Obese Castration-Resistant Prostate Cancer Patients may be at a lower risk of all-cause mortality: Results from the SEARCH Database

At the population level, obesity is associated with prostate cancer (PC) mortality; however, some studies found higher body mass index (BMI) is associated with better long-term PC outcomes among men with metastatic castration-resistant PC (mCRPC).

We tested whether obesity was associated with progression to metastasis, PC-specific mortality (PCSM), and all-cause mortality (ACM) among 1192 non-metastatic CRPC patients from the SEARCH Database. BMI was calculated from height and weight abstracted from the medical records at the time of but prior to CRPC diagnosis and categorized as underweight (<21 kg/m2), normal weight (21-24.9 kg/m2), overweight (25-29.9kg/m2), and obese (≥30kg/m2). Competing risks regression and Cox models were used to test associations between obesity and progression to metastasis, PCSM, and ACM, accounting for confounders.

Overall, 51 (4%) men were underweight, 239 (25%) were normal weight, 464 (39%) were overweight, and 438 (37%) were obese. In adjusted analysis, higher BMI was significantly associated with reduced ACM (HR=0.98, p=0.012) but not PCSM (HR=1.00, p=0.737) or metastases (HR=0.99, p=0.225). Likewise, when BMI was treated as a categorical variable in adjusted models, obesity was not associated with PCSM (HR=1.11, p=0.436) or metastases (HR=1.06, p=0.647), but was associated with decreased ACM (HR=0.79, p=0.016) compared to normal weight. No data were available on treatments received after CRPC diagnosis.

Among non-metastatic CRPC patients, obesity was associated with better overall survival. Although this result mirrors evidence from men with mCRPC, obesity was not associated with PC outcomes. Larger studies are needed to confirm these findings. This article is protected by copyright. All rights reserved.

BJU international. 2018 Mar 09 [Epub ahead of print]

Adriana C Vidal, Lauren E Howard, Amanda de Hoedt, Christopher J Kane, Martha K Terris, William J Aronson, Matthew R Cooperberg, Christopher L Amling, Stephen J Freedland

Division of Urology Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA., Urology Section, Veterans Affairs Medical Center, Durham, NC., Urology Department, University of California San Diego Health System, San Diego, CA., Section of Urology, Veterans Affairs Medical Center Augusta, GA., Urology Section Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA., Department of Urology, UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA., Division of Urology, Oregon Health Sciences University, Portland, OR.