Cancer CausesandControl 1995, 6,425-430 The accuracy of prostate cancer staging in a population-based tumor registry and its impact on the Black-White stage difference (Connecticut, United States) Wen-Liang Liu, Stanislav Kasl, John T. Flannery, Alfic Lindo, and Robert Dubrow (Received 13 March 1995; acceptedin revised form 24 May 1995) Stage at diagnosis of prostate cancer is a major determinant of survival. Among Blacks, prostate cancer is diagnosed at a later stage of disease than among Whites. This study examined the accuracy of routine coding of prostate cancer stage in the Connecticut (United States) Tumor Registry (CTR) and its effect on the Black/ White stage difference. Medical records were collected for 115 Black and 136 White men with prostate cancer diagnosed between 1987 and 1990. Stage at diagnosis was determined by a panel of two of the study members and compared with the stage in the CTR file. According to the panel, 32 percent of Blacks, but only 15 percent of Whites, were diagnosed with distant stage disease. Fifty-eight cases (26 percent of Whites and 20 percent of Blacks) were staged incorrectly by the CT1L Two-fifths of the errors were due to incomplete medical records at the CTR and three-fifths were due to CTR coding or data management errors. The more accurate staging did not have an appreciable impact on the Black/White stage difference. Further work is needed to characterize the accuracy of routinely coded cancer registry stage data for different cancer sites, to devise ways of improving accuracy, and to determine the impact of staging inaccuracies on research that utilizes these data. Cancer Causes and Control 1995, 6, 425-430 Key words: Cancer staging, males, prostate cancer, registries, United States. Introduction Stage at diagnosis of prostate cancer is a major determinant of survival. According to data for the period 1983-90 from the population-based cancer registries that constitute the Surveillance, Epidemiol- ogy, and End Results (SEER) program in the United States, the five-year relative survival rate for White patients diagnosed with localized disease was 95 percent, compared with 30 percent for White patients diagnosed • • 1 with distant metastases. Among Blacks, the five-year relative survival rate was 88 percent for localized disease and 23 percent for distant disease. 1 Cases of prostate cancer among Blacks have been Drs Kasl and Dubrow are with the Department ofEpidemiology and Public Health, Yale University Schoolof Medicine, New Haven, CT, USA.At the time of this research,Dr Liu was with the Department ofEpidemiology and PublicHealth at Yale and is now with the Chang Gung College of Medicine and Technology in Taiwan, ROC Mr Flannery and Ms Lindo are with the Connecticut Tumor Registry, Connecticut Department of Public Health, Hartford, C~. Address correspondence to Dr Robert Dubrow, Department of Epidemiology and Public Health, Yale University School of Medicine, PO Box 208034, New Haven, CT06520-8034, USA This study was supported by grant 5-PO1-CA42101 from the US National Cancer Institute. Dr Dubrow received support from an NCI Preventive Oncology Academic Award, KOT-CAO1463. © 1995 Rapid Science Publishers Cancer Causes and Control. Vol 6. 1995 425