Image-guided core needle biopsy for soft tissue sarcomas: Diagnostic accuracy in determining grade and malignant potential.

Abstract

Background: Core needle biopsy (CNB) has emerged as a less invasive alternative to open biopsy for diagnosing soft tissue sarcomas (STS). However, its accuracy in determining tumor grade and distinguishing between benign and malignant lesions remains a subject of ongoing research.

Objective: To assess the diagnostic accuracy of image-guided CNB for soft tissue sarcomas, focusing on grade determination and benign vs. malignant distinction.

Methods: This retrospective study analysed 83 patients who underwent both CNB and surgical excision for soft tissue tumors between 2020 and 2024. CNB results were compared with final histopathology findings. Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. ROC curve analysis was performed to evaluate diagnostic performance.

Results: The overall accuracy of CNB was 95.18 % (95 % CI: 88.11 % - 98.71 %) for distinguishing between benign and malignant lesions, with a sensitivity of 96.34 % (95 % CI: 89.68 % - 99.24 %) and PPV of 98.75 % (95 % CI: 93.23 % - 99.97 %). For grade determination, CNB showed an accuracy of 86.75 % (95 % CI: 77.52 % - 93.19 %), with sensitivity of 85.92 % (95 % CI: 75.67 % - 93.03 %) and specificity of 91.67 % (95 % CI: 61.52 % - 99.79 %) for high-grade tumors. ROC curve analysis demonstrated excellent discriminatory ability with AUC of 0.982 for benign vs. malignant distinction and 0.888 for grade determination. Diagnostic accuracy varied across sarcoma subtypes, with some rare types showing perfect accuracy and more common types demonstrating moderate to good sensitivity and high specificity.

Conclusion: Image-guided CNB demonstrates high overall accuracy in diagnosing and grading soft tissue sarcomas, particularly in identifying malignant lesions. While performance varies across sarcoma subtypes, these findings support the use of CNB as a reliable diagnostic tool in the management of suspected soft tissue sarcomas.