HPV is thought to be the most common sexually transmitted infection in the world. Most men are infected with HPV at some time in their lives. There are over 100 types of HPV. Some HPV types infect the genital area and may cause warts, i.e. “low-risk” (LR) HPV, type 6 & 11. Other HPV types may cause abnormal cell changes in men of the anus, penis or throat (oropharyngeal), these are “high-risk” (HR) HPV often type 16 & 18 and can lead to cancer. Most HPV infections are transient and go away before they cause any health problems.
The types of HPV found in the anogenital area are usually passed on during sexual contact (sexually transmitted) and may cause visible genital warts (see HPV and genital warts). In contrast most HR HPV infections are subclinical i.e. without clinical signs or symptoms, and often infect areas that are not easily visible such as the throat and anus.
Genital HPV is usually acquired by direct skin-to-skin contact during intimate sexual contact with someone who is infected. Most men are not aware that they have the virus. Increasing numbers of partners increases the risk of getting HPV, but the virus is so common it may be acquired after having only a single lifetime partner. It is usually impossible to determine when or from whom HPV was caught.
Studies have shown men who have sex with men (MSM) to be at significantly higher risk of acquiring HPV and developing HPV-related anal cancers.
Consistent condom use has been shown to reduce the risk of acquiring HPV as well as preventing other sexually transmitted infections such as HIV and gonorrhoea. However condoms do not completely cover all skin in the genital area and so cannot offer complete protection against HPV transmission.
The HPV Vaccine
Gardasil, the approved vaccine in NZ, is active against four strains HPV. HPV 6 & 11 cause 95% of genital warts, while HPV 16 & 18 are found in 93% of HPV related anal cancers, 87% of HPV related penile cancers and 70% of HPV related cancers of the tongue and throat.
Studies have shown Gardasil to be highly effective at reducing the incidence of external genital lesions in all male recipients between 16 and 26 years old. Gardasil has also proven effective at preventing pre-cancerous lesions and anal cancer related to HPV among MSM who have not yet been exposed to HPV types 6, 11, 16 and 18. There have been no serious side effects associated with the Gardasil vaccine.
In NZ Gardasil is licensed for girls and women between 9 and 45 years and males between 9 and 26 years. Ideally vaccination should occur prior to starting sexual activity and therefore before being exposed to the HPV virus.
In NZ it is available free for people with diagnosed HIV under the age of 26 years and for all females between 9yrs and their 20th birthday. Ask your GP or HIV clinician about HPV vaccination.
Recently the MoH Pharmacology and Therapeutics Advisory Committee (PTAC) recommended as a high priority, widening access to HPV vaccine to include males between the ages of 11 and 25 who identify as gay or bisexual.
Men over the age of 26 may still benefit from vaccination as they may not have acquired all the strains covered by the vaccine. If you are outside the licensed age range or group discuss options for vaccination with your GP. The cost for the full 3 doses will vary but is approximately $450.
HIV Positive MSM
HIV positive men are more likely to benefit from receiving the vaccine regardless of age or sexual history as they are more likely to develop pre cancerous lesions or cancer in any form because of the ability of the infection to hide from the immune system. The Gardasil vaccine has been found to be effective and safe for use in individuals with a compromised immune system. Individuals with confirmed HIV can access Gardasil for free up to their 26th birthday.
It is recommended that HIV positive men receive a regular digital rectal examination from their healthcare provider as most early cancers are palpable even in the absence of other clinical symptoms.
Prevention of Anal Cancer Through Early Detection of HR HPV and Anal Intraepithelial Neoplasia (AIN)
There is little evidence currently for the effectiveness of screening and treatment of High grade AIN to prevent anal cancer.
There are multiple ongoing studies hoping to improve anal cancer prevention by looking at AIN/anal cancer natural history and the potential role of anal cancer screening among MSM.
If you are concerned seek advice from your GP and / or a Specialist regarding diagnosis, treatment and management options.