Incidence and outcome of acquisition of human papillomavirus infection in women with normal cytology - A population-based cohort study from Taiwan

Little is known about acquisition of human papillomavirus (HPV) and its outcome among older women with negative HPV testing and normal cytology. A longitudinal 3-yr follow-up of nested-cohort subjects (n 5 8825) from a population-based cervical cancer screening study whose Pap and HPV tests were negative at baseline were conducted. Every active HPV-negative (n = 413) participant had 12-mo follow-ups of Pap smear and HPV testing. Colposcopy was performed if either HPV-positive or cytology was abnormal. The cytology and histology information of the remaining subjects (passive HPV-negative, n = 8412) was obtained from national registry database. Median age of participants was 45 yr (range, 30-73 yr). The incidence of new acquisition was 4.2/100 woman-years. The 3-yr cumulative total HPV acquisition rate was 11.1% (95% confidence interval [CI]: 8.1-14.1). Increased number of sexual partners (≥2 vs. 1) of the participant was associated with risk of acquisition (odds ratio [OR]: 5.0, 95% CI: 2.0-12.6) by multivariate analysis. Three cases of ≥ cervical intraepithelial neoplasia (CIN) 2 were identified in 3-yr follow-up in active HPV-negative subjects. HPV genotypes in the dysplastic tissue were actually present at baseline samples after reanalysis. From the passive HPV-negative group, only 1 case progressed to CIN2 probably after HPV acquisition. Negative Pap and HPV tests assured a very low risk of developing ≥ CIN2 within 3 yr despite incident HPV infection.