Racial differences in CYP3A4 genotype and survival among men treated on Radiation Therapy Oncology Group (RTOG) 9202: a phase III randomized trial.

Abstract

Inherited genotypes may explain the inferior outcomes of African American (AA) men with prostate cancer. To understand how variation in CYP3A4 correlated with outcomes, a retrospective examination of the CYP3A4 *1B genotype was performed on men treated with Radiation Therapy Oncology Group (RTOG) 92-02. From 1,514 cases, we evaluated 56 (28.4%) of 197 AA and 54 (4.3%) of 1,274 European American (EA) patients. All patients received goserelin and flutamide for 2 months before and during RT (STAD-RT) +/- 24 months of goserelin (long-term androgen deprivation plus radiation [LTAD-RT]). Events studied included overall survival and biochemical progression using American Society for Therapeutic Radiology and Oncology consensus guidelines. There were no differences in outcome in patients in with or without CYP3A4 data. There was an association between race and CYP3A4 polymorphisms with 75% of EAs having the Wild Type compared to only 25% of AA men (p <0.0001). There was no association between CYP3A4 classification or race and survival or progression. The samples analyzed support previously reported observations about the distribution of CYP3A4 *1B genotype by race, but race was not associated with poorer outcome. However, patient numbers were limited, and selection bias cannot be completely ruled out.