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Vienna, Austria

ESTRO 2023

Session Item

Lung
Poster (Digital)
Clinical
Prognosticator of SBRT efficacy and toxicity in early-stage NSCLC patients
David Walz, Germany
PO-1336

Abstract

Prognosticator of SBRT efficacy and toxicity in early-stage NSCLC patients
Authors:

David Walz1,2, Patrick Salome1,2, Francesco Sforazzini1,2, Andreas Kudak3,4, Matthias Dostal5,4, Sebastian Regnery6, Kai Schlamp7, Claus Peter Heußel8, Felix Herth9, Michael Thomas10, Juliane Hoerner-Rieber11, Jürgen Debus12, Maximilian Knoll12, Amir Abdollahi12

1German Cancer Research Center (DKFZ), CCU Translational Radiation Oncology, Heidelberg, Germany; 2Heidelberg University Hospital (UKHD), Faculty of Medicine (MFHD), Division of Molecular and Translational Radiation, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; 3Heidelberg University Hospital (UKHD), Division of Molecular and Translational Radiation, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg, Germany; 4German Cancer Research Center (DKFZ), National Center for Radiation Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), CCU Radiation Therapy, Heidelberg, Germany; 5Heidelberg University Hospital (UKHD), Division of Molecular and Translational Radiation, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg Ion-Beam Therapy Center (HIT) , Heidelberg, Germany; 6Heidelberg University Hospital (UKHD) , Department of Radiation Oncology, Heidelberg Institute of Radiation Oncology, Heidelberg, Germany; 7Heidelberg University Hospital (UKHD), Translational lung research center and Dep. of Pneumology and Critical Care Medicine Thoraxklinik, National Center for Tumor Diseases (NCT), German Center for Lung Research (DZL), Heidelberg, Germany; 8Heidelberg University Hospital (UKHD), Translational lung research center and Dep. of Pneumology and Critical Care Medicine Thoraxklinik, National Center for Tumor Diseases (NCT), Heidelberg, Germany; 9Heidelberg University Hospital (UKHD), Translational lung research center and Dep. of Pneumology and Critical Care Medicine Thoraxklinik, National Center for Tumor Diseases (NCT) , Heidelberg, Germany; 10Heidelberg University Hospital (UKHD), Translational lung research center and Dep. of Pneumology and Critical Care Medicine Thoraxklinik, National Center for Tumor Diseases (NCT), Dpt. Thoracic Oncology, Thoraxklinik, Heidelberg, Germany; 11Heidelberg University Hospital (UKHD), Department of Radiation Oncology, CCU Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg Institute for Radiation Oncology (HIRO), National Center for Tumor Diseases (NCT), Heidelberg, Germany; 12Heidelberg University Hospital (UKHD), Faculty of Medicine (MFHD), Division of Molecular and Translational Radiation, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg Ion-Beam Therapy Center (HIT), CCU Translational Radiation Oncology, German Cancer Research Center (DKFZ), National Center for Radiation Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany

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Purpose or Objective

Stereotactic body radiation therapy (SBRT) provides an alternative therapy option in non-operable early-stage non-small cell lung cancer (ES-NSCLC) patients. We aimed to assess clinical parameters correlating with SBRT efficacy and toxicity.

Material and Methods

ES-NSCLC Patients with T1-2N0M0 treated with SBRT (median dose 60Gy/8 fractions) between 2005 and 2019 were included in this analysis. Clinical and pathological status, and treatment characteristics were assessed and correlated with overall survival (OS), local control (LC), regional control (RC; not including LC), distant control (DC), radiation-induced pneumonitis (RP) and radiation-induced lung fibrosis (RILF). Three resampling (iterations = 1000) feature selection methods, including a univariate analysis under Cox proportional hazards model (P<0.1), a random forest-based method and lasso regression, were applied to evaluate the predictive power of the considered features. Multivariate Cox proportional hazards models were then trained for each outcome with the features identified as significant by the feature selection pipeline and assessed based on a 5-fold, respectively 10-fold cross-validated concordance index (C-I).

Results

101 patients were found eligible. Median follow-up time was 18 months (range 1-71 months). Median biologically effective dose (BED 10), D50 Gy and V20 of the total lung was 105 Gy, 1.75 Gy and 9%. Reported 1-year and 3-year OS, LC, RC, DC, were 95%, 92%, 98%, 93%, and 87%, 84%, 94%, 85%, respectively. Overall, pneumonitis rate was 6% and lung fibrosis rate 18%. Univariate analysis (UV) showed that squamous cell (SCC) histology was associated with shorter OS (HR=3.84, p<0.05) and a trend towards reduced tumor control (p<0.1); additional factors linked to poorer tumor control were lower mean dose (ipsilateral lung) and female gender (p<0.1). In multivariate analysis (MV) of OS, tumor histology, D50 Gy (total lung) and FEV1 were identified (C-I: 0.70). For LC (MV), V20 Gy, gender, and tumor location (C-I: 0.61), and for RC (MV) additionally, tumor histology (C-I: 0.61) were identified. DC (MV) parameters were V20 Gy, tumor histology, and D5 Gy at the planning target volume (C-I: 0.60). UV risk factors for RILF were lower lobe tumor localization, as well as BED 10 at the planning target volume periphery (p<0.1). No generalizable multivariate model could be derived for RP. For RILF (MV), tumor location (lower lobe and central vs peripheral) and prescribed biologically effective dose were identified (C-I: 0.74).

Conclusion

SBRT treatment produced excellent loco-regional control rates and consequently OS in ES-NSCLC, favorably in patients with non-squamous histology. Risk of RILF is enhanced for tumors located in the lower lobe.