Anal Cancer

Expert care for cancer of the anus

A smiling mature woman plays with her dog outdoors, representing the full life that can be led after anal cancer treatment.

Expert care for cancer of the anus

Scripps Cancer Center physicians and cancer specialists are experts in diagnosing, treating and helping to prevent anal cancer. U.S. News & World Report has ranked Scripps Memorial Hospital La Jolla and Scripps Green Hospital among the best in the nation for gastroenterology and gastrointestinal surgery.


Our cancer care teams combine expertise and compassion with the most advanced technologies to develop personalized treatment plans that target anal cancer while preserving healthy tissue. Our multidisciplinary, collaborative board of cancer specialists reviews the most complex care plans to ensure patients receive the best possible care from diagnosis to recovery.

About anal cancer

Anal cancer is an intestinal cancer that starts in the anus, which is the opening at the lower end of the intestines. The anus is connected to the rectum by the anal canal, which goes from the rectum to the outside skin of the anus (known as the anal verge). Most anal cancer starts in the mucosa, the inner lining of the anal canal.


According to the American Cancer Society, anal cancer is not common, but the number of new cases has been rising for many years. It usually affects older adults, with the average age at diagnosis in the early 60s. The lifetime risk of anal cancer is about 1 in 500, and women have a slightly higher risk than men. Treatment for anal cancer is often very effective, especially when it is found early.

Types of anal cancer

Several types of tumors can develop in the anus. Anal cancer types can differ depending on where they start in the anal canal. 


Potentially precancerous conditions

Some growths in the anal canal are not cancerous at the start, but can develop into cancer over time. These potentially precancerous conditions are often called dysplasia.


Dysplasia that occurs in the anus is also known as anal intraepithelial neoplasia (AIN) and anal squamous intraepithelial lesions (SILs). These are divided into two groups:


  • Low-grade AIN (AIN1 or low-grade anal SIL) is when cells look much like normal cells. Low-grade AIN often goes away on its own and has a low chance of developing into cancer.
  • High-grade AIN (AIN2 or AIN3, or high-grade anal SIL) is when cells appear abnormal. High-grade AIN is not as likely to go away without treatment and could eventually become cancer. This condition needs treatment or close monitoring.


Carcinoma in situ

Anal cancer is considered carcinoma in situ when abnormal cells on the inner lining of the anus look like cancer cells but have not grown into deeper layers. Some doctors consider this an early form of anal cancer, while others consider it to be the most advanced form of precancer.


Squamous cell carcinoma

Most cases of anal cancer in the United States are squamous cell carcinomas, which develop in the squamous cells that line the anal canal. These cancers have spread into the deeper layers of the lining.


Squamous cell carcinomas that form in the anal margin are treated like squamous cell carcinomas of the skin elsewhere in the body.


Adenocarcinomas

Some cases of anal cancer are adenocarcinomas, which develop in the cells that line the upper part of the anus, or in the glands. Most anal adenocarcinomas are treated the same way as rectal carcinomas. 


When adenocarcinomas develop in the apocrine gland, a type of sweat gland of the perianal skin, it is called Paget’s disease. Paget’s disease can affect skin anywhere in the body, and is not the same as Paget’s disease of the bone.


Basal cell carcinomas

A small number of anal cancers are basal cell carcinomas, which develop in the perianal skin. These are often treated with surgery like other basal cell cancers of the skin.


Melanomas

Melanoma anal cancers develop in cells that make skin pigment (melanin) and are not common. Most melanomas develop in skin that is exposed to the sun. Melanomas that are detected early can often be successfully treated with surgery. But because anal melanomas are not easily seen, they often are not found until they have spread, and require other types of treatment. 


Gastrointestinal stromal tumors (GIST)

Gastrointestinal stromal tumors (GIST) are more common in the stomach or small intestine, but rarely they can start in the anal region.

Anal cancer causes, risks and family history

Researchers do not know the exact causes of anal cancer. Certain viruses can cause the cells to grow out of control and become cancerous, but most people who are infected with these viruses never develop anal cancer.


