Tumor Radiomics Features on Pretreatment CT to Predict Response to First-Line Chemotherapy in Thymic Carcinoma: A Multicenter Study

Objectives Platinum-based chemotherapy as first-line treatment have shown promising results against tumors in thymic carcinoma (TC). However, clinical benefit has been limited to a small proportion of patients. We developed and validated a combined radiomics model to predict progressive disease (PD) in patients suffering from TC following first-line chemotherapy. Methods Patients receiving platinum-based chemotherapy as first-line treatment from four centers in Shandong, China, were retrospectively included (n = 134); 93 and 41 were entered into the training and validation sets. Radiomics features were extracted from pretreatment enhanced CT. After feature selection, radiomics score (RS) was developed by Linear Discriminant Analysis (LDA) and TNM, clinicopathological and clinicopathological-radiomics models (combined radiomics model) were developed by using logistic regression algorithm. Models were assessed for performance, incremental predictive value of radiomics features versus clinicopathological features, and the relationship of RS and clinical factors to survival. Results The clinicopathological model was a modest predictor of PD, with area under curve (AUC) of 0.879 (95% CI: 0.709–0.890) and 0.799 (95% CI: 0.778–0.980) in the training and validation sets. The AUC of the combined radiomics model was 0.937 (95% CI: 0.891–0.984) and 0.899 (95% CI: 0.800-0.997), which is of good calibration and clinical application. The incremental predictive value of radiomics features for clinicopathological features was 27% ( p  < 0.001) and 0.4% ( p  = 0.108) in the training and validation sets. In addition, RS, CD5, and distant metastasis were associated with progression-free survival in both the training and validation sets. Conclusion Radiomics features extracted from pretreatment enhanced CT allow prediction of individualized objective responses to platinum-based chemotherapy as first-line treatment in TC, providing incremental predictive value for clinicopathological features, and are associated with progression-free survival after initiation of this combination regimen.