In a review of the incidence and trends of the Human Papillomavirus- (HPV-) related cancers, a new study found that over the last 17 years, the incidence of cervical cancer has decreased annually by 1%, while the incidence of other HPV-related cancers continues to increase.
The significant decrease in cervical cancer incidence is thought to be related to clear screening and HPV vaccination guidelines.
In 2006, the HPV vaccine was first approved for girls and young women aged 9-26 years to prevent HPV infection and the development of cervical cancer lesions. In 2011, recommendations for HPV vaccination were extended to boys aged 11-12 years. Today it is approved for everyone up to age 45.
However, no clear guidelines exist for other cancers that have a known HPV association, including oropharyngeal, vulvar, vaginal, penile, anal, and rectal cancers.
The study will be presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.
In the population-based study, the researchers found that cervical cancer accounted for 52% of all HPV-related cancers in the United States (U.S.) from 2001 to 2017, and that the incidence of the disease has decreased annually by 1%.
Further, the researchers evaluated age-specific cervical cancer incidence in the age group 20-24. When compared to older cohorts, women in the 20-24 age group were found to have a disproportionately higher decrease in the incidence of cervical cancer, 4.63% per year, suggesting a potential effect of vaccination.
“It is likely that the significant decrease in cervical cancer incidence results from clear guidelines for cervical cancer screening and may also reflect promotion and acceptance of vaccination, particularly in younger women,” said lead author Cheng-I Liao, MD, of Kaohsiung Veterans General Hospital, in Kaohsiung, Taiwan.
The researchers also found that the incidence of HPV-related cancers without standardised screening guidelines dramatically increased in women over the last 17 years.
The prevalence, especially in rates of anal and rectal cancers, is expected to continue to grow and to surpass that of cervical cancer in every age group over 50 by 2025. The overall annual increase in incidence of oropharyngeal, anal, rectal, and vulvar cancers among women was 1.3% per year.
In men, the incidence of oropharyngeal cancer accounted for 81% of all HPV-related cancers from 2001 to 2017 – a nearly fivefold higher incidence compared to women.
Over the last 17 years there was an overall annual increase in HPV-related cancers in men of 2.36% per year, with the highest increase in oropharyngeal cancer.
“Without standardised screening, HPV-related cancers, such as oropharyngeal cancers and anal rectal cancers, are increasing.
In order to reduce these trends and achieve success comparable to what we’re seeing with cervical cancer we must develop effective screening strategies and determine vaccine efficacy in these patient populations,” said Dr. Liao.
Data for 657,317 individuals were obtained from the U.S. Cancer Statistics program from 2001-2017. Incidence trends were calculated for HPV-associated cancers, including oropharyngeal squamous cell carcinoma (SCC), anal and rectal SCC, vulvar SCC, vaginal SCC, cervical carcinoma, and penile SCC.
The researchers plan to analyse the rates of HPV testing and vaccination from other databases to get additional information.
They noted that additional resources and research are needed to address both the lack of disease screening and vaccination recommendations for HPV associated cancers other than cervical cancer.