There are several known risk factors for anal cancer. Having any of these risk factors does not mean you will develop anal cancer, and some people who have the disease have no risk factors.


Anal cancer risk factors include:


Human papillomavirus (HPV) infection

Most anal cancers appear to be related to infection with human papillomavirus (HPV). Evidence suggests that HPV may cause many anal squamous cell cancers. But most people with HPV do not develop anal cancer. For more on HPV, scroll down to the bottom of this section.


Weakened immune system

People who have weakened immune systems due to HIV infection, drugs that suppress the body’s immune system response (such as drugs taken for an autoimmune disease) or other reasons have an increased risk.


Smoking

Numerous studies have found an increased rate of anal cancer among smokers, especially in people who have other anal cancer risk factors.


Anal warts

These growths are caused by a different type of HPV infection than anal cancer, but many people who are infected with this type also have the higher-risk type of HPV, so they may have an increased risk of anal cancer.


Having certain cancers

Women who have had cervical cancer, vaginal cancer or vulvar cancer have a higher risk of anal cancer, most likely because these cancers also are linked with HPV infection. Studies have not shown a link between anal cancer and men with penile cancer.


Sexual behavior

Certain types of sexual activity, especially between two men, may increase the risk of HPV infection, including having multiple sexual partners and having unprotected sex.


HIV infection

People who have the human immunodeficiency virus (HIV), the virus that causes AIDS, have a much higher risk of anal cancer.


If you are concerned about your risk, talk with your doctor. Anal cancer screening exams are available for people with an increased risk.


More on human papillomavirus (HPV)

HPV is a group of more than 150 related viruses that can infect cells lining the genitals, anus, mouth and throat. It is spread from one person to another during skin-to-skin contact, including sex.


Up to 80% of men and women who have had sex have HPV. A vaccine series is available for HPV and is recommended for pre-teens between the ages of 11 and 12. In some cases, the vaccine may be recommended up to age 26.

Anal cancer prevention, screenings and early detection

Anal cancer screening is similar to screening for colon cancer or rectal cancer. Most people should begin having anal cancer screenings at age 50. If you have an increased risk of anal cancer, your doctor may recommend that you begin screening sooner or have screening exams more often.


There are several types of anal cancer screening tests and procedures. Your physician will let you know which screening is most appropriate for you, and how often to have it. 


The most common screenings for anal cancer include:


Colonoscopy

During a colonoscopy, the physician inserts a flexible, lighted tube with a camera attached through the patient’s anus to examine the anal canal, rectum and the entire colon while the patient is under sedation. This is the most thorough screening exam, and often allows the doctor to remove polyps at the same time.


Digital rectal exam

During this exam, a physician inserts a gloved finger into the rectum to feel for abnormalities, such as polyps.


Anoscopy

During this exam, a physician uses a lighted tube called an anoscope to examine the anus and lower rectum.


Proctoscopy

During this exam, a physician uses a lighted tube called a proctoscope to examine the rectum.


Endorectal ultrasound (ERUS)

This screening uses an instrument that is inserted into the anus and rectum with a probe at its end that emits ultrasound (high-energy) waves off organs to create an image known as a sonogram.


If you’re 50 or older and haven’t been screened yet, be sure to make an appointment as soon as possible.


Preventive factors

Anal cancer cannot be completely prevented, but some steps can help with anal cancer prevention:


  • Have HPV tests as recommended
  • Ask your doctor about an HPV vaccine
  • Be treated for HIV if you’re infected
  • Use condoms during sex to protect against sexually transmitted diseases
  • Avoid tobacco
  • Eat a diet high in fruits and vegetables

Anal cancer symptoms, diagnosis and stages

There may be no anal cancer symptoms during the early stages of the disease. But being aware of the signs and symptoms may help you recognize them sooner.

