Genetic and Genomic Testing: a Necessity for Proper Breast Cancer Care

The results of your genetic and genomic testing can drastically change your treatment plan.

“It breaks my heart when I see breast cancer patients coming to see me late in the course of their disease unaware of their genomic or germline testing results or what these tests even are,” says  Carmen Calfa, M.D., Sylvester Comprehensive Cancer Center, part of UHealth – the University of Miami Health System.

A lot of progress has been made in breast oncology, and, according to Dr. Calfa, the chance of dying from breast cancer has gone down by 42% in the last three decades. “But that doesn’t come without effort,” says Dr. Calfa. “Our mission as oncologists is not only to lead research to discoveries but to offer every patient the best opportunity for prevention or treatment at every given time and to empower them with the knowledge needed to thrive.”

Germline tests find genetic mutations.

Testing for a genetic mutation such as BRCA is called germline or genetic testing, says Dr. Calfa. In these types of tests, the scientists are screening your normal, healthy cells to see if you have a mutation that makes you more likely to develop certain types of cancer later in life.

This test can provide insight into what regular screening and treatment regimen is right for you. For example, should you start having annual mammograms earlier than the standard recommended age of 40? Or, who else in the family is at risk, who needs testing and when?

Germline testing can also help direct treatment in those who have already been diagnosed with breast cancer. For example, if you have breast cancer and you carry the BRCA mutation, a particular category of drugs, PARP (poly ADP-ribose polymerase) inhibitors, is likely to be most effective for you. PARP inhibitors block the repair process that happens in damaged DNA and in cancer treatment, and this can cause damaged cells to die. They are effective in treating cancers with genetic mutations, such as those that occur with BRCA gene mutations.

One of the myths about germline testing is that you only need to test for the BRCA gene mutation if you have a family history of breast cancer. In fact, there are many other genes to test for and other aspects of family history that are important in determining whether a test is right for you.

For example, Dr. Calfa saw a patient who had many male relatives with prostate cancer. She was the first in the family to have breast cancer. Unfortunately, her cancer was already stage four when it was caught, and she passed away from it at the age of 39. If she had known that paternal family history is equally important and, in this case, may signal a hereditary predisposition syndrome, it could have saved her life. Had that happened, the woman may have started her screening earlier, and her cancer might have been caught when treatment would have had the potential to be more effective.

At the end of 2022, Sylvester opened the Genetic Predisposition Syndrome Clinic to help anyone with a genetic mutation assess their cancer risk and take steps to maintain their health throughout their lifetime.

Genomic sequencing checks your tumor’s genes.

When recommending genomic sequencing to her breast cancer patients, Dr. Calfa states, “I like to tell patients: we checked your genes; now we’re going to check the tumor’s genes.”

The cells of your tumor are different from the rest of the cells in your body. As the tumor remains in your body, more and more genetic mutations can occur in those tumor cells. That means it can be helpful to get genomic sequencing shortly after your diagnosis to help determine your treatment plan and repeat the testing throughout your treatment. This can help doctors understand how your tumor is transforming and guide treatment decisions throughout the disease course.

For example, Dr. Calfa explains, it can tell you how likely someone is to respond to immunotherapy, or it can open new doors toward the standard of care or clinical trial options. “Genomic sequencing is so, so important,” she says. “But we see so many patients who haven’t had genomic testing.”

Dr. Calfa met one of her patients when she was told it was time for her to focus on palliation of her symptoms and embrace hospice care, but her tumor had never been sequenced. Fortunately, the result revealed molecular alterations that qualified the patient for immunotherapy on the American Society of Clinical Oncology (ASCO) TAPUR’s trial, and she’s been cancer-free for four and a half years.

“She’s not the only one, but that’s likely one life saved right there,” says Dr. Calfa. “We wish we could see patients like her earlier. You don’t have to wait until nothing else is working to do this analysis and give personalized treatment.

“I am optimistic that, by expanding the germline and genomic testing to all who qualify, we will have a great impact on cancer prevention and cancer outcomes. It is up to us to spread the word and make it happen.”

Emma Yasinski is a contributing writer for Sylvester Comprehensive Cancer Center.

Tags: DNA damage, Dr. Carmen Calfa, hereditary risk, heredity cancer risk, Sylvester Comprehensive Cancer Center, tumor DNA