Over the past decade there has been a lot of information and debate over if, how, and when to screen men for anal cancer. In 2015, there were 7,270 estimated new cases reported and 1,010 estimated deaths from anal cancer. Although it’s true that when compared to other cancers, anal cancer is rare, the rates for new anal cancer cases have been rising on average 2.2% each year over the last 10 years and that death rates have been rising on average 3.8% each year over 2003-2012. (SEER Cancer Statistics Fact Sheet)
What is anal cancer?
Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus. According to the National Cancer Institute (NCI) at the National Institutes of Health risk factors for anal cancer include the following:
- Being infected with human papillomavirus (HPV)
- Having many sexual partners
- Having receptive anal intercourse (anal sex)
- Being older than 50 years
- Frequent anal redness, swelling, and soreness
- Having anal fistulas (abnormal openings)
- Smoking cigarettes
Another consideration is that people infected with HIV are at higher risk of several types of cancer including anal cancer.
I think it’s critical to note that the NCI cites several studies that indicate infection with human papillomavirus (HPV) is a major risk factor for anal cancer. In fact, about 95 percent of anal cancers are caused by HPV with most of these caused by HPV type 16.
What is HPV?
“Human papillomaviruses (HPVs) are a group of more than 200 related viruses. More than 40 HPV types can be easily spread through direct sexual contact, from the skin and mucous membranes of infected people to the skin and mucous membranes of their partners. They can be spread by vaginal, anal, and oral sex.” (National Cancer Institute)
HPVs are generally classified into two types, low-risk which do not cause cancer, and high-risk which can cause cancer. Two types of the dozen high-risk ones, HPV 16 and 18, are responsible for most cases of HPV-caused cancers.
If you think you’re immune from or will never get HPV, think again, the Centers for Disease Control and Prevention (CDC) estimates that more than 90 percent and 80 percent, respectively, of sexually active men and women will be infected with at least one type of HPV at some point in their lives. There is no test to find out your “HPV status.” There are, however, some HPV tests that can help screen for cervical cancer. Some people find out they have HPV when they develop genital warts. (CDC) Although some HPV infections will go away within a year or two without showing symptoms or you even knowing, persistent infections with high-risk HPV types can lead to cell changes that, if untreated, may progress to cancer.
What screening is available for anal cancer?
Although there’s still uncertainty about the best way to screen for and treat anal cancer, some researchers recommend anal Pap test screening to detect and treat early lesions before they progress to anal cancer. This type of screening may be most beneficial for men who have had sexual intercourse with other men.
From “Anal Pap smears: Should we be doing them?” the authors concluded, “Performing anal Pap smears is a valuable tool to detect cytologic changes associated with some strains of HPV infection. For persons participating in receptive anal intercourse, this diagnostic procedure provides the opportunity for early detection to guide appropriate follow-up and interventions.” (Lindsey K, DeCristofaro C, James J., PubMed)
HIV infected patients, especially, should discuss such screening with their medical providers. In a recent study that evaluated the prevalence of anal cytology (ACyt) abnormalities among HIV-infected and HIV-uninfected men who have sex with men (MSM), the researchers concluded that “Prevalence of abnormal anal cytology remains elevated in HIV-infected men during the current antiretroviral therapy era.” (JAIDS)
A study from 2011 indicated that men who have sex with men (MSM) showed a 44 times greater incidence of anal cancer than the general population and that the risk of anal cancer was 60 times more likely for HIV-positive MSM than the general population. (The Journal of Infectious Disease)
What is an anal pap smear?
An anal pap test is a screening test that can be done on men and women. It is a test that looks for changes in the cells of the anus that could lead to anal cancer (very much like pap smears of the cervix in women). The anal pap test does not test for colon or rectal cancer.
How is the test done?
The anal pap test will take less than 5 minutes. In most cases, it will cause little or no discomfort. During the test, you may be asked to lie on your side on an exam table, or may be asked to bend forward over an exam table. Your health care provider will insert a swab, which looks like a long, thin Q-tip, about 1 ½ – 2 inches into your anus, and will collect a sample of cells. The sample is then sent to the lab, where the cells are looked at under a microscope to see if there are any changes. You should receive the results of the test in 1-2 weeks. (Cellnetix)
Screening timeline, outcomes, and prevention
The anal pap test has not been studied enough to know how often it should be done, or if it actually reduces the risk of anal cancer by catching anal intraepithelial neoplasia (AIN, a potentially pre-cancerous condition) early. Some experts recommend that the test be done every year in men who have sex with men who are HIV-positive, and every 2 to 3 years if the men are HIV-negative. But there is no widespread agreement on the best screening schedule, or even exactly which groups of people can benefit from screening. (American Cancer Society)
Whatever your situation, it’s very important that you have honest, open discussions with your health care providers. You should always feel comfortable in asking any question that’s on your mind, no matter how small it might seem. Because the topic of screenings for anal cancer is still relatively new, some health care providers may not know enough or understand the nature of this type of screening. When you are forthcoming with your health care providers they can provide the best care and recommendations possible. If you think you’re at risk for anal cancer read more, do your research, and open the discussion with your health care providers.