Anal cancer symptoms

Symptoms of anal cancer include:


  • Rectal bleeding
  • Rectal itching
  • A lump or mass at the anal opening
  • Pain or a feeling of fullness in the anal area
  • Narrowing of stool or other changes in bowel movements
  • Abnormal discharge from the anus


Having any of these symptoms does not mean you have anal cancer. Infections, hemorrhoids, irritation from foods or products, and other factors may cause similar symptoms. But if your symptoms persist or become worse, let your doctor know so that you can find the cause and any potential health problems.

Diagnostic testing

In addition to anal cancer screening exams, Scripps physicians may use other tests and procedures to detect and diagnose the disease and determine the most effective treatment. These tests include:


Biopsy

Biopsy involves removal of a small sample of suspicious tissue. The sample, which can be taken during a colonoscopy or sigmoidoscopy, is tested and examined by pathologists in a lab.


Endoscopy

An endoscope is a tube with a lens or tiny video camera on the end, which can be inserted into the rectum to diagnose anal cancer and remove tissue samples for testing.


Rigid proctosigmoidoscopy

This procedure allows the physician to examine the anus and lower rectum with a lighted tube.


Computed tomography (CT) scan

A CT scan is a form of X-ray imaging test that captures images of the body from different angles. The images are combined to create detailed cross-sectional views of organs, bones and blood vessels.


Magnetic resonance imaging (MRI)

MRI relies on a powerful magnet, radio waves and advanced digital technology to provide detailed images of organs, bone and soft tissue.


Positron emission tomography (PET) scan

A PET scan involves imaging after the patient swallows a type of radioactive sugar that existing cancer cells will quickly absorb so they can be identified under a special camera. It is combined with a CT scan to give physicians the ability to view a picture of potentially cancerous areas through the PET while also seeing more detailed images from a CT scan.

Anal cancer stages

The lining of the anal canal has several layers. Anal cancer stages indicate how far the cancer may have grown into the lining and beyond to other parts of the body. This helps doctors determine the best course of treatment.


Stage 0

Stage 0 anal cancer is very early cancer that is found only in the top layer of anal tissue. This stage is also known as carcinoma in situ (CIS) or Bowen disease.


Stage I

Stage I anal cancer is when cancer cells have spread beyond the top layer of anal tissue. The tumor is less than 2 cm (about 4/5 inch) and has not spread to nearby lymph nodes or beyond.


Stage II

Stage II anal cancer is larger than 2 cm across, but has not spread to nearby lymph nodes or organs.


Stage IIIA

Stage IIIA anal cancer is either of the following:


  • The cancer can be any size, but it has not grown into nearby organs. It has spread to the lymph nodes around the rectum but has not spread to distant sites.
  • The cancer has grown into nearby organs, such as the vagina or bladder, but has not spread to nearby lymph nodes or to distant sites.


Stage IIIB

Stage IIIB anal cancer is either of the following:


  • The cancer has grown into nearby organs, such as the vagina or bladder, and has spread to lymph nodes around the rectum but has not spread to distant sites, or
  • The cancer can be of any size and may or may not have grown into nearby organs. It has spread to lymph nodes in the groin or pelvis, and may or may not have spread to lymph nodes around the rectum. It has not spread to distant sites.


Stage IV

Stage IV anal cancer can be any size and may or may not have grown into nearby organs. It may or may not have spread to nearby lymph nodes and has spread to distant organs or tissues.

Understanding your diagnosis

No one wants to hear that they have cancer. You may feel frightened, overwhelmed, anxious or sad. All of these feelings are perfectly normal. The more you learn about your diagnosis and next steps, the sooner you can begin to make informed decisions about your treatment.


Questions and considerations

Your cancer care team offers a wealth of information for the many questions that come with an anal cancer diagnosis. Here are some you might want to bring up with your physician or health insurance provider:


  • Should I get a second opinion?
  • How do I find a specialist?
  • What is my treatment plan?
  • Will I have to miss work/school?
  • What are the side effects of anal cancer treatment?
  • How successful is my treatment likely to be?
  • What costs will be covered by insurance?
  • Which costs will I be responsible for?


