Genomic Health Expands Oncotype DX Breast Cancer
Genomic Health's study confirms RT-PCR by Oncotype DX can deliver quantitative gene expression levels for assessing estrogen receptor (ER) and progesterone receptor (PR) status, which are critical factors in determining the use and benefit of hormonal therapy for the treatment of breast cancer. Based on these results, Genomic Health is now providing quantitative ER and PR scores to physicians and patients in addition to the Recurrence Score result provided in the Oncotype DX(R) report.
Unlike traditional methodologies that provide either a positive or negative result, or a semi-quantitative result, RT-PCR by Oncotype DX generates a specific score across a continuous range of expression which allows physicians to factor the quantitative level of ER and PR gene expression into their treatment planning.
"Every breast tumor expresses the estrogen receptor gene at a specific level and, similar to other diagnostic measures, the ability to more accurately pinpoint that level increases the confidence in a diagnosis and treatment plan," said Sandra Swain, M.D., Medical Director, Washington Cancer Institute, Washington Hospital Center. "Having quantitative ER and PR scores provides added certainty in confirming expression levels of these important genes in predicting how likely a patient is to benefit from hormonal therapy."
This study published in JCO was originally presented at the American Society of Clinical Oncology Breast Cancer Symposium in September 2007. It measured ER and PR gene expression in 776 breast cancer patients by both local laboratory and central immunohistochemistry (IHC), and quantitative RT-PCR, as performed by the Oncotype DX assay. Results showed a high degree of agreement between the two methods. In an accompanying editorial, Dr. Craig Allred comments, "RT-PCR is at least equivalent to IHC in its ability to identify receptor-positive cases (considering ER and PR combined), marginally superior in predicting outcome in ER-positive patients, and superior in technical precision."
"We believe the methodology of the future is the quantitative measure of the biology of each individual tumor," said Steven Shak, M.D., chief medical officer of Genomic Health. "Providing physicians with quantitative ER and PR scores enhances the value of Oncotype DX by providing more patient-specific information to help individualize treatment decisions for breast cancer patients. We are continuing to conduct additional studies, including studying the use of RT-PCR by Oncotype DX to quantify HER-2 gene expression, another cancer-related gene that plays an important role in the determination of optimal treatment for breast cancer patients."
About Oncotype DX
Oncotype DX is the first and only multi-gene expression test commercially available that has clinical evidence validating its ability to predict the likelihood of chemotherapy benefit as well as recurrence in early-stage breast cancer. Oncotype DX has been extensively evaluated in multiple independent studies involving more than 3,600 breast cancer patients, including a large validation study published in The New England Journal of Medicine and a chemotherapy benefit study published in the Journal of Clinical Oncology. To date, 7,500 physicians have ordered more than 55,000 tests, and health plans covering over 80 percent of U.S. insured lives provide reimbursement for Oncotype DX through contracts, agreements and policy decisions. Both the American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network recommend the use of Oncotype DX for patients with node-negative breast cancer that is estrogen-receptor positive and/or progesterone-receptor positive.