Influences on the risk of recurrent high grade cervical abnormality

The objective of this study is to determine the risk of recurrent abnormality after a first episode of high-grade epithelial abnormality and its evolution over time in a population setting. Two cohorts were established from a statewide registry. The cervical intraepithelial neoplasia (CIN) cohort comprised 6849 women with a biopsy of CIN 2, 2/3 or 3 (squamous or glandular) during 1990-92. A cohort of 6857 women with negative cytology during 1990-92 was used for comparison. The CIN cohort had a significantly greater rate of subsequent high-grade epithelial abnormality than the negative cohort. The risk increased with age. For women over 50 years at the incident biopsy, the rate ratio for subsequent high-grade epithelial abnormality was 24.45 (95% CI, 7.2, 84.3). The rate of subsequent high-grade epithelial abnormality was greater if the incident biopsy was CIN 3 (rate 13.50 per 1000 person years [95% CI, 12.5, 14.6]) rather than CIN 2 or 2/3 (rate 7.83 per 1000 person years [95% CI, 7.1, 8.7]). The rate ratio for subsequent invasive cancer was 9.46 (95% CI, 2.5, 35.3) when the CIN cohort was compared with the negative cohort. We conclude the risk of recurrent high-grade epithelial abnormality is related to the age and degree of abnormality on the incident biopsy. Screening policies should acknowledge the risk does not diminish with time.