What Is an Anal Pap Smear?
Key takeaways:
An anal Pap smear checks a sample of cells from the anus for an abnormal appearance that may indicate anal cancer.
Certain groups of people are at higher risk of developing anal cancer and may want to consider this screening. These groups include those with HIV, people who practice anal intercourse, and people with weakened immune systems.
Your healthcare provider can help you determine if you are at higher risk or should consider an anal Pap smear.
Many people are familiar with Pap smears to screen for cervical cancer. But this test can also be used to screen for anal cancer, a cancer that can also result from the sexually transmitted HPV virus.
Anal cancer is relatively rare, so most people do not need to consider having an anal Pap smear. In fact, it affects 0.2% of people — though cases are rising. However, in certain groups of people, the risk of developing anal cancer is higher than for the general population.
We’ll review who’s at higher risk, the process of an anal Pap smear, and how to dicuss with your provider whether you should consider this test.
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What types of cancer can an anal Pap smear detect?
The anus is the very last part of the intestinal tract. It is the opening where stool exits the body. An anal Pap smear can detect the most common type of cancer that affects the anus — squamous cell carcinoma (SCC). SCC makes up more than 70% of all anal cancers. And most squamous cell carcinomas of the anus are caused by the HPV virus.
There are a few other types of anal cancer that are much less common. For example, adenocarcinoma affects the more internal parts of the anus. And skin cancers can develop on the skin around the anus. Anal Pap smears do not test for these cancers, which are much rarer.
An anal Pap smear can detect both cancer as well as precancer. Precancer — sometimes called dysplasia — is when the cells look abnormal but are not cancer. Precancerous cells have a higher risk of becoming cancer over time. If an anal Pap smear finds precancerous cells, they can be removed before they have the chance to become cancer.
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Who should consider getting an anal Pap smear?
Some providers recommended anal Pap smears for people at higher risk of developing anal cancer, such as:
People who have anal intercourse regularly: This is because anal intercourse is a major risk factor for anal exposure to HPV.
People who are immunosuppressed: This group includes those with a history of HIV or organ transplant. An HPV infection causes most anal cancers, and a weakened immune system puts people at higher risk of infection.
People with a history of HPV infection: HPV is a risk factor for anal (and cervical) cancer.
People who have a history of anal or cervical dysplasia: People who were diagnosed with anal dysplasia have a higher chance of those abnormal cells turning into anal cancer. And people with a history of cervical dysplasia were possibly exposed to HPV. So they might be at risk of developing anal cancer as well.
If one or more of these risk factors applies to you, it’s a good idea to discuss an anal Pap smear with your healthcare provider. They can help you decide if this procedure is right for you.
How does an anal Pap smear work?
An anal Pap smear is simlar to a cervical Pap smear. But there are some important differences.
During the procedure, a healthcare provider inserts a small swab into the anus to collect a sample of cells from the proper location. They rotate the swab a few times to collect cells from inside the anus. After the swab, the provider also performs a rectal exam with their finger to check for any abnormalities — like swelling, bleeding, or enlarged glands.
The sample is then sent to a laboratory where a specialist looks at the cells under a microscope. They can then see if the cells have any signs of precancer or cancer. Your provider may also check for HPV itself.
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The procedure may be slightly uncomfortable, but not painful. Avoid inserting anything into the anus for 24 hours prior to the procedure. The procedure is usually repeated yearly depending on your risk factors for anal cancer.
How do you schedule an appointment for an anal Pap smear?
Not every healthcare provider is familiar with performing this procedure. This is because it is not performed as commonly as other types of sexual health testing. But there are several ways to find a healthcare provider who is familiar with anal Pap smears and has experience performing the procedure.
You can start by asking your primary provider to help you find a local clinic or provider that can help. Another good place to start is a clinic that specializes in caring for people with HIV, the LGBTQ+ community, or organ transplant recipients. Some local health centers that screen for sexually transmitted infections may also be more familiar with anal Pap smears.
Some insurance plans do not cover this procedure. So it’s a good idea to contact your insurance provider and ask if this procedure is covered or if you will need to pay out of pocket.
The bottom line
Anal Pap smears are recommended for people who are at higher risk of anal cancer. If you have questions about your sexual health or your risk for HPV infection, don’t hesitate to bring these up with your healthcare provider. They can help you determine whether this procedure is recommended in your case. An annual anal Pap smear can help catch cancer early so that it can be treated and cured.
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References
American Cancer Society. (2017). What is anal cancer?
Grulich, A. E., et al. (2012). The epidemiology of anal cancer. Sexual Health.
Leeds, I. L., et al. (2016). Anal cancer and intraepithelial neoplasia screening: A review. World Journal of Gastrointestinal Surgery.
Liszewski, W., et al. (2014). Anal Pap smears and anal cancer: What dermatologists should know. Journal of the American Academy of Dermatology.
National Cancer Institute: Surveillance, Epidemiology, and End Results Program. (2021). Cancer stat facts: Anal cancer.
Thompson, M. A., et al. (2021). Primary care guidance for persons with human immunodeficiency virus: 2020 update by the HIV Medicine Association of the Infectious Diseases Society of America. Clinical Infectious Diseases.
University of California San Francisco Anal Dysplasia Clinic. (2014). Anal cancer: Distribution in the population and causes.
University of California San Francisco Anal Dysplasia Clinic. (2014). DARE and HRA.
University of California San Francisco Anal Dysplasia Clinic. (2014). Obtaining a specimen for anal cytology.
