Administration of a quadrivalent human papillomavirus (HPV) vaccine has proven effective in preventing high-grade vulval and vaginal lesions that can lead to cancers in those areas, conclude authors of a study published in this week's edition of The Lancet.
Professor Jorma Paavonen, Department of Obstetric and Gynecology, University Central Hospital, Helsinki, Finland, and colleagues carried out their analysis of three randomised clinical trials involving more than 18,000 women aged 16-26 years in 24 countries across Europe, Asia, and the Americas. The women were randomly assigned to receive either quadrivalent HPV6/11/16/18 vaccine or placebo.
The women were then followed up for an average of three years. Vaccine efficacy varied from 71% in women previously exposed to the human papillomaviruses to 100% in those not previously exposed. Additionally, a 49% reduction in all high-grade vulval and vaginal lesions, irrespective of casual HPV type, was seen in the intention-to-treat population of sexually active young women.
There has been a striking increase of high-grade vulval pre-cancer lesions and cancer over the past 30 years.
The authors say: "This trend is worrying because these cancers are not amenable to a screening programme. Whereas previously vulval cancer was seen almost exclusively in older women, recent studies have shown that 20% of these cancers now occur in women under 50 years."
They add (although this quote is not within the article) "Vulval and vaginal cancers are often not recognised. Treatment of choice is surgery which can be mutilating, and causes anxiety, depression, sexual dysfunction and poor self image."
They conclude: "In summary, these combined studies provide substantial evidence that a quadrivalent HPV L1 VLP vaccine is highly effective in preventing high-grade vulval and vaginal lesions associated with HPV16 or HPV18. The maximum effect of vaccination is expected in girls who are vaccinated in early adolescence, before exposure. The effect of vaccination in the general population of sexually experienced young women is expected to be lower initially, due to prevalent HPV infection.
"This intervention could greatly reduce the morbidity, mortality and health-care costs associated with these diseases."