,855 (58.5% male) adolescents were screened for GI disease. Peptic ulcer disease, irritable bowel syndrome, and nonulcer dyspepsia were the most prevalent disorders affecting 466/10, 460/10, and 296/10, respectively. There was an increase in the prevalence of lactose intolerance during the study period and also an increase in the prevalence of peptic ulcer disease in females. The prevalence of inflammatory bowel disease has also increased from 100/10 to 149/10, although this trend failed to reach statistical significance (P=0.097). Higher BMI was associated with statistically significant higher prevalence rates of gastroesophageal reflux disease (P<0.05). A stronger association in females was found in gallbladder disease (P<0.001). Lower BMI was associated with higher prevalence rates of irritable bowel syndrome (P<0.001), and higher rates of inflammatory bowel disease and lactose intolerance in males (P<0.01 and <0.001, respectively).

CONCLUSIONS

GI diseases are not uncommon among adolescents, and for some disorders prevalence is rising. The association between BMI and prevalence has been further clarified.

Extra-intestinal manifestations of familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited disorder, which results from a germ line mutation in the APC (adenomatous polyposis coli) gene. FAP is characterized by the formation of hundreds to thousands of colorectal adenomatous polyps. Although the development of colorectal cancer stands out as the most prevalent complication, FAP is a multisystem disorder of growth. This means, it is comparable to other diseases such as the MEN syndromes, Von Hippel-Lindau disease and neurofibromatosis. However, the incidence of many of its clinical features is much lower. Therefore, a specialized multidisciplinary approach to optimize health care-common for other disorders-is not usually taken for FAP patients. Thus, clinicians that care for and counsel members of high-risk families should have familiarity with all the extra-intestinal manifestations of this syndrome. FAP-related complications, for which medical attention is essential, are not rare and their estimated lifetime risk presumably exceeds 30%. Affected individuals can develop thyroid and pancreatic cancer, hepatoblastomas, CNS tumors (especially medulloblastomas), and various benign tumors such as adrenal adenomas, osteomas, desmoid tumors and dental abnormalities. Due to improved longevity, as a result of better prevention of colorectal cancer, the risk of these clinical problems will further increase. We present a clinical overview of extra-intestinal manifestations, including management and treatment options for the FAP syndrome. Furthermore, we provide recommendations for surveillance of FAP complications based on available literature.

Clinical characterization and the mutation spectrum in Swedish adenomatous polyposis families

BACKGROUND

The dominantly inherited condition familial adenomatous polyposis (FAP) is caused by germline mutations in the APC gene. Finding the causative mutations has great implications for the families. Correlating the genotypes to the phenotypes could help to improve the diagnosis and follow-up of patients.

METHODS

Mutation screening of APC and the clinical characterization of 96 unrelated FAP patients from the Swedish Polyposis Registry was performed. In addition to generally used mutation screening methods, analyses of splicing-affecting mutations and investigations of the presence of low-frequency mutation alleles, indicating mosaics, have been performed, as well as quantitative real-time polymerase chain reaction to detect lowered expression of APC.

RESULTS

Sixty-one different APC mutations in 81 of the 96 families were identified and 27 of those are novel. We have previously shown that 6 of the 96 patients carried biallelic MUTYH mutations. The 9 mutation-negative cases all display an attenuated or atypical phenotype. Probands with a genotype (codon 1250-1464) predicting a severe phenotype had a median age at diagnosis of 21.8 (range, 11-49) years compared with 34.4 (range, 14-57) years among those with mutations outside this region (P < 0.017). Dense polyposis (> 1000) occurred in 75% of the probands with a severe phenotype compared with 30% in those with mutations outside this region. The morbidity in colorectal cancer among probands was 25% at a mean age of 37.5 years and 29% at a mean age of 46.6 years.

