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New guideline recommends younger screening for colorectal cancer

mom and teen son
Dr. Shady Ashamalla

Question: I heard there are new guidelines for screening for colorectal cancer for high-risk patients. My maternal grandpa had colon cancer – does that mean I’m in this category, or is it first-degree relatives like mom, dad or sibling?

Answer: Let me start by saying that you being aware that your grandfather had colon cancer is a very important first step. The new national guidelines released this week specifically target high-risk patients, and without knowing your family history, you don’t know whether you’re at risk!

What we do know is that if you have a first-degree relative with colorectal cancer, your chance of developing this disease is doubled, making you high risk. That means we need to be more vigilant with your colorectal cancer screening.

Before we dive into this, it’s important to remind you that the definition of ‘screening’ is someone with no signs or symptoms of colorectal cancer. If there are any signs or symptoms, like changes in your bowel habits or blood in your stool as outlined in another post here, then the term ‘screening’ does not apply and you need diagnostic tests regardless of age or family history. In this post, we are talking specifically about people with absolutely no symptoms. In the general population, these people can be divided into high risk and normal risk of developing colorectal cancer.

So let’s look at these new guidelines for screening in high-risk people.

Firstly, what is a first-degree relative? A first-degree relative is a sibling, mother, father or child. A second-degree relative would be an uncle, aunt, cousin or grandparent. These new guidelines differentiate the intensity of colorectal screening based on either a first-degree or a second-degree relative diagnosed with colorectal cancer, and at what age the diagnosis was made. The guidelines state that if you have a first-degree relative diagnosed with colorectal cancer, you should be screened with a colonoscopy at the age of 40-50 (40 in my opinion!) or 10 years prior to that person’s diagnosis. If that colonoscopy is normal, you should have another in five-year intervals.

So what does that timeline look like?

Here’s an example. Let’s say Peter is diagnosed with colon cancer at age 75. His first-degree relatives (his kids) should start being screened at age 40-50. Peter should speak to his siblings about getting screened if they haven’t already taken part in a screening program.

Here’s another example. Say Gina, aged 35, has three small children. She has been diagnosed with colon cancer. When those kids hit age 25 (10 years prior to her age at diagnosis) they should begin their colonoscopy screening. Let’s say Gina has a younger brother who just turned 29. He should start his screening now. Maybe Gina’s Mom and Dad haven’t taken part in colonoscopy screening before. They should start. Now that a first-degree relative has been diagnosed, the whole family moves into the high-risk category.

One day last week, I conducted colon cancer removals in three patients all in their 30s. For those patients, it means all of their first-degree relatives — any siblings, and current or future children — should have colonoscopies when they are in their 20s (or for their siblings and parents already passed that age, screening should start now.)

This means a lot of people will now need colonoscopies starting in their 20s and for me, that raises a lot of questions: Do they all know about being screened? Will they all do it? Will their primary care physicians or nurse practitioners identify this need in time? You can help spread the word by telling people about the new guidelines!

And so what about your grandfather’s diagnosis? The guidelines state that if you have a second-degree relative with colorectal cancer, you should begin screening with either a stool test or a colonoscopy at the age of 50. For your mom – his first-degree relative – she should have (and hopefully has) already started being screened, and should continue to do so every five years.

So you can see why knowing your family history, and knowing your risk, can save your life. I can’t stress that enough: when caught early, colorectal cancer is treatable. But it often has no symptoms in its early stages, so screening can help us catch it early. And screening if you are high-risk is extremely important. Talk to your family about your family history.

See the entire new guidelines here (it’s a PDF from the Canadian Association of Gastroenterology) and if you have questions, talk to your doctor.

About the author

Dr. Shady Ashamalla

Dr. Shady Ashamalla

Dr. Shady Ashamalla is a colorectal cancer surgeon at Sunnybrook’s Odette Cancer Centre specializing in minimally invasive surgical treatments. He’s also a teacher and researcher in surgical education and simulation. Check out more from The Brief: Colorectal Cancer Blog. Follow Dr. Ashamalla on Twitter: @ShadyAshamalla.