Great question. Patients, particularly with early stage (stage I-II) estrogen receptor positive breast cancer, have benefited immensely from the testing you describe. Gene expression profiling evaluates the risk of cancer returning after surgery on a molecular level. In my practice, this type of testing has allowed me to safely avoid chemotherapy in many patients who would likely have otherwise received chemotherapy prior to validation of these tests.
Prior to ”gene score” tests, decisions regarding whether to recommend chemotherapy were informed by a few pathologic features of the tumor (how the tumor looked under the microscope) and whether the patient was felt to be fit enough to tolerate chemotherapy.
For the majority of early stage breast cancer patients, uncertainty would persist regarding the added benefit for chemotherapy based on microscopic review alone. As a result, in order to ensure that patients would not receive inadequate treatment, many patients were treated with chemotherapy who ultimately would have had an excellent prognosis with hormone therapy alone.
With genomic expression profiles, we can get a more thorough evaluation of a tumor’s activity, including how much it relies on estrogen to grow and how fast it is growing (among other features). These tests classify patients into risk categories, which differ slightly based on the test, and can be used to estimate a patient’s probability of recurrence. Clinical trials involving thousands of patients have validated several of these tests and have specifically evaluated the benefit of chemotherapy based on the calculated risk of the patient’s tumor. These studies enable your doctor to feel confident in his/her decision and truly provide personalized care.
It is important to note that these tests have largely been studied in estrogen receptor positive breast cancer and, despite the strong level of evidence supporting their use, there are still clinical scenarios where these tests may not be appropriate. Additionally, which test is performed should be based on the clinical scenario of the individual patients being treated.
It is very important that you feel comfortable discussing your concerns with your oncologist and he/she should always be willing to discuss how they arrived at their decision.
To schedule an appointment, or to learn more about the NYU Winthrop Breast Health Program, visit www.nyuwinthrop.org or call 1-866-WINTHROP.
Douglas Marks, MD
Dr. Douglas Marks is an Attending Physician in the Division of Oncology/Hematology at NYU Winthrop Hospital, having joined the Hospital following a fellowship program in Oncology/Hematology at Columbia University Medical Center. Dr. Marks also serves as a Clinical Instructor with a primary clinical focus on breast cancer. Dr. Marks was awarded an American Association for Cancer Research (AACR) Scholar in Training Award in 2017 and is currently involved in several research endeavors focused on better understanding the interaction between an individual patient’s immune system and breast cancer.