Improved Biopsy Accuracy in Retroperitoneal Dedifferentiated Liposarcoma

Diagnostic accuracy and safety of percutaneous core needle biopsy of retroperitoneal tumours

BACKGROUND

Histologic subtype of cancer guides treatment sequencing and the extent of surgery for retroperitoneal tumours (RPTs) but concerns persist regarding percutaneous core needle biopsy (CNB).

OBJECTIVE

Endpoints were the incidence of early complications, needle tract seeding (NTS) after CNB, diagnostic accuracy.

METHODS

Between 2015 and 2022, data from patients with RPT who underwent a CNB and who operated on at Institut Curie were collected. We retrospectively reviewed the medical records and microscopic analysis of both CNB and surgical specimens to evaluate the diagnostic accuracy of CNB (quantified using positive and negative predictive values, PPV/NPV).

RESULTS

313 patients underwent CNB. In 10/326 (3 %) procedures, minor complications were observed. One of 212 (0.47 %) resected RPSs exhibited a local recurrence compatible with NTS. Microscopic analysis of CNB specimens allowed the classification of tumours between groups of cancers and benign/intermediate mesenchymal tumours in 307/313 (98 %) patients. Among the 204 patients with retroperitoneal sarcoma, the overall concordance between CNB and final pathology following resection was 178/204 (87.2 %). The respective PPVs of solitary fibrous tumour, dedifferentiated liposarcoma, leiomyosarcoma and well-differentiated liposarcoma were 100 %, 98 %, 97 % and 68 %, respectively. The diagnosis of a high-grade (G 2-3) sarcoma resulted in a high specificity (97 %) and PPV (98 %) but low sensitivity (76 %).

CONCLUSIONS

CNB allowed the classification of RPT in the vast majority of patients with a low morbidity rate. Concordance with final diagnosis was high for sarcomas with the exception of well-differentiated liposarcoma. As a result, CNB results should be integrated with imaging/radiomics by multidisciplinary tumour boards.

Updated Review and Clinical Recommendations for the Diagnosis and Treatment of Patients with Retroperitoneal Sarcoma by the Spanish Sarcoma Research Group (GEIS)

Soft tissue sarcomas (STS) are an uncommon and biologically heterogeneous group of tumors arising from mesenchymal cells. The incidence is estimated at five cases per 100,000 people per year. Retroperitoneal sarcomas (RPS) account for 10-15% of all STS, and their management depends on their anatomical characteristics and histotype. Due to their very low incidence, it is recommended that RPS be treated in reference centers and evaluated by an experienced multidisciplinary team (MDT). In Spain, the Spanish Group for Research in Sarcomas (GEIS) brings together experts from various specialties to promote research on sarcomas and improve treatment results. This paper summarizes the GEIS recommendations for the diagnosis, treatment, and follow-up of patients with RPS.

Current management of benign retroperitoneal tumors

Benign retroperitoneal tumors (BRT) represent a rare group of heterogeneous diseases. The literature lacks high-quality evidence about the optimal management of BRT, and most of the information available takes the form of case reports or case series. The aim of this review is to provide an overview of current management strategies for adult patients with BRT. A literature search using PubMed indexed articles was conducted and BRT were classified into five different biological subgroups: 1) lipomatous tumors, 2) smooth muscle tumors, 3) peripheral nerve sheath tumors, 4) myofibroblastic tumors, and 5) others. Tumors that are primarily pelvic in origin were excluded. Despite the significant heterogeneity of the disease, several generic considerations have emerged and can be applied to the management of BRT. Specifically, the risk of misdiagnosing a BRT with another pathology such as retroperitoneal sarcoma is notable. When encountered, suspected BRT should therefore be referred to a specialized sarcoma center. Multidisciplinary tumor boards, present at these centers, have a pivotal role in managing BRT. The decision of whether to offer surgery, nonsurgical treatment or a "watch-and-wait" approach should be made after multidisciplinary discussion, depending on tumor histology. Moving forward, collaborative research efforts dedicated to BRT remain crucial in gathering evidence and knowledge to further optimize patient care.

