Histology-Tailored Approach to Soft Tissue Sarcoma

Soft tissue sarcomas are a diverse and heterogeneous group of cancers of mesenchymal origin. Each histological type of soft tissue sarcoma has unique clinical particularities, which makes them challenging to diagnose and treat. Multidisciplinary management of these rare diseases is thus key for improved survival. The role of surgery has been well established, and it represents the cornerstone curative treatment for soft tissue sarcomas. To date, local recurrence is the leading cause of death in low-grade sarcomas located at critical sites, and distant metastasis in high-grade sarcomas, regardless of the site of origin. Management must be tailored to each individual histologic type. We describe the most common types of extremity, trunk, abdominal, and retroperitoneal soft tissue sarcoma along with characteristics to consider for optimized management.

Progress in Retroperitoneal Sarcoma Management: Surgical and Radiotherapy Approaches

Surgical resection is the cornerstone of curative treatment for retroperitoneal sarcomas (RPS), aiming for complete excision, yet the complexity of RPS with its proximity to vital structures continues to lead to high local recurrence rates after surgery alone. Thus, the role of radiotherapy (RT) continues to be refined to improve local control, which remains an important goal to prevent RPS recurrence. The recently completed global randomized trial to evaluate the role of surgery with and without preoperative RT - STRASS1, did not demonstrate a significant overall benefit for neoadjuvant RT based on the pre-specified definition of abdominal recurrence-free survival, however, sensitivity analysis using a standard definition of local recurrence and analysis of outcomes by compliance to the RT protocol suggests histology-specific benefit in well- and some de-differentiated liposarcomas. Ultimately, multidisciplinary collaboration and personalized approaches that consider histological sarcoma types and patient-specific factors are imperative for optimizing the therapeutic strategy in the management of RPS.

IGF2BP3 as a Prognostic Biomarker in Well-Differentiated/Dedifferentiated Liposarcoma

BACKGROUND

Although IGF2BP3 has been implicated in tumorigenesis and poor outcomes in multiple cancers, its role in soft-tissue sarcoma (STS) remains unknown. Preliminary data have suggested an association with IGF2BP3 expression among patients with well-differentiated/dedifferentiated liposarcoma (WD/DD LPS), a disease where molecular risk stratification is lacking.

METHODS

We examined the survival associations of IGF2BP3 via univariate and multivariate Cox regression in three unique datasets: (1) the Cancer Genome Atlas (TCGA), (2) an in-house gene microarray, and (3) an in-house tissue microarray (TMA). A fourth dataset, representing an independent in-house TMA, was used for validation.

RESULTS

Within the TCGA dataset, IGF2BP3 expression was a poor prognostic factor uniquely in DD LPS (OS 1.6 vs. 5.0 years, p = 0.009). Within the microarray dataset, IGF2BP3 expression in WD/DD LPS was associated with worse survival (OS 7.7 vs. 21.5 years, p = 0.02). IGF2BP3 protein expression also portended worse survival in WD/DD LPS (OS 3.7 vs. 13.8 years, p < 0.001), which was confirmed in our validation cohort (OS 2.7 vs. 14.9 years, p < 0.001). In the multivariate model, IGF2BP3 was an independent risk factor for OS, (HR 2.55, p = 0.034).

CONCLUSION

IGF2BP3 is highly expressed in a subset of WD/DD LPS. Across independent datasets, IGF2BP3 is also a biomarker of disease progression and worse survival.

In situ hybridization to detect DNA amplification in extracellular vesicles

EVs have emerged as an important component in tumour initiation, progression and metastasis. Although notable progresses have been made, the detection of EV cargoes remain significantly challenging for researchers to practically use; faster and more convenient methods are required to validate the EV cargoes, especially as biomarkers. Here we show, the possibility of examining embedded EVs as substrates to be used for detecting DNA amplification through ultrasensitive in situ hybridization (ISH). This methodology allows the visualization of DNA targets in a more direct manner, without time consuming optimization steps or particular expertise. Additionally, formalin-fixed paraffin-embedded (FFPE) blocks of EVs allows long-term preservation of samples, permitting future studies. We report here: (i) the successful isolation of EVs from liposarcoma tissues; (ii) the EV embedding in FFPE blocks (iii) the successful selective, specific ultrasensitive ISH examination of EVs derived from tissues, cell line, and sera; (iv) and the detection of MDM2 DNA amplification in EVs from liposarcoma tissues, cell lines and sera. Ultrasensitive ISH on EVs would enable cargo study while the application of ISH to serum EVs, could represent a possible novel methodology for diagnostic confirmation. Modification of probes may enable researchers to detect targets and specific DNA alterations directly in tumour EVs, thereby facilitating detection, diagnosis, and improved understanding of tumour biology relevant to many cancer types.

