HPV16 and HPV18 genotyping triage in young women with borderline cytology or mild dyskaryosis: effect of age on genotype-specific risk of high-grade CIN.

Abstract

Human papillomavirus (HPV) triage of borderline cytology or mild dyskaryosis is limited by the higher prevalence of HPV in women with these findings relative to those with high-grade cervical intraepithelial neoplasia (≥CIN2). This is particularly relevant in young women in whom HPV prevalence is discernible. In a previous analysis of HPV triage and colposcopy outcomes in Northern Ireland, we revealed a substantial amount of prevalent high-grade disease in women below 30 years of age. We explored the role of genotyping for HPV16/HPV18 in this population by assessing the risk of high-grade lesions associated with these genotypes and the effect of age on type-specific risk. Of the 866 women eligible for HPV triage, those who tested positive for HPV were referred to colposcopy. The relative risk of ≥CIN2 for HPV16, HPV18 and non-HPV16/18 high-risk genotype positivity was determined for cobas(®) HPV Test-positive results. The relative risk of high-grade CIN was significantly greater in women infected with HPV16 and/or HPV18 compared with non-HPV16/18 infections, regardless of age (2.23 and 0.45, respectively). In women under 30 years of age, HPV16-associated risk of ≥CIN2 was significantly greater than that of HPV18 and the non-HPV16/18 genotypes (1.74 versus 1.03 and 0.58, respectively). In women aged ≥30 years, HPV18 infection presented the greatest risk of ≥CIN2 (3.03). The relative risk of ≥CIN2 associated with non-HPV16/18 genotypes was lower (range, 0.32-0.58) for both age groups. This analysis demonstrates the value of genotyping for HPV16/HPV18 and age stratification to improve the specificity of HPV triage and to tailor management relative to the risk of high-grade CIN and cancer.