We all carry genes that protect against cancer and correct any naturally occurring damage when cells divide. Genetic cancer screening uses medical tests to look for specific mutations (changes) in your genes. In cancer, genetic mutations change how our cells work, particularly how they divide and multiply. In some cases, we inherit mutations that put us at risk of developing inherited (hereditary) cancer. Here at Dr. Susan A. Baker, we perform genetic cancer screening to confirm or rule out hereditary cancer. Read on to learn more about the importance of the test.

Why Is Genetics Essential to My Health?

Genetic testing for hereditary cancers is a proactive health checkup that helps predict certain risks for cancer. Preventive measures and medical interventions may be recommended if detected early to save you from cancer. Your genes contain code (instruction manuals) for making proteins that control millions of actions, including cell growth and multiplication. 

Mutations that change the instructions needed to create and protect certain proteins can turn healthy cells into cancerous ones. Cancer may happen when a single or several genes mutate. This test can predict the risk for cancers which are caused by genetic mutations such as:

  • Breast cancer
  • Ovarian cancer
  • Prostate cancer
  • Colorectal (Colon)cancer
  • Thyroid cancer
  • Gastric cancer
  • Cutaneous melanoma
  • Pancreatic cancer
  • Renal cancer
  • Uterine cancer

Who Should Have Genetic Testing for Cancer Risk?

Certain factors in your family health history may indicate that you need to have genetic cancer screening, which includes: 

  • Several first-degree family members, including your biological parents, siblings, and children, have or have had cancer.
  • You were diagnosed with cancer before age 50.
  • You have cancer in both sets of an organ, such as cancer in both your kidneys or breasts.
  • A known genetic mutation in one or more family members who have had genetic testing.
  • You have several different kinds of cancer.
  • You have a specific cancer type that usually doesn’t happen in people of your age or sex, such as breast cancer in a man or retinoblastoma.
  • You have physical differences linked to certain hereditary cancer syndromes. For example, neurofibromatosis Type 1 is hereditary cancer that also causes other symptoms, such as noncancerous tumours known as neurofibromas.
  • You are a member of a racial or ethnic group known for having certain hereditary cancer syndromes, such as Askenazi (Central and Eastern European) Jewish ancestry.

What Are the Types of Tests for Genetic Cancer Screening?

Hereditary genetic cancer tests include:

  • Single mutation: This test looks for changes in a specific area of a single gene.
  • Single gene testing: This test looks at the DNA of a specific gene.
  • Panel tests: These tests look for mutations in several genes.

Other types of genetic testing include testing cancer cells for gene changes. This test looks for only acquired gene changes in the cancer cells.

What Happens During Genetic Testing for Cancer Risk?

Genetic cancer screening is typically done if you and your healthcare team feel it’s best for you and your family. The entire process involves:

Information gathering

This is to collect information about your personal and family medical history. It is done by a genetic counsellor, doctor, or trained nurse in genetic counselling.

You will be asked about your medical history, including biopsies or surgeries, cancer screening tests, gynecologic history (for women), lifestyle factors, and exposure to things that can cause cancer (carcinogens).

Risk evaluation

Your doctor, genetic counsellor, or other trained professional will go through the information collected to help determine the following:

  • Your risk of developing cancer.
  • If genetic testing might be helpful for you.
  •  What specific gene changes should be tested.

Sometimes, a test looking at only one gene might be recommended, while at other times, testing for a panel or group of gene changes might be better.

Education, Counselling, and Informed Consent

During the visits, information such as inherited cancer will be explained, and the risks, benefits, costs, and limits of genetic testing will be discussed. In some cases, you should discuss who in your family should be tested. It is often a person who has had cancer. More than one member of the family may also be offered to try.

Before testing, you must consider how the results might affect you and your relatives. This and other issues will require you to talk to a professional counsellor to help you with the process. The counsellor will explore ways to help you cope with genetic testing results and ease your fears and concerns. The counsellor can also help you with how to discuss the test results and what they mean with other family members. An increased risk of cancer, especially for children, and the potential for discrimination can be frightening.

After risk assessment and genetic counselling, you can take your time and decide if you will go ahead with the testing. If you choose to be tested, you will be asked to give your consent in writing. It will involve the following:

  • The purpose of the genetic test
  • The reason for offering the test to you and other family members.
  • The benefits and shortcomings of testing, including the limits of what the result might reveal.
  • Screening or treatment options that might be available depending on test results.
  • Further decisions may need to be made once the results are back.

You have the right to refuse even if the counsellor recommends you be tested or advises that genetic testing might be helpful for you.

Specimen Collection and Lab Test

Once you have signed the consent form, genetic cancer screen is carried out, and it is usually done on blood samples, saliva, and cheek cells (from swabbing inside your mouth). They can also be done on other body tissues. Those with active blood cancer (leukaemia) or a history of bone marrow (stem cell) may need to give other samples for accurate results.

What Results Would I Get from Genetic Testing for Cancer?

The test results often take 2-3 weeks, and your counsellor will share them with you once they are out by phone or at a scheduled appointment. Counsellors are trained to interpret and explain results and what they might mean to you and your family. The results of each test might come back as follows:

  • Positive: A positive result means a mutated gene (or genes) may place you at higher risk for developing certain types of cancer. If you have already been diagnosed with cancer, the results might have found a factor that played a role in causing cancer. It might also suggest a higher risk of developing other cancers.

In most cases, there’s no way to know with certainty when or if cancer will develop. 

  • Negative: If your results are negative, it means the test did not find a mutation in the tested genes.
  • Variant of uncertain significance (VUS): This genetic test result shows that you have a change in the gene, but it is unknown if this gene change can cause cancer. Most VUS results have later been found benign, meaning they don’t cause medical harm.

What If Genetic Testing Shows an Increased Cancer Risk?

If it is a positive result of a gene mutation that could increase the risk of cancer, managing your risk should be a priority, and you should lower the risks by:

  • Lifestyle changes: Making healthy choices and changing behaviour to help reduce the risk of cancer.
  • Chemoprevention: Taking medicines to help reduce risk
  • Preventive or prophylactic surgery: Removing a healthy organ or gland to try to keep cancer from starting there
  • Early detection: Doing what you can to find pre-cancer or cancer early through screening tests

How can I Benefit from Genetic Testing?

  • A positive result means you can take steps to manage your risk of developing cancer.
  • You can make lifestyle changes to lower your risk and have regular screening and preventive treatment.
  • Knowing the results may reduce any stress and anxiety of not knowing.

For more information on genetic cancer testing, contact Dr. Susan A. Baker today or request an appointment online.