Cost comparison of predictive genetic testing versus conventional clinical screening for familial adenomatous polyposis

Incorporating Cascade Effects of Genetic Testing in Economic Evaluation: A Scoping Review of Methodological Challenges

Cascade genetic testing is indicated for family members of individuals testing positive on a genetic test, and is particularly relevant for child health because of their vulnerability and the long-term health and economic implications. Cascade testing has patient- and health system-level implications; however cascade costs and health effects are not routinely considered in economic evaluation. The methodological challenges associated with incorporating cascade effects in economic evaluation require examination. The purpose of this scoping review was to identify published economic evaluations that considered cascade genetic testing. Citation databases were searched for English-language economic evaluations reporting on cascade genetic testing. Nineteen publications were included. In four, genetic testing was used to identify new index patients—cascade effects were also considered; thirteen assessed cascade genetic testing strategies for the identification of at-risk relatives; and two calculated the costs of cascade genetic testing as a secondary objective. Methodological challenges associated with incorporating cascade effects in economic evaluation are related to study design, costing, measurement and valuation of health outcomes, and modeling. As health economic studies may currently be underestimating both the cost and health benefits attributable to genetic technologies through omission of cascade effects, development of methods to address these difficulties is required.

Hereditary colorectal cancer registries in Canada: report from the Colorectal Cancer Association of Canada consensus meeting; Montreal, Quebec; October 28, 2011

At a consensus meeting held in Montreal, October 28, 2011, a multidisciplinary group of Canadian experts in the fields of genetics, gastroenterology, surgery, oncology, pathology, and health care services participated in presentation and discussion sessions for the purpose of developing consensus statements pertaining to the development and maintenance of hereditary colorectal cancer registries in Canada. Five statements were approved by all participants.

Identification, management, and evaluation of children with cancer-predisposition syndromes

A substantial proportion of childhood cancers are attributable to an underlying genetic syndrome or inherited susceptibility. Recognition of affected children allows for appropriate cancer risk assessment, genetic counseling, and testing. Identification of individuals who are at increased risk to develop cancers during childhood can guide cancer surveillance and clinical management, which may improve outcomes for both the patient and other at-risk relatives. The information provided through this article will focus on the current complexities involved in the evaluation and management of children with cancer-predisposing genetic conditions and highlight remaining questions for discussion.

Cost-utility analysis of genetic screening in families of patients with germline MUTYH mutations

Background

MUTYH associated polyposis (MAP) is an autosomal recessive inherited disorder. Carriers of bi-allelic MUTYH germline mutations have a risk of approximately 60% to develop colorectal carcinoma (CRC). In the general population about 1.5% is a heterozygous MUTYH mutation carrier. Children of MAP patients have an increased risk of inheriting two MUTYH mutations compared to the general population, implicating an increased risk for developing CRC.

Methods

Using data from the literature and Dutch MAP patients (n = 40), we constructed a Markov model to perform a societal cost-utility analysis of genetic screening in MAP families. Genetic screening was done by testing the spouse first and, in case of a heterozygous spouse, also testing of the children.

Results

The cost of genetic screening of families of MAP patients, when compared to no genetic screening, was estimated at €25,000 per quality-adjusted life year (QALY). The presence of Fecal Occult Blood testing (FOBT) population screening only slightly increased this cost-utility ratio to €25,500 per QALY. For a MUTYH heterozygote index-patient, the ratio was €51,500 per QALY. The results of our analysis were sensitive to several of the parameters in the model, including the cost assumed for molecular genetic testing.

Conclusion

The costs per QALY of genetic screening in families of MAP patients are acceptable according to international standards. Therefore, genetic testing of spouses and/or children should be discussed with and offered to counselees.

