Headline: Broadly speaking, patients with persistently elevated PSA after radical prostatectomy do not appear to benefit from the addition of short course androgen deprivation therapy (ADT) to salvage radiation.
The Study: We have seen several iterations of trials of salvage radiation after radical prostatectomy, and we’ve learned that the addition of ADT to salvage radiation reduces the risk of biochemical recurrence and even improves survival depending on the pre-salvage PSA level. Trials of salvage radiation have included those with persistently elevated PSA after radical prostatectomy along with those who had an initially undetectable PSA. The randomized, phase 2 GETUG-AFU 22 trial was designed to specifically assess the benefit of adding short-course ADT to salvage radiation in patients with a persistently elevated PSA (0.2-2.0) post-op. Enrolled patients (n=125) received radiation to the pelvis (46 Gy in 23 fractions) and prostate fossa (66 Gy in 33 fractions) with or without 6 months of degarelix. They were staged with conventional imaging prior to treatment (no PET/CT). At 5 years, the primary endpoint of event free survival was not significantly longer with ADT (63.5% v 62.3%). While there was also no difference in biochemical progression-free survival (bPFS, 66% v 62.3%), the rate of metastasis free survival (MFS) was higher with ADT (HR 0.51, p=0.048). A pretreatment PSA <0.6 was associated with better bPFS and MFS. Does this mean there is no benefit to short course ADT for those with a persistently elevated PSA? That’s unlikely. What is more likely is that this population of patients is enriched with micrometastatic disease. Hence the <70% rates of freedom from progression events at 5 years. Perhaps newer trials will better stratify treatment intensification according to advanced imaging findings and molecular classification.
TBL: Patients with a persistently elevated PSA after radical prostatectomy need restaging with advanced imaging before fretting over whether or not to add short course ADT. | Latorzeff, ASTRO 2022