Percutaneous core needle biopsy versus open biopsy in diagnostics of bone and soft tissue sarcoma: a retrospective study

BACKGROUND: Biopsy is a crucial step within the diagnostic cascade in patients with suspected bone or soft tissue sarcoma. Open biopsy is still considered the gold standard. However, recent literature suggests similar results for percutaneous biopsy techniques. Therefore, the aim of this retrospective analysis was to compare open and percutaneous core needle biopsy (CNB) regarding their accuracy in diagnosis of malignant musculoskeletal lesions. METHODS: From January 2007 to December 2009, all patients with suspected malignant primary bone or soft tissue tumour undergoing a percutaneous CNB or open biopsy and a subsequent tumour resection at our department were identified and enrolled. Sensitivities, specificities, positive predictive values (PPV), negative predictive values (NPV) and diagnostic accuracy were calculated for both biopsy techniques and compared using Fisher’s exact test. RESULTS: A total of 77 patients were identified and enrolled in this study. Sensitivity, specificity, PPV, NPV and diagnostic accuracy were 100% for CNB in bone tumours. Sensitivity (95.5%), NPV (91.7%) and diagnostic accuracy (93.3%) for open biopsy in bone tumours showed slightly inferior results without statistical significance (p > 0.05). In soft tissue tumours favourable results were obtained in open biopsies compared to CNB with differences regarding sensitivity (100% vs. 81.8%, p = 0.5), NPV (100% vs. 50%, p = 0.09) and diagnostic accuracy (100% vs. 84.6%, p = 0,19) without statistical significance. The overall diagnostic accuracy was 92.9% for CNB and 98.0% for open biopsy (p = 0.55). A specific diagnosis could be obtained in 84.2% and 93.9%, respectively (p = 0.34). CONCLUSION: In our study we found moderately inferior results for the percutaneous biopsy technique compared to open biopsy in soft tissue tumours whereas almost equal results were obtained for both biopsy techniques for bone tumours. Thus, CNB is a safe, minimal invasive and cost-effective technique for diagnosing bony lesions. In soft tissue masses, the indication for percutaneous core needle biopsy needs to be made carefully by an experienced orthopaedic oncologist with respect to the suspected entity, size of necrosis and location of the lesion to avoid incorrect or deficient results.