Metastasis-free Survival in High-risk Prostate Cancer: A Valid Surrogate, but Is it Transportable Across Strategies of Unequal Systemic Exposure?

Metastasis-free survival (MFS) may not have the same meaning after radical prostatectomy (RP) and radiotherapy (RT), largely because RT is typically combined with prolonged androgen-deprivation therapy (ADT), which can delay the clinical emergence of metastases. Therefore, MFS benefits cannot be assumed to have the same implications for overall survival across treatment strategies with different durations of systemic therapy. SPCG-15 will be important to clarify the interpretation of MFS when comparing RP with RT plus long-term ADT.