The cytological screening history of 469 patients with squamous cell carcinoma of the cervix uteri; Does interval carcinoma exist?

Background. To determine whether interval carcinomas occurred and to determine the level of screening-participation by women who developed a cervical carcinoma. Methods. A retrospective study of the cytological history of 469 patients diagnosed between January 1980 and December 1989 with cervical squamous cell carcinoma in 12 hospitals in the western part of The Netherlands. Clinical data, and cervical smear histories in 3.5 years preceding the diagnoses were obtained. Cervical smears diagnosed as Pap I, II or IIIA were traced for review. Results. 306 patients' data were completed. Two hundred and twenty-three patients (72.9%) had never been screened and 83 patients (27.1%) had had at least one smear, of which 39 were normal. The percentage of women over 54 was higher in patients who had never been screened (58%) than in those screened (46%). Women over 54 were in higher Figo stage. Interval carcinoma was proven in six of 306 (2%) patients. Of the normal smears 53% were false negative. Conclusion. The high number of non-participants still forms the main reason for the failure of cervical cancer screening. Secondly, the assumed existence of frequent interval carcinoma could not be demonstrated. There are grounds for changing the age limits of the current Dutch screening program without changing the screening interval.