Anal Cancer
Anal cancer is an uncommon cancer that develops in the tissues of the anal canal or near the opening of the anus, most often linked to infection with certain strains of the human papillomavirus (HPV). While symptoms can sometimes resemble common conditions like hemorrhoids, early detection and treatment often lead to successful outcomes.
Table of contents
- What Is Anal Cancer?
- Where Anal Cancer Develops
- Signs and Symptoms
- Causes and Risk Factors
- How to Lower Your Risk
- Diagnosis and Testing
- Treatment Approaches
- Living After Treatment
What Is Anal Cancer?
Anal cancer is a growth of cells that starts in the anal canal. It is a rare type of cancer, with only about 11,000 people in the United States receiving this diagnosis each year[2][12]. The anal canal is a short tube at the end of the rectum (the lower part of the large intestine) that measures about 1 to 1½ inches in length[1][4].
Most anal cancers are squamous cell carcinomas, meaning they develop in the flat cells that line the anal canal[2]. The good news is that anal cancer is usually curable, especially when it’s caught early[2][12]. This is why it’s important to see a healthcare provider if you notice any concerning symptoms.
Where Anal Cancer Develops
- Anal canal
- Anus
- Rectum
- Large intestine
The anus is the opening at the end of your digestive system where stool (solid waste) leaves the body[2][4]. Muscles called sphincters surround the anal canal. These muscles relax to allow waste to leave the body and contract to hold it in[1].
Anal cancer can start in the lining of the anal canal, called the mucosa, or in the perianal skin, which is the skin near the opening of the anus that contains hair follicles and sweat glands[4]. The anus is connected to the rectum by the anal canal[4].
Signs and Symptoms
The signs of anal cancer can sometimes be similar to those of more common conditions, like hemorrhoids. This is why it’s important to get checked out by a healthcare provider if you experience any of these symptoms[2]:
- Bleeding from the anus or rectum, or blood in the stool (this is the most common symptom)[2][1]
- Pain or fullness in the area of the anus[1][2]
- Changes in bowel habits or what your stools look like, such as having thinner stools[2]
- A lump or mass at your anal opening[1][2]
- An itchy anus[2]
- A feeling of constantly needing to have a bowel movement[2]
Having one or more of these symptoms doesn’t mean you have anal cancer, so there’s no need to panic. But you should talk to a healthcare provider if things get worse or don’t improve within a few days[2]. Anyone can develop anal cancer, even if you don’t think you have a higher chance of getting it[3].
Causes and Risk Factors
Experts don’t know exactly what causes anal cancer in every person. However, most cases are linked to certain types of human papillomavirus (HPV) infection[2][3]. HPV is a very common virus that spreads through skin-to-skin contact of the genital area, including vaginal, anal, or oral sex, and sharing sex toys[3]. The same strains of HPV that can lead to cervical cancer can also lead to anal cancer[2].
It’s important to know that HPV infection is very common and doesn’t usually cause symptoms, so most people who have it are completely unaware[2]. Most people with HPV don’t get anal cancer, and not everyone with anal cancer has HPV[2][12].
In addition to HPV infection, several other factors may increase your chance of developing anal cancer[2][10]:
- Engaging in unprotected anal sex as the receiving partner (this is true for everyone, regardless of sex)[2]
- Having many sexual partners[2]
- Not being vaccinated against HPV[2]
- Having HIV or other conditions that weaken your immune system[2][10]
- Taking medicines that weaken your immune response, such as after an organ transplant[2][10]
- Having a personal history of vulvar cancer, vaginal cancer, or cervical cancer[2][10]
- Smoking cigarettes[2][10]
- Being over the age of 75[3]
Many of these risk factors don’t directly cause cancer. Instead, they increase the chance of changes to the way cells function, especially how they grow and divide[10].
How to Lower Your Risk
There’s no guaranteed way to prevent anal cancer. However, you can reduce your chances by taking several important steps[2][3]:
- Don’t start smoking, and quit if you do[2]
- Use condoms when you have anal sex[2][3]
- Keep sex toys clean and do not share them[3]
- Get the HPV vaccine if you’re eligible for it[2]
The HPV vaccine is one of the best ways to protect against anal cancer[3]. This vaccine not only helps prevent anal cancer but also cancers of the mouth and throat, cervical cancer, and penile cancer[2]. All children aged 12 to 13 are offered the HPV vaccine[3]. The vaccine is also recommended for other groups at higher risk, including men aged 45 years old and under who have sex with men, trans men and trans women aged 45 years old and under if their risk of getting HPV is similar, sex workers, and people with HIV[3].
Healthcare providers don’t typically screen for anal cancer. However, if you have a lot of risk factors, screenings like an anal pap test or an anal HPV test may be a good idea[2][12]. This is especially the case as anal cancer doesn’t always cause symptoms in the early stages. These tests check a sample of tissue for abnormal cells or the HPV virus. A healthcare provider can advise you on whether screenings may be helpful[2].
