Pre-cancerous lesions

It’s important to note that the overwhelming majority of people with anal HPV infection will not go on to develop anal cancer. But rates of anal cancer are higher amongst people with HIV.

Before cancer develops, cells in the anus will go through a number of changes over many years and pre-cancerous lesions called AIN (anal intraepithelial neoplasmia) may develop. AIN lesions are graded AIN I, AIN II, and AIN III depending on their stage.

Monitoring

Having a regular sexual health screen which involves an examination of the anus and rectum (called a proctological examination) will mean that anal warts and lesions can be detected early. There is no link between visible anal warts and anal cancer. The strains of HPV which can cause cancer do not cause a wart-like growth to develop. Nevertheless, they can cause lesions. It is worth having a regular anal examination even if you do not have receptive anal sex, or if you always use condoms for anal sex. Studies have found that men and women who have never had anal sex, or always have protected anal sex, nevertheless have anal warts. This could be because HPV can be spread by touch.

Make sure that you tell your doctor if you notice any unusual symptoms in your rectum or anus.

Some HIV clinics are looking at the value of regularly screening individuals with anal HPV for precancerous cell. This involves using a test very similar to the PAP (Papanicolaou) smear used to detect pre-cancerous cervical cells in women. Cells are scraped from the lining of the anus (which can be uncomfortable), and then examined for signs of abnormalities. Anal PAP smears are not 100% accurate and many doctors aren’t convinced of their value. The anus can be examined in more detail using a magnifying instrument during a procedure called an anoscopy. During this procedure small tissue samples from the anus can be removed – biopsied – and examined under a microscope to see if potentially cancerous changes to cells have occurred.

Treatment

Often the immune system successfully clears infection with HPV. Treatment with HIV drugs can restore the immune system and improve its ability to fight infections, including HPV. HIV therapy however, does not have a direct effect against HPV, and cases of anal cancer have occurred in people with good CD4 cell counts and undetectable viral loads.

Imiquimod cream has been shown to be an effective treatment for anal and genital warts and works against HPV.

Anal cancer is usually treated aggressively with a combination of chemotherapy and radiotherapy. You’ll normally stay on anti-HIV drugs during this treatment. The cure rate is approximately 60%, but the treatment has very unpleasant side-effects.

Surgery can be used to remove precancerous and cancerous cells from the anus. However, in many cases the precancerous or cancerous cells may recur.

Vaccination

Vaccines have recently become available that provide a very high level of protection against the main cancer-causing strains of HPV. But they don’t really work in people who’ve already been infected with these stains of HPV and don’t have any treatment effect for cancerous or pre-cancerous cell changes. There is no information yet about how safe and effective the vaccines are in people with HIV, but studies are underway.

Final words

Remember, anal cancer is rare, even amongst individuals with anal HPV infection, and the sooner any potentially cancerous changes are detected and treated occur the better.