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About Anal Cancer

Anal cancer is a disease in which cancerous cells form in the anus, the last part of the large intestine.

The most common type of anal cancer is squamous cell carcinoma, which begins in flat cells that line the anal canal.

Signs & Symptoms

These are signs and symptoms of anal cancer:

  • A lump near the anus
  • Bleeding from the anus or rectum
  • Pain or pressure around the anus
  • Itching or discharge from the anus
  • A change in bowel habits

Many other health problems can also cause these signs. If you have any of these signs, see your doctor as soon as possible.

Learn more about anal cancer from the National Cancer Institute.

Image of the Lower Digestive System

Anatomy of the lower digestive system, showing the colon and other organs.
Anatomy of the lower digestive system, showing the colon and other organs.

Specialties & Treatments

The treatment or combination of treatments each patient has depends on the stage of the cancer, recommendations of the care team, and the patient’s wishes. These are the most common types of treatment for anal cancer:

  • Surgery
  • Radiation therapy
  • Chemotherapy

Huntsman Cancer Institute’s Gastrointestinal (GI) Cancers Program provides comprehensive, compassionate, state-of-the-art care for cancers of the digestive system. Our experts treat and diagnose all types of GI cancers and conditions.

Learn more about types of cancer treatments and cancer screenings.

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Causes & Risk Factors

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean you are sure to get cancer. It means your chances are higher than the average person’s. Talk with your doctor to learn more about your cancer risk.

These are risk factors for anal cancer:

  • Infection with human papillomavirus (HPV)
  • Having many sexual partners
  • Having receptive anal sex
  • Being older than 50 years
  • Frequent anal redness, swelling, and soreness
  • Having anal fistulas
  • Smoking

Learn more about ways to prevent cancer and about HPV.

Diagnosis & Stages

Diagnosis of Anal Cancer

These tests are used to diagnose anal cancer:

  • Physical exam and history: A health care provider examines your body for signs of disease. Your personal health habits, past illnesses, and symptoms help guide the exam.
  • Digital rectal examination (DRE): As part of the physical exam, the health care provider may examine the anus and rectum with a gloved finger.
  • Scopes: A short, lighted scope allows the health care provider to look inside the anus and rectum.
  • Biopsy: The health care provider removes cell or tissue samples so they can be viewed under a microscope to check for signs of cancer.
  • Ultrasound: Ultrasound uses high-energy sound waves to create a picture of the anus and surrounding tissues. The health care provider gently inserts an ultrasound probe into the anus and rectum.

Stages of Anal Cancer

Doctors use cancer stages to find out if cancer has spread within the anus or to other parts of the body. There are three ways that cancer spreads in the body: through tissue, the lymph system, or the blood.

These are the stages of anal cancer:

  • Stage 0: Stage 0 cancers are often called carcinoma in situ. For anal cancer, stage 0 means there are abnormal cells on the innermost lining of the anus. These abnormal cells may become cancer cells and spread.
  • Stage 1: Cancer cells have formed and the tumor is 2 centimeters or smaller.
  • Stage 2: The tumor is larger than 2 centimeters.
  • Stage 3 (3A, 3B): The cancer has spread to lymph nodes or nearby organs.
  • Stage 4: The cancer has spread to distant parts of the body such as the liver or lungs.

When cancer spreads from where it started to another part of the body, it is called metastasis. These metastatic cancer cells are the same type of cancer as the primary tumor. For example, if anal cancer spreads to the bone, the cancer cells in the bone are actually anal cancer cells. The disease is metastatic anal cancer, not bone cancer.

Learn more about the stages of anal cancer from the National Cancer Institute.

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