Virtual Biopsy in Soft Tissue Sarcoma. How Close Are We?

A shift in radiology to a data-driven specialty has been unlocked by synergistic developments in imaging biomarkers (IB) and computational science. This is advancing the capability to deliver "virtual biopsies" within oncology. The ability to non-invasively probe tumour biology both spatially and temporally would fulfil the potential of imaging to inform management of complex tumours; improving diagnostic accuracy, providing new insights into inter- and intra-tumoral heterogeneity and individualised treatment planning and monitoring. Soft tissue sarcomas (STS) are rare tumours of mesenchymal origin with over 150 histological subtypes and notorious heterogeneity. The combination of inter- and intra-tumoural heterogeneity and the rarity of the disease remain major barriers to effective treatments. We provide an overview of the process of successful IB development, the key imaging and computational advancements in STS including quantitative magnetic resonance imaging, radiomics and artificial intelligence, and the studies to date that have explored the potential biological surrogates to imaging metrics. We discuss the promising future directions of IBs in STS and illustrate how the routine clinical implementation of a virtual biopsy has the potential to revolutionise the management of this group of complex cancers and improve clinical outcomes.

[Differentiated surgical approach for retroperitoneal non-organ liposarcoma]

OBJECTIVE

To determine the indications for combined and organ-sparing surgery depending on malignancy grade of retroperitoneal liposarcoma.

MATERIAL AND METHODS

A retrospective study included 190 patients with retroperitoneal liposarcoma. Influence of malignancy grade, lesion of adjacent organs and resection/excision of adjacent organs on the overall and recurrence-free survival was studied. Moreover, we analyzed the issue of kidney-sparing surgery and nephrectomy.

RESULTS

Overall and recurrence-free survival were significantly worse in high grade (G2-3) compared to low-grade tumors (G1) (p=0.0001; log-rank test). Visceral invasion was revealed in 23% of patients with low-grade (G1) tumors and 53% of patients with high-grade (G2-3) neoplasms. Visceral invasion significantly impairs overall and recurrence-free survival in both low grade (G1) and high-grade (G2-3) tumors (p=0.0001; log-rank test). In case of low grade (G1) retroperitoneal liposarcoma, overall and recurrence-free survival was similar after combined surgery without histologically confirmed visceral invasion of liposarcoma and organ-sparing surgery (p=0.006; p=0.053; log-rank test). On the contrary, high grade (G2-3) tumor was followed by significantly better overall and recurrence-free survival after combined surgery without histologically confirmed visceral invasion compared to organ-sparing surgery (p=0.006; p=0.053; log-rank test). Recurrence-free survival was similar after kidney-sparing surgery and nephrectomy among patients with low-grade (G1) tumor (p=0.456; log-rank test). In case of high-grade retroperitoneal liposarcoma (G2-3), recurrence-free survival was significantly worse after kidney-sparing surgery compared to nephrectomy (p=0.039; log-rank test).

CONCLUSION

Surgery is the only potentially radical treatment of patients with retroperitoneal liposarcoma. Organ-sparing including kidney-sparing surgery is advisable for low-grade liposarcoma (G1). On the contrary, organ-sparing surgery impairs long-term results and prognosis in patients with high-grade tumors (G2-3). Combined operations including nephrectomy are justified for high-grade retroperitoneal liposarcoma (G2-3).

Gene Expression Changes Associated with Dedifferentiation in Liposarcoma Predict Overall Survival

Simple Summary

Previous studies have performed integrative analyses of genomic aberrations in soft tissue sarcomas. Utilising clinical information, groups have proposed nomograms for prediction of survival and recurrence in retroperitoneal sarcomas. Expanding on clinical nomogram prediction models with molecular classification of tumours may allow us to further identify clinical phenotypes within this heterogeneous group. We showed that a five-gene molecular prognostic panel can provide additional prognostic information in patients with retroperitoneal DDLS, independent of clinical features. A combined clinical and molecular prediction model may offer the best way to prognosticate patients for patient counselling and therapeutic decision making.

Abstract

Up to 10% of well-differentiated liposarcoma (WDLS) progress to dedifferentiated liposarcoma (DDLS). We aimed to identify gene expression changes associated with dedifferentiation and whether these were informative of tumour biology of DDLS. We analysed datasets from the Gene Expression Omnibus (GEO, ID = GSE30929) database to identify differentially expressed genes between WDLS (n = 52) and DDLS (n = 39). We validated the signature on whole and laser-capture microdissected samples from patients with tumours consisting of mixed WDLS and DDLS components. A subset of this signature was applied to an independent dataset from The Cancer Genome Atlas (TCGA, n = 58 DDLS) database to segregate samples based on gene expression and compared for recurrence and overall survival (OS). A 15-gene signature consisting of genes with increased expression in DDLS compared to WDLS was generated. This signature segregated WDLS and DDLS samples from patients with mixed component tumours and across multiple recurrences. A further subset of this signature, consisting of five genes (AQP7, ACACB, FZD4, GPD1, LEP), segregated DDLS in a TCGA cohort with a significant difference in OS (p = 0.019) and recurrence-free survival (RFS) (p = 0.061). The five-gene model stratified DDLS into prognostic groups and outperformed clinical factors in existing models in retroperitoneal DDLS.

