A Cost-Effectiveness Analysis of Screening Strategies for Cervical Intraepithelial Neoplasia

Abstract

The authors created a decision model to compare the cost-effectiveness of 3 different screening strategies for cervical intraepithelial neoplasia (CIN). In strategy 1, patients were screened annually with a conventional Pap smear. If the results were normal, the patient was notified and scheduled for screening in 1 year. Patients with atypical squamous cell of undetermined significance (ASGUS) had repeat Pap smears every 6 months with referral to colposcopy after 2 ASGUS results. Strategy 2 involved annual screening with liquid-based cytology. Patients with normal results were scheduled for repeat screening in 1 year. When ASGUS was found, human papillomavirus (HPV) testing of the cervical specimen was performed, and patients with positive results were referred for immediate colposcopy. Negative patients were scheduled for rescreening in 1 year. In strategy 3, screening with liquid-based cytology was performed, and patients with normal results were scheduled for rescreening in 2 years. Cervical specimens containing ASGUS were subjected to HPV testing and referred for immediate colposcopy when positive results were found. Rescreening was scheduled in 1 year if results of HPV testing were negative. Direct costs of each strategy, rather than charges, were estimated using information from the University of Alabama at Birmingham and data from the state health department. Analyses used conservative cost estimates, which included a $12 direct cost for a conventional Pap smear, $19 for liquid-based cytology, $62 for HPV testing, and $27 for an office visit. Charges were estimated for a 24-month period. The least expensive strategy was biennial screening with liquid-based cytology, which had a total cost of $9.5 million per 100,000 patients and referred the fewest patients to colposcopy (11.8%). In contrast, annual liquid-based screening had a total cost of $13.7 million per 100,000 patients and was the most expensive strategy. Annual screening with conventional Pap smear was the intermediate option with a cost of $11.6 million. Decreasing the estimated direct costs of the Pap smear, liquid-based cytology, or HPV testing did not change the outcome of the model. Similarly, increasing from 2 to 3 the number of ASGUS results from liquid-based screening necessary for referral to colposcopy, although it did reduce the number of colposcopic examinations, did not reduce the overall costs. The cost savings were more than offset by the increased cost of annual screening.