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Headline: Androgen deprivation therapy (ADT) kills.
The Study: If you don’t know how Dan Spratt feels about giving ADT to all patients receiving salvage radiation for prostate cancer, you haven’t been listening. But who needs conjecture when you can point to a secondary analysis? As a reminder, RTOG 9601 randomized 780 men receiving post-prostatectomy salvage radiation to +/- the addition of ADT in the form of oral bicalutamide 150 mg daily x 2 years. We all know the final analysis showed an improvement in overall survival (OS) with the addition of ADT, and that had all the lumpers doling out ADT to all biochemical recurrences big and small. This study looks at OS among dichotomous groups based on the PSA cut point of 1.5 ng/dl used to stratify (i.e., balance) the randomized arms. Indeed, no OS benefit was seen among those with a PSA ≤ 1.5. What’s more, OS was significantly worse with ADT among those with a PSA ≤ 0.6, with a hazard ratio of death of nearly 2, and even more depressingly so with a PSA 0.2-0.3, with a hazard ratio of over 4. Perhaps due to the significant increase in grade 3-5 cardiac events with ADT. Final words of caution from the discussant: don't let PSA-colored glasses blind you to other red flags like high Gleason score or genomic risk given these characteristics are very poorly represented on trial.
TBL: PSA at time of treatment is strongly predictive of the survival impact of the addition of ADT to salvage prostate radiation, with no clear benefit seen at levels below 0.6 and a clear detriment seen below 0.3. | Spratt, ASTRO 2019