The value of preoperative prediction of microsatellite instability in colon cancer based on CT-derived extracellular volume fraction ( fECV )
Author Block: F. Wu, C. Huang; Guiyang City, Guizhou Province/CN
Purpose: To investigate the value of CT-derived extracellular volume fraction (fECV) in predicting microsatellite instability (MSI) status in colon cancer.
Methods or Background: The clinical and imaging data of 168 patients with colon cancer who underwent radical surgery were retrospectively analyzed. The imaging features of the lesions were extracted and fECV was calculated. According to the postoperative results, the patients were divided into MSI group ( 17 cases ) and MSS group ( 151 cases ). The binary logistic regression model was constructed for combined diagnosis, and the ROC curve was used to evaluate the diagnostic efficacy.
Results or Findings: The differences in tumor location, differentiation grade, and lymph node status between the MSI and MSS groups were statistically significant (P<0.05); both fECV and △tumor values in the MSI group were higher than those in the MSS group (P<0.05). The area under the curve (AUC) for predicting MSI status using fECV, tumor location, differentiation grade, and lymph node metastasis were 0.834, 0.661, 0.667, 0.623, and 0.684 respectively. The imaging model (fECV + tumor location), pathological model (lymph node metastasis + differentiation grade), Model 1 (tumor location + pathological model), and Model 2 (fECV + Model 1) showed AUC, sensitivity, and specificity for predicting MSI status as follows: 0.915, 76.47%, 90.07%; 0.770, 94.12%, 51.66%; 0.818, 70.59%, 77.48%; 0.951, 100.00%, 79.47%. DeLong test suggests Model 2 was superior to all single indicators and models (P<0.05), followed by the imaging model which outperformed all single indicator models and pathological combination models (all P<0.05).
Conclusion: fECV have high diagnostic value for MSI and can be used to predict MSI status.
Limitations: This study is a single-center retrospective study lacking external validation; due to MSI-positive cases constraints, detailed subgroup analysis could not be conducted.
Funding for this study: No funding was provided for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Hospital Ethics Committee (Approval No. 2025 Review No. 20250004)