HPV type distribution in invasive cervical cancers in Italy: pooled analysis of three large studies

Objective The aim of this study is to describe the prevalence of HPV types in invasive cervical cancers in Italy from 1996 to 2008. Methods A pooled analysis of the three largest case series typed to date was performed. HPV typing was performed on paraffin-embedded slices. Molecular analyses were performed in four laboratories. Multivariate analyses were performed to test the associations between calendar time, age, and geographical area and the proportion of types 16/18. Results Out of 574 cancers, 24 (4.2%) were HPV negative. HPV 16 and 18 were responsible for 74.4% (378/508) and 80.3% (49/61) of the squamous cancers and adenocarcinomas, respectively. Other frequent types were 31 (9.5%), 45 (6.4%), and 58 (3.3%) for squamous cancers and 45 (13.3%), 31, 35, and 58 (5.0%) for adenocarcinomas. The proportion of HPV 16 and/or 18 decreased with age (p-value for trend <0.03), while it increased in cancers diagnosed in more recent years (p-value for trend < 0.005). Conclusions The impact of HPV 16/18 vaccine on cervical cancer will be greater for early onset cancers. In vaccinated women, screening could be started at an older age without reducing protection.