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Purpose: Stereotactic body radiation therapy for tumors near the central airways implies high-grade toxic effects, as concluded from the HILUS trial. However, the small sample size and relatively few events limited the statistical power of the study. We therefore pooled data from the prospective HILUS trial with retrospective data from patients in the Nordic countries treated outside the prospective study to evaluate toxicity and risk factors for high-grade toxic effects., Methods and Materials: All patients were treated with 56 Gy in 8 fractions. Tumors within 2 cm of the trachea, the mainstem bronchi, the intermediate bronchus, or the lobar bronchi were included. The primary endpoint was toxicity, and the secondary endpoints were local control and overall survival. Clinical and dosimetric risk factors were analyzed for treatment-related fatal toxicity in univariable and multivariable Cox regression analyses., Results: Of 230 patients evaluated, grade 5 toxicity developed in 30 patients (13%), of whom 20 patients had fatal bronchopulmonary bleeding. The multivariable analysis revealed tumor compression of the tracheobronchial tree and maximum dose to the mainstem or intermediate bronchus as significant risk factors for grade 5 bleeding and grade 5 toxicity. The 3-year local control and overall survival rates were 84% (95% CI, 80%-90%) and 40% (95% CI, 34%-47%), respectively., Conclusions: Tumor compression of the tracheobronchial tree and high maximum dose to the mainstem or intermediate bronchus increase the risk of fatal toxicity after stereotactic body radiation therapy in 8 fractions for central lung tumors. Similar dose constraints should be applied to the intermediate bronchus as to the mainstem bronchi., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The introduction of immune checkpoint inhibitors has transformed the treatment landscape of metastatic non-small cell lung cancer. However, challenges remain to increase the fraction of patients achieving durable clinical responses to these drugs and to help monitor the treatment effect. In this phase II trial, we investigated the toxicity, systemic responses and circulating tumour DNA responses in patients (n = 21) with advanced non-small-cell lung cancer treated with atezolizumab and stereotactic body radiotherapy in the second or later line. We found the combined treatment to be safe with grade 3 toxicity reported in three patients. As the best overall response, four patients had a partial response, eight had stable disease and five had progressive disease. Median overall survival time was still not reached after a median follow-up of 26.5 months and 10/15 patients with programmed death-ligand 1 negative tumours were alive >18 months after the start of the study treatment. ctDNA was detectable at baseline in 11 patients. A rapid decline in ctDNA to <30% of baseline levels was seen in three patients, two of which were radiographic responders and one was considered clinically benefiting from therapy for almost 1 year., (© 2022 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Introduction: Stereotactic body radiation therapy of thoracic tumors close to the central airways implies risk of severe toxicity. We report a prospective multicenter phase 2 trial for tumors located less than or equal to 1 cm from the proximal bronchial tree with primary end point of local control and secondary end point of toxicity., Methods: Stereotactic body radiation therapy with 7 Gy × 8 was prescribed to the 67% isodose encompassing the planning target volume. The patients were stratified to group A (tumors ≤ 1 cm from the main bronchi and trachea) or group B (all other tumors). Risk factors for treatment-related death were tested in univariate analysis, and a logistic regression model was developed for fatal bronchopulmonary bleeding versus dose to the main bronchi and trachea., Results: A total of 65 patients (group A/group B, n = 39/26) were evaluated. The median distance between the tumor and the proximal bronchial tree was 0 mm (0-10 mm). The 2-year local control was 83%. Grade 3 to 5 toxicity was noted in 22 patients, including 10 cases of treatment-related death (bronchopulmonary hemorrhage, n = 8; pneumonitis, n = 1; fistula, n = 1). Dose to the combined structure main bronchi and trachea and tumor distance to the main bronchi were important risk factors. Dose modeling revealed minimum dose to the "hottest" 0.2 cc to the structure main bronchi and trachea as the strongest predictor for lethal bronchopulmonary hemorrhage., Conclusions: On the basis of the presented data, 7 Gy × 8, prescribed to the planning target volume-encompassing isodose, should not be used for tumors located within 1 cm from the main bronchi and trachea. Group B-type tumors may be considered for the treatment on the basis of an individual risk-benefit assessment and a maximum dose to the main bronchi and trachea in the order of 70 to 80 Gy (equivalent dose in 2 Gy fractions)., (Copyright © 2021 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Introduction: Technological innovations have taken stereotactic body radiotherapy (SBRT) from frame-based strategies to image-guided strategies. In this study, cone beam computed tomography (CBCT) images acquired prior to SBRT of patients with lung tumors was used to study the dosimetric impact of a pure frame-based strategy., Material and Methods: Thirty patients with inoperable lung tumors were retrospectively analyzed. All patients had received CBCT-guided SBRT with 3 fractions of 15 Gy to the planning target volume (PTV) margin including immobilization in a stereotactic body frame (SBF). Using the set-up corrections from the co-registration of the CBCT with the planning CT, all individual dose plans were recalculated with an isocenter position equal to the initial set-up position. Dose Volume Histogram (DVH) parameters of the recalculated dose plans were then analyzed., Results: The simulated plans showed that 88% of all fractions resulted in minimum 14.5 Gy to the internal target volume (ITV). For the simulated summed treatment (3 fractions per patient), 83% of the patients would minimum receive the prescription dose (45 Gy) to 100% of the ITV and all except one would receive the prescription dose to more than 90% of the ITV., Conclusions: SBRT including SBF, but without image guidance, results in appropriate dose coverage in most cases, using the current margins. With image guidance, margins for SBRT of lung tumors could possibly be reduced.

Background: Spine radiosurgery has been performed at Oslo University hospital, The Norwegian Radium Hospital since July 2011. Our approach has been to develop a simple planning technique, where the organs at risk are spared while substantially reducing the planning time. Materials and methods: We have developed a library plan with nine static beams, where each beam is automatically formed to the PTV, but also manually ensuring that a spinal cord planning risk volume (PRV) is excluded in all directions. This is a fast forward planning (FFP) technique compared to regular IMRT or VMAT techniques for spine radiosurgery. In this work ten patient plans using FFP were compared to IMRT and VMAT plans for the identical patients. The dose distributions were compared for the different plans, emphasizing the dose to the target volumes and reduced dose to the surrounding tissue. The planning time consume and treatment time were also registered. Results: We found that the risk organs dose criteria normally were fulfilled within a sufficient margin for FFP, IMRT and VMAT techniques. The dose distribution following FFP yields a steeper gradient close to the spinal cord, but also gives a more heterogeneous dose distribution within the PTV. The GTV dose applying a FFP technique is normally higher than from IMRT and VMAT. For single fraction spine radiosurgery, the average GTV dose was 25.8 Gy for FFP, while the objective for an IMRT or VMAT optimization should exceed 18 Gy to D98%. Planning time for FFP is normally less than 30 minutes, while IMRT or VMAT optimization may last for several hours. Conclusions: The main alternative for this patient group at our hospital has traditionally been 30 Gy in 10 fractions, conventionally planned with one or two opposing fields. Our preliminary findings using this FFP technique suggest a sufficient and comparable dose distribution to those resulting from IMRT or VMAT, while the total time consume is comparable or less than the conventional method. Disclosure: No significant relationships. [ABSTRACT FROM AUTHOR]