This test is an effective screening tool for anal cancer.
The lesser-known cousin to the cervical Pap smear, an anal Pap test—or more technically, anal cytology—is a screening test that collects cells from the anal canal to determine if you have anal cancer or are at risk of getting it.
The anal canal is the area of the gastrointestinal tract that starts at the top end of the rectum inside the body and moves past the anal sphincter to outside the body. This area is made up of cells that can be infected by HPV, the human papillomavirus, which can cause anal cancer just as it causes cervical cancer.
Like the cervix, you can detect cancer at any early stage, when it’s still treatable, via a sampling of cells.
“Pap smears have been highly effective as a (cervical cancer) screening tool for women, so why not do the same thing for the anal canal?” says Peter Leone, MD, infectious diseases expert at UNC Medical Center.
A Simple Swab Test
The anal Pap test is quick. Your provider inserts a swab that looks like a long Q-tip into your anus, collects a sample of cells and sends them to a pathologist in a lab.
The pathologist then views these cells under a microscope to determine if they are normal, dysplastic (precancerous) or cancerous. Based on what the results show, you may need a follow-up visit for further testing.
“It’s something that can be collected during a routine visit that is a useful screening tool,” Dr. Leone says.
Anal Cancer Screening Tool
Dr. Leone says screening for anal cancers became necessary in recent years because “anal cancer rates in the U.S. had been going up at about a 2 percent increase per year, in particular with HIV-infected individuals.”
There are a few reasons for this. First, because of the availability of more effective treatment for HIV beginning in the mid-1990s, people began to live longer with HIV. As a result, they had other health problems over time, including anal cancer.
“People were dying before they actually would develop cancer. So now that we’re looking at life spans that are approaching a normal life span, we are actually seeing an increase in anal cancer in men who have sex with other men, but in particular, men who are HIV-infected,” Dr. Leone says.
In addition, cancers linked to HPV, including anal cancer, have increased significantly over the past 15 years in the United States. And HPV is not limited to one area in the genital tract. So if you’re infected in one area, you can be infected elsewhere—HPV can migrate.
“The misnomer is you have to have receptive anal intercourse to have anal cancer and that’s not true,” Dr. Leone says. “We see heterosexual individuals with anal cancer, and we see men who have sex with men who have never had receptive anal intercourse. You don’t have to have anything inserted up there to get HPV in the anal canal.”
Who Should Be Screened for Anal Cancer?
While there are no national guidelines on who should have an anal Pap test, Dr. Leone says several medical societies have guidelines in place that recommend this annual screening at age 25 to 30 if you are HIV-infected.
The greatest risk is among smokers and those infected with HIV, but any immunosuppressive therapy, particularly one that affects T-cell function, can increase risk. This is seen in people with organ transplants.
And if you’ve had HPV, especially high-risk HPV (genital warts or dysplasia elsewhere), you should consider getting an anal Pap test even if you’re HIV-negative, Dr. Leone says. In addition, he recommends everyone receive the HPV vaccine.
“Most anal cancers are due to HPV 16 and 18. Both of those are contained in the HPV vaccine and we believe will prevent anal cancer,” Dr. Leone says.
Dr. Leone says that while getting vaccinated if you’re under 25 is vital, he also recommends those older than 25 consider vaccination.
“We have such a high divorce rate in the U.S. People may be reentering into the dating world, getting new partners and being sexually active with different people,” he says. “So even though you may have been negative (for HPV) up until age 30, if you’re now divorced and meeting new people, you’re now at risk, and unlike cervical cancer, the risk for anal cancer increases with age.”
If you’re concerned about your risk for anal cancer, talk to your doctor. If you need a doctor, find one near you.