Racial differences in prognostic value of adult height for biochemical progression following radical prostatectomy

Purpose: Adult height, as a surrogate of childhood and adolescent hormone activity and diet, has been associated with the risk for development and death from prostate cancer in predominantly White populations. However, hormonal activity and diets vary between races. We examined whether height was significantly associated with biochemical progression following radical prostatectomy and whether there was an interaction between height and race. Experimental Design: Multivariate Cox proportional hazards analysis was used to determine if height significantly predicted biochemical progression among 1,503 men (450 Black and 1,053 White) treated with radical prostatectomy between 1988 and 2003. We examined for possible interactions between height and race. Results: Taller men (>175.3 cm) were significantly younger (P = 0.001), treated in more recent years (P = 0.02), had more clinical stage T ₁ disease (P = 0.001), and were less likely to have extraprostatic extension (P = 0.02) than shorter men (≤175.3 cm). Height was not significantly related to race, preoperative serum prostate-specific antigen concentrations, biopsy or pathologic Gleason sum, positive surgical margins, seminal vesicle invasion, or lymph node metastasis. Height was significantly associated with progression among Black men [relative risk (RR), 1.67; 95% confidence interval (95% CI), 1.00-2.79] but not among White men (RR, 1.03; 95% CI, 0.77-1.38). The interaction between race and height for predicting biochemical progression was statistically significant (P _interaction = 0.05). Conclusions: There was an interaction between height and race in that height predicted progression for Black men but not for White men. The explanation for these findings is unclear, although lower insulin-like growth factor-binding protein-3 concentrations among Black men may be involved.