The vaccine, which protects patients from seven different strains related to HPV-related cancers, may be considered part of routine oncology care for survivors.
The immune response obtained from the three-dose HPV vaccine series in cancer survivors was similar to that of the general population, according to recent study results.
Findings from the study also demonstrated that the vaccine had similar safety effects in cancer survivors and the general population.
“We looked specifically at the two HPV types that are most highly associated with the development of cancers, so that’s HPV types 16 and 18,” Wendy Landier, a professor in the Division of Pediatric Hematology/Oncology at the University of Alabama at Birmingham Marnix E. Heersink School of Medicine and the School of Nursing, told CURE®. “We found that the response in the cancer survivors was similar to the response in the general population, so they got similar levels of antibody response to the general population.”
Assessing whether the HPV vaccine offers effective protective levels in cancer survivors aged nine years to 26 years resulted from a concern about vaccine uptake.
“Our concern is, and the reason we did the study was, because the uptake among cancer survivors of the vaccine is actually lower than the already low uptake in the general population,” Landier said. “Our cancer survivors are not taking this vaccine. They’re not getting that protection. Our hope is that with this new information that the vaccine is equally able to provide these protective levels to cancer survivors, but this will, in fact, encourage it to become part of routine oncology care.”
Assessing Immune Response to the HPV Vaccine
Landier and her colleagues analyzed data from 436 cancer survivors ages nine to 26 (55% aged nine to 15 years) who received at least one dose of the HPV vaccine at a mean age of 15.6 years. The mean age that patients were diagnosed with cancer was 10.9 years. Within this group of cancer survivors, 42% were women and 47% survived leukemia.
Of these survivors, 378 had available immunogenicity data, which allowed researchers to assess immune response to the HPV vaccine. This information was compared with data from 26,486 people from the general population who did not have cancer.
“We really wondered what the uptake would be for the vaccines in young cancer survivors as well as what would be their immune response to the vaccine,” Landier said. “So those two things together, we thought it was important to understand the immune response so that there would be confidence in prescribing it and making sure that it would have an equivalent protective effect in cancer survivors. Sometimes vaccines … in immunocompromised population, they don't always get the full effect of the vaccine.”
The antibody responses against HPV types 16 and 18 in cancer survivors were noninferior to those in the general population, meaning that the responses were similar. In addition, both groups had similar side effect profiles.
‘The Vaccine Now Protects You’
Landier commented that these findings may show that all patients, especially those who are cancer survivors, should get the HPV vaccine.
“The vaccine now protects you,” she said. “In the U.S., there's only really one HPV vaccine that is given … the Gardasil 9 vaccine. That vaccine protects against seven different strains that are associated with the large majority of HPV-related cancers, and then the two strains that are associated with the large majority of genital warts. So it has nine different types of protection in the one vaccine. Even if you had been exposed to some HPV, the chances are that you've not been exposed to all of those.”
Current recommendations emphasize that children should receive the HPV vaccine at age 11 or 12, before they become sexually active, although it can be administered up to age 45, Landier explained.
“It's just that people (who) do respond have a more robust response when they're younger, which is what we found in our study as well, but that they do still have a response that has been shown to be effective as they get older as well,” she concluded. “The downside is that as you get older, you may have already been exposed (to HPV) and have developed some precancerous lesions. So yes, you want to give it as early as you can, but it's still absolutely fine to give it when it is possible to give it, even if that's a bit later than the recommended timeframe.”
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