What is Anal Cancer?

What is Anal Cancer?

Anal cancer occurs when cancer cells form in the tissues of the anus, the end of the rectum, where stool leaves the body. Anal cancer is different from rectal cancer (cancer in the rectum) and colorectal cancer (cancer in the colon or rectum).

Although its incidence is rising, anal cancer is considered a rare and less common type of cancer than other gastrointestinal cancers. The average age for anal cancer diagnosis is 55-64 years old, and it is more commonly diagnosed in women than in men.

What is anal dysplasia?

Anal warts, called condyloma acuminata or HPV anal warts, are tiny pin-sized growths or spots on the skin that develop in and around the anus. These warts may also extend into the genital area. Caused by a sexually transmitted disease called HPV, or human papillomavirus, anal wart symptoms may include itching, mucus, bleeding, or noticeable lumps in the anus area. Your physician may remove the warts to test them for abnormalities. If they find precancerous cells within the warts, it is called anal dysplasia.

Anal dysplasia is not anal cancer. It means there are precancerous or cancerous cells within the warts, but these cells have not traveled deeper into your skin. If you are diagnosed with anal dysplasia, your physician will closely monitor your condition and test for any new growth. Anal dysplasia is treated with topical medications, surgical removal, or wart freezing. Regular visits are necessary because the condition often returns.

Your physician may recommend check-ups every three to six months to monitor for recurrent anal dysplasia and any signs of early-stage anorectal cancer. If warts with abnormal cells are left untreated, they may develop into anal cancer.

Signs & Symptoms of Anal Cancer


There are several signs and symptoms of anal cancer, although some people may experience little to no symptoms. Some of the most common anal cancer symptoms include:

  • Abnormal anal discharge
  • Bleeding from the rectum
  • Itchiness in the affected area
  • Fullness or discomfort near the anus
  • Growths or lumps near the anus

Certain conditions, such as anal fissures, hemorrhoids, and anal warts, may also cause these symptoms. It is important to see your healthcare provider if you are experiencing any possible signs of anal cancer to receive a proper diagnosis.

What Causes Anal Cancer?


Anal cancer is a digestive system cancer that forms when a genetic mutation turns healthy cells into abnormal cells. These abnormal cells, found in the tissues that form the skin, are called squamous cells or squamous cell carcinoma. When the cells continue to multiply and do not die, they may form a mass or tumor. Cancer cells invade nearby tissue and separate from the initial tumor, and cancer may spread further into the body.

Anal cancer is closely related to a sexually transmitted infection called human papillomavirus (HPV), a virus detected in most anal cancers. Long-term infection with HPV is the most common cause of anal cancer.

Risk Factors for Anal Cancer

Risk Factors

According to the American Cancer Society, the lifetime risk for getting anal cancer is low at 1 in 500 people. There are several risk factors for anal cancer, and doctors may recommend those at higher risk have routine screenings. Anal cancer risk factors include:

  • HPV, Human Papillomavirus, which is the cause of 90 percent of all anal cancers
  • Personal history of cervical, vulvar, vaginal, or penile precancer or cancer
  • Multiple sexual partners increase your HPV risk
  • Anal sex, a history of anal intercourse, or sexually transmitted infection 
  • Smoking or drug use, compromises your overall health and immunity to disease
  • Immunodeficiency, from HIV, AIDS, or other causes such as kidney or heart transplant



Anal cancer may develop in some people with no known risk factors and may not be preventable. There are ways to reduce your anal cancer risk, by practicing safe sex, and other measures, such as:

  • Anal cancer screenings and regular exams for those who regularly have anal sex or have HPV 
  • Condom use to reduce the transmission of HPV and other sexually transmitted diseases
  • Getting the HPV vaccine, which is recommended for women, from adolescence through age 26, and men up to age 21
  • Regular treatment for HIV
  • Smoking cessation to reduce your cancer risk
Get Care

Trust NewYork-Presbyterian for Anal Cancer Care

NewYork-Presbyterian offers the latest treatments, therapies, and state-of-the-art care for anal cancer. Our medical oncologists, radiation oncologist, and cancer care teams provide a multidisciplinary approach to anal cancer that treats the whole body and mind.