Pretreatment serum prostate-specific antigen (PSA) level and PSA doubling times (PSADT) in black and white men with prostate cancer referred for radiation therapy

Abstract

Numerous racial differences have been reported for carcinoma of the prostate diagnosed in African-American (AA) men when compared to whites. These differences include: (1) a higher incidence in AA compared to whites, (2) a more advanced stage at diagnosis in AA, and (3) higher mortality rates in AA even after adjusting for clinical stage. We examined pretreatment serum PSA levels and calculated PSA doubling times (PSADT) in men referred for radiation therapy with clinically localized prostate cancer and determined if there are any discernible differences between AA and whites. 739 men (670 whites, 69 AA) with histologically proven nonmetastatic prostate cancer who were referred for radiation therapy had a pretreatment serum PSA level (Hybritech assay) available at the time of referral. PSADT were calculated by linear regression for 251 of these men (221 whites, 30 AA) who had at least three serum PSA values obtained prior to the start of definitive therapy. Differences in percentages for grouped pretreatment PSA and PSADT between AA and whites were evaluated by the Pearson chi-square test. The pretreatment serum PSA level was higher for AA than whites in patients with T1-2 tumors. One hundred eighty-three of the 251 patients (73%) with serial PSA determinations were noted to have rising values. Of the patients with rising PSA values, the calculated PSADT was less than 2 years in 39% of white patients and 56% of AA patients (P = .14). Conclusions: African-American men with organ-confined prostate cancer referred for radiation therapy had evidence of a higher volume of disease at diagnosis than whites. In patients with serial PSA levels that were noted to rise, there were no discernible differences between AA and whites, although the number of patients is relatively small and further follow-up is necessary. Radiat Oncol Invest 1996; 4:135–139. © 1996 Wiley-Liss, Inc.