Apa/Enza-short Study: Shorter Treatment With Androgen Receptor Pathway Inhibitor in Patients With Low-volume Metastatic Castration-sensitive Prostate Cancer

The goal of this clinical trial is to evaluate the outcomes of a shorter treatment duration (12 months) with an androgen receptor pathway inhibitor (ARPI), in this study Apalutamide or Enzalutamide, in patients with low-volume, hormone-sensitive metastatic prostate cancer (mCSPC), with the possibility to restart treatment if needed. The main research question is whether discontinuation of ARPI therapy after 12 months, with the option to restart treatment upon disease progression, is non-inferior to continued ARPI therapy, potentially reducing toxicity and costs. Eligible patients will be randomized after completing 12 months of ARPI treatment, to one of the following two arms: 1. ADT + continued ARPI (Apalutamide or Enzalutamide) 2. ADT + ARPI discontinued after 12 months, with the option to resume ARPI in case of a confirmed PSA rise. The confirmatory PSA sample must be obtained at least 4 weeks after the initial rise. This study aims to minimize toxicity associated with prolonged use of ARPIs in patients with low-volume, hormone-sensitive metastatic prostate cancer.