Cytologically detected chlamydial changes and progression of cervical intraepithelial neoplasias. A retrospective case-control study.

Fifty-four patients with Chlamydia-associated changes on the cervical smears, in whom adequate follow-up had been obtained over a two-year period, were investigated. The progression to biopsy-proven cervical intraepithelial neoplasia (CIN) III in this group was 42.6%, significantly higher than the 15.8% progression rate noted in a control group of patients with similar cytologic abnormalities but unassociated with Chlamydia. This finding suggests that Chlamydia may be a cocarcinogen or a potentiating agent in the progression of CIN.