CONCLUSION

Using a variety of mutation-detection techniques, we have achieved a 100% detection frequency in classical FAP. Probands with APC mutations outside codon 1250-1464, although exhibiting a less-severe phenotype, are at high risk of having a colorectal cancer at diagnosis indicating that age at diagnosis is as important as the severity of the disease for colorectal cancer morbidity.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal-dominant colorectal cancer syndrome, caused by a germline mutation in the adenomatous polyposis coli (APC) gene, on chromosome 5q21. It is characterized by hundreds of adenomatous colorectal polyps, with an almost inevitable progression to colorectal cancer at an average age of 35 to 40 yr. Associated features include upper gastrointestinal tract polyps, congenital hypertrophy of the retinal pigment epithelium, desmoid tumors, and other extracolonic malignancies. Gardner syndrome is more of a historical subdivision of FAP, characterized by osteomas, dental anomalies, epidermal cysts, and soft tissue tumors. Other specified variants include Turcot syndrome (associated with central nervous system malignancies) and hereditary desmoid disease. Several genotype-phenotype correlations have been observed. Attenuated FAP is a phenotypically distinct entity, presenting with fewer than 100 adenomas. Multiple colorectal adenomas can also be caused by mutations in the human MutY homologue (MYH) gene, in an autosomal recessive condition referred to as MYH associated polyposis (MAP). Endoscopic screening of FAP probands and relatives is advocated as early as the ages of 10-12 yr, with the objective of reducing the occurrence of colorectal cancer. Colectomy remains the optimal prophylactic treatment, while the choice of procedure (subtotal vs proctocolectomy) is still controversial. Along with identifying better chemopreventive agents, optimizing screening of extracolonic cancers and applying new radiological and endoscopic technology to the diagnosis and management of extracolonic features are the major challenges for the future.

Immunohistochemical characteristics of duodenal adenomas in familial adenomatous polyposis with special reference to cell kinetics

The duodenum is the second most frequent site of cancer in patients with familial adenomatous polyposis (FAP). The main objective of this study was to evaluate the cell kinetics in duodenal and ampullary adenomas in FAP. The endoscopic and biopsy findings of duodenal adenomas in 22 FAP subjects and 18 non-FAP subjects were compared. Adenomas in FAP included 15 ampullary adenomas and 17 nonampullary adenomas. The cell kinetics was evaluated by immunohistochemistry for Ki-67, p53, bcl-2, and cyclooxygenase 2 (COX2), and the apoptotic index (AI) as determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) method. Any correlations between the indices for cell kinetics and the endoscopic findings were identified. All 50 adenomas were histologically verified to be tubular adenoma with low-grade dysplasia. Neither the expression of Ki-67, p53, bcl-2, and COX2 nor the AI differed substantially between FAP and non-FAP subjects. In patients with FAP, duodenal adenoma tended to have a higher Ki-67-labeling index than the ampullary adenoma (54.3 +/- 11.3 versus 46.8 +/- 12.7; .05 < P < .1). In addition, the Ki-67-labeling index in endoscopically normal or slightly enlarged ampullary adenoma was significantly higher than that in markedly enlarged ampullary adenoma (51.8 +/- 11.4 versus 39.4 +/- 11.3; P < .05). Duodenal adenoma in FAP subjects was not found to have a higher proliferative activity or a smaller degree of apoptosis compared with those in non-FAP subjects. The smaller proliferative activity in larger ampullary adenoma may thus be related to the static nature of ampullary adenoma in FAP.

Familial association of colorectal adenocarcinoma with cancers at other sites

Data on the familial associations of colorectal cancer (CRC) of adenocarcinoma histology are limited, but they are of interest because they may give us clues about as yet unknown family clusters. We calculated standardised incidence ratios (SIRs) for right- and left-sided colon cancer and rectal cancer in offspring using data from the Swedish Family-Cancer Database covering familial tumours from 1991 to 2000. The offspring were at an increased risk of developing colon adenocarcinoma when parents presented with CRC (SIR 1.81), endometrial (SIR 1.52) and kidney (SIR 1.42) cancers. The SIRs in siblings were increased when a co-sibling was diagnosed with CRC (SIR 3.26), myeloma (SIR 2.65) and leukaemia (SIR 2.53). Right-sided colon cancer was associated with familial pancreatic, squamous cell skin cancers, thyroid gland cancer and Hodgkin's disease. Left-sided colon cancer was associated with testicular cancers. Rectal cancer was associated with cervical and genital cancers in mothers. Most of the findings were consistent with data on known cancer syndromes. A new association was noted where rectal cancer in offspring was related to cervical and female genital cancers in mothers through an unknown mechanism. Hodgkin's disease and myeloma were also associated with right-sided colon cancer in offspring. The association with carcinoma of the testis, renal parenchyma, skin and leukaemia need to be confirmed in an independent series.

