ESTRO 2025 - Abstract Book

S1140

Clinical – Head & neck

ESTRO 2025

Conclusion: Delay of > 78.5 days between RT-T were associated with a significant increase in the risk of LRR.

Keywords: Adjuvant radiotherapy, Locoregional control, Delay

References: 1. Jacques Bernier , Christian Domenge, Mahmut Ozsahin. European Organization for Research and Treatment of Cancer Trial 22931. Postoperative irradiation with or without concomitant chemotherapy for locally advanced head and neck cancer 2. Huang J, Barbera L, Brouwers M, Browman G, Mackillop WJ. Does delay in starting treatment affect the outcomes of radiotherapy?. A systematic review. J Clin Oncol 2003;21:555–563

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Digital Poster Long-term Outcomes of Salivary Gland Cancer: A Five-Year Analysis of Survival and Disease Control from a Single Center Jorge F Obeso-Herrera, Carmen Hernández-Carrillo Martínez-Almeida, María L Pérez-Rodríguez, Lucía Juan Rodriguez, Paula Martín-Barrientos, Marta Lloret Sáez-Bravo Radiation oncology, Doctor Negrín University Hospital, Las Palmas de Gran Canaria, Spain Purpose/Objective: Salivary gland tumors, though comprising a small proportion of head and neck cancers, present significant diagnostic and treatment challenges due to the infrequency and histological diversity. In this context, the aim of this study is to analyze five-year survival outcomes and disease control patterns in salivary gland cancer patients treated with radical and adjuvant radiotherapy at our institution. Material/Methods: We conducted a descriptive single-center analysis of salivary gland cancer patients treated with curative intent from March 2013 to September 2024. Treatment simulation was performed using CT imaging with a thermoplastic mask for head and shoulder immobilization. External radiotherapy was delivered using the VMAT technique on a linear accelerator, with patient and isocenter positioning verified through cone-beam computed tomography (CBCT) during each session. For non-operated malignant tumors a total dose of 70 Gy was delivered. In a postoperative setting, the total dose in tumor bed was 60 Gy (66 Gy in case of R1 resections). In both cases, the elective areas received 54 Gy. Results: We analyzed the outcomes of 41 patients with salivary gland cancer. Regarding clinicopathological data (Table 1), the carcinomas were mostly stage-III and IVA (31.71%) across both subgroups and the most frequent location was the parotid gland (85.37%), followed by submandibular (14.63%). The most frequent histology was squamous cell carcinoma (31.71%) and only 3 patients presented a rare histology such as basal cell adenocarcinoma, oncocytic carcinoma, and small cell neuroendocrine carcinoma (2.44%). Regarding histologic features, most tumors were moderately differentiated (43.9%). Positive PNI and LVI were observed in 34.15% and 14.63%, respectively. Surgical margins were positive in 43.9% and there were 9.76% of extracapsular extension, both the main indications for adjuvant radiotherapy. The most used treatment in our series was surgery plus adjuvant radiotherapy (53.66%). Hormone receptors and molecular alterations were studied in only a few patients, all non-squamous carcinomas, 9.76% expressed androgen receptors and 4.88% were Her2 positive. The median follow-up is 24.53 months (4.5 70.5). The five-year Kaplan-Meier survival analysis showed an overall survival of 56%, progression-free survival of