Artikel
Radiomics for the non-invasive assessment of the PDL-1 expression in patients with non-small cell lung cancer brain metastases
Radiomics zur nicht-invasiven Bestimmung der PDL-1 Expression bei Patienten mit Hirnmetastasen bei nicht-kleinzelligem Lungenkrebs
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Veröffentlicht: | 25. Mai 2022 |
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Gliederung
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Objective: The expression level of programmed cell death ligand 1 (PDL-1) might be an indicator for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As intra-tumoral differences and discrepancies between the PDL-1 expression in the primary tumor and the brain metastases may occur, a method for a reliable non-invasive assessment of the intracranial PDL-1 expression would be of clinical value. We evaluated the potential of MRI radiomics for a non-invasive assessment of the PD-L1 expression in patients with NSCLC brain metastases.
Methods: Thirty-six patients with brain metastases from NSCLC underwent brain tumor resection with subsequent immunohistochemical assessment of the PDL-1 expression. Brain metastases were manually segmented on preoperative contrast-enhanced MRI. After radiomics feature extraction from T1-weighted contrast-enhanced and T2-weighted MRI, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using five-fold cross validation. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.
Results: An intracranial PDL-1 expression was found by immunohistochemistry in 18 of 36 patients (50%). Univariate analysis identified tumor volume as a significant clinical feature for PDL-1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a six-parameter radiomics signature yielded an AUC of 0.88 ± 0.07. The combination of the radiomics features with tumor volume did not further increase the model performance.
Conclusion: The developed radiomics classifiers allows a non-invasive assessment of the intracranial PD-L1 expression in patients with NSCLC brain metastases with a high diagnostic performance. Further evaluation of the developed radiomics model in an external test dataset is ongoing.