Predicting the performance of a genetic testing service for cancer susceptibility

A genetic testing service can determine which members of a population might benefit most from cancer prevention. The eligibility criteria will affect the number of people who use a service and the proportion who test positive. This affects both the service's costs and benefits. The goal of this study was to create computer software that predicts the effect of eligibility restrictions on the performance of a genetic testing service. The software allows eligibility restrictions based on age, gender, and family history of disease. As performance measures, we considered the sensitivity and specificity of eligibility criteria to identify people with genetic cancer susceptibility, the likelihood of genetic susceptibility among people who are eligible for the service, and the likelihood of genetic susceptibility among people who are ineligible. We compared the performance predicted by our model with the observed performance of the Hereditary Cancer Program at the BC Cancer Agency, and studied the effects of changes to model parameters. There was good agreement between model predictions and observed outcomes, however, performance measures were affected by changes to the underlying model parameters. Computer software to predict the performance of a genetic testing service for cancer susceptibility is implemented on the website http://142.103.207.51:8080/gtsim.

Familial adenomatous polyposis: The practical applications of clinical and molecular screening

Familial adenomatous polyposis (FAP) is an autosomal dominant condition mostly due to a mutation of the APC gene on the chromosome 5q. Carriers have an almost 100% chance of developing colorectal cancer after having multiple (typically 100s to 1000s) of adenomatous polyps. It is usually readily identified through this phenotype of multiple adenomas. Correlations between the location of the family-specific mutation on the APC gene and clinical manifestations of the disease are of some assistance in clinical management, though there is heterogeneity in clinical course even between family members with the same mutation. FAP is important to recognize, as there are disease-specific management implications with respect to offering mutational analysis of the APC (and perhaps other) genes for predictive testing of other family members, endoscopic diagnostic procedures, surveillance planning, and surgical management. Extra-colonic manifestations, including duodenal polyposis, desmoid disease and other tumours, can dominate clinical care after colectomy. The inheritable and lethal nature of the disease, together with the availability of effective treatment strategies, makes a sensitive clinical and psychosocial approach important to maximize compliance and good outcomes for all members of affected families.

Genetic screening by DNA technology: A systematic review of health economic evidence

Objectives:The Human Genome Project has led to a multitude of new potential screening targets on the level of human DNA. The aim of this systematic review is to critically summarize the evidence from health economic evaluations of genetic screening in the literature.

Methods:Based on an extensive explorative search, an appropriate algorithm for a systematic database search was developed. Twenty-one health economic evaluations were identified and appraised using published quality criteria.

Results:Genetic screening for eight conditions has been found to be investigated by health economic evaluation: hereditary breast and ovarian cancer, familial adenomatous polyposis (FAP) colorectal cancer, hereditary nonpolyposis colorectal carcinoma (HNPCC), retinoblastoma, familial hypercholesterolemia, hereditary hemochromatosis, insulin-dependent diabetes mellitus, and cystic fibrosis. Results range from dominated to cost-saving. Population-wide genetic screening may be considered cost-effective with limited quality of evidence only for three conditions. The methodology of the studies was of varying quality. Cost-effectiveness was primarily influenced by mutation prevalence, genetic test costs, mortality risk, effectiveness of treatment, age at screening, and discount rate.

Conclusions:Health economic evidence on genetic screening is limited: Only few conditions have properly been evaluated. Based on the existing evidence, healthcare decision makers should consider the introduction of selective genetic screening for FAP and HNPCC. As genetic test costs are declining, the existing evaluations may warrant updating. Especially in the case of hereditary hemochromatosis, genetic population screening may be about to turn from a dominated to a cost-effective or even cost-saving intervention.

Retinoblastoma: genetic testing versus conventional clinical screening in India

INTRODUCTION

Genetic testing is increasingly being used to evaluate susceptibility to hereditary diseases because it is a cost effective screening method. Predictive testing for retinoblastoma can help to save the vision and avoid unnecessary (and invasive) eye examinations for probands and their close relatives. This study was undertaken to evaluate the cost effectiveness of the retinoblastoma genetic screening strategy established in our hospital.

STUDY DESIGN

Cytogenetic study of peripheral blood, mutational, and methylation analyses from the tumor DNA of 25 patients with retinoblastoma was undertaken. The cost for retinoblastoma (RB1) gene screening was calculated based on the cost of the chemicals and consumables used and the clinical examination charges at our hospital. A comparison was made between the cost of genetic screening and clinical testing for retinoblastoma. Retinoblastoma patients underwent clinical management and genetic testing at Sankara Nethralaya, Chennai, India.

