DETECTION RATES FOR ABNORMAL CERVICAL SMEARS - WHAT ARE WE SCREENING FOR

We analysed rates of detection for smear abnormalities in 255 000 wome n served by the Bristol screening programme. The programme began in 19 66 with the aim of eradicating the 30-40 deaths each year in Bristol f rom cervical cancer. Organisation has been good and population uptake has been high for the past 15 years. Records were computerised in 1977 . During the 1988 to 1993 screening round, 225 974 women were tested. New smear abnormalities were found in 15 551, of whom nearly 6000 were referred for colposcopy. These numbers are excessively high in compar ison with the incidence of the malignancy we are trying to prevent. Th e effect of screening on death rates in Bristol is too small to detect . Our conclusion is that despite good organisation of the service, muc h of our effort in Bristol is devoted to limiting the harm done to hea lthy women and to protecting our staff from litigation as cases of ser ious disease continue to occur. The real lesson from 30 years' cervica l screening is that no matter how obvious the predicted benefit may se em for any screening test, introduction should never take place withou t adequate prior evaluation of both positive and negative effects in c ontrolled trials.