Long-term outcome and relative risk in women with atypical squamous cells of undetermined significance.

Few studies have compared long-term follow-up and risk for invasive cancer in women with atypical squamous cells of undetermined significance (ASCUS). We conducted a 6-year review of pathology files for 651 women in whom ASCUS had been diagnosed in 1992. Data collected included patient demographics, follow-up diagnoses, time between follow-up examinations, and procedures performed. At follow-up, high-grade squamous intraepithelial lesions (HSIL) had developed in 9.0% of the women, and invasive cancer in none. Previous cervical history did not affect risk for an HSIL. Although the average time to first follow-up was 6.18 months, in 20.9% of the women the diagnosis of HSIL was not established until after 2.0 years. For individual pathologists, the percentage of HSILs ranged from 0% to 18.8%. Thus women with ASCUS who are followed up regularly are at low risk for development of invasive cancer.