RESULTS

By adopting a genetic screening strategy, a 3.5-fold cost saving was seen for a proband while a 6-fold saving was seen for a family with two sibs compared to the cost of clinical examination. The clinical examination fee and cost of genetic screening for a proband was dollarUS536 and dollarUS152, respectively, while for a nuclear family with two sibs the costs were dollarUS1071 and dollarUS175, respectively.

DISCUSSION

Savings for a family will be higher if indirect costs, such as savings in travel times to and from the hospital and labor savings, were taken into account. Cost will be a major factor in determining the implementation of genetic screening for RB1 gene in the clinical practice.

CONCLUSION

In our study in India, genetic screening for retinoblastoma was cheaper than conventional screening and was useful in the genetic counseling of the families.

Risk assessment for inherited susceptibility to cancer: a review of the psychosocial and ethical dimensions

The objective of this study was to conduct a broad-based systematic review of social, ethical, and legal considerations associated with genetic cancer risk assessment technologies (CaRATs). This paper focuses on psychosocial and ethical issues. Search results were limited to papers published in English, French, or German from January, 1990, to May, 2003. A quality assessment tool was developed and applied to retrieved papers. Application of the quality assessment tool resulted in 77 of 247 qualitative and quantitative primary research papers being reviewed and synthesized. A broad range of issues were addressed and grouped into content areas. Despite a large literature addressing psychosocial and ethical issues associated with CaRATs, many existing studies are not adequate to inform decision-makers and stakeholders. Careful policy analysis, as in some of the economic analyses reviewed here, is important to bridge this gap.

Cancer genetics services: a systematic review of the economic evidence and issues

This paper systematically reviews the published economic research upon cancer genetics services for families at risk of having familial breast, ovarian or colorectal cancer. A structured search was made of 15 electronic databases. The search identified 1030 papers, of which 31 fulfilled the inclusion criteria, two were cost–benefit studies, five were cost consequences, four were cost-effectiveness studies, one was a cost analysis, two were cost-minimisation studies, one was a cost–utility study, 10 modelled life years and six were reviews. Modelling studies indicate that surveillance, prophylactic and chemoprevention techniques extend survival for carriers of identified mutations. Genetic testing has been estimated to cost $70–2400 [£48^*–1591] and genetic counselling $129–800 [£89–£551]. The technology of genetic testing has been found to be cost effective. Cost effectiveness was particularly influenced by targeting genetic services for patients with a strong family history of cancer rather than screening the entire population. Future economic evaluation must go beyond merely assessing health outcomes and mutation identification, and account for the impact of genetic services upon the individual, the family and society, establish the value of services to these groups and determine the most effective ways of delivering genetic services.

Genetic screening for hereditary diffuse gastric cancer

Knowledge regarding the genetic basis of hereditary diffuse gastric cancer has greatly increased in the past 4 years, namely due to the discovery of segregating germline mutations in the gene coding for E-cadherin, within families with this cancer predisposing syndrome. Members of hereditary diffuse gastric cancer families have predominantly high predisposition to develop diffuse carcinomas of the stomach but can also be associated with an elevate risk for other types of cancer, namely lobular breast carcinoma. In this review, we focus on the epidemiology, pathology and genetics of gastric cancer, describe families, E-cadherin mutations, and suggest alternative candidate genes underlying the hereditary diffuse gastric cancer syndrome. This knowledge is a fundamental step towards accurate genetic counselling, in which a highly specialized presymptomatic therapeutic intervention should be offered.

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.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a dominantly inherited familial cancer syndrome characterized by an increased predisposition to colorectal cancer and other benign and malignant extra-colonic lesions. FAP has been linked to germline mutations of the adenomatous polyposis coli (APC) gene that encodes a protein with 2,843 amino acids that has important functions in the regulation of cell growth. A genotype-phenotype correlation has also been observed between mutations in the APC gene and polyp phenotype. We review the clinical and genetic features of this disorder and provide information on the diagnostic approaches and treatment options available for this disease.

