What is the difference between colon cancer and rectal cancer?

The colon and rectum are both part of the large intestine, which is sometimes called the bowel. Cancers of both organs are often grouped together as colorectal cancer.

• The colon is the first five feet of the large intestine. It absorbs water from stool. Surgery is generally simpler for colon cancer, which is in a large area of the body.
• The rectum is the last six inches of the large intestine. It is where the body stores stool until you have a bowel movement. The rectum is a tighter space and close to the bladder, as well as the vagina for women and the prostate for men. That may affect the kind of treatment that doctors can do.

Learn more about rectal cancer.

Types of Colon Cancer

Most people who are diagnosed with colon cancer have a type called adenocarcinoma. There are other rarer tumor types too. These other types of colon cancer may be treated differently than adenocarcinoma. The section of this guide on the diagnosis and treatment of colon cancer refers primarily to adenocarcinoma.

Learn more about the types of colon cancer below.

Adenocarcinoma

The vast majority of colon cancer is adenocarcinoma. This is a cancer of the cells that line the inside surface of the colon.

Carcinoid Tumors

Carcinoid tumors start in hormone-producing cells in the intestines.

Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors can be a type of soft tissue sarcoma that can be found anywhere in the gastrointestinal tract but is rare in the colon. These tumors can also be other types of sarcoma that start in the blood vessels or connective tissue of the colon.

Lymphoma

Lymphoma is a cancer of the immune system. It more commonly starts in the lymph nodes but can start in the colon.

Hereditary Colon Cancer

About 5 to 10 percent of people get colorectal cancer because of specific mutations in the genes that are passed from parents to children, which are referred to as hereditary. MSK’s colon cancer experts may offer you genetic testing to see if you have hereditary mutations in your genes that can increase your cancer risk. Whether you should have this testing is based on an assessment of your personal risk. Learn more about genetic testing for colon cancer and the types of hereditary conditions that often lead to the disease.