The accuracy of prostate cancer staging in a population-based tumor registry and its impact on the black-white stage difference (Connecticut, United States).

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 CTR. 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.