Colon cancer forms in the colon, also known as the large intestine. The colon is the last part of our digestive system. Colon cancer is one of the most common cancers. It usually begins with small clumps of cells called polyps. When caught early, treatment can be very effective.

The National Cancer Institute recognizes the OHSU Knight Cancer Institute as one of the best places in the nation to receive cancer care. At the Knight, you will get:

• World-class experts in cancers of the digestive system
• A team approach, with specialists working together to care for you
• Treatments you can’t find anywhere else in the region
• Nurses to guide you through treatment
• Social workers, dietitians and other cancer experts to support you
• Hundreds of clinical trials

Quick links

• Colon cancer signs and symptoms
• Colon cancer stages
• Colon cancer screening
• Colon cancer diagnosis
• Colon cancer treatment
• Colon cancer team
• Rectal cancer

What makes us different

• Highly trained teams: Our doctors have advanced training in areas such as colon surgery. They can treat the most complex cases. 
• Working together: We are the only program in Oregon with specialists who meet weekly to develop treatment recommendations patient by patient.
• Innovation: The Knight is a leader in radiation therapy to target cancer while avoiding healthy tissue. If your cancer has spread, you might benefit from HIPEC surgery, which combines chemotherapy with surgery.
• National excellence: The Knight has the nation’s highest cancer care designation. We are also research leaders. Our Cancer Early Detection Advanced Research Center, or CEDAR, focuses on finding cancer early.

Colon cancer happens when cells inside the colon grow out of control, forming abnormal growths called polyps. Polyps aren't cancer but can turn into cancer if left untreated. 

Colon cancer is sometimes called colorectal cancer, combining colon and rectal cancer. The colon is a tube about 5 feet long, and the rectum is about 6 inches long. Together, they make up the large intestine. 

Colon cancer is America’s fourth most common major cancer. About 96% of colon cancers are adenocarcinomas, or cancers that grow in gland cells lining the colon.

Who gets colon cancer?

About 100,000 cases of colon cancer a year are diagnosed in the United States. Most cases are found in people over 50, although younger people are increasingly at risk. It is more common in men.

Learn more about colon cancer risk factors. 

Colon cancer survival rates

Researchers gather data from across the U.S. to calculate the portion of people who live at least five years after diagnosis compared with the general population. This is called the relative survival rate. It excludes the risk of dying from something else.

The numbers are averages and cannot predict the outcome for one person. They are also, by definition, based on treatments available five or more years ago. Researchers at the Knight are always improving how we treat cancer.  

The National Cancer Institute reports rates for colorectal cancer (colon and rectal cancer combined):

• For people whose colorectal cancer is found before it spreads, 91% live at least five years after diagnosis.
• About 35% of patients are diagnosed before the cancer has spread.
• For all patients, the five-year relative survival rate is 65%.

Clinical trials and research

Clinical trials are research studies that test new tests or treatments on humans. Sometimes trials test new drugs. Trials can also test existing drugs in new combinations.

• The Knight is a leader in clinical trials, offering early access to promising new treatments. We have research partners across the country and around the world, connecting you to the latest advances.
• Our translational oncology teams work to quickly turn lab discoveries into treatments.
• The Knight Cancer Research Building is designed to encourage scientists to work together.
• Patients can join our colorectal cancer registry to help research and receive updates. 

Learn more

• Colorectal Cancer, National Cancer Institute
• Colorectal Cancer, American Cancer Society
• Basic Facts About Colorectal Cancer, American Society of Colon and Rectal Surgeons
• Colorectal Cancer Alliance, a nonprofit that manages a private Facebook support group
• Colon Cancer Coalition, a nonprofit that promotes screening and prevention
• Fight Colorectal Cancer, a nonprofit supporting policy changes, patients and research
• The Colon Club, an organization dedicated to colorectal cancer screening