S550
Clinical – Head & neck
ESTRO 2026
Material/Methods: Participating patients receive weekly HT treatments directly after the RT fraction, within a maximum of 2 hours. The trial includes a HT-dose escalation scheme to determine the recommended phase 2 dose (RP2D) as primary endpoint, with combined feasibility and dose-limiting toxicity endpoints (i.e. pain, burns, or increased RT-toxicity). Dose escalation is done per cohort, and is based on the maximum Specific Absorption Rate (SAR) in 50 cc of healthy tissue, where side effects can occur. This is determined according to treatment planning, comparable to RT-dose planning. At the first dose level, 75 W/kg SAR was delivered to healthy tissues. Upon additional informed consent, invasive temperature measurements are performed during one HT-treatment, preferably during the second session, to monitor temperature increase. Results: A clinical workflow was implemented (Fig 2.). The first patient received HT alongside curative RT for stage III laryngeal carcinoma and successfully completed all seven HT-treatments. The patient is currently in follow-up, with no acute or late HT-related adverse events observed. Invasive temperature measurements reached 40°C in the high SAR locations, indicating effective tissue heating. Conclusion: These initial findings mark an encouraging step toward combining HT with curative (chemo)radiation for LAHNC. Support for feasibility of our approach comes from successful integration of the HC3D into clinical practice, absence of HT-related toxicity in the first patient, and observed temperature increase near the tumor. Further patient data from our ongoing trial are needed to confirm safety and clinical benefit and determine the RP2D for hyperthermia treatment for LAHNC. References: 1. Leeman JE et al. Failure patterns after chemoradiotherapy for advanced H&N SCC. JAMA Oncol. 2017;3(11):1487-94. doi:10.1001/jamaoncol.2017.09732. Kristensen MH et al. Image-based locoregional failure in HNSCC: meta- analysis. Radiother Oncol. 2025;207. doi:10.1016/j.radonc.2025.1108383. Kouloulias V et al. Hyperthermia in NCCN breast cancer recurrences. Breast Care. 2015;10(2). doi:10.1159/0003765944. I M et al. Hyperthermia in advanced cervical cancer:
review. Int J Gynecol Cancer. 2022;32(3). doi:10.1136/ijgc-2021-0024735. Datta NR et al. Hyperthermia and radiotherapy in H&N cancer: meta- analysis. Int J Hyperther. 2016;32(1):31-40. doi:10.3109/02656736.2015.1099746 Keywords: Hyperthermia, phase 1 trial, first in-human Digital Poster 836 Prognostic factors in HPV-associated oropharyngeal squamous cell carcinoma: an unicenter study Ying Chao Weng 1 , Jolien Heukelom 1 , Frederik W.R. Wesseling 1 , Martin Lacko 2 , Stijn van Weert 2 , Francesco Missale 2 , Laura Baijens 2 , Ann Hoeben 3 , Johanna W.M. Nin 3 , Lars C. Steggink 3 , Mari F.C.M. van den Hout 4 , Frank J.P. Hoebers 1 1 Radiation Oncology, MAASTRO, GROW School for Oncology and Reproduction, Maastricht University, Maastricht, Netherlands. 2 Otorhinolaryngology, Head and Neck Surgery, GROW - Research Institute for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands. 3 Internal Medicine, Division of Medical Oncology, GROW - Research Institute for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands. 4 Pathology, GROW School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands Purpose/Objective: Determine prognostic factors in human papilloma virus-associated (HPV+) oropharyngeal squamous cell
carcinoma (OPSCC). Material/Methods:
In this retrospective, single-center cohort study, we included non-metastatic HPV+ OPSCC patients treated with curative-intent with either radiotherapy alone (RT), concurrent RT with platinum-based chemotherapy (CCRT), or concurrent RT with EGFR- inhibitor (RT+EGFRI), between 05-2008 and 11- 2024. HPV-status was assessed by p16 immunohistochemistry, followed by HPV-PCR in 54% of p16+ cases. Endpoints were overall survival (OS), locoregional control (LRC) and distant metastasis (DM)- free interval. Hazard ratios (HRs) were determined with univariable and multivariable Cox-regression models, adjusted HRs for age, TNM8-stage, smoking status, pack years (PY), ECOG performance status (ECOG-PS) and cancer-treatment modality. All patients entered our Standard Follow-up Program (ClinicalTrials.gov NCT01985984). Results: We included 270 HPV+ OPSCC patients (TNM8-stage: I- 51%; II-20%; III-29%). Mean age was 63 years (range 44–94); 77% were male. Median follow-up of all
Made with FlippingBook - Share PDF online