Anal cancer

What is anal cancer?

Anal cancer is a form of cancer that occurs in the anus—the area where stool leaves your body when you go to the bathroom.

What causes anal cancer?

Human papillomavirus virus (HVP) is considered the most common cause of anal cancer and is commonly found in those with anal cancer.

Who’s at risk?

Certain environmental and lifestyle factors can increase your risk of getting anal cancer. Anal cancer is more common in smokers and people over the age of 50. Having anal sex, and multiple sexual partners increases your risk of developing anal cancer as it increases your risk of getting HPV. Those who have had vulvar, vaginal, or cervical cancer may be at greater risk as well.

What can you do to prevent anal cancer?

  • Reduce your risk of getting a sexually transmitted disease by using condoms.
  • Don’t smoke.
  • Get the HPV vaccination.

Stages of anal cancer

Anal cancer is classified by four different stages. The stage is determined by the size of cancer and how far it has spread.

  • Stage I and II: This classifies cancer that has grown into the anal wall.
  • Stage III: If anal cancer has spread to the lymph nodes it is considered to be stage III.
  • Stage IV: This defines anal cancer that has spread to distant parts of the body, such as the lungs or liver.

Early detection of anal cancer generally offers the best chances of complete recovery.

All stages of anal cancer are treated with chemotherapy and radiation. If this is not effective, treatment may include surgery.


Anal cancer is rare, and many of the signs or symptoms of anal cancer are identical to symptoms of other non-cancerous conditions that affect the anus.

Possible signs of anal cancer:

  • Pain or fullness in the anal area
  • Rectal bleeding
  • Rectal itching
  • Abnormal rectal discharge
  • Lumps in the anal opening
  • Swollen lymph nodes in the anal area
  • Changes in bowel movements, such as narrow stools

When to see a provider

If you are experiencing symptoms of anal cancer, especially rectal bleeding, rectal pain, fullness or lumps in the area, or changes in bowel movements, visit your doctor for a check-up.


Your doctor will perform a series of exams to determine if you have anal cancer. Depending on your symptoms, they may first perform a digital rectal exam. Digital rectal exams check the anal area for lumps, changes, and abnormalities. If an abnormality is found, your doctor can recommend additional exams and/or a specialist to continue tests, and treatment. Additional exams are required to confirm a diagnosis.

Tests that can confirm anal cancer include

  1. Anal biopsy - After taking a sample of cells from the affected area, the sample can be screened for cancer.
  2. Imaging tests - X-rays can help doctors find cancer. Additionally, they can help doctors see if it has spread or determine if treatment is working.


A treatment plan for anal cancer will depend on how serious the cancer is. Factors that determine severity are whether or not it has spread, whether or not it is reoccurring, or whether or not the patient has HIV. Typical treatment options for anal cancer include surgery, radiation therapy, and chemotherapy.

Last reviewed: 
July 2018

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