APC genotype is not a prognostic factor in familial adenomatous polyposis patients with colorectal cancer

PURPOSE

Several studies have shown that the clinical phenotype of patients with familial adenomatous polyposis is influenced by the position of the associated germline mutation in the APC gene. The aim of this work was to assess whether the site of the APC mutation may also predict the survival of familial adenomatous polyposis patients with a confirmed diagnosis of colorectal cancer.

METHODS

A total of 387 familial adenomatous polyposis patients with colorectal cancer were examined. Of these, 287 (74 percent) belonged to families with an identified mutation, whereas 100 (26 percent) were from families in which no detectable APC mutation had been found by standard screening methods. The subjects were subdivided into four groups, according to the presence and localization of the identified mutation: with mutation before (a), at (b), or beyond codon 1309 (c), and without identified mutation (d).

RESULTS

The cumulative five-year survival estimate of all cases included in the study was 0.56 (95 percent confidence interval, 0.51-0.61). No difference was observed in survival probability among patients from families with mutations before (0.56; 95 percent confidence interval, 0.49-0.63), at (0.58; 95 percent confidence interval, 0.43-0.72), or beyond (0.52; 95 percent confidence interval, 0.31-0.73) codon 1309 or those from families that were mutation negative (0.58; 95 percent confidence interval, 0.48-0.68) (log-rank test, P = 0.9). Survival analysis did not reveal any significant advantage for patients carrying a mutation in a specific region of the APC gene, after adjustment for age, gender, site, and stage.

CONCLUSION

These data do not support the hypothesis that APC mutation may influence the outcome of familial adenomatous polyposis cases affected by colorectal cancer.

Colorectal cancer as a complex disease: defining at-risk subjects in the general population - a preventive strategy

Over the last few decades it has become clear that highly penetrant disease genes are responsible for a minor proportion of colorectal cancer cases. Families with hereditary syndromes are today recognized and included in surveillance programs known to reduce morbidity and mortality in colorectal cancer. Colorectal cancer is preventable and screening strategies in whole populations are currently under debate. Colorectal cancer can be considered a complex disease, with a combination of predisposing genetic variants and environmental factors that contribute to the illness as a whole. The progress made in the genome project provides an opportunity to determine such genetic variants and environmental factors. This knowledge can be used to define a subpopulation at increased risk for colorectal cancer. It will be more feasible to design preventive strategies for this subgroup than for a whole population.

Context of deletions and insertions in human coding sequences

We studied the dependence of the rate of short deletions and insertions on their contexts using the data on mutations within coding exons at 19 human loci that cause mendelian diseases. We confirm that periodic sequences consisting of three to five or more nucleotides are mutagenic. Mutability of sequences with strongly biased nucleotide composition is also elevated, even when mutations within homonucleotide runs longer than three nucleotides are ignored. In contrast, no elevated mutation rates have been detected for imperfect direct or inverted repeats. Among known candidate contexts, the indel context GTAAGT and regions with purine-pyrimidine imbalance between the two DNA strands are mutagenic in our sample, and many others are not mutagenic. Data on mutation hot spots suggest two novel contexts that increase the deletion rate. Comprehensive analysis of mutability of all possible contexts of lengths four, six, and eight indicates a substantially elevated deletion rate within YYYTG and similar sequences, which is one of the two contexts revealed by the hot spots. Possible contexts that increase the insertion rate (AT(A/C)(A/C)GCC and TACCRC) and decrease deletion (TATCGC) or insertion (GCGG) rates have also been identified. Two-thirds of deletions remove a repeat, and over 80% of insertions create a repeat, i.e., they are duplications.

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.

