Genetic Test Will Help Thousands of Breast Cancer Patients Avoid Chemo

Approximately 100,000 U.S. women each year who are diagnosed with the most common form of early breast cancer may be spared chemotherapy under a new precision medicine approach, according to a landmark study — Trial Assigning Individualized Options for Treatment (Rx) or TAILORx. TAILORx, which was sponsored by the National Cancer Institute, enrolled over 10,000 women with early-stage breast cancer across the U.S. and five additional countries.

When a physician suspects breast cancer, he/she will test biopsied cells for specific molecules found in tumors.  The test will typically look for characteristics that include what receptors, if any, are present on the surface of detected cancer cells. Hormone receptors are proteins located in and around breast cells. These receptors signal cells — both healthy and cancerous — to grow. In the case of breast cancer, the hormone receptors tell the cancer cells to grow uncontrollably, and a tumor results. Some breast cancers have high levels of another growth-promoting protein called HER2/neu. If a tumor has this property, it is called HER2/neu-positive.  The axillary nodes are a group of lymph nodes located in the armpit region of the body. A prognosis is better when the cancer is only in the breast, and the lymph nodes are not affected.  Women recently diagnosed with estrogen-receptor and/or progesterone-receptor positive, HER2/neu-negative breast cancer that had not yet spread to the lymph nodes were eligible for the study.

The majority of women with early-stage breast cancer have been advised to receive chemotherapy in addition to radiation and hormonal therapy. It was determined that a molecular profiling test, the Oncotype DX Breast Recurrence Score® genomic test, which analyzes 21 genetic markers, could reveal the unique biology of a tumor. This genetic test will more precisely inform physicians and their patients about who will, or will not, benefit from the addition of chemotherapy.

“By stratifying these breast cancer patients and finding that only those with the highest risk of recurrence need to have chemotherapy based on their tumor genetics, TAILORx shows great potential to ensure more gentle treatment without compromising its effectiveness,” said Professor Arnie Purushotham, Senior Clinical Adviser at Cancer Research UK.

For more information: National Cancer Institute TAILORx Study