Racial disparity in clinical course and outcome of metastatic androgen-independent prostate cancer

Abstract

Objectives: To perform a review of patient and disease characteristics and response and survival outcomes of patients with metastatic androgen-independent prostate cancer. Racial differences in prostate cancer have usually been attributed to socioeconomic status, quality of care, comorbidities, and dietary factors. In a clinical trial population, some of these factors, such as access to care and performance status, are likely to be relatively uniform.

Methods: The patients included in the review had been registered in clinical trials between 1991 and 2001 at Wayne State University.

Results: Of 145 patients, 90 (62%) were white Americans and 55 (38%) were black Americans, 27% were 70 years or older, and 34% had minimal metastatic disease (axial bony involvement and/or lymph node involvement) and 66% had extensive disease (appendicular skeleton and/or visceral involvement). The chi-square test demonstrated no statistically significant difference by race in the distribution of the patient and disease characteristics. The prostate-specific antigen response rate was 41% in whites and 29% in blacks (P = 0.12). Log-rank analysis revealed race to be the only statistically significant factor predictive of the time to prostate-specific antigen progression (P = 0.02, median 4.6 months in whites and 2.3 months in blacks). No statistically significant difference by race was found in overall survival. Poor performance status, extensive disease, elevated alkaline phosphatase and lactate dehydrogenase levels, and a lack of prostate-specific antigen response were statistically significant predictors of worse overall survival.

Conclusions: In patients with androgen-independent metastatic prostate cancer studied in clinical trials, race was an independent predictor of therapeutic outcome. Additional investigation of the biologic and genetic differences underlying this clinical disparity is warranted.