Accounting for Intergenerational Cascade Testing in Economic Evaluations of Clinical Genomics: A Scoping Review

Reduced Breast and Ovarian Cancer Through Targeted Genetic Testing: Estimates Using the NEEMO Microsimulation Model

Background: The effectiveness and cost-effectiveness of genetic testing for hereditary breast and ovarian cancer largely rely on the identification and clinical management of individuals with a pathogenic variant prior to developing cancer. Simulation modelling is commonly utilised to evaluate genetic testing strategies due to its ability to synthesise collections of data and extrapolate over long time periods and large populations. Existing genetic testing simulation models use simplifying assumptions for predictive genetic testing and risk management uptake, which could impact the reliability of their estimates. Our objective was to develop a microsimulation model that accurately reflects current genetic testing and subsequent care in Australia, directly incorporating the dynamic nature of predictive genetic testing within families and adherence to cancer risk management recommendations. Methods: The populatioN gEnEtic testing MOdel (NEEMO) is a population-level microsimulation that incorporates a detailed simulation of individuals linked within five-generation family units. The genetic component includes heritable high- and moderate-risk monogenic gene variants, as well as polygenic risk. Interventions include clinical genetic services, breast screening, and risk-reducing surgery. Model validation is described, and then to illustrate a practical application, NEEMO was used to compare clinical outcomes for four genetic testing scenarios in patients newly diagnosed with breast cancer (BC) and their relatives: (1) no genetic testing, (2) current practice, (3) optimised referral for genetic testing, and (4) genetic testing for all BC. Results: NEEMO accurately estimated genetic testing utilisation according to current practice and associated cancer incidence, pathology, and survival. Predictive testing uptake in first- and second-degree relatives was consistent with known prospective genetic testing data. Optimised genetic referral and expanded testing prevented up to 9.3% of BC and 4.1% of ovarian cancers in relatives of patients with BC. Expanding genetic testing eligibility to all BC patients did not lead to improvement in life-years saved in at-risk relatives compared to optimised referral of patients eligible for testing under current criteria. Conclusions: NEEMO is an adaptable and validated microsimulation model for evaluating genetic testing strategies. It captures the real-world uptake of clinical and predictive genetic testing and recommended cancer risk management, which are important considerations when considering real-world clinical and cost-effectiveness.

Cascade testing in mitochondrial diseases: a cross-sectional retrospective study

BACKGROUND

Cascade testing can offer improved surveillance and timely introduction of clinical management for the at-risk biological relatives. Data on cascade testing and costs in mitochondrial diseases are lacking. To address this gap, we performed a cross-sectional retrospective study to provide a framework for cascade testing in mitochondrial diseases, to estimate the eligibility versus real-time uptake of cascade testing and to evaluate the cost of the genetic diagnosis of index cases and the cost of predictive cascade testing.

METHODS

Data was collected through retrospective chart review. The variant inheritance pattern guided the identification of eligible first-degree relatives: (i) Males with mitochondrial DNA (mtDNA) single nucleotide variants (SNVs) - siblings and mothers. (ii) Females with mtDNA SNVs - siblings, mothers and offspring. (iii) Autosomal Dominant (AD) nuclear DNA (nDNA) variants - siblings, offspring and both parents. (iv) Autosomal Recessive (AR) nDNA variants - siblings.

RESULTS

We recruited 99 participants from the Adult Mitochondrial Disease Clinic in Sydney. The uptake of cascade testing was 55.2% in the mtDNA group, 55.8% in the AD nDNA group and 0% in AR nDNA group. Of the relatives in mtDNA group who underwent cascade testing, 65.4% were symptomatic, 20.5% were oligosymptomatic and 14.1% were asymptomatic. The mean cost of cascade testing for eligible first-degree relatives (mtDNA group: $694.7; AD nDNA group: $899.1) was lower than the corresponding index case (mtDNA group: $4578.4; AD nDNA group: $5715.1) (p < 0.001).

CONCLUSION

The demand for cascade testing in mitochondrial diseases varies according to the genotype and inheritance pattern. The real-time uptake of cascade testing can be influenced by multiple factors. Early diagnosis of at-risk biological relatives of index cases through cascade testing, confirms the diagnosis in those who are symptomatic and facilitates implementation of surveillance strategies and clinical care at an early stage of the disease.

Economic evaluation of germline genetic testing for breast cancer in low- and middle-income countries: a systematic review

BACKGROUND

Breast cancer (BC) is the most common cancer affecting women globally. Genetic testing serves as a prevention and treatment strategy for managing BC. This study aims to systematically review economic evaluations and the quality of selected studies involving genetic screening strategies for BC in low and middle-income countries (LMICs).

METHODS

A search was performed to identify related articles that were published up to April 2023 on PubMed, Embase, CINAHL, Web of Science, and the Centre for Reviews and Dissemination. Only English-language LMIC studies were included. Synthesis of studies characteristics, methodological and data input variations, incremental cost-effectiveness ratios (ICERs), and reporting quality (Consolidated Health Economic Evaluation Reporting Standards (CHEERS) 2022 checklist) were performed.

RESULTS

This review found five pertinent studies, mainly focusing on economic evaluations of germline genetic testing in upper-middle-income countries (Upper MICs) like Malaysia, China, and Brazil. Only one study covered multiple countries with varying incomes, including lower-middle-income nations (Lower MICs) like India. The ICERs values in various screening scenarios for early-stage BC, HER2 negative BC patients, and healthy women with clinical or family history criteria were ranging from USD 2214/QALY to USD 36,342/QALY. Multigene testing for all breast cancer patients with cascade testing was at USD 7729/QALY compared to BRCA alone. Most studies adhered to the CHEERS 2022 criteria, signifying high methodological quality.

CONCLUSIONS

Germline testing could be considered as cost-effective compared to no testing in Upper MICs (e.g., Malaysia, China, Brazil) but not in Lower MICs (e.g., India) based on the willingness-to-pay (WTP) threshold set by each respective study. Limitations prevent a definite conclusion about cost-effectiveness across LMICs. More high-quality studies are crucial for informed decision-making and improved healthcare practices in these regions.