HPV vaccine reduced further disease in women treated for cancer precursors

The Society for Gynecologic Oncologists’ 2010 Annual Meeting

SAN FRANCISCO — HPV vaccine quadrivalent (types 6, 11, 16 and 18) decreased HPV-related disease in women previously treated for cancer precursors, according to the post-hoc analysis of findings from two trials.

Warner Huh, MD, associate professor in the department of obstetrics and gynecology at the University of Alabama at Birmingham, presented these findings at The Society for Gynecologic Oncologists’ 2010 Annual Meeting on Women’s Cancer in San Francisco.

Although the HPV4 (Merck, Gardisil) has been shown to prevent cervical intraepithelial neoplasia, vulvar intraepithelial neoplasia, vaginal intraepithelial neoplasia, genital warts and adenocarcinoma, it is unclear if the vaccine may benefit patients who have already been exposed to the virus and had subsequent surgery.

Researchers analyzed data from 17,622 women who were randomly assigned to the HPV4 or placebo.

Overall, 587 women assigned to the vaccine and 763 assigned to placebo underwent cervical definitive therapy. Patients in the placebo group were at higher risk for incidence of CIN, vulvar intraepithelial neoplasia, vaginal intraepithelial neoplasia, genital warts and adenocarcinoma at a rate of 11.1 per 100 person-years, with an average of 1.4 years after surgery, compared with patients assigned to HPV4.

Regardless of causal HPV type, patients who were vaccinated had a reduced risk for developing further disease, with a rate of 45% (95% CI, 21-62). Women treated for vulvar intraepithelial neoplasia, vaginal intraepithelial neoplasia and genital warts assigned to placebo had the highest risk for further disease, with a rate of 33.7 per 100 person-years. The risk for further disease in the vaccine group, however, was reduced by 38.6% (95% CI, 17-55).

He did stress two important points- in this analysis, women were not vaccinated after treatment and as such, it is unknown if there is any benefit in this specific setting and the findings in this study do not imply there is any specific therapeutic benefit associated with the HPV vaccine.

"Although we do not know the exact underlying mechanisms, the observed reductions were clinically significant, and on an individual level, vaccination of women with past or pre-existing disease is warranted and should be considered and discussed," Huh said during the presentation. – by Christen Cona

Huh W. #LB3. Presented at: The Society for Gynecologic Oncologists’ 2010 Annual Meeting on Women’s Cancer; March 14-17, 2010; San Francisco.

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