What’s New in Breast Cancer: Panel Testing

By now, you've probably heard of genetic testing for breast cancer, used to determine the risk of breast cancer predisposition. Genetic testing traditionally has tested for mutations in the BRCA1 and BRCA2 genes; however, newer findings during the past two decades make it possible to test at least ten other genes that predispose to breast cancers – and other cancer types – so high-risk patients can be identified and start taking preventive measures earlier.

What is Panel Testing?

Testing several genes for changes at one time is called panel testing. "We might run a panel as small as six genes if the family history seems very focused. Or, for a family with a wide range of cancers suggestive of more genes, we can include  a greater number of genes. Right now, our largest panel is 61 genes – and that number is increasing all the time," Karen Huelsman, licensed and certified genetic counselor at the TriHealth Cancer & Blood Institute and TriHealth's Precision Medicine, explains.

How Does it Work?

If you're interested in genetic testing, usually your doctor will make a referral; however, patients can also self-refer. Initially, you'll meet with a genetic counselor, who will carefully review your medical and family history, and will give you an assessment, which includes the following questions:

• How many relatives in your family have cancer (as well as what type and what was your relationship to him or her)?
• For relatives who had or do have cancer, what was the age of diagnosis?
• Were any breast cancers triple negative (ER, PR, her2neu negative)?
• Were any breast cancers bilateral or include two separate cancers?
• Have any men in your family been diagnosed with breast cancer?
• In addition to breast cancer in the family, it is important to consider other cancers such as thyroid, pancreatic, uterine, colon, prostate, kidney, adrenal gland, brain tumors, etc.  because these can provide clues to other genes.
• There are some non-cancerous features that can be related to other genes, including macrocephaly (large head size), uterine fibroids, sebaceous adenomas, goiter or thyroid nodules.

"Also, we don't want to people to overlook their grandmother, aunts, cousins or their father's side," Karen points out. "The father's history is equally important to the mother's history."

From there, you'll discuss genetic testing – the recommendations, benefits, limitations, and if you choose to proceed with testing it can be started on the same day as your initial appointment. Testing is typically done through a blood draw. If you're averse to blood draws, your counselor may also offer a buccal wash, where a mouthwash solution is used to collect a sample of cells from the inside of your mouth (cheek) for study.

Depending on how many genes are being tested, it can take anywhere from one to eight weeks to get results back. If you're being tested for a known mutation in the family, it usually requires less time, about one to two weeks, to get results because a full gene analysis is not required in that case.

I've Tested Positive for Gene Mutations: Now What?

Your genetic counselor will usually contact you by phone, regardless of the results, and then, if you have a positive result, you'll schedule a follow-up appointment. You'll discuss:

• The exact nature of the mutation
• The associated risks identified, as far as what organs could potentially be affected
• New surveillance, or monitoring, protocols

"For example, for a woman with high-risk breast cancer, we may choose to suggest a breast MRI, alternating with mammography, instead of mammography alone," Karen explains. "We may also start that screening earlier, as early as age 25. Often patients are unaware of the increased risk for associated cancers, such as ovarian, pancreatic, thyroid, melanoma so we identify screening for other related cancers too. This requires a multidisciplinary team approach to address the multi-faceted needs of these high risk patients."