Accuracy and Safety of Ultrasound-Guided Core Needle Biopsy of Soft Tissue Tumors in an Outpatient Setting: A Sarcoma Center Analysis of 392 Consecutive Patients

SIMPLE SUMMARY: In patients with unclear soft tissue lesions, treatment planning largely depends on histology. Core needle biopsy is the diagnostic standard in these cases. The aim of this retrospective study was to investigate accuracy and safety of ultrasound guided core needle biopsy at a tertiary referral center. We show that ultrasound guided biopsy was feasible as a one stop shop procedure in an outpatient setting in 87.6% of the cases. The rate of conclusive biopsies was 88.5%. After surgical resection, the dignity, tumor type and histopathological grading of the biopsy matched one of the resection specimens in 97.2%, 92.7% and 92.5% of the cases, respectively. Major complications occurred in 0.8% of the cases. With this study, we confirm that ultrasound guided core needle biopsy is safe, effective and can be performed at the first outpatient presentation to speed up the diagnostic and therapeutic cascade in sarcoma patients. ABSTRACT: Background: The aim of this study was to investigate diagnostic accuracy, safety and histologic results of ultrasound guided core needle biopsy (CNB) in patients with soft tissue lesions (STL) at a tertiary referral center. Methods: A retrospective analysis of all consecutive patients undergoing ultrasound guided CNB for STL at our sarcoma outpatient service between January 2015 and August 2020 was performed. Results: A total of 392 patients were identified. Main histologic entities were sarcomas, lipomas and desmoid tumors. Biopsy was performed in an outpatient setting in 87.6% of the cases. Conclusive biopsies were obtained in 88.5% of the cases. In patients who underwent surgical resection after CNB, the concordance of dignity, tumor entity and histopathological grading between biopsy and resection specimen were 97.2%, 92.7% and 92.5% respectively. The risk of inconclusive CNB was highest in intraabdominal or retroperitoneal tumors (19.5%) and lowest in lesions at the lower extremity (4.4%). Major complications after CNB occurred in three cases (0.8%). No case of biopsy tract seeding was observed during the study period. Conclusions: Ultrasound guided CNB for STL at first presentation in a dedicated surgical outpatient setting is a safe procedure and yields a high diagnostic accuracy.