Direct estimates of human per nucleotide mutation rates at 20 loci causing Mendelian diseases

I estimate per nucleotide rates of spontaneous mutations of different kinds in humans directly from the data on per locus mutation rates and on sequences of de novo nonsense nucleotide substitutions, deletions, insertions, and complex events at eight loci causing autosomal dominant diseases and 12 loci causing X-linked diseases. The results are in good agreement with indirect estimates, obtained by comparison of orthologous human and chimpanzee pseudogenes. The average direct estimate of the combined rate of all mutations is 1.8x10(-8) per nucleotide per generation, and the coefficient of variation of this rate across the 20 loci is 0.53. Single nucleotide substitutions are approximately 25 times more common than all other mutations, deletions are approximately three times more common than insertions, complex mutations are very rare, and CpG context increases substitution rates by an order of magnitude. There is only a moderate tendency for loci with high per locus mutation rates to also have higher per nucleotide substitution rates, and per nucleotide rates of deletions and insertions are statistically independent on the per locus mutation rate. Rates of different kinds of mutations are strongly correlated across loci. Mutational hot spots with per nucleotide rates above 5x10(-7) make only a minor contribution to human mutation. In the next decade, direct measurements will produce a rather precise, quantitative description of human spontaneous mutation at the DNA level.

De novo mutations in familial adenomatous polyposis (FAP)

Familial Adenomatous Polyposis (FAP) results from a germline mutation in the APC gene. A new mutation rate of 4-9 x 10(-6) mutations/gametes/generation has been reported. In other familial cancer syndromes a bias for paternal origin of new mutations has been described. This bias is probably due to a larger number of cell divisions during spermatogenesis compared to oogenesis; giving a larger susceptibility for mutagenesis. We report here a molecular genetic analysis of 26 FAP patients with putative de novo APC mutations. In 15 families the novel origin of the mutations was confirmed by haplotyping and sequencing. Analysis of 10 of these mutations, in which the parental origin could be established, gave a 6 : 4 distribution in favour of maternal origin. This is in agreement with a 1 : 1 distribution and does not indicate an expected paternal bias. Moreover, no parental age effect was identified. We propose that APC germline mutations are not premeiotic events but more likely arise during the meiosis. This would give an equal susceptibility for mutagenesis during spermatogenesis and oogenesis, respectively. The model is in concordance with the previously established difference between APC somatic mutations, as being a mitotic event and APC germline mutations, as being a meiotic event. The confirmation of 15 de novo mutations by a molecular genetic approach is in fine agreement with previous results based on clinical records.

Periampullary adenomas and adenocarcinomas in familial adenomatous polyposis: cumulative risks and APC gene mutations

BACKGROUND & AIMS

Patients with familial adenomatous polyposis (FAP) have a high prevalence of duodenal adenomas, and the region of the ampulla of Vater is the predilection site for duodenal adenocarcinomas. This study assessed the risk of stage IV periampullary adenomas according to the Spigelman classification and periampullary adenocarcinomas in Swedish FAP patients screened by esophagogastroduodenoscopy (EGD). The genotype of patients with stage IV periampullary adenomas and periampullary adenocarcinomas was also investigated.

METHODS

A retrospective study of 180 patients screened by EGD in 1982-1999 was undertaken. Kaplan-Meier analysis was performed to evaluate cumulative risk. Mutation analysis was carried out in patients with periampullary adenocarcinomas diagnosed outside the screening program, in addition to patients in the screening group with stage IV periampullary adenomas and adenocarcinomas.

RESULTS

Periampullary adenoma stage IV was diagnosed in 14 patients (7.8%), with a cumulative risk of 20% at age 60 years. Periampullary adenocarcinoma was diagnosed in 5 patients (2.8%), with a cumulative risk of 10% at age 60. Three of the adenocarcinomas occurred in patients with stage IV periampullary adenomas compared with 2 in patients with less severe periampullary adenomatosis at screening (odds ratio, 31; 95% confidence interval, 4.6-215). Fifteen (88%) of the APC gene mutations were detected; 12 of these were located downstream from codon 1051 in exon 15.

CONCLUSIONS

The life time risk of severe periampullary lesions in FAP patients is high, and an association between stage IV periampullary adenomas and a malignant course of the periampullary adenomatosis is strongly suggestive. Mutations downstream from codon 1051 seem to be associated with severe periampullary lesions.

