ESTRO 2025 - Abstract Book

S1131

Clinical – Head & neck

ESTRO 2025

. Multivariate analysis (figure 2) demonstrated significant benefit of NIM together with WHO) performance and schedule of Cisplatin (Figure 2).

The number of patients with hypoxic-gene positive tumors were too low to yield a meaningful analysis. For the secondary endpoints, no important clinical difference was observed between the 2 schedules. Compliance to treatment did not differ significantly irrespective of NIM/placebo and Cisplatin regime, nor did the treatment related morbidity expect for nephrotoxicity which appeared to be higher in the 3-weekly cisplatin regimen, also receiving NIM. Conclusion: Despite the reduced patient number, NIM was found to improve locoregional control in advanced HPV-neg HNSCC, but without significant improvement in DSS or OS. This underlines that hypoxic modification is still active in concomitant chemo-radiotherapy of squamous cell carcinoma. The incompleteness of the study precludes analysis of the predictive value of the hypoxic-gene signature.

Keywords: Randomized trial, Phase 3, Hypoxic modification,

4365

Digital Poster Investigation of a novel methodology to select patients for PTV margin reduction via daily adaptive radiotherapy for head and neck cancer Alec Hughes, Scott Bratman, B.C. John Cho, Ezra Hahn, Andrew Hope, Ali Hosni, John Kim, Nauman Malik, Brian O'Sullivan, C. Jillian Tsai, John Waldron, Michael Holwell, Tony Tadic, Edward Taylor, Natassia Naccarato, Devin Hindle, Shao Hui Huang, Andrew McPartlin Department of Radiation Oncology, Princess Margaret Cancer Centre/University of Toronto, Toronto, Canada Purpose/Objective: Daily adaptive radiotherapy (DART) for head and neck cancer (HNC), with the potential to reduce PTV uncertainty, is now feasible but has significant time and cost implications[1]. Methods to select patients who might benefit most from this approach are of clinical interest. We investigate whether baseline patient and disease characteristics permit prediction of benefit from DART during treatment.