In a study published in JAMA Oncology, researchers a found that, after adjusting for changes in screening, there was a decrease in all-grade cervical intraepithelial neoplasia (CIN), a known link to cervical cancer, among women 15-19 years old who received the human papillomavirus (HPV) vaccine.
Untreated human papillomavirus (HPV) has been linked to incidence of CIN, which can lead to invasive cervical cancer. While numerous studies have documented the success of HPV vaccination in preventing viral infection and development of CIN, few have examined the effect of reduced screening rates for these patients.
Therefore, researchers led by Vick B Bernard, PhD, Centers for Disease Control and Prevention (Atlanta, GA), conducted a study using data from the New Mexico Pap Registry, the only surveillance system in the United States that captured population-based estimates of both screening prevalence and CIN since the beginning of the vaccine introduction, to estimate the HPV vaccine effect on CIN rates. Pre-specified outcome measures included low-grade CIN (grade 1 [CIN1]) and high-grade CIN (grade 2 [CIN2] and grade 3 [CIN3]).
In New Mexico, the mean uptake of all 3 doses of HPV vaccine was 40% in 2014 among women aged 13-17 years, a significant increase from what was reported in 2008 (17%) and 2013 (38%). Overall, all-grade rates for CIN fell significantly among females 15-19 years during the study period, dropping from 896.4 to 414.9 for CIN2 (APC, −10.5; 95% CI, −18.8 to −1.2; P = .03), and from 240.2 to 0 for CIN3 (APC, −41.3; 95% CI, −65.7 to 0.3; P = .05). Additionally, the incidence of CIN2 was significantly reduced in women 20-24 years, dropping from 1027.7 to 627.1 (APC, −6.3; 95% CI, −10.9 to −1.4; P = .02).
Based on these findings, researchers concluded that rates of CIN fell significantly more than they had expected, supporting vaccine cross-protection.
“Overall, our data demonstrate that clinical outcomes of CIN will be reduced among cohorts partially vaccinated for HPV, which will change clinical practice and reduce the cost-effectiveness of current clinical care that supports cervical cancer prevention,” authors wrote. “Most important, screening modalities and strategies, as well as clinical management algorithms, will need to evolve as we work toward a rational integration of HPV vaccination and cervical screening.”
