Genetic testing: changing the way we treat cancer

December 03, 2019 | by Sania Raza, M.D.

Every day advancements are being made in the fight against cancer. Some of the most important information for treating cancer is already inside of us.

Understanding your genetic makeup and the genetics of cancer are two vital components of understanding cancer — and another line of defense against it.

Genetic testing can help estimate your chances of developing cancer in the future. This information can be used to decide on screenings, medication, surgery, lifestyle changes and other measures to lower your risk.

In addition to helping you understand your risk for cancer, genetic tests can provide useful information about how to treat the disease. By looking at what genetic changes make a tumor grow and spread, doctors can more accurately predict which treatment will work best for a particular disease

Here are answers to common questions about the role of genetic testing in cancer treatment:

How has genetic testing changed the way we treat cancer?

In the era of precision medicine, cancer treatment is getting more and more targeted to a particular individual’s cancer, rather than treating cancer by the organ of its origin. In the past, cancer was treated in very broad strokes. But with the discovery of somatic mutations (i.e., mutations discovered in individual cells), found in cancer cells, scientists can use mutational markers as targets to precisely kill the cancer cell.

Which cancers can genomic testing treat?

Lung cancer has seen the most dramatic benefit from genomic testing. We now understand that more than half of lung cancer in patients who have never smoked are driven by single DNA mutation. These include mutations in a protein called EGFR. If found, doctors can use anoral medication as a targeted therapy for that particular lung cancer. A majority of these patients go into long remission without needing chemotherapy. There are more examples of these mutations in breast, colon and prostate cancers, and others

What is circulating tumor cell DNA sequencing?

Circulating tumor cell DNA sequencing is another method of genomic testing, but instead of using the tumor tissue, doctors can actually can find the tumor DNA in the patient’s serum, isolate it, and then sequence it to find similar mutations.

How do patients benefit from genomic testing?

Genomic testing can help doctors customize cancer treatment to the individual patient. In the past, patients were often put on a universal treatment plan for a specific cancer type. They often received treatment that was more aggressive (and more toxic). Now, genomic testing can help doctors examine the tumor at a molecular level and provide targeted treatments more likely to work for that particular tumor, with fewer unnecessary side effects.

What are the positives and negatives about genomic testing?

Precisely targeting mutations in cancer cells often leads to better control of the cancer with fewer side effects. The problem is the discovery of mutations is much faster than findings drugs that can target these mutations. Therefore, the doctor is often left with discovery of mutations that may not have a target. Genomic sequencing is also very costly and time consuming — time that is very precious when it comes to cancer treatment. 

Scientists are learning more every day about how to better fight cancer. We know you can make certain lifestyle changes to live healthier and help prevent cancer. Genetic testing can help clarify if you inherited a specific genetic mutation that may cause cancer so you can take measures to stay on top of it. And with genomic testing, doctors are better able to tailor cancer treatments for some individuals.

Your physician can help you better understand if genetic testing is right for you.

Learn more about genetic testing and counseling at Edward-Elmhurst Health.

Related Blogs:

Genetic screening can provide vital health information

Your genes and your health: 5 FAQs about genetic testing

There’s no one size fits all in cancer treatment

Learn more from Healthy Driven Chicago:

Five tips to reduce risk for breast cancer

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