Cervical cancer: cytological cervical screening in Iceland and implications of HPV vaccines.
This paper reviews the Icelandic experience regarding the age-specific effectiveness, optimal targeted age range and intervals in cervical cancer screening and the screening implications of the HPV16/18 vaccines. The background material is based on data from a screening programme with centralized records dating back to 1964, as well as from population-based studies on the distribution of oncogenic HPV types in cancer and histologically verified CIN2-3 lesions and from the Icelandic arm of the Future II trial with Gardasil. The findings confirm significant increased rates in the screened population of CIN2-3, stage IA (microinvasive) cancer since 1979, mainly in the age group 20-34 years. These lesions start to accumulate within 3 years of a normal smear. Studies on the distribution of HPV types indicate that the marketed vaccines could lower the incidence of cancer and CIN2-3 by about 67% and 53%, respectively, after taking into account reported cross-protection. About 65% of women below 25 years of age had lesions related to the non-vaccine types and after the last normal smear these cases accumulated at the same frequency as cases with vaccine-included types. Cases with combined vaccine and non-vaccine types accumulated at a slower rate. We conclude that screening should continue to start at age 20 years, with invitations at 2-year intervals up to age 39 years and thereafter at 4-year intervals up to age 65-69 years. Current data support the conclusion that the optimal age for catch-up HPV vaccination should be considered in the context of sexual practices and the data do not support changes in the lower age limit or screening intervals for the vaccinated women.
Sigurdsson
K
K
Cancer Detection Clinic, The Icelandic Cancer Society, Reykjavik, Iceland. kristjan@krabb.is
D002584:Cervix Uteri / Q000473:pathology*; D003584:Cytological Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008403:Mass Screening / Q000379:methods*; D053918:Papillomavirus Vaccines / Q000276:immunology*; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*
D053918:Papillomavirus Vaccines