Pilot (early feasibility) ConformalFLASH ultra-high–dose-rate proton therapy (FLASH radiotherapy) for HNSCC reirradiation

This pilot interventional study (C-FLASH-01) evaluates whether ultra-high dose-rate conformal proton therapy (ConformalFLASH®) can be planned and delivered safely and reproducibly for patients who need head and neck re-irradiation and are not candidates for surgical resection. The investigational intervention is ConformalFLASH irradiation, which delivers proton radiation at ultra-high dose rates intended to harness the “FLASH effect” (normal-tissue sparing at very high instantaneous dose rates) while keeping target coverage conformal, using workflows described as comparable to stereotactic body radiation therapy (SBRT). The sponsor is IBA Proton Therapy, Inc., positioning this as a clinically oriented test of a novel delivery paradigm rather than a new systemic agent. The key scientific/commercial angle is translation of proton FLASH from physics/planning promise into a real-world, protocolized re-irradiation workflow in a population with tight organ-at-risk constraints. Today’s care for unresectable recurrent/second primary head and neck cancer after prior definitive radiation is individualized salvage—often systemic therapy (e.g., immunotherapy-based regimens when appropriate) with or without highly conformal re-irradiation such as SBRT/IMRT/proton therapy—because cumulative toxicity limits curative dosing.