Accuracy of screening for cervical cancer in Taiwan, 1974-1984

The cervical cancer screening program in Taiwan was carried out in two phases. This study attempted to estimate the specificity, predictive value, and cancer detection rate of screening for cervical cancer in Taiwan, 1974-1984. They were 99.30%, 46.28%, and 0.60% respectively for Phase I screening (1974-1978) and 99.44%, 50.14% and 0.57% respectively for Phase II screening (1979-1984). It was found consistently that the suspicious rate for women screened for the first time in Taiwan was around 1.30%. Some issues of laboratory errors (or technical errors) in the screening were discussed by screening year and by geographic area respectively. A problem in the cytologic laboratory which produced some technical errors resulting in high false negative results was identified. In order to correct the above laboratory errors, an intensive and obligatory training program including lecture and laboratory sessions was set up and a quality control protocol was established, in which 10% random samples were selected and re-read by the supervisor, and consistency was established and monitored. Besides, subjectivity of cytopathologists was also considered and discussed. Standardization and quality control of the cytopathological laboratory is the most important issue in the accuracy of screening for cervical cancer.