Background: The 1991 Bethesda System for cervical/vaginal cytology reporting defined adequacy criteria for the unsatisfactory designation. Most laboratories have implemented these criteria, but clinical implications have not been established.
Methods: Researchers at two university hospitals retrieved by computer search all unsatisfactory Papanicolaou (Pap) smears taken between January 1994 and July 1995. Of 71,872 total Pap smears, 208 (0.3%) were unsatisfactory (corresponding atypical rate of 9% and a dysplasia/carcinoma rate of 6.5%). Time interval to follow-up and clinicopathologic outcome were determined.
Results: Approximately 26% of unsatisfactory Pap smears were from patients with a history of epithelial abnormalities. The majority (129 of 208 specimens; 62%) of follow-up Pap smears or biopsies occurred within 6 months, 5.7% within 6-12 months, and 1.4% in 12-18 months. Approximately 31% had no follow-up. The first repeat Pap smear or histologic specimen in 144 patients with follow-up was negative in 107 (74%), unsatisfactory in 6 (4%), atypical squamous cells of undetermined significance in 15 (10%), squamous intraepithelial lesion (SIL) in 13 (9%), and malignant in 3 (2%). Nonmalignant conditions contributing to the unsatisfactory smears on histologic specimens (12%) included cervicitis, endometritis, endometrial hyperplasia, and polyps. Progressive abnormalities after the first repeat specimen were noted in 7 patients (5%). A total of 23 of 144 initial unsatisfactory specimens (16% )were found to be from patients diagnosed with SIL or malignancy when all follow-up specimens were analyzed.
Conclusions: The majority of patients with unsatisfactory Pap smears had follow-up studies within 6 months. A significant number (16%) of those with follow-up had eventual diagnoses of SIL or neoplasia. Benign pathologic conditions also contributed to unsatisfactory smears. This patient subset was more likely to have a history of abnormalities, confirming the importance of peer/hierarchical review of unsatisfactory smears.