Clinical characteristics and a 2-year follow-up of unsatisfactory conventional Pap smears: a retrospective case–control study

The objective of this study was to conduct a 2-year follow-up of individuals having unsatisfactory reports of Pap smears and to analyze the contributing factors. This was a retrospective study at a medical center that performed about 5000–6000 Pap smears annually in Eastern Taiwan. Women who had unsatisfactory results due to scant cellularity between January 1, 2015–December 31, 2016, were included in this study. The control group comprised age-matched women with normal Pap smears at a 1:4 ratio, during the same period. The clinical characteristics and the 2-year outcomes were followed. Patients who were unavailable for follow-up assessments or who had insufficient clinical information were excluded. Student’s t-test and chi-square test were used for continuous and categorical variables, respectively. Statistical significance was defined as a p-value < 0.05. A total of 887 Pap smears were included. A total of 717 and 170 women had normal Pap and unsatisfactory Pap tests, respectively. After excluding women who were unavailable for follow-up, the final analysis included 248 and 67 women with normal and unsatisfactory Pap tests, respectively. The mean age was not significantly different between the two groups (49.97 ± 10.69 and 51.61 ± 11.28 years in the unsatisfactory Pap and control groups, respectively [p > 0.05]). The percentage of menopause and vaginal discharge were significantly different between the two groups. Multivariate analysis revealed that premenopausal status, increased discharge were associated with the risk of unsatisfactory Pap tests. Of the 67 women with unsatisfactory Pap tests, all tested negative for any malignancies at a 2-year follow-up assessment. Women with increased vaginal discharge and without menopause were at an increased risk of having an unsatisfactory Pap test. Our results indicate that an unsatisfactory Pap smear due to scant cellularity might not increase the risk of intraepithelial neoplasia or cancer after 2 years. Further, large-scale studies with longer follow-up periods are required.