ESTRO 2024 - Abstract Book

S1622

Clinical - Lung

ESTRO 2024

[1] Allignet B, De Ruysscher D, Martel-Lafay I, Waissi W. Stereotactic body radiation therapy in unresectable stage III non-small cell lung cancer: A systematic review. Cancer Treat Rev 2023;118. https://doi.org/10.1016/j.ctrv.2023.102573. [2] Arcidiacono F, Anselmo P, Casale M, Zannori C, Ragusa M, Mancioli F, et al. STereotactic Ablative RadioTherapy in NEWly Diagnosed and Recurrent Locally Advanced Non-Small Cell Lung Cancer Patients Unfit for ConcurrEnt RAdio-Chemotherapy: Early Analysis of the START-NEW-ERA Non-Randomised Phase II Trial. International Journal of Radiation Oncology*Biology*Physics 2023;115:886 – 96. https://doi.org/10.1016/j.ijrobp.2022.10.025.

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Poster Discussion

High survival after high dose reirradiation of in-field recurrent lung cancer: a prospective trial

Marloes Duijm 1 , Eugenio Cammareri 1 , Patrick V. Granton 1 , Wilco Schillemans 1 , Steven Petit 1 , Jose Belderbos 2 , Erik van Werkhoven 1 , Robin Cornelissen 3 , Joost Knegjens 2 , Joost J. Nuyttens 1 1 Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Radiotherapy, Rotterdam, Netherlands. 2 The Netherlands Cancer Institute, Department of Radiotherapy, Amsterdam, Netherlands. 3 Erasmus MC Cancer Institute, University Medical Center Rotterdam, Department of Pulmonary Medicine, Rotterdam, Netherlands

Purpose/Objective:

Locoregional failures after (chemo)radiotherapy for primary lung cancer account for 30% of relapses. Reirradiation of in-field recurrences has been used in the past with palliative doses, resulting in a short median overall survival (OS) of 5-8 months. Reirradiation with a high dose in this setting is challenging due to the surrounding organs at risk (OAR). Recent improvement of radiation techniques and the possibility to sum doses of radiation plans, results in new treatment possibilities for recurrent lung cancer, while avoiding toxicity. However the effect of these re irradiation developments on patient outcomes is unknown. Therefore we conducted a prospective phase II trial with high-dose radiotherapy for in-field or marginal in-field recurrences of lung cancer in the thorax focusing on prolonging OS without having high-grade toxicity.

Material/Methods:

The goal of the phase II trial study (NL59876.078.17) was to treat recurrent lung cancer with high-dose (chemo)radiotherapy to reach a median OS of 12 months. Patients with recurrent lung cancer in the thorax (tumor < 5cm from 50Gy EQD 2,10 isodose line of previous radiotherapy) were treated with conventional (chemo)radiotherapy or SBRT, all with a prescribed re- irradiation dose of ≥ 45Gy EQD 2,10 . The interval between initial treatment and reirradiation had to be ≥9 months. A rigid dose summation was performed for every patient per OAR separately and doses were recalculated to an EQD 2 . The accumulated OAR constraints, like a D max to spinal cord, esophagus,