Atypical squamous cells of undetermined significance: a comparative review of original and automated rescreen diagnosis of cervicovaginal smears with long term follow-up.

Abstract

There is an increasing number of articles regarding the long term follow-up of Papanicolaou (Pap) smears with the diagnosis of atypical squamous cells of undetermined significance (ASCUS). Much controversy exists regarding the management of patients with this diagnosis. In a prior study in 1992, the authors performed automated rescreening of 101 ASCUS cases and 91 negative (control) cases. They found that through PAPNET-directed rescreening, 35 of 101 ASCUS cases (35%) could be reclassified as a squamous intraepithelial lesion (SIL). These 192 women were followed since 1992 through manual look backs of subsequent Pap smears and surgical biopsies over a 4-year period. The population studied was comprised of predominantly black women between the ages of 14 and 85 years. The majority were considered a high risk population because many had a history of several sexual partners and multiple pregnancies. Eighteen of 74 patients (24.3%) with an original diagnosis of ASCUS were found on subsequent Pap smears to have an SIL. Only 4 of 64 patients (6%) who originally had a negative Pap smear subsequently were found to have a low grade squamous intraepithelial lesion (LGSIL) within 4 years. Through ordinal logistic regression analysis, it was found that patients with an ASCUS diagnosis had a risk of developing SIL that was 2.6 times greater than the risk for patients with a negative smear diagnosis. Comparing the surgical biopsies in the control and ASCUS groups, there was no statistically significant difference in the risk of developing SIL. This may be because the number of follow-up biopsies were small. A statistically significant difference of the risk of developing SIL exists between patients with a negative smear versus those with an ASCUS smear. Long term follow-up is essential in the management of the patients with an ASCUS smear because there is clearly an increased risk of developing SIL.