Prospective evaluation of a risk scoring system for cervical neoplasia in primary care

Against a background of concern over the costs of the cervical screening programme in the United Kingdom, increased precision in targeting groups at high risk of having an abnormal cervical smear offers a means of increasing efficiency. Previous papers have described the development of a risk scoring system and its feasibility and reliability in primary care.

A study was carried out to assess the validity of the scoring system by testing its predictive ability on a prospective data set.

Consecutive attenders for cervical smear tests at seven practices and three clinics were recruited for the study. The women completed a questionnaire from which their risk scores could be calculated. The scores were compared with cytology and histology results. Various performance statistics were obtained.

In terms of cervical intraepithelial neoplasia (CIN) 2 or 3, there was an 11 fold increased risk among the low risk group (scores of four or five) compared with the very low risk group (scores of three or less). The system enabled the identification of 75% (95% confidence interval 62% to 84%) of cases of CIN 2 or 3 among the 21% of the 3629 women with known histology who had a score of four or five.

Given the ease with which risk status can be ascertained (a risk score could not be calculated for only 23 of 3661 women) and the magnitude of difference in risk, the risk scoring system appears to have potential for assisting the targeting of screening resources. Studies of risk perception and behaviour, and ultimately a randomized controlled trial, are required to assess the effectiveness and cost effectiveness of risk targeting.