HPV genotype prevalence in women with abnormal pap smears in Melbourne, Australia

Abstract

Carcinoma of the cervix and its precursor, high-grade cervical intraepithelial neoplasia (CIN2/3), are associated with persistent oncogenic Human papillomavirus (HPV) infection, particularly HPV 16 and 18. HPV genotype distribution varies with severity of cervical disease, patient demographics such as age, as well as geographical location. In this study, HPV genotype prevalence was determined, using the Roche Linear Array genotyping test, among a cohort of 1,676 women being managed with ablative or excisional treatment following colposcopically directed biopsies, who were referred initially due to cytological abnormalities. HPV genotype prevalence, including presence of single and multiple infections was assessed against both histological diagnosis and age. Overall, 83.9% of women were identified as HPV positive, comprising of 32.2% single and 51.7% multiple HPV infections. Of those with an available histological diagnosis at time-of-treatment (n = 899), HPV positivity increased significantly with disease severity: 62.4% (normal), 77.6% (CIN1), 92.6% (CIN2), and 97.9% (> or =CIN3) (P < 0.006). Similarly, a significant increase in high-risk (HR) HPV detection was observed with severity of disease (P < 0.005). The five most prevalent genotypes were HPV 16 (35.1%), 31 (12.6%), 51 (11.1%), 52 (9.9%), and 18 (8.5%). HPV 16 was the only genotype to demonstrate a significant increase in prevalence with increasing severity of histological or cytological disease (P < 0.0001). Multiple HPV infections, including multiple HR-HPV infections, declined significantly with age (P < 0.02). These findings provide the largest dataset of HPV genotype prevalence rates within Australian women, though are not representative of the general population.