To Biopsy, or Not to Biopsy: Is There Really a Question?

Abstract

Soft tissue sarcomas (STS) represent a diverse group of histologic subtypes, each demonstrating its own unique tumor biology and propensity to recur locally or to metastasize. The retroperitoneum accounts for approximately 15–20% of all STS and about one-third of retroperitoneal masses are STS. As we have learned more about the behavior of retroperitoneal sarcomas (RPS), it has become generally accepted that histologic subtype and grade should determine the treatment algorithm and operative extent. Historically, an open surgical incisional biopsy was the approach of choice for diagnosis of suspected STS. While ensuring adequate tissue for diagnosis, this method is fraught with the potential for significant morbidity. With advances in radiology, the current standard is a percutaneous, image-guided approach. This involves a core-needle biopsy (CNB) using a 12–16 gauge needle that targets the most solid-appearing portion of a mass. A fine-needle aspiration often yields insufficient material to allow accurate diagnosis or distinguish histologic subtypes and should generally be avoided for evaluating a possible STS. The rare example of when a preoperative biopsy may not be warranted is in the example of a well-differentiated liposarcoma (WDLPS) that often demonstrates a characteristic homogeneous fat-dense appearance. However, in light of the recent findings from the European Organization for Research and Treatment of Cancer (EORTC) phase III trial (‘STRASS’), the trend in potential benefit of preoperative radiation for WDLPS would necessitate a preoperative biopsy in order to confirm the diagnosis prior to considering neoadjuvant treatment. A percutaneous approach to biopsy any solid tumor hypothetically has associated risks with regard to immediate periprocedural complications, and more long-term concerns regarding needle-track seeding (NTS). Risks associated with NTS for RPS differ from those for extremity sarcoma as, for the latter, the biopsy track is often aligned with the planned incision, and/or separately excised at the time of surgery. In this issue of Annals of Surgical Oncology, Berger-Richardson and colleagues from the Universities of Toronto and Ottawa report early and late complications in 314 patients undergoing 358 CNBs of suspected RPS. Utilizing data from each institution’s prospective databases, the authors astutely included all patients with suspected RPS, which ultimately included both benign and malignant entities. Early complications were considered procedure-related (i.e. bleeding, pain, unplanned admission, pneumothorax) and were identified in 11 patients (3.1%). Identification of NTS was based on a detailed radiographic review of all patients with a local recurrence in reference to needle tract trajectory used during percutaneous biopsy. With a median follow-up of 44 months, evidence of NTS was identified in only one of 203 patients (0.5%) undergoing CNB and subsequent resection for confirmed RPS (excluding other diagnoses). This study provides a comprehensive analysis of the risks associated with CNB in a population of patients that most accurately reflects real-world patients with both benign and malignant tumors. These data provide important information that can be used to better educate our patients on the procedure-related expectations, as well as the long-term oncologic consequences of NTS. The authors appropriately acknowledge the limitation of retrospective study of early complications and the likely underestimation of these risks. While significant complications requiring Society of Surgical Oncology 2019