For and against 3-yearly Papanicolaou smear for cervical cancer screening

Objective: To analyse the possibility of three-yearly screening for cervical cancer after two consecutive normal annual smears. Method: Review of the literature. Results: In Switzerland 78% of women are screened spontaneously for cervical cancer. For 70% of this group the last smear was less than 18 months before. In other European countries or in North America programmed screening is every 3 or even 5 years. A lowered mortality rate is observed depending on the interval between screening. The benefit is only 2.7% between 3-yearly (90.8%) and yearly smears (93.5%). Finding an oncogenic HPV [16, 18, 31, 45] whilst investigating low grade cervical intraepithelial neoplasia (CIN1) is associated with a 17% risk of conversion into high grade cervical intraepithelial neoplasia (CIN3) within 3 years. Conclusion: In Switzerland the conditions for screening on a 3-yearly basis are not fulfilled. We recommend an interval of only 2 years after 2 normal annual smears.