Age-specific HPV type distribution in high-grade cervical disease in screened and unvaccinated women

BACKGROUND AND AIM: Age-specific type-distribution of high-risk human papillomavirus (hrHPV) in cervical precancerous lesions is subject to change in the HPV vaccination era. Knowing the pre-vaccination type-distribution helps to anticipate changes induced by mass vaccination and optimize screening.

METHODS: We recruited 1279 women referred to colposcopy for abnormal cytology into a population-based study on HPV type distribution in diagnostic cervical samples (ISRCTN10933736). The HPV genotyping findings were grouped as: HPV16/18+, other hrHPV+ (HPV31/33/35/39/45/51/52/56/58/59/66/68), non-vaccine targeted hrHPV+ (HPV35/39/51/56/59/66/68), low-risk HPV, and HPV negative. We estimated the HPV group-specific prevalence rates according to diagnostic histopathological findings in the age groups of <30 (n = 339), 30-44.9 (n = 614), and ≥45 (n = 326).

RESULTS: Altogether 503 cases with high grade squamous intraepithelial lesion or worse (HSIL+) were diagnosed. More than half, 285 (56.7%) of HSIL+ cases were associated with HPV16/18: 64.3% (101/157) in women <30 years (reference group), 58.4% (157/269) in women 30-44.9 years (risk ratio (RR) 0.91, 95% confidence interval (95% CI) 0.78-1.06), and 35.1% (27/77) in women ≥45 years of age (RR 0.55, 95% CI 0.39-0.75). Conversely, other hrHPV's were associated with 191 (38.0%) of HSIL+: 31.9% (50/157) in women <30, 36.8% (99/269) in women 30-44.9 years, 54.6% (42/77) and in women ≥45 (RR 1.71, 95% CI 1.26-2.33). The proportion of non-vaccine targeted hrHPV and HPV negative HSIL+ increased with advancing age.

CONCLUSIONS: Pre-vaccination HPV type distribution in HSIL+ was distinctly polarised by age with HPV16/18 attributed disease being markedly more prevalent in women aged <30. In the older women the other hrHPV types, however, dominated suggesting a need for more age-dependent screening strategies.