[Population screening for uterine cervix cancer: the negative effects of insufficient knowledge as to what is normal and abnormal].

Screening for asymptomatic disease seems attractive but has severe disadvantages if not evaluated properly. The side-effects may be greater than the benefits, especially in countries with a very low incidence of the disease. In 1997, invasive cervical cancer was diagnosed in approximately 700 women in the Netherlands. Knowledge about the effect of cervical cancer screening has been derived from observational studies since randomised trials are non-existent. For many findings in the cervical smear we do not know the natural course. As a result, a substantial number of women (10%) are advised to undergo repeated screening after a shorter interval than the regular screening interval of 3 years (since 1996 this is 5 years). In 1996, a new guideline was developed to limit the number of women in the repeat circuit. The percentage of women with a Pap 2 smear (mild dysplasia) decreased from 10% in 1992 to 2% in 1998. However, the follow-up with repeat smears was less rigorous: for 28% no repeat smear was performed after 2 years and 3 months, compared to 10% in 1992. Incomplete follow-up will lead to a decreased cost-effectiveness of the programme, which already appears to be only marginally effective. The value of screening for cervical cancer should be reconsidered from time to time.