Prevalence of cervical intraepithelial neoplasia grades II/III and cervical cancer in patients with cytological diagnosis of atypical squamous cells when high-grade intraepithelial lesions (ASC-H) cannot be ruled out

context and objective: the latest update of the bethesda system divided the category of atypical squamous cells of undetermined significance (ascus) into asc-us (undetermined significance) and asc-h (high-grade intraepithelial lesion cannot be ruled out). the aims here were to measure the prevalence of pre-invasive lesions (cervical intraepithelial neoplasia, cin ii/iii) and cervical cancer among patients referred to instituto fernandes figueira (iff) with asc-h cytology, and compare them with asc-us cases. design and setting: cross-sectional study with retrospective data collection, at the iff cervical pathology outpatient clinic. methods: ascus cases referred to iff from november 1997 to september 2007 were reviewed according to the 2001 bethesda system to reach cytological consensus. the resulting asc-h and asc-us cases, along with new cases, were analyzed relative to the outcome of interest. the histological diagnosis (or cytocolposcopic follow-up in cases without such diagnosis) was taken as the gold standard. results: the prevalence of cin ii/iii in cases with asc-h cytology was 19.29% (95% confidence interval, ci, 9.05-29.55%) and the risk of these lesions was greater among patients with asc-h than with asc-us cytology (prevalence ratio, pr, 10.42; 95% ci, 2.39-45.47; p = 0.0000764). pre-invasive lesions were more frequently found in patients under 50 years of age with asc-h cytology (pr, 2.67; 95% ci, 0.38-18.83); p = 0.2786998). there were no uterine cervical cancer cases. conclusion: the prevalence of cin ii/iii in patients with asc-h cytology was significantly higher than with asc-us, and division into asc diagnostic subcategories had good capacity for discriminating the presence of pre-invasive lesions.