New Study: Colon Cancer Risk Extends to 2nd and 3rd Degree Relatives

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New research suggests colon cancer risk extends to 2nd and 3rd degree relatives.

In a new study, carried out by doctors and researchers from the University of Buffalo and the University of Utah, shows having a 2nd or 3th relative with colorectal cancer increases a person’s risk of developing the disease.

Previous Research has shown:

  • 1st Degree Relatives, have a 50% Risk.
    • First Degree Relatives: Children, siblings, and parents of people with a hereditary cancer genetic mutation have a 1 in 2 chance of inheriting the same gene mutation
  • 2nd Degree Relatives, have a 25% Risk
    • Second Degree Relatives: Nieces, nephews, aunts, uncles, and grandparents/grandchildren of people with a hereditary cancer genetic mutation have a 1 in 4 chance of inheriting the same gene mutation
  • 3rd Degree Relatives, new study shows an increased chances
    • Third Degree Relatives: an individual’s great-grandparents, great grandchildren, great uncles/aunts, and first cousins

The New Study found:

  • 1st Degree Relatives are 6 times (6X) more likely to be diagnosed with early-onset colorectal cancer before the age of 50
  • 2nd Degree Relatives are 3 times (3X)  more likely to be diagnosed with early-onset colorectal cancer before the age of 50
  • 3rd Degree Relatives are 1.56 times (1.56X) more likely to be diagnosed with early-onset colorectal cancer before the age of 50

Currently, colonoscopy screen is often recommended for 1st degree relatives of individuals diagnosed with early-onset (meaning before the age of 50) colorectal cancer, cases of which have been significantly increases over the past few decades. This new study suggests that early screen may be beneficial for 2nd and 3d degree relatives as well.

The findings were published in the journal Cancer Epidemiology.

“Unique Utah resources, including a decades-old National Cancer Institute statewide cancer registry and computerized genealogy data for the majority of the population, made this important collaboration possible,” says Lisa Cannon-Albright, Ph.D., professor and leader of the genetic epidemiology program in the Department of Internal Medicine at the University of Utah School of Medicine. She is also a Huntsman Cancer Institute investigator.

“Our study provides new insight into the magnitude of risk for more distant relatives of colorectal cancer cases, and in particular, for relatives of cases who were diagnosed before age 50,” says first author Heather Ochs-Balcom, Ph.D., associate professor of epidemiology and environmental health in UB’s School of Public Health and Health Professions. “This work is important given the rising rates of early-onset colorectal cancer.”

Further Insights: 

  • The study also found individuals are at a 2.6 fold higher risk of colorectal cancer at any age with a 1st degree relative diagnosed with early-onset colon cancer
  • The risk is 1.96 and 1.3 times greater for second- and third-degree relatives, respectively. In addition, the risk for all degrees of relatives for early-onset colon cancer is higher than the risk for colon cancer at any age

The researchers also point out that relatives may benefit from being more aware of their extended family history and sharing this information with their physician when making cancer screening decisions.

What does this mean for you and your family?

Genetic testing can further the information on the genes you or a loved one carry. Research shows that genetic testing can help your provider recommend more precise treatment options. Genetic testing can also help you determine whether you (or your loved ones) are at an increased risk for cancer and how to improve the prognosis.

Vita Medical Solutions is proud to partner with laboratories to facilitate access to advanced hereditary cancer (CGx) genetic testing.

Learn more about your personal and family genetic makeup and personalized medicine options through our genetic test offerings. Read more specifically about CGx testing here:

With qualifying insurance, this test can cost you nothing out of pocket. Click below to schedule a call with one of Vita Medical’s Patient Services Consultants to find out your eligibility.

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Article Details: https://medicalxpress.com/news/2021-09-colon-cancer-second-third-degree-relatives.html

More information: Heather M. Ochs-Balcom et al, Early-onset colorectal cancer risk extends to second- and third-degree relatives, Cancer Epidemiology (2021). DOI: 10.1016/j.canep.2021.101973