Extracellular vesicle cross-talk in the liposarcoma microenvironment

Liposarcoma (LPS) is the most prevalent soft tissue sarcoma; among the four different LPS subtypes, dedifferentiated liposarcoma (DDLPS) is especially worrisome given its propensity for local and distant recurrence, with an overall survival rate of only 10% at 10 years. Our understanding of the molecular drivers of this disease is rudimentary at best; knowledge about how DDLPS interacts with cells in the tumor microenvironment (TME) is also lacking. Extracellular vesicle (EVs) have been studied in a number of different systems concerning their ability to influence the TME transferring bioactive molecules. In this review, we outline the role of the TME in the DDLPS progression and recurrence, focusing on the interplay between EVs released from the tumor and their target recipient cells in the TME. Success in the understanding of this process will be critical to an enhanced understanding of the underlying biologic drivers at play, potentially leading to new therapeutic strategies of benefit to patients with this disease.

An Evaluation of the Eighth Edition of the American Joint Committee on Cancer (AJCC) Staging System for Retroperitoneal Sarcomas Using the National Cancer Data Base (NCDB): Does Size Matter?

OBJECTIVES

Retroperitoneal sarcomas (RPS) are often large at diagnosis calling into question the seventh edition AJCC size classification of <5 cm (T1) or ≥5 cm (T2). The eighth edition expands T stage into 4 categories (T1: ≤5 cm, T2: 5<x≤10 cm, T3: 10<x≤15 cm, T4: >15 cm). We evaluated the prognostic ability of the eighth edition using the National Cancer Database (NCDB).

METHODS

Patients with RPS treated between 1998 and 2011 were identified from the NCDB; overall survival (OS) was compared.

RESULTS

Of the 6427 patients identified, 9% had tumors ≤5 cm (n=580), 19.4% 5<x≤10 cm (n=1246), 20.2% 10<x≤15 cm (n=1298) and 47.4% >15 cm (n=3045). With the eighth edition, stage II patients (G2/3 ≤5 cm) have a similar OS to stage IIIA patients (G2/3 5 cm<x≤10 cm), and patients with larger tumors (stage IIIB, G2/3>10 cm) show a decrease in OS. Tumor size as a continuous variable had a modest effect on survival (HR, 1.004; P=0.04). On multivariate analysis, higher T-stage was associated with decreased OS (T4 HR, 1.3; P<0.001) but high grade and incomplete resection (R2) were stronger prognostic factors. The c-index for both editions were similar (80.13 eighth vs. 80.08 seventh).

CONCLUSIONS

The eighth edition AJCC staging system for retroperitoneal sarcoma incorporates larger tumor size parameters that better characterize most patients, but tumor size alone is only a modest predictor of outcome.

MDM2 Derived from Dedifferentiated Liposarcoma Extracellular Vesicles Induces MMP2 Production from Preadipocytes

Dedifferentiated liposarcoma (DDLPS) is frequently diagnosed late, and patients typically respond poorly to treatments. DDLPS is molecularly characterized by wild-type p53 and amplification of the MDM2 gene, which results in overexpression of MDM2 protein, a key oncogenic process in DDLPS. In this study, we demonstrate that extracellular vesicles derived from patients with DDLPS or from DDLPS cell lines are carriers of MDM2 DNA that can be transferred to preadipocytes, a major and ubiquitous cellular component of the DDLPS tumor microenvironment, leading to impaired p53 activity in preadipocytes and increased proliferation, migration, and production of matrix metalloproteinase 2; treatment with MDM2 inhibitors repressed these effects. Overall, these findings indicate that MDM2 plays a crucial role in DDLPS by enabling cross-talk between tumor cells and the surrounding microenvironment and that targeting vesicular MDM2 could represent a therapeutic option for treating DDLPS. SIGNIFICANCE: Extracellular vesicles derived from dedifferentiated liposarcoma cells induce oncogenic properties in preadipocytes.

Did outcomes improve in retroperitoneal sarcoma surgery?

In the last decades, the deeper understanding of the biological basis of the disease, along with the advances of surgical techniques and oncologic multimodal treatments, have led to an overall increase of survival of cancer patients. However, significant amelioration of the prognosis of rare and under-investigated tumors such as soft tissue sarcoma is less evident. In this review, main changes in the surgical management of retroperitoneal sarcoma (RPS) are discussed in order to figure out whether actual improvement in RPS outcome has been occurred in the last years.

