ESTRO 2024 - Abstract Book

S1795

Clinical - Lung

ESTRO 2024

Radiotherapy (SABR) for Early-Stage Lung Tumors: A Pictorial Essay. J Thorac Oncol (2018) 13:855 – 862. doi: 10.1016/j.jtho.2018.02.023

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Comparison of two different dose and fractionation regimens of lung SBRT.

Frederik Przybilla 1,2 , Sonja Adebahr 1,3 , Tanja Schimek-Jasch 1 , Ilinca Popp 1,3 , Eleni Gkika 1,3 , Anca-Ligia Grosu 1,3

1 Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Department of Radiation Oncology, Freiburg, Germany. 2 Klinikum St. Georg, Department of Internal Medicine, Dresden, Germany. 3 German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany

Purpose/Objective:

Although stereotactic fractionated body radiotherapy (SBRT) is commonly used in the management of early-stage NSCLC and oligometastatic lung disease, there is substantial variation in dose and fractionation, planning, and treatment delivery. After completing our prospective STRIPE trial 1 applying SBRT with 3X12.5Gy on the 60% isodose, our department altered the regimen to 3X18.75Gy on the median, according to the respective national guidelines in 2014. Here we compare outcome and pulmonary toxicity of the two different regimens.

Material/Methods:

We retrospectively evaluated patients treated with pulmonary SBRT with 3 X 18.75 Gy prescribed on the median. Applied dose (D max , D min D average , mean lung dose (MLD), volume of lung receiving 5Gy and 20Gy respectively (V5, V20) were assessed. Treatment outcome (local progression, progression free survival (PFS) and overall survival (OS)) was evaluated using Kaplan-Meyer. Radiation pneumonitis was assessed according to CTCAE v5. Results were compared to our previously reported results of the prospective STRIPE trial (109, patients: 56 NSCLC, 44 pulmonary metastases) treated with 3 X 12,5 Gy or risk adapted 5X7Gy, respectively prescribed on 60% isodose 1 .

Results:

We retrospectively evaluated 74 patients (32 with NSCLC, 42 with oligometastatic lung disease) treated from 11/2014 to 03/2018 with 3X 18.75 Gy prescribed on the median. Patients were mainly male (62%) with a median age of 68 years. NSCLC patients had mainly small tumors (T1:78%, T2:9%), most of them located in the right upper lobe. Median D average , D max and D min to the planning target volume (PTV) was BED 165.3 Gy, 211,2Gy and 100,8 Gy, respectively, (vs. BED 131.9 Gy,187,6Gy and 72,2Gy in STRIPE). The median of MLD, V5 and V20 (ipsi – and contralateral) were 2,1Gy, 9,7% and 2,1 % (vs. 2.3Gy, 11,6% and 1.9% in STRIPE). Median follow up was 21.7 months. After 2 years the probability for local recurrence, PFS and OS was 8.1%, 54% (NCSLC 28%, metastases 74%) and 73% (vs. 8.1%, 48.8% (NSCLC 36.9%, metastases 65%) and 62,2% in STRIPE). In the current collective,10 patients (13.5%)