How to treat liposarcomas located in retroperitoneum

Almost half of retroperitoneal (RP) sarcomas are liposarcomas (LPS). The large majority of RP LPS are either well-differentiated LPS (WDLPS) or dedifferentiated LPS (DDLPS), these latter further classified according to grading in G2 and G3 DDLPS. Surgery is the only potentially curative treatment to achieve local control and possibly cure in primary localized disease. Over the last decade, a better delineation of the different histology-specific patterns of failure and the development of nomograms predictors of outcome has led to a better management of these rare tumors, with a special focus on non-surgical treatments. Available evidences - although far from exhaustive - show that radiation therapy might have a role, if any, as neoadjuvant treatment in locally aggressive histologies (i.e. WDLPS and G2 DDLPS), while it does not seem beneficial for histologies with a higher metastatic risk (i.e. G3 DDLPS and leiomyosarcoma). Neoadjuvant chemotherapy, instead, can be considered to reduce the risk of distant metastasis while waiting for the results of an ongoing RCT (STRASS-2) evaluating its effect in these tumors. However, given the rarity of these diseases and the subsequent lack of strong evidences to guide treatment, outcome improvement in these patients remains a challenge. Patients' referral to a sarcoma center where a dedicated specialized multidisciplinary team tailor optimal treatment on a case-by-case basis is crucial to ensure these patients the best outcome. Refining available nomograms - e.g including molecular variables - and identifying predictors of response/toxicity to chemotherapy and immunotherapy might be significantly helpful in tailoring treatments to the patient's characteristics. Also, new systemic agents are eagerly awaited for improving the management further.

Diagnostic accuracy of biopsy after neoadjuvant treatment for well-differentiated and dedifferentiated retroperitoneal liposarcoma

PURPOSE

Accurate histopathological grading of percutaneous biopsies is essential to guide adequate management of patients with suspected retroperitoneal liposarcoma. In this regard, however, limited reliability has been described. Therefore, we conducted a retrospective study to assess the diagnostic accuracy in retroperitoneal soft tissue sarcomas and simultaneously investigate its impact on patients' survival.

MATERIALS AND METHODS

Reports of an interdisciplinary sarcoma tumor board between 2012 and 2022 were systematically screened for patients with well-differentiated (WDLPS) and dedifferentiated retroperitoneal liposarcoma (DDLPS). Histopathological grading on pre-operative biopsy was correlated with corresponding postoperative histology. Additionally, patients' survival outcomes were examined. All analyses were performed in two subgroups: patients with primary surgery and patients with neoadjuvant treatment.

RESULTS

A total of 82 patients met our inclusion criteria. Diagnostic accuracy of patients who underwent upfront resection (n = 32) was significantly inferior to patients with neoadjuvant treatment (n = 50) (66% versus 97% for WDLPS, p < 0.001; 59% versus 97% for DDLPS, p < 0.001). For patients with primary surgery, histopathological grading on biopsy and surgery was concordant in only 47% of cases. Sensitivity for detecting WDLPS was higher than for DDLPS (70% versus 41%). Higher histopathological grading in surgical specimens correlated with worse survival outcomes (p = 0.01).

CONCLUSION

Histopathological grading of RPS may no longer be reliable after neoadjuvant treatment. The true accuracy of the percutaneous biopsy may need to be studied in patients who do not receive neoadjuvant treatment. Future biopsy strategies should aim to improve identification of DDLPS to inform patient management.

Is preoperative CT-guided biopsy a valuable tool in the diagnostic workup of patients with visceral and retroperitoneal sarcoma?

PURPOSE

We aimed to analyze the diagnostic accuracy of preoperative CT-guided biopsy to identify patients that might profit from neoadjuvant chemotherapy in a specialized high-volume sarcoma center.

MATERIAL AND METHODS

We retrospectively reviewed all patients with suspected soft tissue tumors of the abdomen cavity including the retroperitoneum, who received CT-guided biopsy followed by surgical tumor resection. Sensitivity, specificity, PPV and NPV were calculated in all patients with abdominal sarcomas at our hospital. A subgroup analysis was performed for patients with liposarcoma.

