Statistical analysis of uterine cancer screenings test results in Fukushima Prefecture

Abstract

Cytologic smears for uterine cancer screening tests in Fukushima Prefecture in 1972 were obtained by scraping with a cotton swab and in 1973 with a (Tohoku University-type) spatula. The results of the cytologic examinations were subjected to statistical analysis in order to determine whether there was any significant difference between the two methods in regard to the detection of atypical epithelial cells and uterine cancer.The results were as follow:1) No significant difference (5% level of signi ficance) between the two methods was found in the rate of detection of uterine cancer.2) The rate of detection of cervical dysplasia was significantly higher with the spatula method than the cotton swab method (x2c=25.4128<p=0.001, 0.1% level of significance).3) The rate of detection of preinvasive cancer (carcinoma in situ) also was higher with the spatula method (2% level of significance).4) There was a proportionately higher number of smears obtained by the spatula method falling in the Class II and Class III categories. A comparison between the two years of the relative rates of negative smears (Class I or II) and those indicating highly suspicious atypical or malignant cells (Classes III, IV or V) revealed a significant difference (x2c=168.41945>p=0.001, 0.1% level of singnificance) which would indicate greater reliability of the spatula method in the detection of malignancy.5) A significantly higher rate of malignancies was found in smears showing Class III cytologic findings among those obtained with the cotton swab method than those obtained by the spatula method (x2c36.9744>p=0.001, 0.1% level of significance). This would indicate the need for great care in searching for malignant changes when the cotton swab method is utilized.6) Judging from the results obtained when the two methods were utilized for the same patient on separate occasions within a one-month period, the spatula method was better suited for the detection of atypical cells and the possible presence of preinvasive lesions, providing a more accurate assessment of the histological changes.7) It is considered, on the basis of these observations, that the spatula method of obtaining specimens for cytologic examination is superior to the cotton swab abrasion method for screening tests.