A validation study of the FocalPoint GS imaging system for gynecologic cytology screening

BACKGROUND: Studies of the performance of the automated FocalPoint Guided Screening (FPGS) imaging system in gynecologic cytology screening relative to manual screening have yielded conflicting results. In view of this uncertainty, a validation study of the FPGS was conducted before its potential adoption in 2 large laboratories in Ontario. METHODS: After an intense period of laboratory training, a cohort of 10,233 current and seeded abnormal slides were classified initially by FPGS. Manual screening and reclassification blinded to the FPGS results were then performed. Any adequacy and/or cytodiagnostic discrepancy between the 2 screening methods subsequently was resolved through a consensus process (truth). The performance of each method's adequacy and cytodiagnosis vis-a-vis the truth was established. The sensitivity and specificity of each method at 4 cytodiagnostic thresholds (atypical squamous cells of undetermined significance or worse [ASC-US+], low-grade squamous intraepithelial lesion or worse [LSIL+], high-grade squamous intraepithelial lesion or worse [HSIL+], and carcinoma) were compared. The false-negative rate for each cytodiagnosis was determined. RESULTS: The performance of FPGS in detecting carcinoma, HSIL+, and LSIL+ was no different from the performance of manual screening, but the false-negative rates for LSIL and ASC-US were higher with FPGS than with manual screening. CONCLUSIONS: The results from this validation study in the authors' laboratory environment provided no evidence that FPGS has diagnostic performance that differs from manual screening in detecting LSIL+, HSIL+, or carcinoma. Cancer (Cancer Cytopathol) 2013;121:189196. (c) 2013 American Cancer Society.