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Top Line: The goal of RTOG 0617 was to determine if dose escalation from the standard 60 Gy to 74 Gy at 2 Gy per fraction could improve survival for patients with locally-advanced non-small cell lung cancer (NSCLC).
The Study: Oh yeah, and it also included the obligatory cetuximab-era comparison arm. Here we finally have the long-term results. Every enrollee received concurrent weekly carboplatin and paclitaxel. And every trialist was stone-cold stunned when overall survival (OS) was significantly worse with dose escalation. While there was no overall difference in toxicity, patients in the high-dose arm had more severe esophagitis. So what’s new? Well, 5 year OS results, which showed a nearly 10% absolute decrease in survival (32→ 23%) with high dose radiation. Looking at the multivariable analysis of OS, basically anything that increased central (probably cardiac) dose reduced survival. This included higher prescription, larger tumor, and, of course, actual cardiac dose. They mainly used V5 to evaluate heart dose. If you’ve ever tried to control V5, you know it’s almost completely determined by the extent of your field and the beam arrangement. In their multivariable model, heart V30 produced similar statistical outcomes to V5. In other words, almost any dose to the heart is potentially detrimental. Still, there’s gotta at least be a local control benefit to dose escalation, right? There was no difference in patterns of failure according to dose, and there was no difference in lung cancer deaths.
TBL: Long-term results of RTOG 0617 confirm that 60 Gy at 2 Gy per fraction is the standard chemoradiation regimen for locally-advanced NSCLC. | Bradley, J Clin Oncol 2019