ESTRO 2025 - Abstract Book

S1604

Clinical – Mixed sites & palliation

ESTRO 2025

Furthermore, we analysed treatment-naïve, newly diagnosed positive RPLNs cases (n = 171) to elucidate relationship with LSCLN metastasis. The regression coefficient for the upper RPLN level (β = 2.4173, p = 0.022) indicated an 11.22-fold elevated risk of LSCLN metastasis compared to the lower level.

Conclusion: This study provides anatomical, radiological, and statistical evidence to optimize LSCLN-CTV delineation based on the “block - reflux” lymphatic pattern. Accurate delineation boundaries and conditional irradiation strategies, including limited LSCLN irradiation or expansive V region exposure, were proposed to balance therapeutic efficacy and mitigates side effects. Furthermore, RPLN levels are critical predictors of LSCLN metastasis, prophylactic LSCLN CTV irradiation is recommended for upper-level RPLN metastasis in abdominopelvic cancer patients.

Keywords: supraclavicular lymph node, cervical radiotherapy

References: 1. Chang Y, Li G, Yang Z, et al. Inguinal nodal clinical target volume delineation based on analysis of anatomical locations of normal and metastatic lymph nodes in pelvic malignant tumors[J]. Radiotherapy and Oncology, 2023, 183: 109634. 2. Grégoire V, Ang K, Budach W, et al. Delineation of the neck node levels for head and neck tumors: a 2013 update. DAHANCA, EORTC, HKNPCSG, NCIC CTG, NCRI, RTOG, TROG consensus guidelines[J]. Radiotherapy and Oncology, 2014, 110(1): 172-181. 3. Negus D, Edwards J M, Kinmonth J B. Filling of cervical and mediastinal nodes from the thoracic duct and the physiology of virchow's node — studies by lymphography[J]. British Journal of Surgery, 1970, 57(4): 267-271.

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Digital Poster Stereotactic Body Radiotherapy as Adrenal Gland Metastasis-Directed Therapy in Oligometastatic Patients Federico Colombo, Marco Galaverni, Cristina Dell'Anna, Elisabetta Lattanzi, Claudia Grondelli, Francesco Salaroli, Ilaria Renna, Giovanni Ceccon, Stella Gianni, Maria Luisa Bergamini, Nunziata D'Abbiero, Nicola Simoni Radiation Oncology Unit, AOU Parma, Parma, Italy Purpose/Objective: To evaluate the clinical efficacy of Stereotactic Body Radiotherapy (SBRT) as adrenal gland metastasis-directed therapy in oligometastatic patients (OMPs). Material/Methods: Oligometastatic patients treated at our Institution with SBRT for adrenal gland metastases (AGMs) were retrospectively analyzed. Study endpoints were local progression-free survival (LPFS), disease free survival (DFS), overall survival (OS), and toxicity. Survival was estimated by the Kaplan-Meier method and factors potentially affecting outcomes were analyzed with Cox regression analysis. Results: From January 2018 to June 2024, 46 OMPs according to ESTRO-EORTC criteria accounting for 51 AGMs, received SBRT as metastasis-directed therapy (table 1). Most AGMs originated from non-small cell lung cancers (65.9%). SBRT was delivered with volumetric modulated arc radiotherapy (VMAT) in a median of 5 fractions (range 1-12 fractions). Median prescribed biological effective dose (BED 10 ) was 64 Gy (range 38-101 Gy) to the planning target volume (PTV) and 72 Gy (range 54-113 Gy) to the internal gross tumor volume (IGTV). Median PTV and IGTV volume were 42.9 cc (range 12.9-376.1 cc) and 14.9 cc (range 2.4-235.0 cc), respectively. Median estimated follow-up was 21.3 months (95% CI 20.4-30.4). Overall local control (LC) rate based on RECIST criteria was 84.3% (CR = 37.3%, PR = 41.2%, SD = 5.9%), with a 1- and 2-year LPFS rates of 85.8% (95% CI 75.9-97.1) and 74.0% (95% CI 58.1-94.3), respectively. Among