Speaking of head and neck radiation, could reduced planning target volume (PTV) margins help reduce toxicity? They’ve shrunk with image guided treatment largely based on the theory that, if there is less setup uncertainty, we need less PTV margin of error. But let’s put some data behind the theory. In this Dutch report for patients receiving head and neck radiation, PTV margins were systematically reduced from 5 mm to 3 mm while utilizing similar methods for treatment delivery: VMAT with cone-beam CT. Reducing the margin resulted in a roughly 10% absolute reduction in severe toxicity. Rates of grade 3 mucositis went from 42→ 31% and feeding tube use from 33→ 22%. All the while, locoregional control and survival were identical. TBL: Unlike treatments below the belt, using daily cross-sectional image alignment and tighter 3 mm PTV margins for patients receiving head and neck radiation successfully reduces toxicity while preserving tumor control. | Navran, Radiother Oncol 2018


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