Salvage Surgery for Recurrent Retroperitoneal Well-Differentiated Liposarcoma: Early Reoperation may not Provide Benefit

PURPOSE

Current evidence regarding salvage resection for recurrent retroperitoneal (RP) sarcomas generally lacks detailed histology-specific analyses, but the aggressiveness of these tumors varies widely by histology. We investigated associations between timing and extent of salvage surgery and survival outcomes in patients with recurrent RP well-differentiated liposarcoma (WDLPS).

METHODS

The University of Texas MD Anderson Cancer Center Surgical Oncology sarcoma database was reviewed to identify patients with RP WDLPS who underwent surgical resection for first recurrent disease (salvage surgery) in 1995-2015. Medical records were retrospectively reviewed to identify factors associated with overall survival and disease-free survival.

RESULTS

We identified 52 patients who underwent salvage surgery for RP WDLPS for first local recurrence; 28 (54%) underwent salvage surgery within 6 months after recurrence. Concomitant organ resections were performed in 32 (62%) patients, 4 (13%) of whom had pathologic invasion of resected organs. After R0/R1 resections (n = 45), 38 (84%) experienced a second local recurrence. Multivariable analyses revealed that organ invasion at the primary surgery [hazard ratio (HR) 13.08; p = 0.005] and disease-free interval < 1 year (HR 3.64; p = 0.044) were associated with shorter overall survival. Recurrence-to-salvage interval < 6 months was associated with shorter disease-free survival (HR 2.18; p = 0.025). Concomitant organ resection was associated with a longer hospital stay: ≥ 14 days (odds ratio 21.58; p = 0.007).

CONCLUSIONS

Early salvage surgery may not always be the best approach for recurrent RP WDLPS patients. Because organ invasion is rare among recurrent RP WDLPS patients and concomitant organ resection is associated with a longer hospital stay, preservation of uninvolved organs should be considered.

Concomitant organ resection does not improve outcomes in primary retroperitoneal well-differentiated liposarcoma: A retrospective cohort study at a major sarcoma center

BACKGROUND

We investigated whether concomitant organ removal as part of the primary resection of RP WDLPS confers an outcome advantage in patients treated at a major sarcoma center.

METHODS

The departmental sarcoma database was reviewed to identify patients with RP WDLPS who underwent initial surgical resection for primary disease at MD Anderson Cancer Center during the study period 1995-2011. We retrospectively reviewed medical records and examined associations between clinicopathologic variables and overall survival (OS) as well as disease-free survival (DFS).

RESULTS

Among 83 patients included in this study, 76 patients (92%) underwent complete resection (R0/R1). Concomitant organ resections were performed in 38 patients (46%). Invasion of the resected organ/s was seen in six patients (7%). Estimated OS was 11.3 years (5-year OS, 86%), and DFS was 5.4 years (5-year DFS, 51%). By multivariate analysis, concomitant organ resection was not associated with improved OS (P = 0.428) or DFS (P = 0.946), and lack of organ resection was associated with a lower risk of postoperative complications (P = 0.01).

CONCLUSIONS

Concomitant organ resection was not associated with a survival benefit in RP WDLPS in this study. In patients with primary RP WDLPS, we recommend selective resection of contiguous organs only if there is clinical suspicion of invasion.

A retroperitoneal dedifferentiated liposarcoma mimicking an ovarian tumor

A 74-year-old postmenopausal woman visited our gynecology clinic complaining of a palpable abdominal mass. Physical and radiological evaluation indicated that the mass exhibited features of a left ovarian neoplasm showing heterogeneous enhancement. Surgical resection was performed to confirm this suspicion. During surgery, a mass was observed only in the left ovary with no invasive growth, but adhesions to the surrounding peritoneum were seen. Given the patient's age, large mass size, and accompanying uterine myoma and right ovarian cyst, total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. The final pathologic diagnosis was dedifferentiated liposarcoma. The liposarcoma was suspected to originate from retroperitoneal adipose tissue rather than the ovary. Radiotherapy was planned if a gross lesion indicating recurrence followed 6 months later. This case required a considerable multi-disciplinary approach for diagnosis and treatment because of its ambiguous clinical and radiological findings.

Imaging in retroperitoneal soft tissue sarcoma

Patients with retroperitoneal sarcoma can present to a variety of clinicians with non‐specific symptoms and retroperitoneal sarcomas can be incidental findings. Failure to recognize retroperitoneal sarcomas on imaging can lead to inappropriate management in non‐specialist centers. Therefore it is critical that the possibility of retroperitoneal sarcoma should be considered with prompt referral to a soft tissue sarcoma unit. This review guides clinicians through a diagnostic pathway, introduces concepts in response assessment and new imaging developments.

