Understanding your personal cancer risk

The word “cancer” is a scary one. A Gallup poll shows that people fear a diagnosis of cancer more than any other health condition. Understanding your own cancer risk factors, especially when combined with genetic testing and screening recommendations, can help alleviate anxiety and guide personalized medical decisions. 

“It’s important to know what the likelihood is that you may develop cancer so your doctors can be proactive about any cancer screenings,” said Carson Nestler, a certified genetic counselor at Smilow Cancer Hospital. “Screening tests can help detect cancer at an early stage before symptoms occur – and when the cancer may be easier to treat. In fact, screening tests can sometimes help prevent cancers from developing in the future.” 

Screening tests have other benefits, too. When you understand your cancer risk, you can have more informed discussions with your doctor about surgical options or medications that may prevent or reduce your chances of developing cancer. Knowing your risk factors can also help identify family members who also may be at risk.

Where to start 

You can’t control all cancer risk factors, but you can control some, according to experts with the Smilow Cancer Genetics and Prevention Program.

The team of specialists includes physicians, genetic counselors, genetics clinical coordinators and nurse practitioners. They work together to provide genetics education, genetic test coordination, cancer risk assessment and personalized medical recommendations.

Nestler explained that every person has some risk of developing cancer. In some people their risk might be higher because they have certain risk factors that other people do not.

She said it helps to understand how cancer happens. Every cell in your body contains DNA, and the DNA in these cells get damaged tens of thousands of times each day. Because DNA provides the blueprint for the proteins your cells need to function, this damage can cause serious issues including cancer. 

Some of these gene changes are random; others may be caused by lifestyle risk factors such as smoking. These are known as sporadic variants. In some cases, environmental or lifestyle-related risk factors are shared among family members and may be linked to an increased risk for cancer in that family. 

The cancer risks you’re born with

In other cases, the risk factors are present in DNA at birth – which are known as hereditary or inherited risk factors, according to Nestler. “We can identify people with hereditary risk factors for cancer through genetic testing, which looks for pathogenic variants in a person’s genes,” she  said. 

Pathogenic variants are genetic alterations that increase someone’s predisposition to a certain disease or disorder. You may be born with a pathogenic variant you inherited from your parents. This type of variant accounts for approximately 5 -10 percent of cancers, with more than 50 types of hereditary cancer syndromes currently identified. 

Genetic testing involves examining your DNA to find pathogenic variants in your genes that may cause illness or disease. Testing positive for a pathogenic variant in a hereditary cancer gene does not definitively indicate you will develop cancer, but it does mean that your risk may be greatly elevated. 

Genetic testing is most often done from a blood sample, but sometimes cells from saliva, the cheek, skin or other tissue may be used. 

Do you need genetic testing?

Consider genetic testing if you have a personal or family history of:

• Cancer diagnosed at a young age, especially before age 50 
• A family member with a known inherited harmful genetic change that increases cancer risk
• Multiple cancers of the same type or related cancers in the same person 
• Multiple blood relatives who have had the same type of cancer or related types of cancer
• Rare cancers such as pancreatic, ovarian, aggressive prostrate or male breast cancer
• You are a member of a racial or ethnic group that is known to have an increased risk of having a certain inherited cancer (such as Ashkenazi Jewish ancestry

Inherited vs. familial

Approximately 15 - 20 percent of cancers may develop due to familial risk factors, in which there may be a family history of specific cancers, but genetic testing does not identify a specific pathogenic variant as the cause. People with familial risk factors may still have an increased risk of developing a certain type of cancer, even if a hereditary cause is not identified.
 
“This could be due to other factors an individual has in common with their relatives who developed cancer,” Nestler said. “These factors may include the environment is which we grew up and similar health behaviors that work together with shared genes, resulting in clusters of the same types of cancers in the family.” 

It’s important to compile your family history of cancer(s) and share it with your providers. This information will help them determine your cancer risks and create accurate cancer screening recommendations for you. Collect information about any cancer diagnoses in your family, whether the family member(s) had other risk factors (such as tobacco use), the age of diagnosis, and whether the cancer was a new diagnosis or a recurrence. 

Most cancer risks are random  

The majority of cancer risk factors are not inherited. An estimated 70 percent of cancers are caused by sporadic risk factors which may include the natural aging process, environmental factors, lifestyle factors and random events. 

“People often want to try and pinpoint exactly why their cancer developed. Unfortunately, in most cases we are not able to give them a definitive answer,” said Claire Healy, co-manager of the Smilow Cancer Genetics and Prevention Program. 

While you can’t change your genes, you can take proactive steps to manage your health. 

“We have control over some aspects of our environment, such as diet and physical activity level, as well as alcohol and tobacco use. Limiting your exposure to cancer risk factors as much as possible and pursuing recommended cancer screenings will aid in overall health, regardless of your personal and family genetic history,” said Healy.