Prognostic Significance of Young Age and Non-Bone Metastasis at Diagnosis in Patients with Metastatic Prostate Cancer: a SEER Population-Based Data Analysis

Objective: This study compared the clinicopathological features and survival of metastatic prostate cancer (mPCa) after stratification by age and non-bone-related metastasis to identify prognostic factors. Methods: Patients with mPCa between 2010 and 2015 were identified from the Surveillance, Epidemiology and End Results database and analyzed. The overall survival (OS) rate was assessed using the Kaplan-Meier curve and log-rank test as well as multivariate Cox regression analysis. Results: Among the 10147 patients with mPCa, 5378 were classified as young (<= 70 years), 3140 were classified as middle-aged (70-82 years), and 1629 were classified as elderly (>82 years). The younger patients with a single site metastasis with non-regional lymph nodes (NRLN) had a better prognosis than those with bone metastasis [hazard ratio (HR), 0.59, 95% confidence interval (Cl), 0.47-0.73, P < 0.001], whereas patients with liver metastasis had the worst OS rate (P = 0.001). Moreover, patients in the middle-aged group with NRLN or lung metastasis had a better prognosis than those with bone metastasis (P < 0.05). The OS rate of patient with bone + liver and bone + brain metastasis was poorer (P < 0.001) than those with bone + NRLN metastasis in the younger patients (P < 0.05). The elder patients with bone + lung metastasis had the worst OS (HR, 1.54; 95% Cl, 1.25-1.90, P < 0.001), although the death risk of patients with bone + brain and bone + NRLN metastasis not significantly different (P > 0.05). However, the OS of the patients with bone + liver metastasis remained the worst (P < 0.001). Conclusions: Prostate cancer patients with lung metastasis or younger patients (<= 70 years old) with bone + lung metastases had better OS than patients with other types of metastasis or old age.