Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Cost-effectiveness of screening for anal precancers in HIV-positive men Jonathan M.C. Lam a , Jeffrey S. Hoch a,d,e , Jill Tinmouth a,b,c , Marie Sano b , Janet Raboud a,b and Irving E. Salit a,b Objective: To assess the cost-effectiveness of high-resolution anoscopy (HRA), anal cytology, and anal human papillomavirus (HPV) detection in screening for histologic high-grade anal intraepithelial neoplasia (AIN 2/3) in HIV-positive MSM. Design: Participants were 401 HIV-positive MSM who were screened for anal cancer in a tertiary care HIV clinic. Methods: A decision analytical model was used to determine the cost-effectiveness of three anal cancer screening strategies: the direct use of HRA; HRA only if anal cytology was abnormal; and HRA only if oncogenic HPV was present. The model included the use of different thresholds for abnormal cytology and also combined cytology and HPV testing. The outcome was the number of AIN 2/3 cases detected. Costs were estimated from institutional data and sensitivity/specificity of cytology and HPV tests were obtained from the screening study. Results: The costs ($ US) per procedure for HRA, cytology, and HPV testing were $193, $90, and $95, respectively. The direct use of HRA was the most cost-effective strategy. It detected 98 individuals with AIN 2/3 and had a cost-effectiveness of $809 per AIN 2/3 case detected. Using probabilistic sensitivity analysis, three other strategies had similar costs per case detected and might be as cost-effective as HRA. Conclusion: In HIV-infected MSM, the direct use of HRA is the most cost-effective strategy for detecting AIN 2/3. The higher cost per use for HRA was offset by the high sensitivity and low specificity of HPV and cytology testing. ß 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins AIDS 2011, 25:635–642 Keywords: anal cancer, anal dysplasia, cost-effectiveness analysis, high-resolution anoscopy, human papillomavirus Background The incidence rate of anal cancer in the general population is low (approximately 1/100 000) [1,2], but it occurs at much higher rates in HIV-positive MSM (approximately 60–160/100 000) [3,4]. Although it is not a priority to screen the general population for anal cancer due to its low incidence rate, in the HIV-positive MSM population screening could potentially be cost-effective given that the anal cancer rate in that group is comparable to the rate of cervical cancer in women prior to the initiation of routine screening [5]. Similar to cervical cancer, anal cancer is caused by the human papillomavirus (HPV) [6,7], which can lead to precancerous dysplastic changes in the squamo-columnar transition zone with possible progression to cancer [8]. Because of the similarities between cervical and anal cancer, the same screening techniques used in the detection of cervical cancer and its precursors can be employed for anal cancer. The potential screening techniques might include the use of high-resolution anoscopy (HRA) with directed biopsy, HPV detection, and cytologic sampling using Papanico- laou (Pap) tests [9–11]. HRA is considered the gold standard for the detection of high-grade dysplasia a University of Toronto, b University Health Network, Toronto General Hospital, c Sunnybrook Medical Centre, d St Michael’s Hospital, and e Cancer Care Ontario, Toronto, Canada. Correspondence to Irving E. Salit, MD, Toronto General Hospital, Eaton 13N-215, 200 Elizabeth Street, Toronto, M5G 2C4 ON, Canada. E-mail: irving.salit@uhn.on.ca Received: 20 August 2010; revised: 25 November 2010; accepted: 27 November 2010. DOI:10.1097/QAD.0b013e3283434594 ISSN 0269-9370 Q 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins 635