Prognostic Significance of Sites of Visceral Metastatic Disease in Prostate Cancer: A Population-based Study of 12,180 Patients.

Abstract

Metastatic prostate cancer (MPC) prognosis is variable. Few population-based studies have examined the impact of particular visceral metastatic sites on MPC survival outcomes. We investigated this using the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed the overall survival (OS) and prostate cancer mortality (PCM) risk of 12,180 patients, from SEER 18 registries, diagnosed with MPC from 2010 to 2014. We identified those with metastatic disease in bone, brain, liver, and lung. Kaplan-Meier analyses, competing risks regression, and Cox proportional hazards models were used to assess the impact of visceral metastatic disease sites on OS and PCM. Most patients were coded as having metastatic disease in the bone without disease in the brain, liver, or lung (bone group, n= 10,620; 87% of total). On Cox multivariable regression analysis, patients with lung metastases, with or without bone metastases, did not differ significantly from patients in the bone group with respect to OS (hazard ratio, 0.82; 95% confidence interval, 0.63-1.06; P= .13 and hazard ratio, 1.12; 95% confidence interval, 0.98-1.28; P= .10, respectively). These patients also did not differ from the bone group with respect to PCM incidence on competing risks regression analysis. This study suggests that patients with MPC confined to bone and/or lung may have improved survival relative to those with MPC affecting other visceral sites. Although it was anticipated that patients with bone metastases would represent a favorable subgroup, the favorable outcomes in patents with lung metastases (with or without bone metastases) was unexpected. These findings may inform future therapeutic investigations to improve the prognosis of patients with MPC.