Is a policy of cervical screening for all women attending a genito-urinary medicine clinic justified?

Abstract

BACKGROUND: The study took place at the Genito-Urinary Medicine Department at the University Hospital of South Manchester and the Cytology Department at Christie NHS Trust Hospital. There were two main objectives, as follows: (1) to determine if patients attending a Genito-Urinary Medicine (GUM) Clinic are less likely to have had a cervical smear in the preceding five years than a control group drawn from the general population; (2) to compare the prevalence of cytological abnormalitity in cases and controls. METHODS: Cases comprised all women attending the Withington GUM Clinic, between 1991 and 1993, who had had a cervical smear taken at this clinic. Controls were selected from residents of the North West Regional Health Authority who had a cervical smear taken either by a general practitioner (GP) or in an NHS Community Clinic during the same period. The design was a matched case-control study. The main outcome measures considered the proportion of women who had had a cervical smear taken by a GP or in an NHS Community Clinic during the five years preceding the index smear, and the prevalence of abnormal smears in cases and controls. RESULTS: There was no significant difference in the screening history of cases and controls; 363 (50.2 per cent) cases had had a cervical smear taken in the preceding five years as compared with 380 (52.6 per cent) controls [chi 2 (1df) = 0.95; p > 0.05; 95 per cent confidence interval (CI) on difference in proportions, -7.1 per cent to 2.4 per cent]. There was a small case-control difference of borderline significance in the prevalence of all grades of cytological abnormality: 22.7 per cent of cases had abnormal cytology as compared with 18.5 per cent of controls [chi 2 (1df) = 3.98; 0.01 < p < 0.05; 95 per cent CI on difference in proportions, 1 per cent to 8.2 per cent). This excess was largely attributable to differences in the prevalence of minor cytological abnormality. There was no significant difference in the prevalence of cytological abnormality in those case-control pairs who had had a smear in the preceding five years. CONCLUSION: A policy of cervical screening of all GUM patients can no longer be sustained. We would recommend cervical cytology only for those women who have not been screened in the previous three to five years.