Skip to main content

What is anal cancer?

Anal cancer forms in the anus, the opening to the rectum that controls the elimination of feces during bowel movements. Two sphincter muscles open and close the anus. Anal cancer develops in a section of the digestive system that doctors can easily see and reach—making it more likely that the disease is found early and responds well to treatment. 

There are several types of malignant (cancerous) anal tumors:

  • Squamous cell carcinoma—Begins in cells that line most of the anus and is the most common type of anal cancer
  • Adenocarcinoma—A more rare type of anal cancer that forms in mucous-producing glands and is treated like a rectal cancer
  • Basal cell carcinoma—A type of skin cancer that can develop in skin surrounding the anus
  • Melanoma—A skin cancer that begins in pigment-producing cells in the anal lining

Other tumors and abnormal anal growths like warts and polyps are benign (noncancerous). Some of these could eventually lead to cancer and might require removal. There are several terms for this precancerous condition:

  • Dysplasia
  • Anal intraepithelial neoplasia (AIN)
  • Squamous intraepithelial lesions (SILs)
  • Carcinoma in situ
  • Bowen's disease

Our approach

At Northwell Health Cancer Institute, you gain the advantage of an integrated, multidisciplinary team specialized in treating anal cancer, as well as access to leading-edge therapies and world-class facilities to provide every level of support and care.

Your dedicated team works to achieve the best possible outcome, collaborating with specialists to carefully coordinate your cancer treatment along with any other existing conditions.

Research at Northwell

Through collaboration with leading research laboratories, you may have the opportunity to participate in clinical trials as part of your treatment for anal cancer. While not every patient is a candidate for clinical trials, your care team will work with you to determine eligibility. Learn more about clinical trials at Northwell Health.


Sometimes anal cancer does not cause noticeable problems. However, it may cause one or more of these symptoms in the anus:

  • Bleeding
  • Pain or pressure
  • Itching
  • Unusual discharge
  • Lumps or swelling
  • Change in bowel habits or size of stool

Just because you have these symptoms doesn’t necessarily mean you have cancer. A doctor should always be seen to best diagnose symptoms.


While the causes of anal cancer are not yet known, researchers believe there is a strong link to infection from some strains of human papillomavirus (HPV), a virus that is usually sexually transmitted and has also been associated with cervical cancer and some forms of head and neck cancer.

Risk factors

Researchers have identified other risk factors for anal cancer. Risk increases if you are:

  • Over 50
  • Have had many sexual partners and more possible exposure to HPV
  • Frequently receive anal sex
  • Regularly experience anal redness, swelling or soreness
  • Have anal glands that have become infected and then exposed (anal fistulas)
  • A smoker
  • Have lowered immunity from conditions like HIV or from taking medications to suppress the immune system


If anal cancer seems like a possibility, your physician will take all the steps necessary to ensure an accurate diagnosis. Tests could include: 

  • Physical exam – The doctor feels for lumps and other signs of disease
  • Digital rectal examination (DRE) – The doctor or nurse uses a lubricated, gloved finger to feel the rectum for signs of disease 
  • Anoscopy – A doctor uses a lighted tube called an anoscope to look at the anus and lower rectum
  • Proctoscopy – A doctor uses a lighted tube called a proctoscope to look at the rectum
  • Ultrasound – A doctor inserts a probe into the anus or rectum, creating an image by bouncing sound waves off tissues and organs
  • Biopsy – Cells or tissue are removed and examined under a microscope
  • CT (CAT) scan – X-rays are overlapped from different angles, with dye sometimes injected into veins or swallowed to see delicate, tiny structures
  • PET scan (positron emission tomography) – Radioactive, traceable glucose (sugar) is injected into the veins so a rotating scanner can look for malignant cells throughout the body
  • MRI (Magnetic Resonance Imaging) – A magnet, radio waves and a computer take detailed pictures of the inside of the body

Treatment types

A multidisciplinary team of doctors will work together to create your anal cancer treatment plan, which will likely combine a variety of treatments. Your cancer care team will also include physician assistants, oncology nurses, social workers, pharmacists, counselors, dietitians and others.

Your treatment plan with be based on a variety of factors, including the type and stage of your tumor, side effects, your overall health and personal preferences. Treatment options include:

  • Surgery – Surgical removal of the tumor and some surrounding healthy tissue may be needed to treat anal cancer. The type of surgery you will need will depend on the stage of your cancer. 
  • Chemotherapy and radiation therapy – Patients with anal cancer, who once were treated surgically, are now treated with chemotherapy and radiation therapy. Cure rates between surgical treatment and this combination therapy are comparable. You may be able to avoid surgery with this treatment.
What can we help you find?
Go to top