Colon Cancer (Colorectal Cancer)

Colon (colorectal) cancer is cancer that starts in polyps on the inner lining of your colon and rectum. Colon cancer is a type of cancer that can affect your colon or your rectum in your large intestine.

Polyps in your colon can become cancerous. Cancerous polyps may grow from your colon’s inner lining to spread to other areas of your body. Healthcare providers can do tests, like colonoscopies, that can detect colon polyps before they become cancerous. The tests also detect cancerous colon polyps.

Colon cancer is a serious condition. But removing precancerous polyps can stop colon cancer before it starts. An early diagnosis and treatment to remove cancerous polyps may cure the disease.

Colon cancer symptoms

Colon cancer develops slowly. It takes about 10 years for a precancerous polyp to turn into a cancerous polyp that may cause symptoms. When symptoms appear, they may include:

• Abdominal (belly) pain
• Bloated stomach
• Blood on or in your stool (poop)
• Constipation or diarrhea
• Feeling like there’s still poop in your bowel even after you go to the bathroom
• Feeling tired or weak
• Unexplained weight loss

Common conditions, like stomach flu or food poisoning, can make your gut hurt and cause constipation and diarrhea. Having them doesn’t mean you have colon cancer. But talk to a healthcare provider if these issues last for more than a few days. And don’t hesitate to talk to a provider if you spot blood in your stool, lose weight without trying or feel tired, no matter how much rest you get.

Colorectal cancer causes

Colon cancer happens when genetic mutations turn healthy colon cells into cancerous cells. The cancerous cells divide and multiply to make cancerous colon polyps. Over time, cancer grows through the layers of muscle and tissue that make up your colon wall. Eventually, the cancer breaks through your colon wall and begins to spread outside your colon.

Medical researchers aren’t sure what triggers the change in colon polyps. Research shows certain factors increase your risk. Examples of risk factors include:

• Being age 50 or older: Most people with colon cancer are older than 50. But there’s an increasing number of cases in people younger than 50. Medical researchers aren’t sure what drives this change.
• Having a family history of colon cancer: Your risk may be higher if close biological family members have large colon polyps or colorectal cancer. Close family members include your biological parents, siblings and children. Your risk may be higher if any biological family member develops this disease before they turn 45.
• Having many colon polyps: In general, the more polyps in your colon, the greater the chance that one or more may become cancerous.
• Inheriting certain conditions: Conditions like Lynch syndrome and familial adenomatous polyposis may lead to colon cancer.
• Having obesity or overweight: Research shows having a BMI higher than 25 plays a role in this disease.
• Smoking cigarettes: One study found that smoking cigarettes increases colon cancer risk.
• Regularly drinking alcohol: Even light to moderate consumption may increase your risk.

How doctors diagnose colorectal cancer

A healthcare provider will ask about symptoms, like what they feel like and when you first notice them. They may feel your belly for masses or organs that are larger than normal, or do a digital rectal exam.

Tests include:

• Blood tests: You may have blood tests, including a complete blood count (CBC), complete metabolic panel (CMP) or CEA assay.
• Imaging tests: Examples include computed tomography (CT) scans, magnetic resonance imaging (MRI), positron emission tomography (PET) scans abdominal ultrasounds.
• Diagnostic colonoscopy: A gastroenterologist may do a diagnostic colonoscopy if you have symptoms or other tests detect cancer. They may remove a small piece of tissue from your colon during the colonoscopy. A medical pathologist will examine the tissue under a microscope.

These tests do more than diagnose colon cancer. Test information will help your cancer care team set a cancer stage. Cancer staging involves factors like where you have a cancerous colon polyp, if cancer is in your lymph nodes or has spread from your colon to other organs.

There are four colon cancer stages.

How is colon cancer treated?

Surgery is the most common treatment for colon cancer that hasn’t spread. The different procedures include:

• Polypectomy: This procedure removes precancerous or cancerous polyps in your colon.
• Colectomy: A surgeon removes cancerous sections of your colon.

You may have additional treatment before or after your surgery, including chemotherapy, radiation therapy and targeted therapy.

When should I seek care?

Talk to a healthcare provider if you have belly pain that doesn’t go away or see blood in the toilet or on toilet paper after you poop. Many things may cause these symptoms, including colon cancer. That’s why your provider may do tests to find out what’s going on in your digestive system.

If tests detect colon cancer, you may want to ask your provider questions, including:

• What’s the cancer stage?
• Will treatment get rid of the cancer?
• Is there a chance that cancer will come back?

What are the survival rates?

Colon cancer survival rates estimate the percentage of people who are alive five years after diagnosis. The National Cancer Institute (U.S.) tracks colorectal cancer survival rates based on the cancer location at diagnosis:

• Localized cancer: 91%. Localized cancer only affects your colon.
• Regional cancer: 73%. Regional colon cancer is cancer in nearby organs or lymph nodes.
• Distant: 13%. This is cancer that’s spread from your colon to your liver, lungs or other areas of your body further from your colon.

Cancer survival rate information can be confusing. It’s important to remember that these rates are estimates. They reflect the experiences of many other people who have colon cancer. Your experience may be different. Your cancer care team knows survival rate data may make you anxious or worried about the future. They’ll take time to explain what a survival rate means in your case.

What is the life expectancy for someone with colorectal cancer?

Research shows that in general, having colon cancer can reduce lifespan by about 10 years. How long you’ll live after your treatment depends on factors like your age, the cancer stage at diagnosis, your treatment and your health.

Can colon cancer be prevented?

You may not be able to prevent cancer, but you can reduce your risk of developing the condition by:

• Eating well: Make the most of meal plans that use lean protein, vegetables and whole grains.
• Stopping smoking: There are many ways to stop smoking. Your healthcare provider may have some suggestions.
• Avoiding alcohol: Even having one to two drinks a day may increase your risk.
• Maintaining a weight that’s right for you: Body mass index is one way to calculate a weight goal. Ask your provider for other examples.
• Considering cancer screening: The U.S. Preventive Services Taskforce recommends that most people who have a family history of colon cancer or polyps should have regular screenings starting at age 45, or earlier.