Recognizing the need for anal HPV screening
Vaccine study results in MSM population needed
HIV-positive men who have sex with men (MSM) today more commonly develop cancer of the anus than women developed cervical cancer prior to Pap screening, an expert says.
However, this disease is largely overlooked among the HIV-positive MSM population because of the serious nature of their HIV disease, as well as the prevalence of hepatitis C infection in this population, says Timothy Wilkin, MD, MPH, assistant professor of medicine at Weill Cornell Medical College of Cornell University in New York, NY.
"When you talk about the risk of dying from AIDS or HCV, these have a much higher risk than anal cancer, so people don't feel it's the same pressing issue," Wilkin says.
Researchers still seek answers to questions about how human papillomavirus (HPV) infection is affected by HIV and HIV treatment, Wilkin says.
"Does treating HIV make it less likely that patients are going to have pre-cancerous conditions related to HPV?" he says. "It does seem patients are less likely to develop these precancerous conditions if their HIV is well-controlled, but we're not using that in our decision-making process about whether or not to start HIV therapy."
Among women infected with HIV and HPV, research shows they do not respond as well to treatments for cervical dysplasia, even if they are on antiretroviral medications, Wilkin says.
"HIV-infected women are more likely to have persistent or recurrent disease than women without HIV infection," Wilkin says. "So despite antiretroviral therapy, we need to keep a close watch on these HPV-related conditions."
Thanks to a generation of public health practice and education, cervical screening for dysplasia is commonplace. The same cannot be said for anal screening, although that is changing.
Anal pap tests are a valid cancer screening target, and the screening has gained ground in recent years, Wilkin says.
"When I started this about seven years ago, there really was almost no one doing the test," Wilkin recalls. "Now it's becoming much more widespread and, recently, the New York State AIDS Institute has recommended the screening as part of routine care for people with HIV."
As a result, more physicians and clinics are showing an interest in screening, Wilkin says.
"So we need a lot more people trained in how to diagnose and manage these conditions," he adds.
While anal screening is simple, and clinicians could learn how to do it by reading a brief article on the topic, treating anal dysplasia and cancer is more difficult, Wilkin notes.
While select medical centers are making anal screening routine among HIV-infected MSM, there is some reluctance among clinicians to screen for HPV because there aren't enough clinicians who are trained in the techniques of treating and diagnosing pre-cancer conditions, Wilkin says.
"Anyone with an abnormal pap smear needs to have a high resolution anoscopy," Wilkin says. "You put a speculum in the anus with vinegar and a topic anesthetic, and then take small biopsies of the white areas that are pre-cancerous."
The point is to find high-grade anal intraepithelial, which are the areas that can turn into cancer if left untreated, Wilkin explains.
While screening for anal dysplasia is easier than a cervical pap smear and it's read the same way as a cervical pap smear, performing the high resolution anoscopy is challenging, Wilkin says.
"It doesn't fall into anyone's clinical practice," Wilkin says. "Gynecologists aren't performing this procedure, and surgeons don't really perform this procedure."
So mid-level and general practitioners have to be trained to do the procedure by the American Society for Colposcopy and Cervical Pathology.
"What's really great is they've recently started offering training for anal anoscopy," Wilkin says.
The next step is infrared coagulation, in which infrared light causes abnormal tissue to shrink, allowing normal skin to grow, Wilkin says.
"Once you find high-grade dysplasia, then you have to treat it," Wilkins.
Another new area of HPV prevention and treatment is the newly approved HPV vaccine.
While there is some hope that the newly approved HPV vaccine will provide some protection to MSM in the future, at present, there is not enough data about it being used in this population, Wilkin says.
"There are no published data on its ability to prevent anal HPV infection and anal dysplasia," Wilkin says. "There is an ongoing study sponsored by Merck that is enrolling thousands of young women to see if the vaccine will prevent penile infection with HPV and prevent genital warts."
This study has a subset of young gay men who will be monitored by researchers to see if the vaccine prevents anal dysplasia and HPV infection, but those results are a couple of years away, he adds.
Even if studies show that the vaccine will help prevent anal HPV infection among MSM, the public health system may continue to have problems reaching young MSM for vaccination and screening, Wilkin says.
"I think it's hard to reach young men; they're not really engaged in the health care system," Wilkin explains. "Women go to see their gynecologist regularly for pap smears, but there's not the same access for young men, so it will be challenging to try to administer the vaccine to them."
For women, public health recommendations call for vaccinating them against HPV infection from ages 11 to 26, Wilkin says.
"The vaccine is going to be most effective as a preventive vaccine, and it's going to be most useful prior to any infection with any of the four vaccine types," Wilkin says. "HPV infection occurs quite commonly after a few sexual partners, so I think people should err on the side of vaccinating earlier rather than alter."
A Scandinavian study is investigating the vaccine's durability, following young women who were vaccinated a few years ago to see how long the antibody persists, he adds.
There is no information about the HPV vaccine in HIV infected populations, but studies are planned, Wilkin says.
"The main thing about HIV is that patients have difficulty clearing the HPV infection, which is the norm in patients without HIV," Wilkin says.