Diagnosis and Testing
If you have symptoms that worry you, make an appointment with a doctor or other healthcare professional[1]. In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform several tests and procedures[4][8]:
Digital rectal examination (DRE) is an exam of the anus and rectum. The doctor or nurse inserts a gloved, lubricated finger into the lower part of the rectum to feel for lumps or anything else that seems unusual[4][8].
Anoscopy involves inserting a thin, flexible tube with a light, called an anoscope, through the anal canal and rectum. A lens on the anoscope allows a healthcare professional to examine the inside of the anal canal[8].
Biopsy is a procedure to remove a sample of tissue for testing in a lab. The sample is often collected during an anoscopy. Special tools can go through the anoscope to collect the cells[8]. The sample is tested in a lab to see if it is cancer. Other special tests give more details about the cancer cells, and your healthcare team uses this information to make a treatment plan[8].
Imaging tests make pictures of the body and can show the location and size of the cancer. Tests might include ultrasound, X-ray, MRI (magnetic resonance imaging), CT scan (computed tomography scan), and PET scan (positron emission tomography scan)[8].
If you’re diagnosed with anal cancer, you may have other tests to see if the cancer has spread. These tests help your healthcare team find out the extent of your cancer, also called the stage. The stages of anal cancer range from 0 to 4, with higher numbers indicating more advanced disease[8]. Your healthcare team uses the results of your cancer staging tests to help create your treatment plan.
Treatment Approaches
Anal cancer is often treatable when found early[9]. The treatment you have will depend on the size of the cancer, where it is, if it has spread, and your general health[9]. The specialist care team looking after you will explain the treatments, benefits and side effects, work with you to create a treatment plan that is best for you, and help you manage any side effects[9].
In the past, most people with anal cancer had surgery to remove the cancer. Today, most anal cancer treatment involves chemotherapy and radiation therapy. With this approach, surgery might not be needed[1].
Chemoradiation
The main treatment for anal cancer is a combination of chemotherapy and radiation therapy, called chemoradiation or chemoradiotherapy[9]. Radiation therapy uses high-energy radiation to kill cancer cells, while chemotherapy is medicine taken to kill cancer cells[9].
Chemoradiation is usually given if anal cancer has not spread. It means most people with anal cancer do not need to have surgery[9].
Surgery
Surgery is sometimes used to treat anal cancer. You may have surgery if the cancer is small and has not spread, if chemoradiation does not get rid of all the cancer or it comes back, or if you are not able to have radiation therapy[9].
Surgery for anal cancer usually involves removing just the part of the anus that’s affected[9]. If the cancer has spread or come back, you may need surgery to remove all of the anus, the rectum, and part of the bowel. This means you’ll need to have a pouch (stoma bag) fitted to the outside of your body to collect stool. This is called a colostomy[9].
If you need a colostomy, you’ll be looked after by a specialist stoma nurse who can offer you support[9].
Follow-up Care
You’ll have regular check-ups during and after any treatments. You may also have tests and scans[9]. If you have any symptoms or side effects that you are worried about, talk to your specialists. You do not need to wait for your next check-up[9].
Living After Treatment
Adjusting to life after treatment is different for everyone. Your recovery will depend on many different factors, such as where the cancer was in your body, the stage of the cancer, the organs and tissues removed during surgery, the type of treatment, and side effects[19].
Managing Side Effects
Diarrhea is a common problem for people treated for anal cancer because the digestive system is very sensitive to treatments like radiation therapy and chemotherapy[19]. Diarrhea usually goes away after treatment is finished, but sometimes it can last several months or years. Making changes to your diet can help manage diarrhea. You can try limiting certain foods and drinks, such as greasy foods, high-fiber foods, coffee, tea, and alcohol[19].
Some people may not be able to control their bowel movements, which is called incontinence. This often happens if treatment damages the muscles of the anal sphincter. Special pads or undergarments can help protect your skin and avoid odor. In some cases, you may have surgery to repair the anal sphincter[19].
Sexual Health
Some treatments for anal cancer can cause sexual problems or make having sex difficult[19]. For example, it is common to lose interest in sex around the time of diagnosis and during treatment. Some people may not be able to have anal sex because of cancer or its treatments.
Radiation therapy or surgery may lead to sexual problems. Talk to your healthcare team if you are having problems with sex. They can suggest ways to help you manage these problems, such as medicines or special devices. Some people find that counseling helps them cope with the effects that anal cancer and its treatments have on their sexual relationships[19].
Emotional Support
Coping with anal cancer can be difficult, and you may have a number of different feelings[15]. You may feel shocked, upset, frightened, uncertain, confused, angry, guilty, or sad. You may have some or all of these feelings, or you might feel totally different. Sometimes it’s hard to take in the fact that you have cancer at all[15].
You might find it helpful to talk to other people about how you are feeling. Specialist nurses can help if you’re finding it difficult to cope or if you have any problems[15]. Talking to your friends and relatives about the cancer can help and support you. Some people find great comfort in talking to a local minister, a hospital chaplain, or a religious leader of their faith[15].
