Surveillance after treatment for cervical intraepithelial neoplasia: outcomes, costs, and cost-effectiveness.

Objective: To estimate outcomes and costs of surveillance strategies after treatment for high-grade cervical intraepithelial neoplasia (CIN).
Methods: A hypothetical cohort of women was evaluated after treatment for CIN 2 or 3 using a Markov model incorporating data from a large study of women treated for CIN, systematic reviews of test accuracy, and individual preferences. Surveillance strategies included initial conventional or liquid-based cytology, human papillomavirus testing, or colposcopy 6 months after treatment, followed by annual or triennial cytology. Estimated outcomes included CIN, cervical cancer, cervical cancer deaths, life expectancy, costs, cost per life-year, and cost per quality-adjusted life-year.
Results: Conventional cytology at 6 and 12 months, followed by triennial cytology, was least costly. Compared with triennial cytology, annual cytology follow-up reduced expected cervical cancer deaths by 73% to 77% and had an average incremental cost per life-year gained of $69,000 to $81,000. For colposcopy followed by annual cytology, the incremental cost per life-year gained ranged from $70,000 to more than $1 million, depending on risk. Between-strategy differences in mean additional life expectancy per woman were less than 4 days; differences in mean incremental costs per woman were as high as $822. In the cost-utility analysis, colposcopy at 6 months followed by annual cytology had an incremental cost per quality-adjusted life-year of less than $5,500. Human papillomavirus testing or liquid-based cytology added little to no improvement to life-expectancy with higher costs.
Conclusion: Annual conventional cytology surveillance reduced cervical cancers and cancer deaths compared with triennial cytology. For high risk of recurrence, a strategy of colposcopy at 6 months increased life expectancy and quality-adjusted life expectancy. Human papillomavirus testing and liquid-based cytology increased costs, but not effectiveness, compared with traditional approaches.