YOUNGER INDIVIDUALS WHO DEVELOP COLORECTAL CANCER appear more likely to present with late-stage disease in recent years. That is the conclusion of researchers who looked at people in their 20s and 30s.

Today we explore the growing problem of colorectal cancer occurring at a young age. We will then look at a new study suggesting a later stage presentation for the younger folks.

Early-onset colorectal cancer — A growing problem

First, age is a significant risk factor for colon or rectal cancer development. Large bowel (colon) cancer is relatively uncommon before age 40. The disease incidence increases significantly between 40 and 50, and the age-specific incidence increases in each subsequent decade.

You can see from this US government-provided graph that age is a significant risk factor for colorectal cancer. A recent look at the Surveillance, Epidemiology, and End Results database shows that while colorectal cancer has recently decreased among older folks, the disease is rising among those under age 50.

The rate of increase among younger individuals is striking: In the USA, the incidence of colorectal cancer under age 50 steadily increased at two percent per year from 1995 through 2016.

Even the group under 40 appear to have experienced a rising risk of colorectal cancer (even as we recognize that the absolute numbers are low).

Interestingly, the increases in colorectal cancer risk are predominantly in cancers in the left side of the colon and the rectum. The left side means the right side of the picture above, as the patient is facing us; the increased risk is in the descending colon and rectum.

Over 86 percent of those with colorectal cancer under age 50 have symptoms. We don’t fully understand why young individuals are experiencing an increased risk of developing colon or rectal cancer, but we have some hints:

Up to 35 percent of young adult colorectal cancer is associated with inherited genetics.

The trends are seen in both developing and developed countries, even as the former has historically had lower risks of colon cancer in general. Moreover, early- to late-onset colorectal cancer ratios in several low-resource countries are much higher than in the West.

Early-onset colorectal cancer — Risk factors

Here are some risk factors for early-onset colorectal cancer, as identified by an analysis of a collection of studies (a meta-analysis):

• A first-degree relative with colorectal cancer increases risk by 4.2-times.
• Hyperlipidemia (high cholesterol) raises the risk by 1.6-times.
• Obesity is associated with a 1.5-times increase in risk.
• Alcohol consumption lifts risk by 1.7-fold.

Other potential risk factors are being explored, including sedentary behavior and diet. I previously wrote about some dietary elements:The Perils of Colorful SweetsEARLY-ONSET COLORECTAL CANCER INCIDENCE IS rising, with more disease cases among those under age 50 years. The risk has…medium.com.

Early-onset colorectal cancer — More advanced

Now comes this recent news: Younger individuals who develop colon or rectal cancer appear more likely to present with advanced-stage disease, with cancer spread to distant body sites.

Disturbingly, people in their 20s and 30s had the most pronounced increases in distant-stage colorectal cancer from 2000 to 2016. The increase appears most great among young Black and Hispanic people.

Let’s look at the numbers. Overall, distant-stage disease represented an increasing proportion of colorectal cancer.

Distant-stage disease among those 20 to 29 years old who presented with rectal cancer increased from 18 percent to 31 percent between 2000–2002 and 2014–2016. For those ages 30 to 39, the risk of late disease increased from 20 to 29 percent.

Early-onset colorectal cancer — My take

I have two takeaway messages:

• This new analysis of US SEER data supports the shifting of screening (for those at average risk for the disease) from 50 to 45.
• Young people should be vigilant about reporting symptoms such as rectal bleeding.
• We all should try to get a sense of our family history and get genetic counseling and testing as appropriate.
• The study is only observational, so it doesn’t answer why the increase in colorectal incidence and mortality is on the rise.