Economic evaluation of strategies for managing women with equivocal cytological results in Brazil.

In Brazil, current management of women with screening results of atypical squamous cells of undetermined significance (ASC-US) is to offer repeat testing at 6-month intervals. Alternative management strategies that have been adopted in many high-income settings are to offer immediate colposcopy referral or to utilise human papillomavirus (HPV) DNA testing as a triage for colposcopy referral, and to consider different strategies according to women's age. The objective of our study was to evaluate the lifetime cost effectiveness in terms of cost per years of life saved (YLS) of these alternative strategies for a middle income setting. A Markov model was developed using data from the Ludwig-McGill cohort and calibrated to independent observational datasets and local cost estimates obtained. In the base-case analysis, repeat cytology was the least costly strategy but also the least effective. Based on the WHO threshold for very cost-effective interventions, HPV triage for women above 30 years-old was the strategy with the highest probability of being cost effective. HPV triage including younger women with ASCUS results would also be a cost-effective option. Whilst there was a slight further gain in effectiveness with immediate colposcopy referral, it was also more expensive and did not appear to be cost effective. Threshold analysis indicated that an HPV test would have to be more than twice as expensive as a cytology test for HPV triage to no longer be cost effective. In conclusion, our results indicate that in middle income settings HPV triage is likely to be the optimal strategy for managing women presenting with ASC-US results.