Survival benefit of local versus no local treatment for metastatic prostate cancer-Impact of baseline PSA and metastatic substages

BACKGROUND To test whether local treatment (LT), namely radical prostatectomy (RP) or brachytherapy (BT) still confers a survival benefit versus no local treatment (NLT), when adjusted for baseline PSA (bPSA). To further examine whether the effect of LT might be modulated according to bPSA and M1 substages. METHODS Of 13 906 mPCa patients within the SEER (2004-2014), 375 underwent RP, 175 BT, and 13 356 NLT. Multivariable competing risks regression (MVA CRR) analyses after 1:2 propensity score matching assessed the impact of LT versus NLT on cancer specific mortality (CSM). Interaction analyses tested the association between treatment type and bPSA within different M1 substages. RESULTS MVA CRR analyses revealed lower CSM rates for LT (RP [HR: 0.55, CI: 0.44-0.70, P