Colon cancer and rectal cancer sometimes are grouped together and called colorectal cancer. Not counting skin cancers, colorectal cancers are the third most common type of cancer in the United States. More than 106,000 people in this country are diagnosed with colon cancer each year, according to the American Cancer Society.
One in 19 people, or a little more than 5%, of Americans will develop colon or rectal cancer in their lifetimes. When colon cancer is diagnosed early, it has nearly a 90% chance for cure.
The colon is part of the digestive system, also called the gastrointestinal (GI) tract.
- The colon is the first six feet of the large intestine, also called the large bowel
- The rectum is the last six inches of the large intestine, which ends in the anus
Colorectal cancers grow slowly. They usually start as polyps, which are overgrowths of tissue in the lining of the colon. Colon cancer may start within a polyp, but not all polyps contain cancer.
The survival rate for colon cancers has been increasing for the past 15 years. Because of screening, polyps often are found and removed before they become cancer. Also, treatments have become more advanced and less invasive.
Colon Cancer Types
More than 95% of colorectal cancers are adenocarcinomas. Approximately 90% of colorectal adenocarcinomas began as adenomas, which are a type of polyp that may become cancer.
About 20% of colon cancers are inherited or are associated with a strong history of colon cancer in the family. The main types of colon cancer that are inherited include:
Hereditary nonpolyposis colorectal cancer syndrome or HNPCC (also called Lynch syndrome), accounts for 5% to 7% of colon cancers.
Familial adenomatous polyposis (FAP) causes hundreds to thousands of polyps in the GI tract. FAP may begin during childhood.
Colon Cancer Risk Factors
Anything that increases your chance of getting colon cancer is a risk factor. Colon cancer risk factors include:
- Family history of colorectal cancer or polyps
- Hereditary cancer syndromes such as hereditary nonpolyposis colorectal cancer (HNPCC or Lynch) syndrome or familial adenomatous polyposis (FAP)
- Inflammatory bowel disease (Crohn’s disease or chronic ulcerative colitis)
- Colorectal cancer or polyps
- Lack of exercise
- Diet: If you eat a lot of red meat, processed meats or meats cooked at very high heat, you may be at higher risk for colon cancer
- Diabetes Type 2
- Cigarette smoking
- Drinking too much alcohol
For patients concerned about inherited family syndromes that cause colon cancer, we offer advanced genetic testing to let you know your risk.
Colon Cancer Prevention
Certain lifestyle choices may decrease your chances of getting colon cancer. Try to:
- Have regular screening tests
- Stay at a healthy weight
- Exercise regularly
- Eat a healthy diet with lots of fruits and vegetables
- Avoid cigarettes
- Drink alcohol only in moderation
Visit our prevention and screening section to learn how to manage your colon cancer risk.