The prognosis of men with prostate cancer (PC) with mutations in DNA damage response ( DDR) genes undergoing different treatments is unclear. This systematic review compared clinical outcomes in PC patients with DDR mutations ( DDR⁺) versus no mutations ( DDR^-). 14 resources plus gray literature were searched for studies in PC and subgroups (castration-resistant PC, metastatic PC and metastatic castration-resistant PC) by DDR gene ( ATM, ATR, BRCA1, BRCA2, CHEK2, FANCA, MLH1, MRE11A, NBN, PALB2, RAD51C) mutation status. From 11,648 records, 26 studies were included. For mCRPC, six studies reported comparative efficacy for key outcomes. Improvements in several clinical outcomes were observed for DDR⁺ (vs DDR^-) after PARP inhibitor therapy or immunotherapy. DDR⁺ PC patients may have improved outcomes depending on the treatment they undergo.