Predicting Microsatellite Instability Status in Colorectal Cancer Based on Triphasic Enhanced Computed Tomography Radiomics Signatures: A Multicenter Study

Abstract

Background: This study aimed to develop and validate a computed tomography (CT)-based radiomics model to predict microsatellite instability (MSI) status in colorectal cancer patients and to identify the radiomics signature with the most robust and high performance from one of the three phases of triphasic enhanced CT. Methods: In total, 504 colorectal cancer patients with preoperative contrast-enhanced CT images and available MSI status (441 in the training cohort and 61 in the external validation cohort) were enrolled from two centers in our retrospective study. Radiomic features of the entire primary tumor were extracted from arterial-, delayed-, and venous-phase CT images. The least absolute shrinkage and selection operator method was used to retain the features closely associated with MSI status. Radiomics, clinical, and combined clinicoradiomics models were built to predict MSI status. Model performance was evaluated by receiver operating characteristic curve analysis. Findings: Thirty-two radiomics features showed significant correlation with MSI status. Delayed-phase models showed superior predictive performance compared to arterial- or venous-phase models. Additionally, age, location, carcinoembryonic antigen level, CA125 level, and tumor differentiation were considered useful predictors of MSI status. The clinicoradiomics nomogram that incorporated both clinical risk factors and radiomics parameters showed excellent performance, with an AUC, accuracy, and sensitivity of 0•.903, 0•878, and 0•746 in the training cohort and 0•923, 0•918, and 0•778 in the validation cohort, respectively. Interpretation: The proposed CT-based radiomics signature has excellent performance in predicting MSI status and could potentially guide individualized therapy. Funding: This work was supported by the National Natural Science Foundation of China (82071872). Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: Ethical approval was obtained by the medical ethics committee in both participating centers (center I: Lanzhou University Second Hospital; center II: The Second People’s Hospital of Lanzhou city), and the requirement for informed consent was waived due to the retrospective nature of the study.