Click here to view as PDF.
New evidence presented at the annual meeting of the Society of Gynecologic Oncologists suggests that Gardasil, a vaccine that prevents cervical cancer, also reduces the likelihood of recurrence after surgery by 40%. This finding is important because it means that females who already have the human papilloma virus (HPV) might still benefit from vaccination with Gardasil. The Gardasil vaccine protects against the 4 strains of HPV (including 16 and 18) known to cause 70% of cervical cancer cases. Warner Huh, MD, associate professor, Division of Gynecologic Oncology, University of Alabama at Birmingham (UAB), presented the data.
In this retrospective study, investigators looked at records for 17,622 women aged 15 to 26 years who took part in two clinical trials. Hundreds of the women had undergone surgical excision of precancerous or cancerous lesions of the cervix, vagina, and vulva or had surgical removal of genital warts prior to the trial. Some of the women were vaccinated and others received placebo.
Huh said his team looked at the rate of new incidents in these women. It was not possible, Huh said, to determine conclusively whether the incidents represented new or recurrent disease. The researchers compared the rate of HPV-related cancer or precancerous changes or genital warts subsequent to vaccination in the treatment arm and the placebo arm. Women who received Gardasil were 40% less likely to have an incident in the 3.8 years following the initial surgical procedure.
This is encouraging said Huh, because unvaccinated women treated for an HPV-related condition typically are at increased risk of contracting the same disease after surgery compared with unvaccinated women who have never had the disease. Huh described the data as “compelling” because they suggest Gardasil helps treat virusrelated changes. In an interview with Oncology & Biotech News
, Huh said, “The mechanism is unclear, but we feel the impact is clinically significant nonetheless.”
According to Huh, the recognition that Gardasil offers postoperative protection from recurrent disease will be crucial in follow-up care and overall health planning for teens and women. For community- based oncologists, “The study stresses the importance of vaccination, even for sexually active women and women with a history of disease, as a preventive measure,” said Huh.
Although the study did not include women aged >26 years, which is the cutoff for FDA approval of Gardasil, Huh said UAB might consider doing a similar study with older women. “I would expect similar results, but it is unknown if the degree of impact will be similar,” he said. Asked whether vaccination should be considered for women who are HPV-positive but have not had surgery for any HPV-related condition, Huh responded, “This is a controversial area, since it is known that the efficacy [of the vaccine] is lower in women [who] are sexually active.” He added that “the degree of protection may still be clinically important, at least on the individual level.”
Huh noted that like all vaccines, the problem with Gardasil is that reducing the overall occurrence of lesions requires inoculating a substantial percentage of the population. “We know that the vaccine will have its greatest impact when given to girls 11 to 12 years of age,” Huh said. To increase vaccination rates in this population, Huh suggested a mandate—perhaps at the school level—would likely have the greatest effect “on reducing the burden of HPV-related disease at the population level.” He said researchers needed to figure out other ways to advocate HPV vaccination.
Disclosure: Huh maintains a consulting relationship with Merck & Co Inc, which manufactures Gardasil.
Huh W, et al. “Impact of the quadrivalent HPV 6/11/16/18 vaccine in women who have undergone definitive therapy: Do these women benefit from vaccination?” Abstract LBA 3. Presented at: 2010 SGO Annual Meeting on Women’s Cancer. March 14-17, 2010; San Francisco, California.