The role of online MR-guided multi-fraction stereotactic ablative radiotherapy in lung tumours

BACKGROUND: The aim of this prospective observational study was to evaluate the dosimetry benefits, changes in pulmonary function, and clinical outcome of online adaptive MR-guided SBRT. METHODS: From 11/2020-07/2022, 45 consecutive patients with 59 lesions underwent multi-fraction SBRT (3-8 fractions) at our institution. Patients were eligible if they had biopsy-proven NSCLC or lung cancer/metastases diagnosed via clinical imaging. Endpoints were local control (LC) and overall survival (OS). We evaluated PTV/GTV dose coverage, organs at risk exposure, and changes in pulmonary function (PF). Acute toxicity was classified per the National Cancer Institute-Common Terminology Criteria for Adverse Events version 5.0. RESULTS: The median PTV was 14.4 cm(3) (range: 3.4 - 96.5 cm(3)). In total 195/215 (91%) plans were reoptimised. In the reoptimised vs. predicted plans, PTV coverage by the prescribed dose increased in 94.6% of all fractions with a median increase in PTV V(PD) of 5.6% (range: -1.8 - 44.6%, p < 0.001), increasing the number of fractions with PTV V(PD) 

• Hering, S.
• Nieto, A.
• Marschner, S.
• Hofmaier, J.
• Schmidt-Hegemann, N. S.
• da Silva Mendes, V.
• Landry, G.
• Niyazi, M.
• Manapov, F.
• Belka, C.
• Corradini, S.
• Eze, C.