Obesity, race, and long-term prostate cancer outcomes

Abstract

Background: The authors previously found that obesity was linked with prostate cancer (PC)–specific mortality (PCSM) among men who underwent radical prostatectomy (RP). Herein, in a larger RP cohort, the authors investigated whether the association between obesity and long-term PC outcomes, including PCSM, differed by race. Methods: Data from 5929 patients who underwent RP and were in the Shared Equal Access Regional Cancer Hospital (SEARCH) database were analyzed. Prior to RP, body mass index (BMI) was measured and recorded in the medical records. BMI was categorized as normal weight (<25 kg/m2), overweight (25-29.9 kg/m2), and obese (≥30 kg/m2). The authors assessed the association between BMI and biochemical disease recurrence (BCR), castration-resistant prostate cancer (CRPC), metastasis, and PCSM, accounting for confounders. Results: Of the 5929 patients, 1983 (33%) were black, 1321 (22%) were of normal weight, 2605 (44%) were overweight, and 2003 (34%) were obese. Compared with white men, black men were younger; had higher prostate-specific antigen levels; and were more likely to have a BMI ≥30 kg/m2, seminal vesicle invasion, and positive surgical margins (all P ≤.032). During a median follow-up of 7.4 years, a total of 1891 patients (32%) developed BCR, 181 patients (3%) developed CRPC, 259 patients (4%) had metastasis, and 135 patients (2%) had died of PC. On multivariable analysis, obesity was found to be associated with an increased risk of PCSM (hazard ratio, 1.78; 95% confidence interval, 1.04-3.04 [P =.035]). No interaction was found between BMI and race in predicting PCSM (P ≥.88), BCR (P ≥.81), CRPC (P ≥.88), or metastasis (P ≥.60). Neither overweight nor obesity was associated with risk of BCR, CRPC, or metastasis (all P ≥.18). Conclusions: Obese men undergoing RP at several Veterans Affairs hospitals were found to be at an increased risk of PCSM, regardless of race.