Older women testing positive for HPV 16/18 on cervical screening and risk of high-grade cervical abnormality.

In Australia's HPV-based cervical screening program, we previously showed that risk of histological high-grade abnormality at 1 year post screening decreased with age in women with oncogenic HPV. In this study, we followed 878 HPV16/18 positive women aged 55 years and over for up to 3 years post screening test, to determine the proportion with histological high-grade abnormality (HGA, incorporating high-grade squamous intraepithelial abnormality (HSIL), adenocarcinoma in situ (AIS), squamous cell carcinoma (SCC) and adenocarcinoma) and to correlate risk of HGA with liquid-based cytology result and with prior screening history. HGA was detected in 7.8% at 1 year and 10.0% at 3 years, with no significant difference (p=0.136), despite the number of women with follow-up information significantly increasing from 82.9% to 91.0% (p<0.0001). The proportion of HPV16/18 positive women with HGA at 3 years was highest in those with an HSIL cytology result (79.0%) and lowest in those with negative cytology (6.2%). Women with an adequate screening history had fewer HGA than such women with inadequate prior screening (6.6% vs 16.0%, p=0.001) or with a history of an abnormality (6.6% vs 14.4%, p=0.001). HPV16/18 infection in women over 55 years may have a different natural history from that in younger women, in whom HGA are more common after HPV16/18 detection. In HPV-based cervical screening programs, management algorithms for screen-detected abnormalities based on risk stratification should include factors such as age, screening history and index cytology result, so that women receive appropriate investigation and follow-up.