People younger than 40 who received a human papillomavirus (HPV) vaccination saw lower rates of cancers often caused by HPV, such as oropharyngeal and cervical cancer, according to findings of a retrospective analysis.
Data presented at a press briefing ahead of the 2024 ASCO Annual Meeting showed that vaccinated female patients experienced statistically significant lower rates of all HPV-related cancers and cervical cancer compared with unvaccinated patients. Differences in the rates of vulvar/vaginal cancers and head and neck cancers did not reach statistical significance, and data for anal cancer were not sufficient for analysis.
In male patients, statistically significant lower rates of all HPV-related cancers and head and neck cancers were observed for vaccinated patients versus unvaccinated patients. Data were not sufficient to analyze the rates of penile and anal cancers.
“Our study showed that patients under the age of 40 [who] were vaccinated for HPV could have lower rates of cancer that are typically caused by HPV, including oropharyngeal cancer and cervical cancer,” Jefferson DeKloe, a medical student at Western Michigan University in Kalamazoo and a research fellow at Thomas Jefferson University in Philadelphia, said during the press briefing.
HPV is known to cause cancers in the oropharynx and cervix, as well as in anal and genital regions. HPV vaccines have demonstrated the ability to prevent this infection, and they are recommended for males and females between 9 and 26 years of age. Additionally, patients between 27 and 45 years of age can also receive this vaccine. However, the rates of HPV vaccination in the United States are lower compared with the rates of vaccination for other communicable diseases.
To further study the rates of HPV-related cancers in vaccinated and unvaccinated individuals, DeKloe and colleagues conducted a retrospective analysis using data from the TriNetX Database’s US Collaborative Network, which comprised information from deidentified electronic health records for 90 million patients at 63 US health care organizations. The study included patients between 9 and 39 years of age.
Patients were divided into two cohorts. The first included patients who received an HPV vaccine between 2010 and 2023, and the second consisted of patients who received any other vaccine in the same period but were not administered an HPV vaccine.
The cohort of patients who received HPV vaccines included 760,540 males and 945,999 females. The other vaccination cohort comprised 760,539 males and 945,943 females. Patients in the two cohorts were matched for age, race/ethnicity and body mass index (BMI), and investigators examined cancer outcomes at least five years following vaccination.
Investigators also analyzed the correlation between vaccination history and cervical dysplasia. They identified female patients between 21 and 39 years of age who underwent pap testing, excluding patients with a prior history of abnormal findings on a pap smear. Both the HPV-vaccinated and the HPV-unvaccinated cohort included 41,676 patients. After matching for age, race/ethnicity and BMI, investigators examined the rates of dysplasia (the presence of abnormal cells, according to the National Cancer Institute), carcinoma in-situ (CIS, when abnormal cells haven’t spread to nearby tissue, according to the National Cancer Institute), loop electrosurgical excision procedure (LEEP, use of a heated wire to remove abnormal tissue from a woman’s lower genital tract, according to Johns Hopkins Medicine) and conization (the removal of a cone-shaped piece of abnormal tissue from the cervix, according to the National Cancer Institute).
Findings showed that a statistically significant difference was not observed between HPV-vaccinated and -unvaccinated patients regarding atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesions (abnormal cells that form on the surface of some organs, according to the National Cancer Institute). However, statistically significant lower rates of high-grade squamous intraepithelial lesions, CIS, abnormal pap findings and conization/LEEP were observed for HPV-vaccinated patients versus unvaccinated patients.
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