Trends in the use of local intervention and its impact on oncological outcomes for metastatic castration-sensitive prostate cancer: A multicenter retrospective study.

354 Background: The role of local intervention in addition to the standard of care for metastatic castration-sensitive prostate cancer (mCSPC) is unknown. Therefore, this study evaluated the trends of local intervention and their impact on oncological outcomes in patients with mCSPC in real-world practice. Methods: This multicenter retrospective study included 760 patients treated with either androgen deprivation therapy (ADT) without local treatment (no castration-resistant prostate cancer [CRPC] progression within 12 months, control group) or ADT plus local intervention (intervention group) between January 2005 and March 2022. The primary outcome was trends in the use of local intervention in patients with mCSPC. The secondary outcomes included evaluations of factors associated with CRPC-free survival in the intervention group. Results: The use of local intervention gradually increased in combination with upfront treatment for the duration of our study. The number of patients with local intervention combined with upfront treatment was significantly higher in patients with high tumor burden disease than in those with low tumor burden disease. Of the 108 patients who received local intervention comprising radiation therapy targeted to the prostate, a duration of >7 months of initial therapy before local intervention and a level of prostate-specific antigen <0.20 ng/mL at the time of local intervention were significantly associated with prolonged CRPC-free survival. Conclusions: Regardless of the tumor burden, the use of local intervention in combination with upfront therapy to treat mCSPC increased for the duration of our study. Local intervention in addition to the standard of care for mCSPC may be a feasible treatment option for selected patients, taking into consideration the duration of and response to initial treatment.