Early discharge of low-risk women from cervical screening

The Scottish Cervical Screening Programme currently offers three-yearly screening to all women between the ages of 20 and 60. However, previous studies have indicated that well-screened women over the age of 50 are likely to be at low risk of cervical neoplasia. This study aimed to explore the implications of discharging these women from screening in a typical area of Scotland.

A case-control study of the screening histories of women with and without screen-detected cervical neoplasia between ages 50 and 59 in Lanarkshire was carried out, as well as a cross-sectional study of the prevalence of adequate screening histories among women currently aged 50 in Lanarkshire. Routine screening programme statistics were used to estimate the effects of introducing an early discharge policy.

Women reaching the age of 50 with two recent, consecutive, negative smears had reduced odds of screen-detected neoplasia in the subsequent decade. The estimated odds ratio for all screen-detected neoplasia (CIN 1-3, adenocarcinoma in situ and invasive carcinoma) was 4.4 [95 per cent confidence interval (CI) 1.6-13.2, p = 0.002]. The estimated odds ratio for screen-detected high-grade CIN and invasive squamous carcinoma was 17.0 (95 per cent CI 2.4-243.0, p = 0.0004). A total of 54.0 per cent (95 per cent CI 47.9-59.9 per cent) of screening participants currently aged 50 fulfilled the definition of adequate screening. Discharging these women might be expected to reduce screening workload by approximately 10 per cent, but those discharged would be at increased risk of neoplasia.

Now that full screening histories are available in all health board areas since 1990, the identification of a low-risk group within the screened population could be the first step towards a screening programme targeted more closely on those with the greatest capacity to benefit.