Neoadjuvant chemotherapy in soft tissue sarcomas: latest evidence and clinical implications

Soft tissue sarcomas are a rare and multifaceted group of solid tumours. Neoadjuvant chemotherapy is increasingly used to limit loss of function after wide surgical excision with the ultimate aim of improving patient survival. Recently, advances in the identification of effective treatment strategies and improvements in patient risk stratification have been reached. A randomized trial demonstrated that neoadjuvant epirubicin and ifosfamide improves survival of patients affected by five high-risk soft tissue sarcoma histologies of trunk and extremities, including undifferentiated pleomorphic sarcoma, myxoid liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumours, and leiomyosarcoma. Selection of patients for these treatments is expected to be improved by the eighth edition of the American Joint Committee on Cancer (AJCC) TNM staging system, as it tailors T-stage categories on primary tumour site and considers a prognostic nomogram for retroperitoneal sarcoma, which also includes soft tissue sarcoma histology and other patient and tumour features not directly included in the TNM staging. Within this framework, this article will present neoadjuvant treatment strategies for high-risk soft tissue sarcoma, emphasizing the most recent advances and discussing the need for further research to improve the effectiveness of neoadjuvant treatments.

Recurrence patterns of retroperitoneal leiomyosarcoma and impact of salvage surgery

BACKGROUND

Optimal treatment strategies for retroperitoneal leiomyosarcoma (RPLMS), particularly recurrent disease, are unknown.

METHODS

We searched the tumor registry at The University of Texas MD Anderson Cancer Center (MDACC) to identify patients with RPLMS treated between 1994 and 2013.

RESULTS

We identified 172 patients with a diagnosis of a RPLMS. Among the 85 patients who underwent complete resection included in the survival analysis, the median overall survival (OS) was 8.3 years (95% confidence interval [CI], 5.7-12.3), 5-year local recurrence rate was 21%, and 5-year distant metastasis rate was 47%. Among 114 patients who experienced recurrence, patients who underwent salvage surgery for recurrent disease had longer OS after recurrence than patients who did not undergo salvage surgery (median survival after recurrence 5.6 vs 3.3 years, 3-year OS rates after recurrence 72.6% vs 58.1%, HR 0.402 [95%CI, 0.243-0.666]; P = 0.0004). Whether salvage surgery was performed for local or distant recurrence was not associated with OS. Patients who had a longer disease-free interval (≥12 months) had better progression-free survival after salvage surgery than those who had a shorter interval (HR, 0.437 [95%CI, 0.244-0.783]; P = 0.0055).

CONCLUSIONS

We recommend that salvage surgery be considered for selected patients with local or distant recurrence of RP LMS.

The modified frailty index to predict morbidity and mortality for retroperitoneal sarcoma resections

BACKGROUND

The modified frailty index (mFI) is an important method to risk-stratify surgical patients and has been validated for general surgery and selected surgical subspecialties. However, there are currently no data assessing the efficacy of the mFI to predict acute morbidity and mortality in patients undergoing surgery for retroperitoneal sarcoma.

METHODS

Using the American College of Surgeons' National Surgical Quality Improvement Program from 2007 to 2012, we performed a retrospective analysis of patients with a diagnosis of primary malignant retroperitoneal neoplasm who underwent surgical resection. The mFI was calculated according to standard published methods. Univariate and multivariate statistical analyses including χ² and logistic regression were used to identify predictors of 30-d overall morbidity, 30-d severe morbidity (Clavien III/IV), and 30-d mortality.

RESULTS

We identified 846 patients with the diagnosis of primary malignant retroperitoneal neoplasm who underwent surgical resection. The distribution mFI scores was 0 (48.5%) or 1 (36.3%), with only 4.5% of patients presenting with a score ≥3. Rates of 30-d overall morbidity, serious morbidity, and mortality were 22.6%, 12.9%, and 1.2%, respectively. Only selected mFI scores were associated with serious morbidity and overall morbidity on multivariate analysis (P < 0.05), and mFI did not predict 30-d mortality (P > 0.05).

CONCLUSIONS

Our data demonstrate that the majority of patients undergoing retroperitoneal sarcoma resections have few, if any, comorbidities. The mFI was a limited predictor of overall and serious complications and was not a significant predictor of mortality. Better discriminators of preoperative risk stratification may be needed for this patient population.

