The accuracy of colposcopy in diagnostic and screening settings

1545 Background: We sought to determine the accuracy of colposcopy to diagnose cervical precancer in screening and diagnostic settings. Methods: As part of a larger clinical trial, 1850 patients were recruited into a diagnostic group or a screening group depending on their history of abnormal Papanicolaou smear results. For all patients, colposcopic examination was performed and biopsies were obtained from abnormal and normal colposcopic sites. The gold standard of test result accuracy was the histologic report of biopsies. Results: The diagnostic group had a 29.0% prevalence of high-grade squamous intraepithelial lesions (HGSIL) or cancer, and the screening group had a 2.2% prevalence of HGSIL or cancer. Using a disease threshold of HGSIL or worse, the diagnostic group had a sensitivity of 71.4% and a specificity of 81.3%, and the screening group had a sensitivity of 19.1% and a specificity of 96.1%. The areas under the receiver operating characteristic (ROC) curves for the diagnostic and screening groups at the same disease threshold were 0.854 and 0.511, respectively. Conclusions: We demonstrated that colposcopy performs well in the diagnostic setting and poorly in the screening setting. Colposcopy should not be used for the screening of cervical intraepithelial neoplasia. No significant financial relationships to disclose.