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Novel Genetic Test For Breast Cancer May Guide MRI Screening In Women With Intermediate Lifetime Risk

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Clinical Breast Cancer (Photo credit: Wikipedia)

Researchers from Archimedes Inc., a healthcare modeling and analytics company, have reported the findings of a simulated clinical trial, “Cost-Effectiveness Of A Genetic Test For Breast Cancer Risk,” which demonstrated that the seven single-nucleotide polymorphisms (7SNP) genetic test by BREVAGen TM for breast cancer was most cost effective when utilized for MRI screenings in patients found to have an intermediate lifetime risk of developing the disease.

The research was published December 5th online in the Journal, Cancer Prevention Research.

"This Archimedes Model simulation suggests that genetic screening for breast cancer risk in conjunction with MRI can reduce cancer deaths and identifies a population at an intermediate risk near 20 percent for which it is optimally cost effective,” said Tuan Dinh, PhD, vice president of analytics and modeling at Archimedes and one of the authors of study. “This study further illustrates that risk modeling may provide information that will enable physicians to better determine a patient’s risk of disease and more appropriately allocate resources that will be beneficial.”

The American Cancer Society  in 2007 recommended MRI as an adjunct to mammography for the screening of breast cancer in women who have a lifetime risk of breast cancer of approximately 20-25 percent or greater as predicted by models such as the Gail test which evaluate family history and other key factors in a woman’s reproductive history.

In the simulated trial, investigators used Archimedes’ simulation model of breast cancer risk factors, disease progression, and healthcare processes to estimate the costs and benefits of using genetic testing to focus estimates of risk for the goal of referring women to MRI screening. The simulation first evaluated screening and treatment, but also growth, detection, and spread of tumors.

The Archimedes model examined and compared two tests, the Gail risk test and the 7SNP test, to organize patients according to lifetime risk.  The Gail model, used by the National Cancer Institute (NCI) and most widely employed overall, estimates risk using information on age, race, family history, and age of menarche and first live birth. The 7SNP genetic test uses the genotype or genetic make-up of the patient to clarify and refine the estimate of the Gail test. In the simulated study, average-risk patients received an annual mammogram and high-risk patients received an annual MRI.

According to Dr. Lucy Langer, Medical Director of the US Oncology Network Genetic Risk Evaluation and Testing Program (G.R.E.A.T.) and medical oncologist with Compass Oncology, the BREVAGen genetic test “is a germline genetic test looking at 7 single nucleotide polymorphisms (SNP) on 6 different chromosomes”. Langer explains that the SNPs in this study were hand selected out of the literature as likely to impact the estimate of a woman’s risk of breast cancer.

“Each of the individual SNPs by themselves don’t increase risk of breast cancer very significantly, but taken together the combination of SNPs gives a risk score that then can be used to modify the Gail risk calculation”, said Langer. “The test is targeted toward intermediate risk women--women that do not look that they have a hereditary cancer syndrome which would put them into a high risk category”.

The simulated population consisted of 100,000 non-Hispanic white women starting at the age of 40 with no prior history of cancer and a lifetime Gail risk of breast cancer of at least 10 percent. Cancer incidence was based on Surveillance, Epidemiology, and End Results (SEER) data and validated to the Cancer Prevention Study II (CPS-II) Nutrition Cohort dataset. Risk factors were drawn from the National Health and Nutrition Examination Survey (NHANES-4) and Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial data.  Mammogram characteristics were derived from Breast Cancer Surveillance Consortium data.

For patients with a lifetime risk of at least 10 percent, the model demonstrated that the 7SNP test results in a 2.7 percent reduction in cancer deaths relative to the Gail test alone. For patients with a risk of 16-28 percent, the 7SNP test saved 0.005 quality-adjusted life years (QALY) per person at a cost of $163,264 per QALY. The cost effectiveness of using the 7SNP test for patients with intermediate Gail risk is similar to that of other recommended strategies, including annual MRI for patients with a lifetime risk greater than 20 percent for BRCA1/2 mutations, for which the model estimated a cost of $141,415 per QALY, relative to mammogram.

According to Dr. Henri Folse, lead author of the study, “For 40-year old women, genetic screening of patients with a lifetime risk of breast cancer of 16 – 28% is optimally efficient and results in a 2% reduction in breast cancer deaths compared to current guidelines using the Gail test.”

“These findings may help physicians and their patients as they strive to identify optimal breast cancer screening options for individual women based on their current risk profile,” explained Folse.   “While the BREVAGen test is not likely to re-classify people with very low or high risk, for patients with intermediate risk it can refine risk classification, which reduces cancer mortality and is equivalently cost-effective to the use of the Gail test with MRI.”

“Investigators can use mathematical modeling and cost-effectiveness analyses, such as those described in this study, to identify an optimal range of risk for which prevention and screening strategies are most cost effective,” said Folse .

“By improving identification of patients eligible for MRI screening, the use of genetic testing allows physicians to detect cancers earlier, which improves prognosis and has the potential to save lives”, Folse concluded.

This study was a collaborative project between Archimedes and Genetic Technologies Ltd .

Genetic Technologies Ltd, with offices in Australia and the US, is a diagnostics company with two decades of experience in commercializing genetic testing, as well as product patenting and non-coding DNA. Genetic Technologies is focused on the commercialization of its patent portfolio through an active out-licensing program and the global expansion of its oncology and cancer management diagnostics assets. Phenogen's lead product, BREVAGen is a clinically validated risk assessment , and first in class assay for evaluation of non-familial or sporadic breast cancer. Phenogen Sciences Inc., its US subsidiary, markets unique assessment tools and predictive assays evaluation of women's health.