Metastasis-directed Therapy for Oligorecurrent Prostate Cancer

Metastasis-directed therapy (MDT) has broadened the therapeutic window in patients presenting with oligorecurrent prostate cancer as it postpones the initiation of palliative androgen deprivation therapy (pADT) and its substantial side-effects for several years. Also from a biological point of view, this might be beneficial as the (early) use of ADT promotes the development of the lethal castrate-resistant state, whereby metastatic progression is driven by androgen-independent pathways. Metastasis-directed therapy with stereotactic body radiotherapy (SBRT) or surgery has shown to be able to eradicate metastases with a significant advantage concerning the pADT-free survival compared to active surveillance. And the combination of SBRT with palliative systemic treatment significantly improved overall survival (OS) when compared tot systemic treatment alone. One of the largest retrospective analyses (191 patients) on MDT for oligorecurrent prostate cancer has been conducted previously at UZ Leuven (doi: 10.3390/cancers12082271). Estimated median pADT-free survival was 66 months and estimated median mCRPC-free survival was not reached, but 83% of patients were still free of mCRPC at 10 years. The addition of ADT to primary radiotherapy for intermediate of high risk prostate cancer or to salvage radiotherapy has shown to improve overall survival. Within the context of SBRT for oligorecurrent disease it is not yet known whether the addition of a certain period of ADT prolongs CRPC-free survival and if so, what should be the optimal duration of this ADT administration. Moreover, the addition of an androgen receptor targeted agent (ARTA) to ADT in men with metastatic hormone sensitive prostate cancer and a treated primary tumor resulted in significantly improved clinical outcomes, also in low-volume metastatic disease. In this clinical trial the aim is to investigate whether the addition of short-term ADT during 1 month or short-term ADT during 6 months together with an ARTA to MDT significantly prolongs poly-metastatic free survival (PMFS) and/or metastatic castration-refractory prostate cancer free survival (mCRPC-FS) in patients with oligorecurrent hormone sensitive prostate cancer.