Decrease in cervical cancer rates may be linked to HPV screening, vaccination
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A decrease in cervical cancer rates in the United States, most notably among younger women, may be associated with HPV vaccination approval, according to a retrospective, cross-sectional study published in JAMA Network Open.
Researchers added that an increase in oropharyngeal and anal/rectal cancers, particularly among men, highlights a need for vaccination uptake among both men and women.
“Approximately 45,000 HPV-associated cancers are diagnosed annually in the U.S. and most of these cancers could have been prevented. The HPV vaccine was approved by the U.S. Food and Drug Administration in 2006 for women and in 2009 for men, providing protection against 90% of cervical cancer-causing strains of HPV,” John K. Chan, MD, Denise & Prentis Cobb Hale endowed chair at California Pacific Medical Center and principal investigator lead of the Sutter Cancer Research Consortium, told Healio. “Since some of these cancers can be prevented with vaccination and/or screening, it is important to incorporate both of these interventions in our study.”
Methodology
The analysis included 657,317 HPV-associated cancers (oropharyngeal squamous cell carcinoma [SCC], 40%; anal/rectal SCC, 14.5%; vulvar SCC, 9.1%; vaginal SCC, 2%; cervical carcinoma, 31.4%; and penile SCC, 3%) identified from the U.S. Cancer Statistics Public Use Database between 2001 and 2017. Most of the cancers (59.8%) occurred among women, and 76.1% of all patients were white. More than half of women (52.4%) had cervical cancer and most men (80.1%) had oropharyngeal cancer.
Researchers collected HPV vaccination and screening data from the Behavioral Risk Factor Surveillance between 2001 and 2016 and TeenVaxView between 2008 and 2018. They then evaluated the trends in HPV-associated cancer incidence by age, race and ethnicity, as well as tumor stage, for potential associations between screening and vaccination with incidence of HPV-associated cancers.
Key findings
Among female adolescents aged 13 to 17 years, the vaccination rate increased from 37.2% in 2008 to 69.9% in 2018 (annual percent change, 6.57%; 95% CI, 5.83-7.32).
The researchers also reported that cervical cancer rates decreased 2.29% per year (P = .045) among women aged 20 to 24 years before vaccine approval and 9.5% per year (P = .003) after approval.
Among men, researchers observed annual increases in oropharyngeal (2.71%) and anal/rectal (1.83%) cancers. Among women, incidence of oropharyngeal had remained stable but anal/rectal cancer incidence increased 2.83% annually. The older median age of onset of anal/rectal cancer vs. cervical cancer (62 years vs. 49 years) may partly account for the continued increase in incidence of anal/rectal cancer and apparent lack of potential benefit of vaccination.
“Although the HPV vaccine has been approved for more than 15 years in women, uptake has been slower than other recommended childhood vaccinations,” Chan told Healio. “We did not expect to show that more than 80% of new diagnoses of oropharyngeal cancer occurred in men, with increasing rates.”
Implications
Chan said further work is necessary to increase rates of vaccination among both sexes, in addition to efforts to eliminate racial and ethnic disparities in screening in the U.S.
“These findings on the increasing incidence of anal/rectal cancer highlight the importance of HPV vaccination, as well as the need to develop more effective screening strategies to prevent anal/rectal cancer, particularly in high-risk populations,” Chan said. “We would like to encourage better access to population-based studies with data sharing and develop a national registry of screening and vaccination to prevent cancers.”
For more information:
John K. Chan, MD, can be reached at California Pacific/Palo Alto Medical Foundation/Sutter Research Institute, 1100 Van Ness Ave., 4th Floor, San Francisco, CA 94109; email: chanjohn@sutterhealth.org.
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