PERFORMANCE OF A SEMIAUTOMATED PAPANICOLAOU SMEAR SCREENING SYSTEM - RESULTS OF A POPULATION-BASED STUDY CONDUCTED IN GUANACASTE, COSTA-RICA

BACKGROUND, Automated cytology devices have utility in quality assuran ce applications, but the effectiveness of these devices in primary scr eening is unknown. METHODS. Enrollment smears obtained from 7323 women participating in a population-based study sponsored by the National C ancer Institute were screened manually in Costa Rica and then evaluate d independently in the U.S. with the PAPNET system (Neuromedical Syste ms, Inc., Suffern, NY), a semiautomated, neural network-based device. Smears with abnormal PAPNET images were microscopically rescreened and then diagnosed by a U.S. cytopathologist. ThinPrep slides (Cytyc Corp oration, Boxborough, MA), prepared from rinses of the cytologic sample r, and cervigrams (National Testing Laboratories, Fenton, MO) were als o evaluated. Women with ally abnormal cytologic diagnosis or a positiv e cervigram were referred for colposcopy with biopsy and definitive th erapy if indicated. RESULTS. Based on the U.S. cytotechnologist's revi ew of the PAPNET images, 1017 (13.9%) of 7323 smears were selected for manual screening, resulting in the selection of 492 (6.7%) possibly a bnormal slides for referral to the U.S. pathologist. Ultimately, 312 s mears (4.3% of the total) were diagnosed as containing squamous cells of undetermined significance or a more severe abnormality (greater tha n or equal to ASCUS), resulting, hypothetically, in the referral of 66 .5% of women with a final diagnosis of a squamous intraepithelial lesi on or a more severe abnormality (greater than or equal to SIL) and 86. 0% of patients with greater than or equal to high grade SIL. Conventio nal microscopic screening performed in Costa Rica resulted in the hypo thetical :referral of 6.5% of patients with greater than or equal to A SCUS for colposcopy, including 69.5% of patients with greater than or equal to SIL and 79.8% of those with greater than or equal to high gra de SIL. CONCLUSIONS. In this study, PAPNET-assisted cytologic screenin g accurately identified smears obtained from women with high grade SIL or carcinoma. Determination of the clinical cost-effectiveness of PAP NET-assisted screening in routine practice awaits future study. [See e ditorial on pages 269-72, this issue.] Cancer (Cancer Cytopathol) 1998 ;84:273-80. (C) 1998 American Cancer Society.