Diagnostic accuracy of conventional Pap test, liquid-based cytology and human papillomavirus DNA testing in cervical cancer screening in Korea: a meta-analysis

Screening is the main strategy for secondary prevention of uterine cervical cancer. Cytological screening, Pap test, has led to a significant reduction in the incidence of and mortality from cervical cancer[1]. Conventional Pap test was introduced into Korea in the late 1950’s and has contributed to early detection of precancerous lesions and cervical cancer. Korean National Cancer Screening Program recommends that women of age 30 or more receive the Pap test biannually, whereas the Korean Society of Obstetrics and Gynecology recommends that women of age 20 or more receive the test annually[2]. Although Pap test has the merit of being convenient, reasonably specific and inexpensive, the sensitivity have been questioned. A low sensitivity of Pap test would put women at risk to develop invasive cervical cancer. Considerable variation in the sensitivity and specificity of Pap test has been reported[3]. In attempt to improve sample quality, interest has shifted to use liquid-based cytology (LBC). Although not included as a screening method in Korea, LBC has been rapidly popular among clinicians. In view of the importance of human papillomavirus (HPV) in the etiology of cervical cancer, HPV DNA testing to allow women to be classified as high-risk HPV-positive or negative could be used as an adjunct to Pap test. Currently there is no recommendation for HPV testing in cervical cancer screening guidelines. However, the National Health Insurance Corporation has approved HPV testing to confirm cervical dysplasia or carcinoma resulting from an abnormal Pap. Estimations sensitivity and specificity of screening test are important because they may be used to determine policy decisions, such as recommendations for optimal frequency of screening, management of mild abnormalities, and use of newer methods. To compare the accuracy of Pap test and other alternative screening tools (i.e., LBC and HPV testing), Korean studies that reported accuracy of each screening methods were intensively reviewed and the pooled estimates for sensitivity and specificity was calculated by meta-analysis.