Background: Concern persists regarding percutaneous core needle biopsy (CNB) of a potentially malignant lesion of the retroperitoneum due to the perceived risk of immediate complications and adverse oncologic outcomes, including needle tract seeding (NTS).
Objective: The aim of this study was to evaluate the incidence of (1) early complications and (2) NTS following CNB of suspected retroperitoneal sarcoma (RPS).
Methods: Patients who underwent CNB of an RP mass with pre-biopsy suspicion of sarcoma were identified from a prospective database at two centers: (1) Princess Margaret Cancer Centre/Mount Sinai Hospital, Toronto (2009-2015); and (2) The Ottawa Hospital (1999-2015). Early complications, including bleeding, pain, infection, and organ injury, were recorded. Instances of NTS were identified from long-term follow-up of patients who underwent resection of primary RPS at these two centers after initial CNB (1996-2013).
Results: Of 358 percutaneous CNBs of suspected RPS performed over the study period, 7 (2.0%) resulted in minor bleeding with no transfusion, 3 (0.8%) resulted in significant pain, 1 (0.3%) resulted in unplanned admission to hospital for observation, and 1 (0.3%) resulted in a pneumothorax. There were no infections. In 203 patients who underwent resection of RPS following CNB, crude cumulative local recurrence was 24% at 5 years. At a median follow-up of 44 months, there was one case of NTS (approximately 0.5%).
Conclusion: This large bi-institutional experience with CNB of an RP mass demonstrates that both the early complication rate and the incidence of NTS are very low. Physicians and patients can be reassured that the benefits of CNB in diagnosing sarcoma and determining its histologic subtype and grade far outweigh the risks.