Long-term risk of cervical intraepithelial neoplasia grade 3 or worse according to high-risk human papillomavirus genotype and semi-quantitative viral load among 33,288 women with normal cervical cytology.

ABSTRACT

In this prospective cohort study, we estimated the long-term risk of cervical intraepithelial neoplasia grade 3 or cancer (CIN3+) by high-risk human papillomavirus (hrHPV) genotype and semi-quantitative viral load at baseline among 33,288 women aged 14-90 years with normal baseline cytology. During 2002-2005, residual liquid-based cervical cytology samples were collected from women screened for cervical cancer in Copenhagen, Denmark. Samples were HPV-tested with Hybrid Capture 2 (HC2) and genotyped with INNO-LiPA. Semi-quantitative viral load was measured by HC2 relative light units in women with single hrHPV infections. The cohort was followed in a nationwide pathology register for up to 11.5 years. In women aged ≥30 years at baseline, the 8-year absolute risk for CIN3+ following baseline detection of HPV16 was 21.8% (95% confidence interval [CI] 18.0-25.6%). The corresponding risks for HPV18, HPV31, HPV33, and other hrHPV types, respectively, were 12.8% (95% CI 7.6-18.0%), 11.3% (95% CI 7.7-14.9%), 12.9% (95% CI 7.0-18.8%) and 3.9% (95% CI 2.7-5.2%). Similar absolute risk estimates were observed in women aged <30 years. Higher HPV16-viral load was associated with increased risk of CIN3+ (hazard ratio = 1.34, 95% CI 1.10-1.64, per 10-fold increase in viral load). A similar trend, although statistically nonsignificant, was found for viral load of HPV18. The 8-year absolute risk of CIN3+ in women with HPV16-viral load ≥100.0 pg/ml was 30.2% (95% CI 21.9-38.6%). Our results support that hrHPV genotyping during cervical cancer screening may help identify women at highest risk of CIN3+.