In Men with Castration-Resistant Prostate Cancer, Visceral Metastases Predict Shorter Overall Survival: What Predicts Visceral Metastases? Results from the SEARCH Database

Background: Although visceral metastases (VMs) are widely recognized to portend worse prognoses compared with bone and lymph metastases in men with metastatic castration-resistant prostate cancer (mCRPC), little is known about what predicts VMs and the extent to which men with VMs do worse. Objective: To determine whether men with VMs at initial mCRPC diagnosis have worse overall survival (OS) and identify predictors of VMs. Design, setting, and participants: We analyzed 494 men diagnosed with castration-resistant prostate cancer post-1999 and no known metastases from five Veterans Affairs hospitals of the Shared Equal Access Regional Cancer Hospital (SEARCH) database who later developed metastases. Radiology scans within 30 d of initial metastasis diagnosis were reviewed to collect information on bone, visceral, and lymph node metastases. We analyzed the 236 men who had a computed tomography scan performed. Outcome measurements and statistical analysis: Predictors of VMs and OS were evaluated using logistic regression and Cox models, respectively. Results and limitations: Of the 236 mCRPC patients, 38 (16%) had VMs. Regarding VMs, 19 patients (50%), 8 patients (21%), and 16 patients (42%) had metastases in the liver, lungs, and other locations, respectively. VMs were a predictor of OS on crude analysis (hazard ratio [HR]: 1.88; 95% confidence interval [CI], 1.30–2.72; p = 0.001) and after risk adjustment (HR: 1.84; 95% CI, 1.24–2.72; p = 0.002). Age, year, treatment center, prostate-specific antigen (PSA), and time from CRPC to metastases were significant in predicting OS (all p < 0.05). None of the variables tested were associated with having VMs (all p > 0.09). Prospective studies and larger cohorts are needed to validate our findings. Conclusions: Demographic, tumor, and PSA kinetic characteristics were not predictive of having VMs, but VMs predicted worse OS. Patient summary: Because patients with VMs have worse overall survival, further research is needed to develop better biomarkers and thus diagnose those with VMs at earlier stages in their disease course. At the time of metastatic castration-resistant prostate cancer diagnosis, visceral metastases (VMs) predict worse overall survival. Because demographic, tumor, and prostate-specific antigen kinetics characteristics are not associated with VMs, further research is needed to develop better biomarkers to diagnose those with VMs at earlier stages in their disease course.