Might Men Diagnosed with Metastatic Prostate Cancer Benefit from Definitive Treatment of the Primary Tumor? A SEER-Based Study

Abstract Background Few data exist regarding the impact on survival of definitive treatment of the prostate in men diagnosed with metastatic prostate cancer (mPCa). Objective To evaluate the survival of men diagnosed with mPCa based on definitive treatment of the prostate. Design, setting, and participants Men with documented stage IV (M1a–c) PCa at diagnosis identified using Surveillance Epidemiology and End Results (SEER) (2004–2010) and divided based on definitive treatment of the prostate (radical prostatectomy [RP] or brachytherapy [BT]) or no surgery or radiation therapy (NSR). Outcome measurements and statistical analysis Kaplan-Meier methods were used to calculate overall survival (OS). Multivariable competing risks regression analysis was used to calculate disease-specific survival (DSS) probability and identify factors associated with cause-specific mortality (CSM). Results and limitations A total of 8185 patients were identified: NSR ( n = 7811), RP ( n = 245), and BT ( n = 129). The 5-yr OS and predicted DSS were each significantly higher in patients undergoing RP (67.4% and 75.8%, respectively) or BT (52.6 and 61.3%, respectively) compared with NSR patients (22.5% and 48.7%, respectively) ( p < 0.001). Undergoing RP or BT was each independently associated with decreased CSM ( p < 0.01). Similar results were noted regardless of the American Joint Committee on Cancer (AJCC) M stage. Factors associated with increased CSM in patients undergoing local therapy included AJCC T4 stage, high-grade disease, prostate-specific antigen ≥20 ng/ml, age ≥70 yr, and pelvic lymphadenopathy ( p < 0.05). The major limitation of this study was the lack of variables from SEER known to influence survival of patients with mPCa, including treatment with systemic therapy. Conclusions Definitive treatment of the prostate in men diagnosed with mPCa suggests a survival benefit in this large population-based study. These results should serve as a foundation for future prospective trials. Patient summary We used a large population-based cancer database to examine survival in men diagnosed with metastatic prostate cancer (mPCa) undergoing definitive therapy for the prostate. Local therapy (LT) appeared to confer a survival benefit. Therefore, we conclude that prospective trials are needed to further evaluate the role of LT in mPCa.