Everything you need to know about reducing your risk of colorectal cancer

There’s something strange happening with colorectal cancer trends in the U.S.: Younger patients under the age of 50 are at increasing risk of developing this disease. This trend—and its implications—was perfectly encapsulated in the story of a patient I cared for. She was diagnosed with early-stage colorectal cancer in her 30’s, well below the average age of diagnosis. When we first met, I asked her questions related to her medical history to identify any risk factors. She had none, adding to enigma of her diagnosis. When I was finished with my questions, she asked me one question, simply but devastatingly: “Why?”

My patient asked me the critical question—why, at this inexplicably young age, did she develop colorectal cancer? Let’s delve into this key question, but before we do, I’ll provide a little background on the disease. Colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. It’s a serious disease that is curable when caught early. That’s why it’s important to understand your risk and to start screening for colorectal cancer at the appropriate age.

How colorectal cancer develops

Colorectal cancer begins when typically healthy cells in the colon or rectum stop responding to the usual signals and grow abnormally. Most cases start as benign (noncancerous) growths called polyps, which can become malignant (cancerous) over time. These polyps can develop over 9 to 10 years, so early detection is key to survival, especially in a younger population. 

Symptoms vary depending on the size and location of the cancer. It’s important to consult a doctor if you’re experiencing any of the following:

• Blood in the stool or rectal bleeding
• Persistent changes in bowel habits such as diarrhea or constipation
• Unusual stool caliber (thin or pencil-like stools)
• Anemia
• Chronic abdominal pain
• Fatigue and weakness

In some cases, colorectal cancer might present without any symptoms at all – this is an important reason why age-appropriate screening is critical for this disease.

What are my risk factors for colorectal cancer?

Your risk of developing colorectal cancer increases with age, with a majority of cases occurring in people over 50. The median age of diagnosis is 66. But, as with my patient, there’s a growing trend of patients being diagnosed at a younger age.

Incidence: North American Association of Central Cancer Registries, 2022. Mortality: National Center for Health Statistics, Centers for Disease Control and Prevention, 2022.

Those with first-degree relatives who have had colon polyps or have been diagnosed with colorectal cancer are also at a higher risk and may be encouraged by their doctor to start screening earlier.

While you don’t have control over non-modifiable risk factors like your age, family history, or inherited genetic factors such as familial adenomatous polyposis (FAP) and Lynch syndrome, the links between diet, weight, and exercise, and the risk of developing colorectal cancer are some of the strongest for any type of cancer. 

In the U.S., more than half of all colorectal cancers are attributable to lifestyle factors, such as an unhealthy diet, insufficient physical activity, high alcohol consumption, and smoking. Here’s where you can make a big difference to help decrease your risk:

• Stay physically active and maintain a healthy weight
• Maintain a healthy diet that is high in whole grains and fiber from fruits and vegetables and limits red or processed meats
• Consider adding calcium and vitamin D supplements if you’re not getting enough through diet
• Limit your alcohol use and avoid tobacco

What are the risk factors driving the earlier age of colorectal cancer diagnosis? Not surprisingly, the list is similar to the one above. Studies suggest that diets low in grains and high in meat might be associated with the greatest risk of early-onset colorectal cancer. In addition, alcohol consumption, a sedentary lifestyle, and metabolic disorders like obesity have also been linked to this trend.

Screening and early detection can save lives

While lifestyle, diet, and exercise play a role, the most effective way to reduce the risk of colorectal cancer is to routinely get screened to find it early, even before symptoms arise. Detecting colorectal cancer early allows for more treatment options and the greatest chance of a cure.

There has been a concerning trend of younger people being increasingly diagnosed with colorectal cancer, so the American Cancer Association now recommends people at average risk begin screening at age 45. Those at higher risk because of a personal or family history or other risk factors may be advised to start screening earlier.