RESUMO
INTRODUCTION: In de novo metastatic hormone-sensitive prostate cancer (mHSPC) treated with upfront intensification using androgen receptor signaling inhibitor or chemotherapy (Docetaxel), achieving a PSA nadir less than 0.2 ng/mL, indicative of superior survival in trials, may often be unattainable in real-world settings. We explored the predictive value of the degree of PSA decline and time to PSA nadir (TTPN) on oncological outcomes. METHODS: A prospectively maintained database of consecutive prostate cancer cases in Hong Kong was accessed. Patients diagnosed with de novo mHSPC from 2016 to 2022 and treated with upfront intensification were included in this analysis. Landmark analysis on PSA kinetics at 6-months following treatment intensification was performed. They were classified based on 1) TTPN (≥6 months vs. <6 months), and 2) a combined response (deep responders achieving both ≥95% PSA decline and TTPN ≥ 6 months vs. shallow responders). Multivariable regression analysis was employed to identify the effects of confounders. FINDINGS: A total of 131 patients were included in this analysis. Classifying patients by combined response best predicted survival outcomes. Deep responders had better progression-free survival (HR = 0.56; 95%CI = 0.34-0.91; p = 0.019), overall survival (HR = 0.50; 95%CI = 0.26-0.97; p = 0.036), and cancer-specific survival (HR = 0.43; 95%CI = 0.19-0.99; p = 0.042). Difference in overall survival remained significant after adjustment in multivariable regression analysis. CONCLUSION: Our analysis demonstrates that alternative PSA targets can predict treatment response and survival outcomes in de novo mHSPC patients in a real-world setting, providing valuable information for patient counselling and potentially guiding future trial design.