Soft tissue sarcoma nomograms and their incorporation into practice

The accurate prediction of prognosis in patients with soft tissue sarcoma (STS) is a challenging issue. Extreme variability in the clinical and pathological characteristics of this family of tumors hinders the simple stratification of patients into meaningful prognostic cohorts. Precision medicine tools for the prediction of prognosis, such as nomograms, enable personalized computation of outcome based on clinical and pathological characteristics of both patient and tumor. The eighth edition of the American Joint Committee on Cancer staging manual moved from a "population-based" to a "personalized" approach endorsing high-quality nomograms to improve clinician prediction ability in definite patient subgroups. The first nomogram for STS was published in 2002, and this was followed by several prognostic predictors offered to clinicians. Focusing on a specific STS subgroup or site, nomograms can take into consideration highly specific factors relevant only in that particular scenario, thereby maximizing prognostic ability. The objective of this review was to critically evaluate available nomograms for patients with STS to provide clinicians and researchers with a choice of the most optimal tool for each specific patient. Cancer 2017;123:2802-20. © 2017 American Cancer Society.

Can Abdominal Computed Tomography Imaging Help Accurately Identify a Dedifferentiated Component in a Well-Differentiated Liposarcoma?

PURPOSE

To assess the ability of computed tomography (CT) to differentiate an atypical lipomatous tumor/well-differentiated liposarcoma (WDLPS) from a WDLPS with a dedifferentiated component (DDLPS) within it.

MATERIALS AND METHODS

Forty-nine untreated patients with abdominal atypical lipomatous tumors/well-differentiated liposarcomas who had undergone contrast-enhanced CT were identified using an institutional database. Three radiologists who were blinded to the pathology findings evaluated all the images independently to determine whether a dedifferentiated component was present within the WDLPS. The CT images were evaluated for fat content (≤25% or >25%); presence of ground-glass density, enhancing and/or necrotic nodules; presence of a capsule surrounding the mass; septations; and presence and pattern of calcifications. A multivariate logistic regression model with generalized estimating equations was used to correlate imaging features with pathology findings. Kappa statistics were calculated to assess agreement between the three radiologists.

RESULTS

On the basis of pathological findings, 12 patients had been diagnosed with DDLPS within a WDLPS and 37 had been diagnosed with WDLPS. The presence of an enhancing or a centrally necrotic nodule within the atypical lipomatous tumor was associated with dedifferentiated liposarcoma (P = 0.02 and P = 0.0003, respectively). The three readers showed almost perfect agreement in overall diagnosis (κ r = 0.83; 95% confidence interval, 0.67-0.99).

CONCLUSIONS

An enhancing or centrally necrotic nodule may be indicative of a dedifferentiated component in well-differentiated liposarcoma. Ground-glass density nodules may not be indicative of dedifferentiation.

Primary retroperitoneal soft tissue sarcoma: Imaging appearances, pitfalls and diagnostic algorithm

Although retroperitoneal sarcomas are rare tumours, they can be encountered by a wide variety of clinicians as they can be incidental findings on imaging or present with non specific symptoms and signs. Surgical resection can offer hope of cure and patient outcomes are improved when patients are managed in high-volume specialist centers. Failure to recognize retroperitoneal sarcomas on imaging can lead to inappropriate management in inexperienced centers. Therefore it is critical that a diagnosis of retroperitoneal sarcoma should be considered in the differential diagnosis of a retroperitoneal mass with prompt referral to a soft tissue sarcoma unit. In particular, the most common retroperitoneal sarcoma subtypes, liposarcoma and leiomyosarcoma, have characteristic imaging appearances which are discussed. This review therefore aims to set the context and guide clinicians through a diagnostic pathway for retroperitoneal masses in adults which arise extrinsic to the solid abdominal viscera.

Looking for answers: the current status of neoadjuvant treatment in localized soft tissue sarcomas

PURPOSE

Sarcomas are a rare and heterogeneous variant of cancer. The standard of care treatment involves surgical resection with radiation in high-risk patients. Despite appropriate treatment approximately 50 % of patients will suffer and die from recurrent disease. The purpose of this article is to review the current evidence concerning the use of neoadjuvant chemotherapy with or without radiation in soft tissue sarcomas.

METHODS

An in-depth literature search was conducted using Ovid Medline and PubMed.

RESULTS

The most active chemotherapeutic agents in sarcoma are anthracyclines and ifosfamide. Adjuvant chemotherapy trials show only minimal benefit. Neoadjuvant chemotherapy offers the potential advantage of reducing the extent of surgery, increasing the limb salvage rate, early exposure of micrometastatic disease to chemotherapy, and assessment of tumor response to chemotherapy. Some retrospective and phase II trials suggest a benefit to neoadjuvant chemotherapy. Unfortunately, no clearly positive phase III prospectively randomized trials exist for neoadjuvant therapy in soft tissue sarcomas.

CONCLUSIONS

The current neoadjuvant chemotherapy trials that do exist are heterogeneous resulting in conflicting results. However, neoadjuvant chemotherapy with or without radiation can be considered in patients with high-risk disease in an attempt to improve long-term outcomes.