Lewis antigens and argyrophilic nucleolar organizer regions staining for assessment of potential malignancy of adenomatous polyps of the gastrointestinal tract in children

Adenomatous polyps (AP) of the gastrointestinal tract in children are very rare. Because of their potential malignancy, they are of great clinical importance. There is little experience in the management of children with AP. The immunohistochemical expression of the Lewis blood group antigens (BGA) (sialosyl-Le(a), Le(a), Leb, Le(x), and Le(y)) and the number of activated nucleoli with the silver staining method for nucleolar organizer regions (AgNORs) were studied in two children with AP. In a girl with isolated AP of the stomach and colon, it was found that antigens Le(b) and s-Le(a) were expressed extensively in the gastric adenoma, and sialosyl-Le(a) throughout the entire length of the rectal adenoma crypts, but in the AgNORs stain the number of nucleoli ranged from two to four, evidencing changes of a benign character. In the case of familial adenomatous polyposis diagnosed in a 9-year-old boy, in some colonic adenomas the number of activated nucleoli was greater than five, and the Le(b) antigen was expressed in superficial epithelial cells in one of the adenomas. Also, extensive expression of antigens Le(y) and s-Le(a) throughout the entire length of the crypt in another polyp removed was observed. We believe that immunohistochemical study of the intensity and extent of the expression of Lewis BGA in the polyp tissue simultaneously with the determination of the number of activated nucleoli by the AgNORs staining method can be helpful in better analysis of cytological risk factors of a malignant transformation.

Value of predictive genetic testing in management of hereditary non-polyposis colorectal cancer (HNPCC)

OBJECTIVE

To investigate the impact of predictive genetic testing on colonoscopic surveillance in an extended family with hereditary non-polyposis colorectal cancer (HNPCC).

SETTING

Familial Bowel Cancer Service, The Royal Melbourne Hospital, Victoria.

SUBJECTS

96 people registered with the Service who were apparently unaffected members of an extended family that met the classic Amsterdam criteria for HNPCC and carried an MLH1 gene mutation (IVS9 + 3insT).

INTERVENTION

Predictive genetic testing was offered in a cascade manner to at-risk family members; mutation-positive individuals were advised to have annual colonoscopic surveillance, while mutation-negative individuals were withdrawn from surveillance.

MAIN OUTCOME MEASURES

Previous compliance with recommended colonoscopic surveillance; uptake and results of genetic testing; expected effect of genetic test results on number of colonoscopies over five years.

RESULTS

22 of the 96 family members (23%) were not complying with recommended surveillance. Of 48 individuals offered predictive genetic testing, 41 (85%) responded and 39 (81%) underwent testing. Seven of the 39 (18%) were positive for the family-specific mutation, and 32 (82%) were negative. The 39 tested individuals and 37 of their descendants who were registered with the screening program had undergone 70 colonoscopies in the five years before genetic testing. In the five years after testing, only 37 surveillance colonoscopies were planned (annual or two-yearly colonoscopies for the six mutation-positive individuals and five-yearly colonoscopies for four mutation-negative individuals with previously identified adenoma), an almost 50% reduction in colonoscopies.

CONCLUSION

Predictive genetic testing in HNPCC families allows many individuals to be withdrawn from regular colonoscopic surveillance. It may therefore reduce costs, as well as have emotional benefits for many individuals.

Surrogate endpoint biomarkers for human colon carcinogenesis

Several markers of colon cancer have been described in humans. The study of polyp recurrence is a reliable procedure, but long and expensive. Mucosal cell proliferation is increased in high-risk subjects, often with a displacement of proliferation toward the lumen. Increased apoptosis in colon crypts is associated with protection against experimental cancer, but the method is not validated for humans. Aberrant crypt foci (ACF) can be scored in humans in resected specimens or visualized endoscopically. ACF and colon cancer risk seem connected in Japan, but not in Europe or North America. In conclusion, assessment of individuals or populations at risk of colon cancer still relies on a combination of different methods.