Understanding Colorectal Cancer In Young Adults

Colorectal cancer occurrence and mortality rates have decreased among adults over the age of 50 since the early 1990’s. This is due to a combination of screening, changes in risk factors (less smoking), and improvements in treatment. Colorectal cancer (CRC) is defined as any cancer that begins in either the colon or rectum; located in the last several inches of the large intestine. Colorectal cancer is often thought to affect older people, but according to a recent study by the American Cancer Society, one in five new cases diagnosed today are in people in their early 50’s or younger. Early-onset colorectal cancer, also called young-onset colorectal cancer, is defined as a colorectal cancer diagnosed in anyone aged less than 50 years of age.  

In response to the rising rates of colorectal cancer in younger adults the U.S. (United States) Preventive Services Task Force changed its recommendations in May 2021 to begin screenings at age 45 instead of 50, and those with risk factors may need to start even earlier.  

Being aware of symptoms and seeking early medical care are vital to reversing this alarming trend in colorectal cancer cases.  

Survival Rates are High When Colorectal Cancer is Caught Early 

Young people are often diagnosed with more advanced disease which is unfortunate because survival rates are high if detected early. There are several reasons why young people might be diagnosed later. Younger people often assume they are healthy. If they do experience symptoms, they may not even think they have CRC. Second, very few young adults have a primary care healthcare provider. Finally, stigma may be another reason, they may not feel comfortable discussing rectal symptoms.  

Colorectal Cancer Symptoms  

Most early-onset cancers are found in the rectum and the left colon whereas later-onset cancers are found in the right colon. The most common symptoms for early-onset colorectal cancer include:  

• Blood in the stool or rectal bleeding 
• Dark-colored or tarry stools  
• Regular abdominal pain or bloating 
• A change in your bowel habits or the consistency of stool 
• Unexplained weight loss 

Understanding Risk Factors 

There is no clear explanation for early onset colorectal cancer. Long-term studies with large populations are needed but are expensive and difficult to conduct.  

According to Dr. Sinicrope, Mayo Clinic Gastroenterologist and Oncologist, most early-onset colorectal cancers are not due to a genetic syndrome or family history. The study by the American Cancer Society investigated possible dietary factors such as the consumption of processed foods, red meat, and sugar-sweetened beverages. Other factors investigated include antibiotic use, environmental toxins, higher rates of Cesarean sections and other surgical procedures. All these factors influence the gut microbiome or the type of bacteria in the digestive system which play a key role in our immune system and overall health.  

Do Not Ignore Symptoms 

It is important for patients and medical providers to aggressively investigate any symptoms no matter their age. Colonoscopies are recommended for cancer screening. If you are hesitant to get a colonoscopy, there are less invasive screening options such as the stool-based screening. It is best to talk with your healthcare provider so they can understand your health history and determine the best screening option for you based on your risk factors.  

If you have loved ones under the age of fifty in your life, let them know symptoms of colorectal cancer and encourage early medical care. 

Discover resources here:  

• Join the Colorectal Cancer Support Group on Mayo Clinic Connect 

• Learn more about colon and rectal cancer and colorectal cancer clinic trials at Mayo Clinic.  
• Learn more about the Signs of Early-Onset Colorectal Cancer from Mayo Clinic physician Dr. Frank Sinicrope, Gastroenterologist and Oncologist on the Mayo Clinic Comprehensive Cancer Center Blog