POSITIVE DIAGNOSTIC VALUES AND HISTOLOGICAL DETECTION RATIOS FROM THEROTTERDAM CERVICAL-CANCER SCREENING-PROGRAM

Background In organized screening programmes for cervical cancer, pre- cancerous lesions are detected by cervical smears. However, during fol low-up after a positive smear these pre-cancerous lesions are not alwa ys found. The purpose of the study is to analyse positive diagnostic v alues of smears of at least mild dysplasia, made under the organized s creening programmes in the Rotterdam area (1979-1991), and detection r atios of histologically confirmed CIN greater than or equal to 3, amon g women participating in these screening programmes. Methods Positive diagnostic values and histological detection ratios, by age and histor y of previous smears, recorded during the national screening programme (1989-1991), were compared with those of the experimental cervical ca ncer screening project (1976-1984). Results The positive diagnostic va lue of a smear with at least severe dysplasia (histologically confirme d CIN greater than or equal to 3) remains approximately 78%. For smear s with mild and moderate dysplasia only lower limits of the diagnostic value could be determined. This was 9% for a smear with mild dysplasi a obtained during the national screening programme and 25% and 35% for smears with moderate dysplasia taken during the experimental and nati onal screening programmes respectively. Histological detection ratios for CIN greater than or equal to 3 in the three rounds of the experime ntal screening project were 4.7, 2.9 and 1.9. In the first round of th e national screening programme the ratio was 4.7, and about three time s higher in younger compared to older women. Conclusion Immediate refe rral for colposcopy after a smear showing moderate dysplasia seems que stionable. Whether the increased detection ratio among young women ind icates a rise in the risk of cervical cancer is unclear.