What is rectal cancer?

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was reviewed on August 11, 2022.

The rectum and the colon make up the large intestine, or large bowel. The rectum is the last six inches of the large bowel and connects the colon to the anus. Cancer of the rectum and/or colon is referred to as colorectal cancer and is the fourth most common cancer in the United States. The two cancers are grouped together because they share many characteristics and are treated similarly. About one-third of the 152,810 cases of colorectal cancers diagnosed each year are found in the rectum.

Rectal cancer occurs when cells in the rectum mutate and grow out of control. The disease may also develop when growths, called polyps, on the inner wall of the rectum develop and become cancerous.

The risk of rectal cancer increases with age. The average age of a person diagnosed with colorectal cancer is 68. Men have a higher risk than women. The risk of rectal cancer may be reduced, and the disease may be prevented or caught early, with regular examinations and lifestyle changes, such as:

  • Exercising
  • Eating less red and processed meat and more fiber and vegetables
  • Quitting smoking
  • Reducing alcohol use

Learn more about colorectal cancer

Causes and risk factors for rectal cancer

The cause of rectal cancer is unknown, but the risk of developing the disease increases with age. People with a family history of colorectal cancer or certain hereditary cancer syndromes have a higher risk. Other known risk factors for rectal cancer include:

  • Diet
  • Smoking
  • Alcohol use
  • Sedentary lifestyle
  • Obesity
  • Diabetes

Learn more about the causes and risk factors for colorectal cancer

Signs and symptoms of rectal cancer

Rectal cancer may show no obvious symptoms in early stages. As the disease develops, symptoms may include changes in bowel movements, rectal bleeding and thin, ribbon-like stool. Other signs and symptoms include:

If the cancer metastasizes, or spreads to other parts of the body, symptoms may vary depending on where in the body the cancer is located. Symptoms of metastatic rectal cancer may include:

  • Persistent cough
  • Fatigue
  • Bone pain
  • Shortness of breath
  • Loss of appetite
  • Jaundice
  • Swelling in the hands and feet
  • Changes in vision or speech

Learn more about colorectal cancer symptoms

Types of rectal cancer

Rectal adenocarcinoma: Most rectal cancers—about 95 percent—are adenocarcinoma. These tumors typically start as a polyp, or a growth in the lining of the rectum. Polyps may be removed during a colonoscopy.

Other types of rectal cancer include:

Learn more about colorectal cancer types

Diagnosing and staging rectal cancer

A variety of laboratory and imaging tests may be used to diagnose cancer of the rectum and determine the stage of the disease. Commonly used procedures and tools include:

These tests may also be used to monitor your response to treatment.

Learn more about colorectal cancer stages, which includes bowel, rectal and colon cancer and diagnostic procedures

Rectal cancer treatments

Treatment for rectal cancer often depends on the stage of the disease and the extent to which it has developed. Treatment options include:

If cancer of the rectum is found early, active surveillance may be an option for some patients. During active surveillance, a doctor closely monitors the patient to look for signs that the cancer is growing. Patients may undergo several tests during active surveillance, including a digital rectal examination, MRI and/or colonoscopy.

Learn more about treatment options for colorectal cancer

Supportive care for rectal cancer

Rectal cancer symptoms and the side effects of treatment may impact your quality of life. At City of Hope, our team of cancer care experts not only focus on treating the disease with a wide range of technologies and tools, but we also provide supportive care services to help manage your side effects. For rectal cancer patients, these services may include:

Learn more about supportive care

Get expert advice and care

Understanding when symptoms are a sign of something serious and either diagnosing the disease or confirming a previous diagnosis require expertise from professionals trained and experienced in treating rectal cancer. At City of Hope, our rectal cancer experts treat all stages and types of the disease.

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