Top Line: Does radiation dose escalation for intermediate risk (IR) prostate cancer improve survival?
The Study: Higher radiation doses to the prostate improves PSA and tumor control, but it's still not clear if this benefit translates into an improvement in survival. RTOG 0126, published this week in JAMA Onc, was the first prospective randomized trial designed to detect a possible survival benefit from dose escalated radiation therapy. Spoiler alert: it didn’t. Men with IR disease were randomized to 70.4 Gy or 79.2 Gy to the prostate and seminal vesicles. Despite smoking improvements at 8 years in biochemical failure (35→ 20%), local progression (6→ 3%), distant metastasis (6→ 4%), and receipt of salvage therapy (22→ 14%) with the higher dose, there was no improvement in overall survival (75% across the board). Does this mean we shouldn’t dose escalate? In a word, no. From the ProtecT trial, we know that the rate of low to IR prostate cancer mortality is so low that any treatment is unlikely to demonstrate a survival benefit. But this does not mean higher doses fail to achieve clearly better disease specific outcomes.
Bottom Line: 79.2 Gy dose not improve survival in men with IR prostate cancer despite significant improvements in PSA and disease control.