Human papillomavirus type specific risk of progression and remission during long-term follow-up of equivocal and low-grade HPV-positive cervical smears

Abstract

The prevalence of clinically relevant HPV types and their specific risk for progression and regression in women with atypical squamous cells of uncertain significance (ASCUS) and low-grade squamous intraepithelial lesions (LSIL) were studied in a routine screening population. A 4-year cohort of women (n = 820) with ASCUS/LSIL and a positive HPV test in triage were followed for 6-9 years. The progression risks for CIN2+/CIN3+ were determined for single (71.2%) and multiple HPV infections (28.8%). The CIN2+ progression risk for all HPV 16, all HPV 35, single HPV 16 and single HPV 35 infections were 65.3% (95% CI: 59.6-71.0), 64.4% (95% CI: 50.4-78.4), 63.8% (95% CI: 56.2-71.4) and 73.7% (95% CI: 53.9-93.5), respectively. Based on CIN2+ progression risks four main groups were defined; the HPV 16 group, the HPV 31/33/35 group, the HPV 18/45/51/52 group and the HPV 39/56/58/59/66/68 group with progression risks of 65.3% (95% CI: 59.6-71.0), 62.1% (95% CI: 54.8-69.4), 52.6 (95% CI: 45.9-59.3) and 39.5 (95% CI: 33.0-46.0), respectively. In multivariate analyses, women in the age group 40-49 years had an increased risk of CIN2+ progression. As for CIN3+, HPV 16 had a higher progression risk than other HPV risk groups (p < 0.05). In multiple infections only HPV 16 had a significant additive CIN3+ progression risk (p < 0.05) as compared to other HPV risk groups. In summary, HPV types 16 and 35, including the HPV risk group 31/33/35, had a similar CIN2+ progression risk, but only HPV 16 had a higher risk for CIN3+ progression.

Keywords: ASCUS; CIN2; HPV types; LSIL; progression risk.