A long-term study of women with normal colposcopy after referral with low-grade cytological abnormalities.

Background: About 50,000 women are referred annually to colposcopy in England because of a low-grade smear. About 35% of these women have no colposcopic abnormality but are followed up in the colposcopy clinic because of uncertainty about the risk of significant pathology.

Objective: This study determined the 5-year rate of disease when initial colposcopy was normal and smear was non-dyskaryotic.

Design: Retrospective study.

Setting: Colposcopy clinic of an inner city postgraduate teaching hospital. Population Two thousand one hundred and fifty seven women referred between January 1990 and December 2001 with mild dyskaryosis (Low Grade Squamous Intraepithelial Lesion [LSIL]) or borderline nuclear changes (Abnormal Squamous Changes of Uncertain Significance [ASCUS]).

Methods: Information was obtained from the colposcopy clinic database and Open-Exeter. Time plots of the disease-free rates were generated using the Kaplan-Meier method, and statistical comparisons were performed using Cox regression.

Main Outcome Measures: Cumulative rates of cytological and histological abnormalities.

Results: High-grade or invasive disease was diagnosed histologically in 12.8% of 805 women referred with borderline nuclear changes and in 35.8% of 1352 referred with mild dyskaryosis. Among 620 women with normal colposcopy and a negative or borderline repeat smear, high-grade disease was found after 5 years of follow up in 1.3% of women originally referred with a borderline smear and in 8.5% referred because of mild dyskaryosis.

Conclusion: Women referred to colposcopy with borderline nuclear changes or mild dyskaryosis whose colposcopy findings are normal and whose repeat smear in the clinic is non-dyskaryotic may be discharged for routine 3-yearly screening in the community because the risk of high-grade disease in the next 5 years is small.