Precision medicine and genetic testing for improved cancer treatments

When it comes to genetics, physical characteristics like hair and eye color often come to mind. However, genes can also determine your risk for certain types of cancers.

"Mutations in the BRCA1 (BReast CAncer gene 1) and BRCA2 genes are associated with a predisposition to various cancers, most commonly breast and ovarian carcinomas," explains Priyanka Mittar, DO, medical oncologist and hematologist at the Sandra and Malcolm Berman Cancer Institute at GBMC. "Approximately 15% of ovarian cancer will be associated with a germline BRCA mutation, and for that reason it is standard care to test all ovarian cancer patients."

Those who inherit BRCA1 and BRCA2 tend to develop cancer at a younger age than those who do not have the genetic variant. Knowing about the presence of certain genes goes beyond risk assessment. It can also impact the way a medical team treats a patient who has received a cancer diagnosis.

"We have a dedicated formal department for genetic testing at GBMC," Dr. Mittar says. "Each patient is evaluated and consulted by a genetic counselor if we deem them appropriate for testing."

While there are national guidelines for which patients should receive genetic testing, Dr. Mittar says the threshold for qualification is relatively low and those interested in getting tested should inquire with their doctor. Receiving a genetic test after a cancer diagnosis can benefit both the patient and their families, she adds.

"It may change what we do surgically or enhance our screening strategies if we don't do surgery," she explains. "There are also new medications that we're able to incorporate in a treatment plan if we have that information."

Knowing a person's genetic predisposition for certain cancers can also determine whether their children should be screened at an earlier age or potentially undergo preventive surgery to minimize their cancer risk later in life. Genetic testing of both inherited genes and tumor-related genes can allow for a more targeted approach to help better treat advanced-stage tumors in patients, Dr. Mittar explains.

"By understanding the genes of a tumor, we can use precision medicine to tailor treatment in a more targeted way that incorporates the specific abnormalities of a patient's tumor," Dr. Mittar says. "We know that we're always in a better position to beat the cancer if we have a target, which is why, at GBMC, we incorporate that precision medicine with standards of care and national clinical trials."

Dr. Mittar says, because different cancer types are uniquely treated for each patient, clinical trials play a vital role in developing precision medicine.

"For example, immunotherapy revolutionized how we treat melanoma, but it has had disappointing results as an ovarian cancer treatment. Clinical trials help us to both identify targets in more cancerous tumor types and improve our ability to target for more successful treatments."

Dr. Mittar says many types of genetic tests are available, but getting tested at an institution like GBMC can make the process less stressful and confusing.

"The genetics counselors will meet with you and select which testing panel is appropriate, and they'll follow up with you if there are any changes to the genetic classifications," she says.