Let’s talk about colorectal cancer

Published March 4, 2024

Colorectal cancer diagnoses have been steadily declining since the 1980s, largely due to regular screenings and healthy lifestyle choices. But this positive trend hasn't been the same for everyone. For people under 55—the number is going in the wrong direction and has been rising yearly since the mid-1990s.¹

What is colorectal cancer? 

Cancer happens when cells start growing out of control and don't die off like they should. Usually, cells grow, divide, and create new cells as needed. When cells aren't needed anymore or become harmful, they naturally get rid of themselves through a process called programmed cell death. But in cancer, this process breaks down. Instead of these cells dying off, they survive, and new cells form when they're not needed. Since the human body is made up of trillions of cells, cancer can start almost anywhere.² When this type of out-of-control cell growth happens in the colon or rectum, it’s called colorectal cancer (or colon cancer).³

How does colorectal cancer usually start?

Colorectal cancer affects the colon (the first and longest part of the large intestine) or the rectum (the lower part of the large intestine).³ Colorectal cancer usually starts from small, noncancerous lumps (called polyps) on the inner lining of the colon or rectum. Polyps are common and most don't turn into cancer. But polyps that do become cancerous tend to grow slowly. That’s why colorectal cancer screening is so important in cancer prevention. It helps find polyps that can be removed before they turn into cancer.⁴ Screening also helps find colorectal cancer in its early stages, when treatment can work best.⁵

How is colorectal cancer different from polyps?

Most colorectal cancers start as a polyp on the inner lining of the colon or rectum. While some polyps can slowly turn into cancer over many years, not all do. Some kinds have a higher chance of turning into cancer than others.⁷

The main difference between colorectal cancer and polyps is that colorectal cancer is already cancer. Polyps are growths that might turn into cancer if they're not removed. But colorectal cancer means those cells have already changed and are spreading.⁷

How is colorectal cancer different from colitis?

The colon is a long tube that helps the body digest food. When the lining of this tube becomes inflamed, it's called colitis (pronounced kuh-lie-tis). This inflammation causes pain, diarrhea, and sometimes bleeding.⁸

Inflammation is the immune system’s way of dealing with injury, infection, or toxins. When it detects a threat, it sends special cells to fight it off. This cell activity triggers inflammation, which is the body’s way of sending a message that something needs attention. 

And this is usually a good thing, as inflammation helps the body heal and recover. But sometimes, the immune system doesn't stand down, and the inflammation lasts too long (chronic inflammation). Short-term inflammation is helpful, but chronic inflammation can harm tissues and lead to certain health conditions. 

Inflammation can be short-term or chronic depending on the type of colitis. Each type of colitis has its own causes, symptoms, and ways to treat it.⁸ But what makes colitis different from colorectal cancer is that the inflammation in colitis is caused by the immune system, not by cancerous cells.

Can colorectal cancer be prevented through nutrition? Lifestyle changes?

The good news is that over half of colorectal cancers are linked to factors within our control. This means we all have the power to significantly reduce our risk. This includes things like⁴:

• Going smoke-free
• Eating a healthy diet
• Cutting back on alcohol
• Staying active
• Maintaining a healthy weight

Plus, the key to preventing colorectal cancer or finding it early is by getting regular screenings, starting at age 45.⁹ Some people might need to start earlier or get tested more often. Talk with your doctor about[⁴ ⁹]:

• When to start screening
• What test is right for you
• How often to get tested

What are the signs and symptoms of colorectal cancer?

Colorectal cancer doesn't always show signs. If there are signs and symptoms, they might include³:

• A change in bowel movements
• Diarrhea, constipation, or feeling that the bowel doesn’t empty all the way
• Blood in or on the stool
• Frequent belly pain, gas, bloating, fullness, or cramps
• Weight loss without trying
• Fatigue (feeling tired even when you had enough rest)

►If you notice any of these changes, please talk with a doctor. 

What’s colorectal cancer screening? Who needs it?

Colorectal cancer might not cause symptoms early on. That’s why regular screening is so important. Screening tests look for signs of a disease before symptoms appear. They can help find cancer earlier.

The American Cancer Society & United States Preventive Services Task Force recommends that people at average risk of colorectal cancer start regular screening at age 45 and continue until age 75.¹⁰ ¹¹

What does ‘average risk’ mean?

For colorectal cancer screening, a person is considered to be at average risk if they DO NOT have¹⁰:

• A personal health history of:
• Colorectal cancer
• Certain types of polyps
• Inflammatory bowel disease (like ulcerative colitis or Crohn’s disease)
• Abdominal (belly) or pelvic radiation for a prior cancer
• Lynch syndrome
• Familial adenomatous polyposis (or FAP for short)
• A family health history of:
• Colorectal cancer

►Talk with your doctor if you're unsure about your risk for colorectal cancer. Some people might need to start screening earlier and get tested more often.¹⁰