Genetic Testing for Breast Cancer Risk Supports Prevention and Treatment Strategies
During October, which is Breast Cancer Awareness Month, providers and staff of University of Maryland Shore Regional Health's Clark Comprehensive Breast Center are promoting the availability and benefit of genetic testing for individuals who may have a greater risk of developing breast cancer or other cancers. Having an increased risk of cancer because of an inherited genetic mutation -- also called a genetic variant -- can greatly influence recommendations for surveillance and screening as well treatment decisions.
"No two breast cancers are alike, and neither are two patients alike," said Robin Ford, Nurse Navigator at the Clark Comprehensive Breast Center. "Years ago, to develop a patient's treatment plan, we tried to pigeon-hole cancers into big categories, using tumor size and grade, lymph node involvement, and whether or not the cancer had spread outside the breast. Now with bio-markers and genetic testing, an individualized treatment plan can be achieved for each breast cancer patient."
Bio-markers are additional characteristics of breast cancer cells—hormone receptors such as estrogen and progesterone; protein receptors that influence cell growth, called HER 2 receptors; and proteins inside the cell, called Ki-67—that tell how fast cancer cells are dividing. "These markers are performed on all invasive breast cancers and make planning each breast cancer patient's treatment unique," said Ford.
According to Roberta Lilly, MD, Medical Director of the Clark Comprehensive Breast Center, germline and somatic genetic testing offer different approaches to each person's gene data and help improve overall patient outcomes. "In the germline tests we learn about a patient's heredity, while the somatic tests help identify risk of reoccurrence and if chemotherapy will be effective in breast cancer treatment."
Because nearly 10 percent of breast cancer patients have a genetic variant that is a risk factor for the disease, American Society of Breast Surgeons guidelines recommend all breast cancer patients receive genetic testing, which is offered at the Clark Comprehensive Breast Center as a blood test or saliva test. Variants in the BRCA1 and BRCA2 genes are the most common markers that identify increased risk for breast cancer and also pancreatic cancer, melanoma and prostate cancer. Upon return of the testing results, the Breast Center provides appointments with a University of Maryland School of Medicine genetic counselor who meets with patients via telemedicine to discuss genetic testing and testing results.
"Beyond BRCA, there are other gene variants that can also help identify an individual's risk of developing breast cancer," said Dr. Lilly. "By looking at all of this gene data, we can create a plan to prevent cancer, or to identify the presence of cancer at an earlier or more treatable stage."
Germline testing is performed on non-cancerous cells and identifies changes in all cells in the body. Genetic changes can identify increased risks for hereditary cancers including breast cancer.
Factors for an inherited risk of breast cancer include: whether a person or their close relative has been diagnosed with breast cancer before the age of 50; the number of same-side relatives with breast, ovarian, colorectal, endometrial, or prostate cancer; ancestry; and other relatives known to have a genetic variant related to cancer risk.
Germline testing results are usually returned within two to three weeks, with UM Shore Regional Health providers creating screening and management plans for those with a positive variant risk.
"We typically look at an 84-gene panel to identify mutations that may put a patient at risk for breast or other cancers," said Dr. Lilly. "About 30 of these genes are associated with breast cancers, while other gene mutations identify cancer risks like melanoma, colon, and pancreatic cancers."
Individuals diagnosed with hormone receptor-positive and HER2-negative early stage-invasive breast cancer are candidates for somatic genetic testing, which identifies the gene changes in cancer cells. This testing is performed on tissue collected at the time of surgery or biopsy. Test results are usually returned to the patient's oncology provider within a week or two.
One such test, the Oncotype DX, measures a group of cancer-related genes from breast tumor tissue. The results provide a Recurrence Score, which provides information regarding the chance of the breast cancer recurring and also the likelihood that chemotherapy will or will not benefit the patient -- important data used by oncologists for the creation of each patient's individualized treatment plan. Low scores indicate a less likely recurrence of breast cancer within 10 years, and also a less likely benefit of chemotherapy, whereas a higher score indicates a more likely recurrence as well as a greater benefit of chemotherapy.
"This information is of great value to some patients by sparing them from undergoing chemotherapy," said Ford. "For others, it validates the need for chemotherapy. Either way, it allows for tailored treatment planning, which is very reassuring for patients."
Patients receiving genetic testing may also qualify for participation in a research trial, Medneon iGap Registry. The registry is a databank of information including people who have had or are seeking Genetic or Biomarker Testing. The registry will eventually enroll about 10,000 people and gather data on testing results and how that information is used to manage patient care.
"Our patients' participation is helping us contribute to a very large data set that can be utilized readily by cancer researchers," said Christina Weisenborn, RN, Clinical Trials Coordinator for the Cancer Center at UM SRH. "Having this data in the registry may help researchers develop a better understanding of the role that genetic and other bio-marker tests play in managing and even preventing disease."
For more information about genetic testing through the Clark Comprehensive Breast Center, call 410-820-9400.