Guo F, et al. - Before and after the introduction of human papillomavirus vaccine for young females in the US, researchers compared the incidence of cervical cancer. They found that the introduction of human papillomavirus vaccine resulted in a significant decline in the incidence of cervical cancer among young females. This may be suggestive of early impacts of human papillomavirus vaccination.

Methods

• Using data from the National Program for Cancer Registries and Surveillance, Epidemiology, and End Results Incidence–U.S. Cancer Statistics 2001–2014 database in this cross-sectional study, researchers obtained data for US females aged 15–34 years.
• In the 4 years prior to the human papillomavirus vaccine being introduced (2003–2006) and the 4 most recent years in the vaccine era (2011–2014), the 4-year average annual incidence of invasive cervical cancer was compared.
• They identified the discrete joints (year) that represented statistically significant changes in the direction of the trend after the introduction of human papillomavirus vaccination in 2006 by fitting joinpoint regression models of cervical incidence from 2001 to 2014.
• Data collection was done in 2001–2014; data was released and analyzed in 2017.

Results

• They found that, among females aged 15–24 years, the 4-year average annual incidence rates for cervical cancer in 2011–2014 were 29% lower than that in 2003–2006 (6.0 vs 8.4 per 1,000,000 people, rate ratio=0.71, 95% CI=0.64, 0.80), and 13.0% lower among females aged 25–34 years.
• For both squamous cell carcinoma and non–squamous cell carcinoma, a significant joint at 2009 was revealed in joinpoint analyses of cervical cancer incidence among females aged 15–24 years.
• No significant decrease was noted in cervical cancer incidence after 2006 among females aged 25–34 years.