Introduction

INTRODUCTION: Recent studies have shown a possible survival advantage for men with metastatic prostate cancer (MPCa) who undergo local treatment of the primary tumor in addition androgen deprivation therapy (ADT) when compared to ADT alone. We hypothesize that this benefit will depend on the degree of metastatic burden. We assess this by looking at men with varying levels of metastatic disease, and comparing the overall survival (OS) between those who did and did not undergo local therapy in addition to ADT. _x000D_

Methods

METHODS: Patients with MPCa (cN+ or cM+) who received ADT were identified from the National Cancer Database (NCDB) (2004-2013). We categorized men based on the extent of metastatic disease (NIM0, M1a, m1b and M1c). Within each group we modeled the propensity to receive local therapy to the primary. We then compared those undergoing local therapy in addition to ADT to those undergoing ADT alone in a 1:1 propensity matched analysis. Kaplan-Meir curves and Cox proportional Hazards regression were used to compare overall survival (OS) in men receiving local therapy with ADT to ADT alone within each metastatic category. _x000D_

Results

RESULTS: A total of 17,950 men with MPCa who received ADT were identified. Of these, 1,109 received local treatment and 16,841 did not. After propensity matching we had 1876 patients in the N1M0 group, 76 patients in the M1a group, 244 patients in the M1b group and 12 patients in the M1c group, with an even distribution of men between the two treatment groups in each metastatic category. Survival was not analyzed in the M1c group due to the low number. We found that there was a significant benefit in OS for men underging local therapy in all other sub-groups (Figure 1). Cox regression analysis revealed a benefit from local therapy in all analyzed groups: N1M0: HR=0.56, 95%CI 0.47-0.67, p<0.001, M1a: HR=0.3, 95%CI 0.12-0.73, p=0.008, M1b: HR=0.54, 95%CI 0.38-0.77, p<0.001._x000D_

Conclusions

CONCLUSIONS: Our study shows a significant benefit in OS for men with MPCa undergoing local therapy in addition to ADT, versus ADT alone in men with N1M0-M1b prostate cancer. These results require further validation, ideally via prospective randomized trials. _x000D_

Funding

None