Prognostic significance of race on biochemical control in patients with localized prostate cancer treated with permanent brachytherapy: multivariate and matched-pair analyses

Abstract 

: To compare PSA relapse-free survival (PSA-RFS) between African-American (AA) and white American (WA) males treated with permanent prostate brachytherapy (PPB) for clinically localized prostate cancer.

: One thousand eighty-one consecutive patients, including 246 African-Americans, underwent PPB with ¹⁰³Pd or ¹²⁵I, alone or with external beam radiation therapy between September 1992 and September 1999. Computer-generated matching was performed to create two identical cohorts of WA and AA males, based on the use of neoadjuvant androgen ablation (NAAD), pretreatment PSA, and Gleason score. Presenting characteristics were used to define risk groups, as follows: Low risk had PSA ≤10 and Gleason score ≤6, intermediate risk had PSA >10 or Gleason score ≥7, and high risk had PSA >10 and Gleason score ≥7. PSA-RFS was calculated using the Kattan modification of the ASTRO definition, and the log-rank test was used to compare Kaplan-Meier PSA-RFS curves. Univariate and multivariate analyses were performed to determine predictors of PSA-RFS.

: Overall, univariate analysis revealed that AA males at presentation had lower disease stage (p = 0.01), had lower Gleason scores (p = 0.017), were younger (p = 0.001), and were more likely to receive NAAD (p = 0.001) than their WA counterparts. There were no differences in pretreatment PSA, isotope selection, use of external beam radiation therapy, median follow-up, or risk group classification between AA and WA males. Pretreatment PSA and Gleason score were significant predictors of PSA-RFS in multivariate analysis, and race was not significant. There was no significant difference between the 5-year PSA-RFS for AA males (84.0%) and the matched cohort of WA males (81.2%) (p = 0.384). Race was not a predictor of 5-year PSA-RFS among patients treated with or without NAAD and within low-, intermediate-, and high-risk groups.

: Race is not an independent predictor of 5-year PSA-RFS in patients with localized prostate cancer treated with PPB. This result is consistent with other studies that also show that race does not contribute to differences in outcome after definitive therapies for localized prostate cancer.

Keywords:  Prostate neoplasm, Brachytherapy, Matched-pair analysis, Race, Nomogram