Evaluation of atypical and low-grade cervical cytology in private practice.

OBJECTIVE: To evaluate the adequacy of cytology alone for diagnosis of grade of cervical intraepithelial neoplasia (CIN) and to study performance of cytology, human papillomavirus (HPV) testing, and colposcopy in the evaluation of cytologic findings suggesting low-grade squamous intraepithelial lesions (SIL), or atypical squamous (ASCUS) or atypical glandular (AGCUS) cells of undetermined significance.

METHODS: Standard gynecologic and cytologic evaluation and colposcopic inspection as an additional screening approach were performed on women with no prior hysterectomies screened in a private practice between January 1, 1993, and August 1, 1995. Among these 7651 women, 367 had ASCUS, AGCUS, or SIL cytology or clinically or colposcopically visible cervical lesions. Sensitivity, specificity, and relative risk of CIN in the 367 women were compared by colposcopic, cytologic, histologic and virologic diagnoses.

RESULTS: The sensitivity of all non-negative Papanicolaou smears for CIN 2-3 and cancer was 92%, combined cytologic categories of high- and low-grade SIL were 59%, and high-grade SIL alone was 22%. Colposcopy was performed in all 367 patients, and positive findings led to biopsies in 48%. Colposcopy of patients with ASCUS increased detection of CIN 2-3 by 32% and CIN 1 by 48%. Cervical cytology was false negative in 8% of patients with CIN 2-3 and in 14% of those with CIN 1. These cases of CIN were detected by screening colposcopic inspection. High-risk HPV DNA was positive in 41% of women with CIN 2-3, and in 25% of those with CIN 1. The positive predictive value of ASCUS cytology increased from 5% to 42% for CIN 2-3 and from 30% to 85% for all grades of CIN in patients carrying high-risk HPV DNA. Virologic studies did not add to an increase in the sensitivity for CIN 2-3 among women in the low- and high-grade SIL cytology groups.

CONCLUSION: Because of the limited sensitivity of the high-grade SIL cytologic category for CIN 2-3, we recommend that all women with ASCUS, AGCUS, low- or high-grade SIL cytology be recalled for colposcopy, with biopsy only when indicated by colposcopic findings.