Colorectal cancer: Symptoms and what causes it

Colon cancer screenings should begin at age 45, not 50

Americans should start getting screened for colon cancer earlier, at age 45 instead of waiting until they're 50.

Colorectal cancer has become one of the leading causes of cancer deaths in the United States for people under the age of 50.

By the numbers:

Though cases among older adults have decreased over the past decade, cases among adults 50 years old and younger have seen a 2.9% increase, according to the American Cancer Society.

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Here’s what to know about colorectal cancer and its symptoms: 

What is colorectal cancer? 

Big picture view:

Colorectal cancer typically starts in the colon or the rectum. Though these are two separate parts of the body, these cancers are typically grouped together because they have many common features, according to the ACS. 

Colorectal cancer happens when small clumps of cells, called polyps, form inside the colon or rectum. Polyps generally aren’t cancerous but could form into colorectal cancer over time. 

Polyps also don’t often present symptoms, and because of this, doctors recommend regular screenings, according to the Mayo Clinic website. 

Symptoms of colorectal cancer

Dig deeper:

Symptoms of colorectal cancer can include: 

• Change in bowel habits, such as more frequent diarrhea or constipation
• Rectal bleeding or blood in stool
• Ongoing discomfort in the belly area, such as cramps, gas or pain
• Feeling that the bowel doesn’t empty all the way during a bowel movement
• Weakness or tiredness
• Losing weight without trying

FILE - Doctors points to a model of the human colon after colonoscopy. (Getty Images)

What causes colorectal cancer?

The cause of colorectal cancer, outside of having a family history, isn’t known, but researchers have found several exacerbating factors that can increase the risk of developing it. 

This includes lifestyle habits and underlying health conditions such as: 

• Obesity
• Type 2 diabetes
• Eating a lot of red meats, processed foods
• Smoking 
• Moderate to heavy alcohol use

When to get screened

What you can do:

If you have no family history or symptoms of colorectal cancer, it is typically recommended by health care providers to get screened between 45 and 75 years of age. 

But if you begin experiencing symptoms, even before 45, there’s no harm in asking your health care provider about getting screened, according to the Colon Cancer Coalition. 

People at increased risk should get screened early. These risks include: 

• Family history of colon or rectal cancer
• Inherited genetic syndromes such as FAP or Lynch syndrome
• Have previous history of polyps that were removed (Get another check-up in about three years)
• Have previous history of colon or rectal cancer
• Have previously gotten radiation to the abdomen or pelvic area
• Have IBS (inflammatory bowel disease)