Certain variants of the BRCA1 and BRCA2 genes are well recognized to raise a woman’s risk of inherited breast cancer. A growing body of research finds that five lesser-known genes, including TP53 and PTEN, also raise this risk, according to a study published in the April 2017 issue of Value in Health, the journal of the International Society for Pharmacoeconomics and Outcomes Research (ISPOR).
Researchers at Quest Diagnostics developed a decision-making model for hypothetical cohorts of 50-year-old and 40-year-old asymptomatic women with a family history of breast or ovarian cancer or other hereditary syndromes. The model compared two strategies for detecting pathogenic genetic variants and using the test result to select appropriate breast cancer risk reduction: the usual care strategy tests for variants in the BRCA1 and BRCA2 genes and the other strategy tests for variants in the BRCA1, BRCA2, TP53, PTEN, CDH1, STK11, and PALB2 genes (seven-gene testing). The risk-reduction procedures are those recommended by National Comprehensive Cancer Network guidelines, and the probabilities of breast cancer and death used in the model are based on the peer reviewed literature.
Investigators found that based on the computer modeling, genetic testing for these five genes and BRCA1 and BRCA2 could yield better health outcomes and good economic value than would testing of the two BRCA genes alone.
“Genetic testing of five additional genes known to confer increased risk of hereditary breast cancer along with BRCA1/2 testing provides health and economic benefits beyond BRCA1/2 testing alone,” says lead study author Yonghong Li, PhD, principal scientist, Quest Diagnostics.
Specifically, when factoring in risk-reducing surgery, the impact of enhanced surveillance, or both, hypothetical cohorts of 40- and 50-year-old women undergoing genetic testing with the seven-gene panel would result in an incremental cost-effectiveness ratio (ICER) of $23,734 and $42,067 per life-year gained compared with BRCA1/2 testing alone, according to the study. ICER is a measure of the cost-effectiveness of a healthcare intervention. This study showed that the multigene test can increase life expectancy, and the ICER shows how much it will cost payers for each additional year of life gained by using the multigene test.
By comparison, the estimated ICER for annual MRI for high-risk women is about $179,600. The findings of the Quest study also suggest that the seven-gene test strategy would be cost-effective, according to World Health Organization Thresholds for Cost-Effectiveness of Interventions.
“Managed care executives want to promote better care and outcomes but they also need to control costs,” says Li. “They want to know that a new medical service has health and economic value before they will reimburse it. One of their most challenging issues is determining whether new genetic tests provide this value.”
According to the editors of Value in Health in a commentary in support of the study, “clinical practice guidelines are often proposed without adequate consideration of cost-effectiveness considerations … the test and risk reduction strategy (in the study) could represent a cost-effective option for improving life expectancy in this population (women with inherited breast cancer risk).”
One of the most controversial topics in genetics today is the process of determining the criteria by which genes are thought to meet a baseline for economic value, according to Li.
“The [study] suggests that genetic testing beyond BRCA1 and BRCA2 could potentially generate favorable health and cost outcomes,” Li says. “While the prospect of over testing is always a concern, the present study is a reminder that under testing can also raise risks for patients and payers.”