The limitation of screening effect. A review of cervical disorders in previously screened women.

In the Frederiksberg screening program from 1962 to 1972 invasive carcinoma, carcinoma in situ or severe dysplasia of the cervix were found in 155 previously unscreened women. In previously screened women 137 lesions were later elucidated, 53 of these at rescreening. If a failure of method of 10 per cent is anticipated, 21 cases were probably missed due to the method chosen. Patient failure was noted in six cases and two cases were missed by insufficient follow-up by the doctor. The importance of a high participation rate is emphasized. The cytologist's error was 19 per cent. Sixty-four cases were estimated to represent new cases developed between screenings. A reduction of cytologist's error is assumed to be the most accessible way of improving screening results.