Obesity & Prostate Cancer Patients w/ Androgen Receptor Genotypes
Thursday, 24 May 2007
ANAHEIM, CA (UroToday.com) - S Bruce Malkowicz, MD and colleagues from the University of Pennsylvania presented “OBESITY IS ASSOCIATED WITH POORER CLINICAL OUTCOMES IN PROSTATE CANCER PATIENTS WITH HIGH-RISK ANDROGEN RECEPTOR GENOTYPES”. They studied gene polymorphisms, which are associated with prostate cancer risk and outcome differences in patients with prostate cancer. The objective of their study was to evaluate whether the relationship between biochemical failure [BF] and obesity is modified by polymorphisms on the androgen receptor [AR].
727 radical prostatectomy patients of European American ancestry who underwent radical prostatectomy from 1995 to 2003 were stratified for obesity (BMI>30), AR genotypes, and BF ( PSA > 0.2 ng/ml). Fourteen percent of the cases experienced failure over a mean observation period of 41 months. Cases were divided into risks groups based on AR phenotypes: High risk <21 CAG repeats or > 23 GGN repeats; Low risk > 21 CAG repeats, < 23 GGN repeats. Hazard ratios were generated. After adjusting for age and tumor stage, obesity alone was not associated with BF. A significant risk for BF was associated with obesity in men carrying shorter (<21) AR-CAG repeats [HR 3.26, 95%CI(1.02-10.39)]. For men with low stage (T1, T2) tumors the risk increased to HR 6.61, 95%CI(1.47 - 29.77). No significant effects were noted for longer AR-CAG repeats. Obese men with longer (>23) AR-GNN repeats were more likely to have a BF if they were low stage only (HR 2.38, 95%CI (1.07- 5.32). No effects were noted for men with shorter AR-GGN repeats. They conclude that high risk AR genotypes confer a greater risk of biochemical failure in obese European American men undergoing surgical treatment of prostate cancer. This is especially pronounced in lower stage lesions. The association of obesity with genotypic variations may provide greater stratification of outcomes in obese patients and better clarify the impact of obesity on prostate cancer outcomes.
Obesity & Prostate Cancer Patients w/ Androgen Receptor Genotypes