Why Is Colorectal Cancer on the Rise in Young Adults?

Colorectal cancer is one of the most common cancers in the U.S. Rates of colorectal cancer are decreasing overall, thanks to screening and earlier detection. But in people under the age of 50, colorectal cancer rates are actually increasing. In fact, 12% of colorectal cancer cases are in those under the age of 50. The risk is higher in certain groups, including American Indians and Alaska Natives.

What is causing colorectal cancer rates to increase in younger people?

The reason for this rise of colorectal cancer in young adults isn’t clear. The cause of any cancer — at any age — is usually a mix of genetic and environmental factors. And there’s growing evidence that exposures early in life — even in childhood — may play a role. This likely holds true for colorectal cancer rates among young adults. 

These factors may help explain the increasing rates of colorectal cancer in young adults:

• Obesity: Rates of excess weight have rapidly increased in the U.S. over the past few decades. And carrying excess weight may raise the risk of some cancers, including colorectal cancer. More than half of people diagnosed with colorectal cancer at a young age have a body mass index (BMI) in the obese category (30 or higher).

• Diet: Dietary factors contribute to colorectal cancer risk. Processed meats and low fiber in the diet are known risk factors for colorectal cancer.

• Lack of physical activity: A low level of physical activity is a risk factor for colorectal cancer at young ages. A growing number of people in the U.S. live a sedentary lifestyle with increased screen time.

• Gut microbiome: The gut microbiome likely plays a role in colorectal cancer risk. Your microbiome is shaped by your diet, environment, genetics, medications, and more. 

• Chronic health conditions: Conditions such as Crohn’s disease or ulcerative colitis increase the risk of colorectal cancer in young people. 

How can I reduce my risk of colorectal cancer?

There are important steps you can take to lower your risk of colorectal cancer — at any age:

• Eat a diet high in fiber.

• Avoid or limit processed meats.

• Don’t smoke, or take steps to quit.

• Maintain a balanced weight.

• Do regular physical activity

• Avoid or limit alcohol use.

What’s the role of genetics in colorectal cancer?

Genetics plays a large role in many cases of colorectal cancer — especially for young adults. There are some known genetic conditions that increase the risk of colorectal cancer, including Lynch syndrome and familial adenomatous polyposis.

But as many as 1 in 5 early colorectal cancer cases are due to a genetic mutation. And in around half of these, there’s no personal or family history that suggests an increased risk of colorectal cancer. 

Who should get genetic testing for colorectal cancer?

Genetic testing may be recommended for people with a strong family history of colorectal cancer. If you’re 50 years old or younger and have a diagnosis of colorectal cancer, your healthcare team may offer genetic testing. If you’re concerned about your risk, talk about genetic testing options with a healthcare professional.

What are some early symptoms of colorectal cancer?

Colorectal cancer may not cause any symptoms at all, especially early on. Early symptoms of colorectal cancer may include:

• Change in stool habits, such as new diarrhea or constipation

• A feeling like you still need to have a bowel movement after using the bathroom

• Blood in the stool

• Abdominal or pelvic pain

• Unintentional weight loss

EXPERT PICKS: WHAT TO READ NEXT

• Screening options for colorectal cancer: A colonoscopy isn’t the only way to screen for colorectal cancer. Learn about your options. 

• Excess weight and cancer risk: There’s a complex relationship between a larger body size and some types of cancer. Here’s what the research shows.

• Can fiber really help prevent cancer? Following a high-fiber diet may help lower your risk of some cancers, including colorectal cancer. Here’s how.

Colorectal cancer can lead to low red blood cell counts (anemia). While you may not experience this as a symptom, sometimes a low red blood cell count on a blood test can be the first sign of colorectal cancer.

Should younger people get screened for colon cancer?

Colorectal cancer often doesn’t lead to any symptoms, particularly in early stages. This is why screening is important. The U.S. Preventive Services Task Force (USPSTF) and the American Cancer Society recommend that adults start screening for colorectal cancer at age 45.

There are a handful of screening options for colorectal cancer. How often you need to be screened depends on your risk factors and the type of test. Here are some general guidelines and options: 

• Colonoscopy every 10 years

• Stool DNA test every 1 to 3 years

• Fecal immunochemical test (FIT) or fecal occult blood test yearly

• Virtual colonoscopy every 5 years

• Flexible sigmoidoscopy every 5 years

Connect with your primary care provider about the best screening option for you. If you have a family history or genetic risk, they may recommend earlier screening.

How is colorectal cancer treated?

How you treat colorectal cancer depends on the stage. Colorectal cancer is very treatable with surgery when it’s caught early and hasn’t spread beyond the intestine. This is why it’s so important to catch it early — before the cancer spreads through the intestinal wall and to lymph nodes or other organs.

Surgery also plays an important role in more advanced stages of colorectal cancer. Medical treatments, such as chemotherapy or targeted therapy, are often used along with surgery at this stage. 

Late-stage colorectal cancer means the cancer has spread far beyond the colon. Treatment depends on different factors, including where the cancer has spread, its size, and your goals. At this stage, treatment often aims to control the cancer, help you live as long as possible, while also maintaining your quality of life. A cure may not be possible, though.

Why trust our experts?

Written by:

Christina Palmer, MD

Christina Palmer, MD, is a board-certified family physician with a focus on chronic care management, women’s health, and mental health. She’s the co-author of “Open Heart: When Open-Heart Surgery Becomes Your Best Option.”.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Farzon A. Nahvi, MD

Farzon Nahvi, MD, is an emergency medicine physician and author of “Code Gray: Death, Life, and Uncertainty in the ER.” He works at Concord Hospital in Concord, New Hampshire, and teaches at the Geisel School of Medicine at Dartmouth.

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