Colon cancer

Colon cancer affects the large intestine, which includes the colon and rectum. At Atrium Health Floyd and Harbin Clinic, our cancer doctors provide advanced treatments for all types and stages of colon cancer.

What is colon cancer (colorectal cancer)?

Colon cancer (also called colorectal cancer) can occur in any part of your colon or rectum, which make up the large intestine. The large intestine is part of your digestive system.

The colon is a long tube that absorbs water and nutrients from digested food after it leaves your small intestine. It’s the first and longest section of the large intestine. Your colon changes digested food into poop (stool), which then travels to your rectum.

The rectum is the lowest part of the large intestine. Your rectum stores stool until it passes through your anus and out of your body.

Causes of colon cancer

Colorectal cancer occurs when cells in the lining of the colon or rectum change and grow uncontrollably. These cancer cells can clump together into polyps. Colon polyps are common, and most are not cancerous (benign). But some polyps become cancerous (malignant).

Some people inherit gene changes (mutations) that cause colorectal cancer. But in most cases, the cause of colon cancer is unknown.

Colon cancer symptoms

Colon cancer doesn’t always cause symptoms, especially during the early stage. Common signs of colon cancer may include:

• Bloated stomach or abdominal pain
• Blood in stool
• Bowel movement changes, such as chronic constipation or diarrhea
• Extreme fatigue
• Narrow or unusual-looking stool
• Unintentional weight loss

Colon cancer diagnosis

Gastroenterologists are doctors who specialize in digestive diseases like colon cancer. Your gastroenterologist will perform a procedure called a colonoscopy, in which they use a scope to find and remove polyps from your colon. They will send removed polyps to a lab to test them for signs of cancer (biopsy).

Other tests that help detect colon cancer include:

• Fecal tests to check for blood in stool
• Genetic testing (blood test) to check for gene changes and inherited conditions that cause colorectal cancer
• Imaging tests, such as CT scan, MRI and positron emission test (PET) scan, to see if cancer has spread outside the colon or rectum
• Sigmoidoscopy to examine the rectum and anus

Colon cancer staging

After a colon cancer diagnosis, doctors determine whether the cancer has spread outside the colon or rectum. This process, called cancer staging, describes the severity of the cancer and informs the best treatment approach.

There are several stages of colorectal cancer. Stages 2 through 4 have distinct substages. The main stages of colorectal cancer include:

• Stage 0: There are abnormal or precancerous cells in the inner layer (mucosa) of the colon or rectum wall. This stage is also called carcinoma in situ or intramucosal carcinoma.
• Stage 1: Cancer has spread into the intestine wall but not to lymph nodes or other organs.
• Stage 2: Cancer has spread into the outer layers or through the wall of the colon or rectum. It hasn’t spread to nearby lymph nodes or other organs.
• Stage 3: Cancer has spread to nearby lymph nodes or fatty areas near the lymph nodes. It hasn’t spread to other organs.
• Stage 4: Cancer has spread to the liver, the lungs, the lining of the abdominal cavity (peritoneum) or other organs.

Colon cancer risk factors

Anyone can develop colon cancer. But certain factors can increase your risk, including:

• Addiction to alcohol or tobacco
• Diet high in red meat or processed meat
• Excess weight or obesity
• History of abnormal colon polyps (colorectal adenomas)
• Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease
• Inherited genetic conditions, such as Lynch syndrome and familial adenomatous polyposis
• Native American, Native Alaskan, Ashkenazi Jewish or African ancestry
• Parent, sibling or child with colon cancer
• Radiation therapy to the abdomen or pelvis
• Type 2 diabetes

Colon cancer prevention

A colonoscopy to remove noncancerous polyps before they become cancerous is the best way to prevent colon cancer. The American Cancer Society (ACS) recommends a first screening at age 45 for people at average risk of colon cancer. Your health care provider may recommend getting a colonoscopy sooner if you have certain risk factors.

Other actions that may help lower your chances of developing colon cancer include:

• Being physically active and maintaining a healthy weight
• Eating more fresh fruits, vegetables and whole grains, and cutting back on red or processed meats
• Limiting alcohol to one drink per day for females or two drinks per day for males
• Seeking help to quit cigarettes and other forms of tobacco

Colon cancer treatments

Colon cancer treatment options depend on the cancer stage, your overall health and your preferences. Surgery to remove cancerous tumors is a common treatment.

Other colorectal cancer treatments include:

• Chemotherapy and/or radiation therapy to destroy cancer cells
• Immunotherapy to help your immune system find and destroy cancer cells
• Targeted therapy to target certain proteins that spur the growth of cancer cells