Re-screening of negative smears in uterine cervical cancer mass screening

Objective : Re-screening of smears diagnosed as negative for intraepithelial lesion or malignancy (NILM) by routine screening has been recommended to increase the accuracy of cytological diagnosis. We conducted this study to clarify the effectiveness and significance in uterine cancer screening.Study Design : Re-screening of specimens diagnosed as NILM by routine screening revealed false-negative cases. The false-negative rate was calculated. In addition, the histologic findings of the cases with false-negative smears were compared with those of the negative smears confirmed by re-screening.Results : We performed re-screening of 20987 cases (3.97%) out of the 528402 cases routinely diagnosed as NILM over a 7-year period. Upon re-screening, the cytologic result changed from negative to abnormal in 44 cases. Thus, the false negative rate was determined to be 0.99% and the sensitivity of routine screening was calculated to be 99.01%. The cytologic diagnoses in aforementioned 44 cases were ASC-US (16 cases), ASC-H (9 cases), LSIL (17 cases), HSIL (1 case) and ACG (1 case). Histological examnation of 41 of the 44 cases diagnosed as abnormal by re-screening revealed CIN1 in 12 cases (29.3%), CIN2 in 8 cases (19.5%) and CIN3 in 4 cases (9.8%).Conclusion : In mass screening for uterine cervical cancer, re-screening of negative smears improves the sensitivity over that of the first screening. Re-screening may improve the sensitivity and accuracy of cytologic diagnosis, and occasionally allow detection of cervical neoplastic lesions.