Meta-analysis of PSA, DRE and TRUS cific antigen (PSA), transrectal ultrasonography (TRUS), prostatic acid phosphatase, bone scan, computed tomography, magnetic resonance im- aging and etc]. Proteomics (surface-enhanced laser desorption/ionization mass spectrometry8) and cDNA microarray analysis9 have recently been used as sensitive and specific diagnostic serum and tissues tests for prostate cancer. Among these diagnostic methods of prostate cancer, the digital rectal examination (DRE) is the oldest and least invasive test modality. Although false negative and positive exams on DRE may occur, DRE does detect some prostate cancers that are missed by PSA screening. PSA (i.e., 33-kd glycoprotein consisting of 240 amino acids) is a serine protease that is secreted by the prostate into the semen where it causes lysis of the seminal coagulum. The determination of serum PSA has become the most commonly used tumor marker for prostate cancer10 since the earliest investiga- tion of tissue-specific antigens of the human prostate by Ablin et al. in 197011 and the applica- tion of an immunoassay method for PSA by Wang et al. in 1979.12 This diagnostic procedure was introduced to Korea by Dr. Kang J. H. in the early 1980s.13 After 1990, there has been an even more dramatic surge in the incidence of prostate cancer following the widespread adoption of serum PSA testing. Moreover, since the introduction of a clinical diagnostic method of prostatic diseases by Watanabe et al. in 1971, the TRUS test has been the diagnosis of choice for prostate cancer.14 A research result on this diagnostic test was pub- lished in Korea by Dr. Kim N.D. in 1982.15 There- fore, urologists commonly perform clinical assess- ment by using DRE and serum PSA for patients presenting with urinary symptoms. Additionally, radiological examinations including TRUS may also be employed for assessing the size, form and glandular structure of the prostate and any pos- sible capsular or seminal vesicle involvement. Numerous retrospective series have been per- formed and published to date on this diagnostic triad (PSA, DRE and TRUS). In addition, meta- analyses have been conducted to evaluate the effectiveness of this diagnostic triad or on two of these methods that are related to prostate can- cer.16-22 Two of these studies have indicated that if all three tests were abnormal, the risk of cancer on meta-analysis was 68%,18 and when an ex- aminee has abnormal findings using PSA and DRE, the chance of cancer was from 20-25%.22 However, after 1990, various individual studies on combined PSA, DRE and TRUS for the diagnosis of prostate cancer also have been reported in Korea, but no meta-analysis has been conducted. Therefore, the aim of this study was to examine the Korean literature with a focus on sensitivity and specificity for comparing the major diagnostic methods of prostate cancer, i.e., PSA, DRE and TRUS, by employing quantitative meta-analysis, and we wanted to determine the relative merits of this diagnostic triad for symptomatic Korean men. MATERIALS AND METHODS Searching of data The first step of our study involved searching the medical journal database sites, i.e., the Medical Research Information Center (MedRIC) (http:// www.medric.or.kr/) and the National Assembly Library of the Republic of Korea (http://www. nanet.go.kr/) from 1980 to 2003. In addition, we searched other potential sources and gave priority to the Korean Journal of Urology (http://www.u rology.or.kr/) and the Korean Journal of Androl- ogy (http://www.andrology.or.kr/). The second step involved a manual search of the contents and bibliographies of each of the retrieved studies. This search was restricted to the Korean-lan- guages studies that were conducted on men with lower urinary symptoms. The medical subject headings used for this search were prostate cancer and diagnosis, prostate-specific antigen, digital rectal examination and transrectal ultrasono- graphy. Meta-analysis A total of 108 Korean articles were selected that contained information on the comparative results of using PSA, DRE and TRUS for the diagnosis of prostate cancer. Two observers who were both urologist and meta-analyst independently placed the results of the individual articles onto a data sheet; any disagreements were resolved by discus- Yonsei Med J Vol. 46, No. 3, 2005