Rectal Cancer

Expert-reviewed information summary about the treatment of rectal cancer.Rectal Cancer (PDQ®): TreatmentRectal Cancer Treatment

General Information About Rectal Cancer

Rectal cancer is a disease in which malignant (cancer) cells form in the tissues of the rectum.

The rectum is part of the body’s digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The first 6 feet of the large intestine are called the large bowel or colon. The last 6 inches are the rectum and the anal canal. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).

Anatomy of the lower digestive system, showing the colon and other organs. | View a Larger Version



Age and family history can affect the risk of developing rectal cancer.

The following are possible risk factors for rectal cancer:


Age 50 or older.
A family history of cancer of the colon or rectum.
A personal history of cancer of the colon, rectum, ovary, endometrium, or breast.
A personal history of ulcerative colitis (ulcers in the lining of the large intestine) or Crohn disease.
Certain hereditary conditions, such as familial adenomatous polyposis and hereditary nonpolyposis colon cancer (HNPCC; Lynch syndrome).



Possible signs of rectal cancer include a change in bowel habits or blood in the stool.

These and other symptoms may be caused by rectal cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:


A change in bowel habits.
Blood (either bright red or very dark) in the stool.
Diarrhea, constipation, or feeling that the bowel does not empty completely.
Stools that are narrower than usual.
General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps).
Weight loss for no known reason.
Feeling very tired.
Vomiting.