ESTRO 2024 - Abstract Book

S1204

Clinical - Head & neck

ESTRO 2024

It can thus be interpreted that ‘Chemoradiation therapy with Once high dose three weekly Cisplatin and accelerated fractionation treatment – 6#/week’ is a feasible treatment option which may have potential to offer superior response rates with manageable toxicities.

Keywords: AcceleratedFractionation,ThreeWeeklyChemotherapy

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Phase IIa trial of postoperative CRT with hyperfractionated IMRT in high-risk patients with HNSCC

Shinya Hiraoka 1 , Aya Nakajima 1 , Masahiro Kikuchi 2 , Motoo Nomura 3 , Toshiyuki Imagumbai 4 , Michio Yoshimura 1 , Ryota Nakashima 1 , Yo Kishimoto 5 , Shogo Shinohara 2 , Masaki Kokubo 4 , Koichi Omori 5 , Takashi Mizowaki 1 1 Graduate School of Medicine, Kyoto University, Department of Radiation Oncology and Image-Applied Therapy, Kyoto, Japan. 2 Kobe City Medical Center General Hospital, Department of Otolaryngology-Head and Neck Surgery, Kobe, Japan. 3 Graduate School of Medicine, Kyoto University, Department of Clinical Oncology, Kyoto, Japan. 4 Kobe City Medical Center General Hospital, Department of Radiation Oncology, Kobe, Japan. 5 Graduate School of Medicine, Kyoto University, Department of Otolaryngology, Head and Neck Surgery, Kyoto, Japan

Purpose/Objective:

Patients with head and neck squamous cell carcinoma (HNSCC) who undergo surgical resection with high-risk features require postoperative chemoradiotherapy (POCRT) with cisplatin administration. We hypothesized that dose escalation with hyperfractionation in intensity-modulated radiotherapy (HF-IMRT) can improve the outcome of POCRT. However, no prospective trial has assessed the feasibility of POCRT in HF. We aimed to evaluate the feasibility of POCRT using HF-IMRT.

Material/Methods:

We designed a single-arm multi-institutional phase IIa clinical trial (jRCTs051210100) and recruited patients from two hospitals. Patients with HNSCC with positive microscopic margins and/or extranodal extension after surgery were included in the trial. IMRT was delivered with 73.6 Gy in 64 fractions twice daily for 5 days per week with a daily interval time of at least 6 hours, 1.15 Gy per fraction. Cisplatin was administered at 40 mg/m2 once a week for seven cycles during radiotherapy. Follow-up was scheduled weekly for 90 days after the initiation of radiotherapy. Thereafter, the patients were followed up regularly by head and neck surgeons and radiation oncologists. Adverse events were graded using the common terminology criteria for adverse events (CTCAE), version 5.0. The primary endpoint was the proportion of patients with treatment completion, defined as the finalization of planned radiotherapy within 66 days and the administration of ≥200 mg/m2 of cisplatin. The treatment protocol was considered feasible when the proportion of patients with treatment completion exceeded 60% using the one-sided binomial test. The secondary endpoints were the proportion of patients with grade 3 or higher acute non hematologic adverse events, laryngeal edema requiring emergency procedures (such as tracheostomy or tracheal