RESULTS

A total of 82 patients (35 female, 47 male, age: 62.0 ± 14.7) received preoperative CT-guided biopsy followed by surgical resection. Overall accordance of CT-guided biopsy to identify final histology was 77 %. CT-guided biopsy revealed the diagnosis of liposarcoma in 23 patients whereas final analysis of the surgical specimen identified liposarcoma in 29 patients. Here, sensitivity, specificity, PPV and NPV was 79.3 %, 100.0 %, 100.0 % and 89.8 % respectively. Subgroup analysis revealed a better accuracy for correctly identifying patients with well-differentiated liposarcoma than patients with dedifferentiated liposarcoma (75.0 % vs 62.5 %). In patients with other sarcoma, sensitivity, specificity, PPV, NPV and diagnostic accuracy was 87.5 %, 95.5 %, 82.4 % and 96.9 %, respectively.

CONCLUSION

CT-guided biopsy in a specialized high-volume sarcoma center is an accurate and effective method to assess patients with abdominal sarcoma and especially abdominal liposarcoma. Therefore, it is an indispensable tool in the pretherapeutic workup process. Nevertheless, our study underlines the previously reported difficulties in dedifferentiated liposarcoma diagnostics, whereby these patient cohort would profit the most from a neoadjuvant therapy regime.

Preoperative Biopsy in Patients with Retroperitoneal Sarcoma: Usage and Outcomes in a National Cohort

INTRODUCTION

Preoperative biopsy (PBx) is often recommended for retroperitoneal sarcoma (RPS), but its utilization rate and impact on perioperative management and outcomes remains undefined.

METHODS

Using the National Cancer Database, patients who underwent resection of non-metastatic RPS were identified (2006-2014). Patients who did and did not undergo PBx of the primary tumor were compared using propensity matching, and factors associated with survival were assessed by multivariable analysis.

RESULTS

Of 2620 patients, 1110 (42.4%) underwent PBx. Factors significantly associated with performance of PBx included male sex [odds ratio (OR) 1.2, P = 0.035], tumor size ≤ 5 cm (OR 1.5, P = 0.012), tumor size > 5 to ≤ 10 cm (OR 1.3, P = 0.009), non-well-differentiated liposarcoma histology (OR 2.0, P ≤ 0.001), and treatment at a high-volume center (OR 1.3, P = 0.021). Receipt of PBx was significantly associated with administration of neoadjuvant radiation (OR 8.8, P < 0.001) or systemic therapy (OR 3.3, P < 0.001), radical surgical resection (OR 1.6, P < 0.001), and complete tumor resection (OR 1.5, P < 0.003). Neoadjuvant radiation [hazard ratio (HR) 0.7, P = 0.003] and complete tumor resection (HR 0.6, P < 0.001) were significantly associated with improved overall survival (OS). Performance of PBx was not associated with OS (HR 1.1, P = 0.070), and following propensity matching, 5-year OS did not differ between the two groups (56.5% PBx vs 58.4% no PBx, P = 0.247).

CONCLUSIONS

A minority of patients with non-metastatic RPS undergo PBx. PBx does not negatively impact survival, but may indirectly improve outcomes in select patients by virtue of receipt of neoadjuvant therapy and attainment of complete tumor resection.

The role of 18 F-FDG PET/CT in retroperitoneal sarcomas-A multicenter retrospective study

BACKGROUND

The role of ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸ F-FDG PET/CT) in the evaluation of retroperitoneal sarcomas is poorly defined. We evaluated the correlation of maximum standardized uptake value (SUVmax) with pathologic tumor grade in the surgical specimen of primary retroperitoneal dedifferentiated liposarcoma (DDLPS) and leiomyosarcoma (LMS).

METHODS

Patients with the above histological subtypes in three participating institutions with preoperative ¹⁸ F-FDG PET/CT scan and histopathological specimen available for review were included. The association between SUVmax and pathological grade was assessed. Correlation between SUVmax and relapse-free survival (RFS) and overall survival (OS) were also studied.

RESULTS

Of the total 58 patients, final pathological subtype was DDLPS in 44 (75.9%) patients and LMS in 14 (24.1%) patients. The mean SUVmax was 8.7 with a median 7.1 (range, 2.2-33.9). The tumors were graded I, II, III in 6 (10.3%), 35 (60.3%), and 17 (29.3%) patients, respectively. There was an association of higher histological grade with higher SUVmax (r_s  = 0.40, p = .002). Increasing SUVmax was associated with worse RFS (p = .003) and OS (p = .003).

CONCLUSION

There is a correlation between SUVmax and pathologic tumor grade; increasing SUVmax was associated with worse OS and RFS, providing a preoperative noninvasive surrogate marker of tumor grade and biological behavior.