ESTRO 2025 - Abstract Book

S983

Clinical – Head & neck

ESTRO 2025

similar but lower doses (469.48 cGy and 466.1 cGy, respectively; p = 0.017). For carotid arteries, VMAT delivered lower doses (left: 780.85 cGy, right: 990.41 cGy) compared to HT (left: 1,479.25 cGy, right: 1,354.35 cGy) and IMRT (left: 982.0 cGy, right: 678.8 cGy; p = 0.015 for left carotid, p = 0.188 for right carotid). T1a tumors were most common (46.2%), followed by Tis (23.1%), T1b (15.4%), and T2 (15.4%). Right vocal cords were predominantly treated (69.2%), with 7.7% for the left and 23.1% involving both. Conclusion: This study underscores the need for careful technique selection in early vocal cord cancer. HT excelled in PTV95 coverage but increased OAR doses, while VMAT balanced coverage and sparing. IMRT minimized spinal cord dose but relied on single-patient data. Techniques should align with clinical and anatomical need.

Keywords: RT techniques, Dosimetry, Organ-at-risk sparing

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Digital Poster Geriatric head and neck squamous cell carcinomas (GHNC) treated with modulated radiotherapy (MRT): Preliminary single Institution outcome. Jay Prakash Sahu 1 , Trinanjan Basu 1 , Rohith R Menon 1 , Ghazala K Roshan 1 , Ajinkya Gadekar 1 , Shounak J Kamat 1 , Ankit Mahuvakar 2 , Indumati Ammbulkar 3 1 Radiation Oncology, HCG Cancer Centre, Mumbai, India. 2 Surgical Oncology, HCG Cancer Centre, Mumbai, India. 3 Medical Oncology, HCG Cancer Centre, Mumbai, India Purpose/Objective: Geriatric head and neck squamous cell carcinomas (GHNC) remain challenging due to multiple patient and treatment related factors. The primary objective was to realise the learning curve ahead with geriatric G8 screening and to analyse efficacy and acute toxicity. Secondary objective was to analyse early treatment outcomes. Material/Methods: We analysed 120 patients (M:96, F:24) with median age of 78 years (70-96) between January 2018 to march 2024, treated by MRT with at least 6 months of follow up. G8 score screening done pre-treatment. Acute toxicity analysed by Common Terminology Criteria for Adverse Events (CTCAE) version 5. Demographic, disease related parameters, compliance to treatment, rate of hospitalisation, analgesia dependency and early clinical outcomes were analysed. Overall survival (OS) and Locoregional control (LRC) documented by SPSS version 20. Results: With median follow up of 17 months, 65% patients were locally advanced and 40% had oropharynx primary site. 80% received radical MRT and 20% received palliative MRT. Radical MRT dose ranged between 66-70 Gy in 33 fractions. 83% completed intended treatment with 30% had MRT interruptions. Rate of hospitalisation was 28% and 35% had two or more types comorbidities. 48% patients had concurrent chemotherapy with 20% receiving nimotuzumab. Post MRT 85% and 70% had endoscopic evaluation and imaging respectively. Acute toxicity grade 3 was observed in only 10 patients with no grade 4. Long term (>3months) tube dependency rate was 30% and 10% had morphine dependency. There were 15 deaths while on MRT both due to associated cardiac and pulmonary comorbidities. The complete response rates observed 85% in radical MRT and 40% in palliative MRT. All patients underwent psychological counselling and dietician evaluation. The median G8 screening score was 15. During follow-up 23.8% patients died, 76.1% were alive. Median OS was 12.8 (range 1 to 72) months and LRC 10.8 months. Local recurrence was observed in 15 patients and 4 received re-irradiation.

Conclusion: The learning curve of GHNC was the need of specialised setting coupled with modern MRT for effective outcome.