Are we seeing more colorectal cancer cases in younger adults?

Clinical Symptoms Health & Wellness Hot Health Topics

Yes. There is a recent global uptick in colorectal cancer rates among adults under 50. If you are aged 45 or older (or <45  with increased risk of colorectal cancer due to family history or certain medical conditions), talk to your clinician about getting screened.

In the US, colorectal cancer (CRC) – cancer that starts in either the colon or rectum –  is the second-leading cause of cancer-related deaths in men and women combined. Specifically, the National Cancer Institute predicts that colorectal cancer will comprise 7.6% of all new cancer cases and 8.7% of all cancer deaths in 2024.  The American Cancer Society further estimates that there will be about 106,590 new colon cancer cases and 46,220 new rectal cancer cases across all ages in the US in 2024.  While rates have been declining in older adults since the mid-1980s, CRC rates in US adults under age 50 have been rising in recent years. Specifically, newly diagnosed colorectal cancer cases in US adults under age 50 rose from 6.6 per 100,000 people in 2010 to 7.6 per 100,000 people in 2019. While this is still a low overall level of CRC in younger adults, an increase rather than decrease over time is cause for concern.

Racial disparities in CRC are even starker: African Americans across all age groups are 20% more likely to receive a CRC diagnosis and 40% more likely to die from the disease than their white counterparts, with the lowest five-year CRC survival rate of any racial or ethnic group in the US. And for young adults in every U.S. racial and ethnic group, CRC is increasingly being detected at more advanced stages.

45 Is The New 50!

Following this rise in colorectal cancer in younger adults, organizations like the American Gastroenterological Association and US Preventive Services Task Force have recommended lowering the screening age to 45, and have been encouraging people to get screened with the slogan #45IsTheNew50! Screening enables us to detect cancer in its early stages, or identify and remove polyps that have the potential of becoming cancerous. Screening can really, truly, save lives!

What can you do?

➡️ If you are 45 or older (or under age 45 with an increased risk of colorectal cancer due to family history or a personal history of Type 2 diabetes, inflammatory bowel disease (IBD), or certain other conditions), talk to your clinician about getting screened. While colonoscopies remain the golden standard of screening, there are lots of other options for you as well.

Who should be screened for colon cancer?

What’s this new at-home colon cancer test?

➡️ Don’t ignore red flag symptoms such as sudden weight loss (when you are not trying to lose weight), rectal bleeding, dark stool or blood in the stool, abdominal pain, low iron levels, sudden but persistent changes in your bowel movements (diarrhea, constipation or narrowing of the stool). Don’t be shy to talk to your clinician about any concerning symptoms or symptoms that have started suddenly/are new. We know that it can feel awkward to talk about what’s going on “down there”, but healthcare providers talk about these things every day, and there is great effort to remove the stigma that comes along with discussing bowel habits.

➡️ Lifestyle changes like maintaining a healthy weight, reducing alcohol and processed meat intake, and regular exercise can also mitigate risk, alongside maintaining a diverse, fiber-rich diet.

Why are CRC rates increasing  for younger adults?

⚠️ Family history is an important risk factor for colorectal cancer at a young age. Data show that someone with a first-degree relative with colorectal cancer has a two-to-four times greater risk of being diagnosed with the disease before the age of 50.  But since human genetics can’t change in a short time span, this can’t be the explanation for recent trends.

Beyond non-modifiable risk factors (factors that cannot be controlled or changed) like family history and race, scientists think environmental factors such as a diet high in ultra-processed foods and low in fiber, high alcohol consumptionphysical inactivity, and obesity might be contributing to this rise in young adults, but solid data is lacking. The field would benefit from further research on how food systems – and particularly food insecurity – might impact rates of colorectal cancer across all age groups, young adults included. Some literature further suggests that past and present structural inequalities, including structural racism (which, yes, shows up in our food systems, among other systems), can exacerbate these environmental factors and “trigger cancer-specific immune and genetic changes”, which may help to explain the disproportionate rates of colorectal cancer incidence and death in African Americans.

There’s speculation that imbalances in the diverse community of microbes in our gut, known as the gut microbiome, might have an impact on colorectal cancer incidence in younger populations. We don’t have definitive evidence, however. These tiny organisms work hard to (amongst other things) make important chemicals for our health, strengthen our immune system, and keep the wall of the gut healthy to prevent the passage of harmful pathogens and toxins. Changes in diet, particularly consuming highly processed foods, low fiber, high alcohol, and red meats like bacon and sausage, can affect the microbiome. Frequent use of antibiotics, which disturb the gut microbiome, might also be contributing to this. ⚠️Note: These are associations and no direct causal effect has been established.

Bottom line: There has been a small but noticeable uptick in colorectal cancer rates among adults under 50. Between 2010 and 2019, there has been an increase in cases in the US from  6.6 per 100,000 to 7.6 per 100,000 people. So far this is still a puzzle, and we don’t know exactly what mechanisms are driving the rise. But the good news is that colorectal cancer is very treatable with early detection. If you are 45 or older, or younger than 45 but with increased risk of colorectal cancer (due to family history or certain medical conditions), it’s time for that first screening. Talk to your clinician about your options.

Stay safe, stay well, and when it’s time, make sure you get screened!


Those Nerdy Girls


Related Works by Those Nerdy Girls

Who should be screened for colon cancer?

What’s this new at-home colon cancer test?

General Overviews of Colorectal Cancer: Facts and Trends

“Under the Skin” and into the Gut: Social Epidemiology of the Microbiome (Dowd and Renson, 2018)

American Cancer Society Releases New Colorectal Cancer Statistics; Rapid Shifts to More Advanced Disease and Younger People

Patterns in Cancer Incidence Among People Younger Than 50 Years in the US, 2010 to 2019

Colorectal Cancer Risk Factors and Disparities

Racial disparities and early-onset colorectal cancer: a call to action (Harvard Medical School)

Roots of Change: Food Justice & Racism in the Food System

Rising Cancer Incidence in Young Adults: Knowns, Unknowns, and Recommended Next Steps

Colon cancer is rising in young Americans. It’s not clear why. (The Washington Post)

Colon cancer is rising among young adults. Here are signs to watch for. (National Geographic)