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Genetic Testing Can Reduce Cancer Risk, Guide Treatment

Scientists are making new discoveries and establishing links between our genes and certain types of cancer all the time. And there are potentially many more risk genes yet to be identified. 

In the United States, an estimated 10% of cancer cases are from inherited genetic mutations. Certain cancers can be hereditary, including breast, ovarian and colorectal cancers. 

If you have close relatives who’ve been diagnosed with these cancers, genetic testing can provide information to help you avoid cancer. 

“If you know you’re at a higher risk, you can take action to reduce the chances of developing cancer,” said Yarrow McConnell, MD, FACS – a breast specialist and surgical oncologist with Good Samaritan Regional Medical Center Breast & Surgical Oncology. And for people who already have cancer, genetic testing can provide information that your doctor can use to tailor treatment decisions. 

What Is Genetic Testing?

Genetic testing is a powerful detection tool to assess changes in our genes that can indicate a greater risk of cancer. It starts with collecting a detailed family health history. Your health care provider will evaluate this information to determine testing recommendations. A test might only look at one gene, or you may be testing for a panel of changes. Testing is done by taking a blood or saliva sample that is sent to a lab to check for gene mutations. 

“Many mutations can increase the risk of cancer,” said Dr. McConnell.

There are more than two dozen common mutations, including the BRCA1 and BRACA2 mutations that are related to breast and ovarian cancer. Other mutations are associated with an increased risk of colorectal cancer, prostate cancer or stomach cancer.

There are different reasons for genetic testing. It can focus on a specific mutation if there is a known family history. It can also be used after a cancer diagnosis to help an oncologist guide treatment. 

Who Should Get Tested?

Generally, evaluation for genetic testing is encouraged for three groups:

  • People who have been diagnosed with breast, pancreatic, uterine or colorectal cancer and/or who have a close family member with these cancers. 
  • People with a first-degree relative with a genetic mutation known to cause cancer. 
  • People diagnosed with cancer at a very young age (<50 years of age) or multiple cancers.

Decades after the discovery of genes that cause cancer, many people who have an inherited risk of cancer still don’t know it.

“To determine if you should pursue genetic testing, talk with your health care provider,” said Dr. McConnell.

When genetic testing first came out, it cost thousands of dollars and was only rarely offered. Now testing is more widely available and relatively inexpensive. Over 90% of patients pay nothing out-of-pocket when genetic testing is done according to accepted guidelines. Even without insurance coverage or if an out-of-pocket expense applies, it is almost always less than $250.

How Are Test Results Used? 

When testing shows a genetic mutation, a person can take preventive steps to detect cancer early or lower the risk for developing cancer. 

For women with BRCA mutations, that may include earlier or more frequent mammograms, additional screenings or surgery.

Knowing a mutation is present can also inform treatment options. For example, a patient with a BRCA gene mutation may choose to have a bilateral mastectomy, instead of a lumpectomy to reduce the chances of getting a second cancer. 

There are benefits and drawbacks if you are considering genetic testing. Knowing you have a mutation can be distressing. But it provides you and your family with valuable information that can guide your health care decisions. 

“Sometimes, results of genetic testing can be confusing,” said Dr. McConnell. “We don’t always find a mutation in a patient with many affected relatives – we still consider these patients as having a higher risk. It may be that there is a mutation in their family that hasn’t been discovered yet. And sometimes the test results show genetic variations that are unknown if they affect the risk of developing cancer. These results are being closely tracked and updated reports issued to patients when there are new discoveries.” 

“The more we learn about the hereditary causes of cancer, the more links we find,” said Dr. McConnell. 

Good Samaritan Regional Medical Center Breast & Surgical Oncology offers specialty breast care, surgical oncology, as well as genetic testing and counseling, for eligible patients.