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Top Line: In the thorax, attempts at radiation dose escalation have fallen flat.
The Study: When it comes to esophageal cancer, you should be able to quote to the radi-haters out there that most deaths in the dose-escalated arm of Intergroup 0123 occurred before those patients even made it to 50.4 Gy. While the cardiac and pulmonary effects of conventional radiation fields are well recognized, it remains to be seen if more sophisticated planning techniques (and modalities?) can allow for dose escalation sans the toxicity escalation. In this phase 1/2 trial from MD Anderson, 46 patients receiving definitive chemoradiation for esophageal squamous cell or adenocarcinoma received dose-escalated radiation via a simultaneous integrated boost (SIB). The clinical target was the esophageal gross tumor + 3 cm sup-inf and 1 cm radial, and it included a 5 mm expansion around involved nodes. The final planning target margin was 5 mm and received 1.8 Gy x 28 = 50.4 Gy. The SIB target was gross tumor + 3 mm circumferentially, and it received 2.25 Gy x 28 = 63 Gy. Treatment was delivered using either intensity modulated photons or protons. There were no grade 4 or 5 toxicities and most grade 3 toxicities were esophageal. The in-field local control rate was 70% at 1 year, which fell short of the optimistic primary endpoint of an improvement from 70→ 85%.
TBL: Simultaneous integrated boost during definitive chemoradiation for esophageal cancer may offer a safe way to dose escalate. | Chen, JAMA Oncol 2019