Variability in Patterns of Recurrence After Resection of Primary Retroperitoneal Sarcoma (RPS): A Report on 1007 Patients From the Multi-institutional Collaborative RPS Working Group

BACKGROUND

Retroperitoneal sarcomas (RPS) are rare tumors composed of several well defined histologic subtypes. The aim of this study was to analyze patterns of recurrence and treatment variations in a large population of patients, treated at reference centers.

METHODS

All consecutive patients with primary RPS treated at 6 European and 2 North American institutions between January 2002 and December 2011 were included. Five, 8, and 10-year overall survival (OS) and crude cumulative incidence (CCI) of local recurrence (LR) and distant metastasis (DM) were calculated. Multivariate analyses for OS, CCI of LR, and DM were performed.

RESULTS

In all, 1007 patients were included. Median follow-up was 58 months (first and third quartile range 36-90). The 5, 8, and 10-year OS were 67% [95% confidence interval (CI), 63, 70), 56% (95% CI, 52, 61), and 46% (95% CI, 40, 53). The 5, 8, and 10-year CCI of LR and DM were 25.9 (95% CI, 23.1, 29.1), 31.3 (95% CI, 27.8, 35.1), 35% (95% CI, 30.5, 40.1), and 21% (95% CI, 18.4, 23.8%), 21.6 (95% CI, 19.0, 24.6), and 21.6 (95% CI, 19.0, 24.6), respectively. Tumour size, histologic subtype, malignancy grade, multifocality, and completeness of resection were significant predictors of outcome. Patterns of recurrence varied depending on histologic subtype. Different treatment policies at participating institutions influenced LR of well differentiated liposarcoma without impacting OS, whereas discrepancies in adjuvant systemic therapies did not impact LR, DM, or OS of leiomyosarcoma.

CONCLUSIONS

Reference centers are critical to outcomes of RPS patients, as the management strategy requires specific expertise. Histologic subtype predicts patterns of recurrence and should inform management decision. A prospective international registry is under preparation, to further define our understanding of this disease.

Retroperitoneal liposarcomas: a representative literature review occasioned by a rare case of laterelapse abdominal liposarcoma

Soft tissue sarcomas (STS) are rare and heterogeneous tumours representing approximately 0.7%-1% of all adult tumours. In the adults and among the retroperitoneal sarcomas (RPS), Liposarcoma (LS) is the most common variant accounting for 12% -20% of all sarcomas and up to 45% of sarcomas at retroperitoneal localization. A rare case of LS relapsed after 15 years is giving the occasion to review the published literature and emphasise the followings concepts: 1) Despite extensive surgery remains the mainstay of treatment for localized STS at present, anatomical complexity and occult localization result in local recurrence in the majority of patients; 2) The role of imaging and tumour markers is still limited; 3) Indefinite prolonged surveillance is a key point of treatment; 4) Referral to tertiary centres with dedicated Retroperitonal Surgeons and Oncology expertise is mandatory.

Outcome following resection of retroperitoneal sarcoma

Background

Retroperitoneal sarcoma comprises a range of different histological subtypes with dissimilar behaviour and biology. This study sought to characterize the morbidity and mortality associated with multivisceral resection and oncological outcomes according to subtype.

Methods

All patients undergoing resection of primary retroperitoneal sarcoma at the Royal Marsden Hospital between January 2005 and December 2014 were identified from a database.

Results

Some 362 patients underwent resection, with 292 requiring multivisceral resection. The 30-day mortality rate was 1·4 per cent (5 patients), the 30-day morbidity rate was 15·7 per cent (57 patients), and 27 patients required a return to theatre. Age over 75 years was predictive of 30-day mortality (hazard ratio 1·37, 95 per cent c.i. 1·13 to 1·65). The overall disease-specific survival rate at 3 years was 81·2 per cent. For well differentiated liposarcoma, dedifferentiated liposarcoma and leiomyosarcoma, 3-year local recurrence-free survival rates were 98 (95 per cent c.i. 83 to 99), 56·7 (45·7 to 66·2) and 80 (67 to 89) per cent respectively. At 3 years the distant metastasis-free survival rate was 100, 85·9 (77·4 to 91·4) and 65 (49 to 77) per cent, and the disease-specific survival rate was 97 (89 to 99), 78·5 (74·6 to 82·4) and 79 (63 to 85) per cent for well differentiated liposarcoma, dedifferentiated liposarcoma and leiomyosarcoma respectively.

Conclusion

Resection of retroperitoneal sarcoma was associated with a 30-day mortality rate of less than 2 per cent and a morbidity rate of 15·7 per cent. The overall 3-year disease-specific survival rate was 81·2 per cent.