Your Scripps team is here to help you find the answers you need to take an active role in your care. In addition, there are a number of community resources that provide education, information and helpful resources — often at no cost.


Learn more about the many cancer patient resources available to you and your loved ones.

Treatment and clinical trials

If you or a loved one has been diagnosed with anal cancer, you need a team of specialized physicians with expertise in treating the disease. Our multidisciplinary teams fight anal cancer using advanced treatments and therapies.

Our approach to treating anal cancer

At Scripps, your cancer care team includes professionals from every area of oncology medicine, including physicians, surgeons, radiation oncologists and nurses who specialize in cancer care. Many patients are partnered with a nurse navigator, who will help coordinate care and ensure patients get the support they need throughout treatment and recovery. Learn more about how Scripps puts you at the center of care.

Anal cancer treatment options at Scripps

Treatment for anal cancer usually includes a combination of radiation therapy and chemotherapy (often called chemoradiation). If initial treatments are not successful, surgery may be an option.


Treatment options include:


Radiation therapy for anal cancer

Scripps has the most comprehensive radiation therapy offerings in San Diego for anal cancer, including 3-D conformal radiation therapy and intensity-modulated radiation therapy (IMRT). These highly targeted radiation therapy technologies treat cancerous cells while protecting surrounding tissues and organs from excess radiation damage.


  • 3-D conformal radiation therapy allows physicians to visualize a patient’s anatomy in 3-D through the use of advanced computer software to match the radiation dose to the shape of the tumor while minimizing exposure of surrounding healthy tissues and organs.
  • Intensity-modulated radiation therapy (IMRT) is an advanced form of radiation therapy that allows the radiation oncologist to specify the dose of radiation for the tumor while restricting the dose to surrounding healthy tissues.


Chemotherapy

Chemotherapy for anal cancer can be combined with radiation therapy before and after local excision surgeries for squamous cell carcinoma anal cancers. It may also be used alone or in combination with radiation therapy for recurrent anal cancers or to provide palliative care for patients with cancers that have spread to other parts of the body.


Anal cancer surgery

If chemotherapy and radiation do not eliminate the cancer, two types of anal cancer surgeries are most commonly performed.


  • Abdomino-perineal resection is for advanced cases of anal cancer. The surgeon may remove the entire rectum and anus, along with nearby lymph nodes. Scripps surgeons may perform the abdominal portion of this procedure using minimally invasive robotic surgery. Patients who have this surgery will require a permanent colostomy.
  • Local excision, also called a resection, is usually performed to remove squamous cell cancers of the perianal skin. With a wide local excision, surgeons seek to preserve the patient’s sphincter muscles so normal bodily functions can be maintained.


Treatment for gastrointestinal stromal tumors (GIST)

Gastrointestinal stromal tumors (GIST) are rare in the anal area. When these tumors are found at an early stage, they are removed with surgery. If they have spread beyond the anus, other treatments may be needed.

Anal cancer clinical trials

In some cases, patients may be eligible for clinical trials as part of their anal cancer treatment plan. Talk with your oncologist about whether a clinical trial is right for you.


At this time, we do not offer any clinical trials for anal cancer. See our current list of clinical trials that are enrolling patients.

Your custom cancer treatment plan

Your Scripps cancer team will develop a customized treatment plan outlining the treatments and therapies we recommend for your care. Before you begin treatment, you and your physician will review your plan together and discuss any questions or concerns you may have.


Your anal cancer treatment plan generally includes:


  • Family and medical history
  • A summary of your cancer diagnosis and staging information
  • Diagnostic testing completed (e.g., imaging, biopsy, lab tests)
  • Plans for surgery, radiation, chemotherapy and/or other treatments
  • Potential side effects of treatments
  • Contact information for your cancer care team members


Along with helping you understand your course of treatment and encouraging discussion between you and your physician, your plan helps your team coordinate your care. You also can share your treatment plan with other providers who may be involved in your medical care.

