Anal Cancer

Anal cancer is a type of cancer that develops in the tissues of the anus or anal canal. The anus is the opening at the end of the digestive tract, and the anal canal is the short passage connecting the rectum to the outside of the body.

Cancer occurs when cells grow and divide uncontrollably. Over time, these abnormal cells can form a tumor, invade nearby tissues, and in some cases spread to other parts of the body.

Most anal cancers begin in squamous cells, which are the thin, flat cells that line the anal canal and the area around the anal opening. These cancers are called squamous cell carcinomas.

Some people develop precancerous cell changes before cancer forms. These changes may be called high-grade dysplasia, carcinoma in situ, or Bowen's disease. While these conditions are not invasive cancer, they may increase the risk of developing anal cancer. If you are concerned about your risk for anal cancer, request an appointment with our colorectal specialists.

What are the symptoms of anal cancer?

Anal cancer often causes symptoms, although some people may have no symptoms in the early stages.

Common symptoms include:

• Rectal or anal bleeding
• A lump or mass near the anus
• Pain or pressure in the anal area
• Persistent itching around the anus
• Changes in bowel habits
• Increased straining during bowel movements
• Narrower stools
• Mucus or discharge from the anus
• Swollen lymph nodes in the groin or anal region

Many of these symptoms can also be caused by noncancerous conditions such as hemorrhoids. However, any persistent or concerning symptoms should be evaluated by a healthcare professional.How Common Is Anal Cancer?

Anal cancer is considered a relatively uncommon cancer. It accounts for a small percentage of cancers affecting the digestive tract.

Although anal cancer is rare compared with colorectal cancer, the number of diagnosed cases has increased over time. The disease can affect both men and women and is often highly treatable when detected early.

What causes anal cancer?

Most cases of anal cancer are linked to persistent infection with certain types of human papillomavirus (HPV). HPV is a common virus that can be spread through intimate skin-to-skin contact.

While many people are exposed to HPV during their lifetime, most infections clear on their own. In some individuals, however, persistent HPV infection can lead to cellular changes that may increase the risk of anal cancer.

Not everyone with HPV develops cancer, and not all anal cancers are caused by HPV.

Who is at risk for anal cancer?

A risk factor is anything that may increase a person's likelihood of developing a disease. Having one or more risk factors does not mean that you will develop anal cancer. Factors that may increase risk include:

• Persistent HPV infection
• Age over 50
• Smoking or tobacco use
• A weakened immune system, including people living with HIV or those taking immunosuppressive medications after organ transplantation
• A history of anal warts or HPV-related disease
• Chronic inflammation or long-standing anal fistulas
• Previous radiation therapy to the pelvic area
• Multiple sexual partners or other factors that increase HPV exposure

If you have concerns about your risk, make an appointment to talk with one of our experienced clinicians.

Can anal cancer be prevented?

There is no guaranteed way to prevent anal cancer, but several steps may help reduce risk:

• Get vaccinated against HPV if recommended by your healthcare provider.
• Avoid tobacco products.
• Practice safer sex to reduce the risk of HPV and other sexually transmitted infections.
• Attend recommended medical screenings and routine healthcare visits.
• Discuss anal cancer screening with your healthcare provider if you have risk factors.

Screenings for anal cancer

For some people at higher risk, screening may include:

Anal Pap test

An anal Pap test collects cells from the anal canal using a small swab. The cells are examined for abnormal changes that may require further evaluation.

Anoscopy

Anoscopy allows a healthcare provider to examine the lining of the anal canal using a specialized instrument. If abnormal tissue is identified, additional testing or a biopsy may be recommended.

People who may benefit from discussing screening with their healthcare provider include:

• Individuals living with HIV
• Men who have sex with men
• People with a history of HPV-related disease
• Individuals with a weakened immune system
• People with multiple risk factors for HPV exposure

How is anal cancer diagnosed?

Diagnosis typically begins with a medical history and physical examination.

If an abnormal area is identified or symptoms raise concern, your healthcare provider may recommend:

• Anoscopy
• Imaging studies
• A biopsy, in which a small tissue sample is removed and examined under a microscope

A biopsy is the only way to confirm a diagnosis of anal cancer.

Once cancer is diagnosed, additional testing may be recommended to determine whether it has spread and to help guide treatment planning. 

How is anal cancer treated?

Treatment depends on the size, location, and stage of the cancer, as well as your overall health.

Common treatment options include:

Radiation therapy

Radiation therapy uses high-energy beams to destroy cancer cells.

Chemotherapy

Chemotherapy uses medications to kill cancer cells or prevent them from growing.

Surgery

Surgery may be used to remove certain early-stage tumors or cancers that persist after other treatments.

For many patients, treatment involves a combination of chemotherapy and radiation therapy. Your care team will recommend a treatment plan based on your individual situation.

Will I need a colostomy?

Most people treated for anal cancer do not need a colostomy.

In some cases, surgery may be recommended if the cancer does not respond completely to treatment, returns after treatment, or has characteristics that make surgery the best option.

When removal of the anus and rectum is necessary, a colostomy may be created to allow waste to leave the body through an opening in the abdomen. This procedure is called an abdominoperineal resection (APR).

Your surgeon will discuss all treatment options and potential outcomes before surgery.

What happens after treatment?

Follow-up care is an important part of recovery and long-term health.

Regular follow-up visits allow your healthcare team to:

• Monitor your response to treatment
• Look for signs of recurrence
• Manage side effects
• Address any new symptoms or concerns

The frequency and type of follow-up testing will depend on your individual situation.

Be sure to report any new or worsening symptoms to your healthcare provider promptly.

Outlook for people with anal cancer

Many people with anal cancer respond well to treatment, especially when the disease is diagnosed at an early stage.

Treatment outcomes vary from person to person and depend on factors such as the stage of the cancer, overall health, and response to therapy.

Early evaluation of symptoms and timely treatment can help improve outcomes.