Significance of atypical squamous cells of undetermined significance on ThinPrep Papanicolaou smears

Objective. The aim of this study was to assess the prevalence and risk fact ors predictive of dysplasia among women seen in a gynecologic oncology serv ice with the cytologic diagnosis of atypical squamous cells of undetermined significance (ASCUS) on Papanicolaou smears obtained by the ThinPrep metho d. Methods. Patients with ASCUS ThinPrep Papanicolaou smears seen at the Divis ion of Gynecologic Oncology, University of Vermont, between 1997 and 1999 w ere identified. The cytologic smears were reviewed and subtyped into reacti ve or suggestive of squamous intraepithelial lesion (SIL). The charts of th ese patients were reviewed and the following information was abstracted: ag e, gravidity, parity, menopausal status, use of hormonal replacement therap y, smoking, history of pelvic cancer, history of radiation therapy, history of abnormal Papanicolaou smear and its treatment, history of human papillo mavirus (HPV) infection, and follow-up information including results of rep eat Papanicolaou smears, colposcopy, and biopsies. The prevalence of dyspla sia was calculated. The demographic features of women with ASCUS, reactive, were compared with those with ASCUS, SIL, using a two-sample t test, chi(2 ), and Fisher's exact test. Risk factors predictive of dysplasia were calcu lated using the odds ratio and the 95% confidence interval. P < 0.05 was co nsidered significant. Results. One hundred twenty-six patients with ASCUS on ThinPrep Papanicolao u smear were identified; 63 patients had ASCUS, reactive, and 63 patients h ad ASCUS, SIL. The demographic features of both groups were similar. The ov erall prevalence of dysplasia was 15.9% and was significantly higher among women with ASCUS, SIL, than among women with ASCUS, reactive (25.4% versus 6.4%, P = 0.003). The type of ASCUS cytology (reactive versus SIL), smoking , and history of HPV were significant risk factors for dysplasia (P = 0.003 , 0.037, and 0.042, respectively). Conclusions. The prevalence of dysplasia among women seen in a gynecologic oncology service with ASCUS cytology on ThinPrep Papanicolaou smears is 15. 9%. Women with ASCUS favor Sn, those who smoke, and those with a history of HPV are at higher risk for dysplasia and should be offered colposcopy. (C) 2000 Academic Press.