2019•Japanese Journal of Clinical OncologyOpen access
A comparison of liquid-based and conventional cytology using data for cervical cancer screening from the Japan Cancer Society
Kiyoshi Ito, Ryusei Kimura, Hiroshi Konishi, Nobuyoshi Ozawa, Nobuo Yaegashi, Yasuo Ohashi, Mitsuaki Suzuki, Tadao Kakizoe
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Abstract
OBJECTIVE: Liquid-based cytology has replaced conventional cytology in cervical cancer screening in many countries. However, a detailed comparison of liquid-based cytology with conventional cytology has not been reported in Japan. Therefore, the aim of the study is to evaluate efficacy of liquid-based cytology in Japan. METHODS: We first evaluated the prevalence of use of liquid-based cytology and then examined the efficacy of liquid-based cytology and conventional cytology for detecting CIN and the rate of unsatisfactory specimens using data from cancer screening collected by the Japanese Cancer Society from FY2011 to FY2014. A Poisson regression model with random effects analyses was used to classify histological outcomes and unsatisfactory specimens using liquid-based cytology compared to conventional cytology. RESULTS: A total of 3 815 131 women were analyzed in the study. The rate of liquid-based cytology increased from approximately 8% in FY2011 to 37% in FY2014. Compared to conventional cytology, the detection rates with liquid-based cytology were significantly higher (1.42 times) for CIN1+ [detection rate ratio (DRR) = 1.42, 95% confidence interval (CI) 1.35-1.48, P < 0.001] and CIN2+ (DRR = 1.16, 95% CI 1.08-1.25, P < 0.001). Positive predictive value ratios of CIN1+ and CIN2+ were also significantly higher for liquid-based cytology than for conventional cytology. However, there was no significant difference between liquid-based cytology and conventional cytology for detection rates and positive predictive values of CIN3+ and cancer. The rate of unsatisfactory specimens was significantly lower with liquid-based cytology compared to conventional cytology (DRR = 0.07, 95% CI 0.05-0.09, P < 0.001). CONCLUSIONS: In order to avoid the unsatisfactory specimens in cervical cancer screening, the results of this study did indicate that liquid-based cytology was more useful than conventional cytology in practical standpoints.