Outcome of primary and secondary ileal pouch-anal anastomosis and ileorectal anastomosis in patients with familial adenomatous polyposis

PURPOSE

The aim of this study was to present Swedish experiences of the ileal pouch-anal anastomosis in patients with familial adenomatous polyposis from the introduction in 1984. The study also compared the surgical and functional outcome of different anal continence preserving procedures: ileal pouch-anal anastomosis as primary surgery, ileal pouch-anal anastomosis as secondary surgery after colectomy and ileorectal anastomosis, and ileorectal anastomosis alone.

METHODS

The material comprises all 120 patients with familial adenomatous polyposis reported to the Swedish Polyposis Registry who had undergone prophylactic colorectal surgery, including those operated on because of colorectal cancer from 1984 until the end of 1996. Anal continence preserving surgery was performed on 102 patients: 20 had ileal pouch-anal anastomosis as primary surgery at a median age of 24.5 years, 39 had ileal pouch-anal anastomosis as secondary surgery at a median age of 34 years, and 43 had ileorectal anastomosis alone, at a median age of 26 years, because 6 of the initially ileorectal anastomosis-operated patients were converted to ileal pouch-anal anastomosis as secondary surgery. Surgical outcome was assessed on the basis of hospital records. A questionnaire was used to evaluate the functional outcome. Fisher's exact probability test was used for statistical analysis.

RESULTS

Complications occurred in 51 percent of the patients after ileal pouch-anal anastomosis: 40 percent after ileal pouch-anal anastomosis as primary surgery and 56 percent after ileal pouch-anal anastomosis as secondary surgery. When the previous ileorectal anastomosis was taken into account 67 percent of the patients suffered complications which was significantly more compared with ileal pouch-anal anastomosis as primary surgery. After ileorectal anastomosis, 26 percent had complications which was significantly less compared with all other procedures but ileal pouch-anal anastomosis as primary surgery. No cancer occurred after ileal pouch-anal anastomosis, either in the ileal pouch or in retained rectal mucosa, but two of the patients who had an ileorectal anastomosis developed rectal cancer. One pouch excision was performed compared with ten rectal excisions. Functional outcome did not differ between ileal pouch-anal anastomosis as primary surgery and ileal pouch-anal anastomosis as secondary surgery. However, ileorectal anastomosis-operated patients had significantly better bowel function with regard to nighttime stool frequency, continence and perianal soreness.

CONCLUSION

These findings indicate that major advantages of ileal pouch-anal anastomosis are the low excision rate and, so far, no cancer in the ileal pouch. Moreover, the surgical outcome of ileal pouch-anal anastomosis as primary surgery is not significantly different from that of ileorectal anastomosis. However, the good surgical and functional outcome of ileorectal anastomosis, despite the long-range prognosis including rectal cancer and excision risks, has to be taken into consideration when selecting patients with familial adenomatous polyposis for primary surgery.

Colonic screening and surveillance

Screening for colorectal cancer has not obtained worldwide acceptance in spite of its proven survival benefit for average-risk persons and some high-risk groups. The incidence of and mortality from colorectal cancer are worrying in Europe as well as in the USA, Australia and Japan. The best evidence-based studies are those published on screening using faecal occult blood tests, endoscopic methods and different tumour markers having been evaluated to a lesser degree. Feasibility studies are necessary before massive screening can be undertaken because the results obtained from randomized studies may not be reproduced to a satisfactory degree in average- as well as high-risk populations. Primary prevention by dietary intervention and drugs has been studied in great detail, so far without any major breakthrough. This chapter will address different screening methods in populations with a varying risk of colorectal cancer, together with providing a short review of prevention and intervention strategies.

Different mechanisms in the tumorigenesis of proximal and distal colon cancers

Environment or genetic constitutions can lead to an increase of genetic or epigenetic events and increase the risk for malignancy. Genomic instability is seen in most types of malignancies. Two forms of genetic instability have been described in colorectal cancer: chromosomal instability (CIN), and microsatellite instability (MIN). Almost all sporadic MIN tumors occur in the proximal colon, whereas most sporadic CIN tumors are distributed in the distal colon. The two familial syndromes, familial adenomatous polyposis and Lynch syndrome, constitute models for the different carcinogenic mechanisms in CIN and MIN tumors, respectively. This article reviews the principal differences between CIN and MIN tumors, evidence for a proximal and distal route in carcinogenesis, gender differences, and aspects of methylation in CIN and MIN colorectal tumorigenesis.