Prevention of cervical intraepithelial neoplasia and cervical cancer.

We review the current status of prevention trials in the management of cervical intraepithelial neoplasia (CIN) and cervical cancer. Two large, randomized controlled trials have shown that folic acid is inactive in reversing low to moderate grade CIN. A large randomized trial of locally applied beta-trans retinoic acid showed that the agent was effective in reversing moderate but not severe CIN. Results from a pilot trial involving 30 patients with CIN I (mild dysplasia) and CIN II (moderate dysplasia) indicate that beta-carotene can suppress CIN; a large ongoing randomized trial will answer the question more definitively.