The human papilloma virus (HPV) is the virus that causes genital warts, most cervical and vulvar cancers, and many anal cancers. HPV is particularly troublesome because even after optimal treatment recurrence is problematic. Never mind the ongoing risk of cancer, it often takes multiples visits with painful biopsies to closely monitor the situation. Many women (and men) are very affected emotionally by the need for invasive surveillance and the fact that the virus just won’t go away.
The HPV vaccine, when given before an individual is exposed to HPV, reduces the incidence of pre-cancer of the cervix, pre-cancer of the vulva, and genital warts for women and for men prevents genital warts and anal pre-cancers. Vaccinating young women and men before they initiate sexual activity is paramount to vaccine effectiveness as the HPV vaccine doesn’t halt progression of an active HPV related disease, meaning if you already have a cervical pre-cancer or genital warts and then get the HPV vaccine it isn’t much help in preventing progression to cancer or clearing the warts. However, what if you once had HPV related disease and have now been treated? Could the HPV vaccine help prevent recurrence?
This question was just addressed (Joura et al BMJ March 2012) by re-analyzing data from two excellent studies that followed more than 17,000 women for four years (the FUTURE I and FUTURE II studies). The investigators looked at the data from women who were diagnosed with genital warts or HPV-related pre-cancers shortly after they entered into the study. They picked women who were diagnosed within 60 days of enrollment to ensure the HPV wasn’t due to vaccine failure. The women were followed for four years, so it was an ideal study to address recurrence risk.
After adequate treatment of pre-cancer of the cervix 12.2% of women who received the placebo developed another HPV-related disease, and 5.3% developed another high-grade lesion (meaning another pre-cancer). Women with genital warts or a pre-cancer of the vulva or vagina had a 31% risk of developing another HPV-related disease, with 13% developing a pre cancer of the cervix, vulva or vagina.
However, this is what happened for women who received the vaccine:
- Those who were treated for a cervical pre-cancer had their risk of getting another pre-cancer drop by 46% and their risk of getting genital warts was reduced by 63%.
- Those who were diagnosed and treated for genital warts or a pre-cancer of the vagina/vulva were 35.2% less likely to develop another HPV related disease.
While the vaccine was far more effective at preventing recurrence of the HPV types included in the vaccine, what is interesting is that vaccination also conferred some protection against the types of HPV not in the vaccine.
The study is not perfect. There were more smokers in the placebo group, simply by chance, and while smoking does increase the risk of HPV recurrence this factor alone was not felt to account for the difference in recurrence risk.
Bottom line: HPV recurrence after treatment is a common problem and devastating for many women (and men). More long-term studies are needed to tell us if HPV vaccination is a useful strategy to prevent recurrence in those already infected or if vaccination simply delays recurrence.
Of course, treating HPV after the fact is sub-optimal. The vaccine is most effective at reducing the burden of HPV-related diseases when given before the onset of sexual activity, but this study offers some hope to those who are currently struggling with persistent HPV.