Your cancer care team

Your anal cancer care team includes health and medical professionals from a wide range of specialties. Scripps will customize your team to ensure you have the expertise and support you need. 


Your team may include:


  • Surgeons and surgical oncologists
  • Radiation oncologists
  • Medical oncologists
  • Registered nurses
  • Nurse navigators
  • Dietitians
  • Oncology social workers


For specific details about the multidisciplinary approach to treatment at Scripps, visit your cancer care team.

Anal cancer treatment locations

Scripps diagnoses and treats anal cancer at numerous locations throughout San Diego County. From Chula Vista and La Jolla to Encinitas and beyond, our extensive network of Southern California cancer care centers includes:


  • Four Scripps hospitals on five campuses
  • Outpatient clinics
  • Specialty cancer treatment centers


Visit cancer care locations for details of each cancer hospital, clinic and specialty center.

Support groups, services and resources

As leaders in anal cancer care, we know what it takes to fight a winning battle. That’s why we equip our patients with the support and resources necessary to achieve their best possible outcome. From connecting you with support groups and services to empowering you with the latest resources and research, Scripps offers a comprehensive lineup to help you along every step of your cancer journey.

Anal cancer support groups

In support of our patients, survivors, their family members and the community, we host a handful of cancer support groups as well as a range of free workshops and health and wellness events on a number of topics such as:


  • Nutrition
  • Expressive writing
  • Yoga
  • Meditation


Check the current list of support offerings or contact your oncology social worker or cancer care coordinator.


For info about other cancer support groups in the San Diego community, call the American Cancer Society at 800-227-2345.

Support services for cancer patients

We are here for you — not only as your oncologists, but as a robust multidisciplinary team of experts who understands that your cancer journey is about much more than your medical treatment. Specifically, Scripps Cancer Center offers a variety of patient support services to ensure your physical, psychological and emotional well-being as well as resources for dealing with the logistical and financial aspects of cancer care. Our services and resources include:


  • Oncology nurses and nurse navigators with extensive clinical expertise in cancer care to help guide you and your caregivers to make informed decisions and ensure your optimal care.
  • Palliative care to provide an extra layer of supportive care to manage pain and relieve symptoms, offer emotional and spiritual support, and improve your quality of life. 
  • Oncology social workers specially trained to provide counseling, connect you with community and medical resources, assist with transportation and housing and coordinate care after discharge.
  • Our registered dietitian nutritionists offer individualized nutrition support for patients whose efforts to optimize their nutrition may be affected by cancer symptoms or treatment side effects.
  • Referrals and professional care from experts in psychology, psychiatry and emotional health, including individual and family counseling to help with the emotional challenges of cancer.
  • Physical rehabilitation and occupational therapy services, including wound care, voice therapy and swallowing therapy, lymphedema therapy, balance and vestibular rehabilitation, yoga and more.
  • Scripps Center for Integrative Medicine for patients interested in mind-body healing through acupuncture, biofeedback, herbal nutrition, massage therapy, integrative cancer care and more.
  • Nondenominational spiritual care offered by our chaplains to help coordinate spiritual care with your own clergy, rabbi or spiritual advisor.
  • Visiting patient services if you reside beyond San Diego and want help arranging appointments or learning more about short-term lodging.


For the full spectrum of offerings, please visit our cancer patient support services section.

Additional resources for patients, caregivers and family members

Patient education is an integral part of understanding and coping with your cancer diagnosis and treatment. To stay informed, we encourage our patients, along with their caregivers and family members, to:


  • Bookmark the Scripps glossary of cancer terms for easy referencing.
  • Download the appointment form and list of medications form on our resources page.
  • Consult your oncology team for educational materials and a list of trusted online sources beyond the Scripps site. 


Navigating cancer might seem overwhelming — especially with so much information online. To ensure you receive the most accurate details, always look to your multidisciplinary team of cancer care experts first.