Personalizing surgical margins in retroperitoneal sarcomas

Retroperitoneal sarcomas are a group of diseases that behave differently from one another. Well-differentiated liposarcomas have an indolent biology but show a tendency to recur locally even years after primary resection. Dedifferentiated liposarcomas are characterized by a very high local recurrence risk, while the metastatic risk mainly depends on the histological characteristics of the dedifferentiated component. In leiomyosarcomas, hematogenous spread informs prognosis while local recurrences are far less common. Surgery is the cornerstone of treatment of all retroperitoneal sarcoma subtypes and its quality is the only treatment-related factor able to improve the oncological outcome. A frontline extended surgical approach is all the more critical in subtypes in which local control directly impacts prognosis.

Retroperitoneal liposarcoma: current insights in diagnosis and treatment

Retroperitoneal liposarcoma (RLS) is a rare, biologically heterogeneous tumor that present considerable challenges due to its size and deep location. As a consequence, the majority of patients with high-grade RLS will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Here, we review current insights and controversies regarding histology, molecular biology, extent of surgery, (neo)adjuvant treatment, and systemic treatment including novel targeted agents in RLS.

Surgical management of retroperitoneal and pelvic sarcomas

Management of retroperitoneal sarcomas presents technical and oncological challenges. Imaging is crucial for diagnosis and to define local tumor extent. Complete gross resection at initial presentation is the best chance for cure, but there is controversy as to how this can be best achieved. There is a long-term risk of local recurrence, which is best treated with repeat resection if feasible. The roles of radiation and chemotherapy remain undefined.

Predictors of outcomes in patients with primary retroperitoneal dedifferentiated liposarcoma undergoing surgery

BACKGROUND

Although sarcoma histology is recognized as a prognostic factor, most studies of retroperitoneal sarcomas report results combining multiple histologies and are inadequately powered to identify prognostic factors specific to a particular histology. We reviewed our experience with retroperitoneal dedifferentiated liposarcoma (RP DDLPS) to identify factors predictive of outcomes.

STUDY DESIGN

All patients with RP DDLPS treated at our institution between 1998 and 2008 were reviewed. Multivariable Cox regression analyses were performed to identify factors predictive of progression-free survival (PFS), local recurrence-free survival (LRFS), distant recurrence-free survival (DRFS), and overall survival (OS).

RESULTS

We identified 119 patients with primary DDLPS. Median tumor size was 20.5 cm; 21% were multifocal. French Federation of Cancer Centers Sarcoma Group tumor grades were intermediate in 53% of patients and high in 28% (unknown 19%). Resections were complete (R0/R1) in 80% of patients and incomplete (R2) in 11% (unknown 9%). Tumors were removed intact in 72% of patients and fragmented in 16% (unknown 12%). Median follow-up was 74.1 months. One hundred patients (84%) experienced recurrence or progression, with 92% occurring in the retroperitoneum. Median PFS, LRFS, DRFS, and OS were 21.1, 21.5, 45.8, and 59.0 months, respectively, and were significantly worse with R2 resection. On multivariate analysis, tumor integrity (intact vs fragmented) was predictive of PFS, multifocality predicted LRFS, and extent of resection (R0/R1 vs R2), grade, and tumor integrity predicted OS.

CONCLUSIONS

In this cohort of primary RP DDLPS, factors under surgeon control (tumor integrity, extent of resection) and reflective of tumor biology (grade, multifocality) impact patient outcomes.

Heterogeneity and immunophenotypic plasticity of malignant cells in human liposarcomas

Liposarcomas are tumors arising in white adipose tissue (WAT) with avidity for local recurrence. Aggressive dedifferentiated liposarcomas (DDLS) may arise from well-differentiated subtypes (WDLS) upon disease progression, however, this key issue is unresolved due in large part to knowledge gaps about liposarcoma cellular composition. Here, we wished to improve insights into liposarcoma cellular hierarchy. Tumor section analysis indicated that the populations, distinguishable based on the expression of CD34 (a marker of adipocyte progenitors) and CD36 (a marker of adipocyte differentiation), occupy distinct intra-tumoral locations in both WDLS and DDLS. Taking advantage of these markers, we separated cells from a panel of fresh human surgical specimens by fluorescence-activated cell sorting (FACS). Based on chromosome analysis and the culture phenotypes of the composing populations, we demonstrate that malignant cells comprise four mesenchymal populations distinguished by the expression of CD34 and CD36, while vascular (CD31+) and hematopoietic (CD45+) components are non-neoplastic. Finally, we show that mouse xenografts are derivable from both CD36-negative and CD36-positive DDLS cells, and that each population recreates the heterogeneity of CD36 expression in vivo. Combined, our results show that malignant cells in WDLS and DDLS can be classified according to distinct stages of adipogenesis and indicate immunophenotypic plasticity of malignant liposarcoma cells.

Retroperitoneal tumours: review of management

INTRODUCTION

The retroperitoneum can host a wide spectrum of pathologies, including a variety of rare benign tumours and malignant neoplasms that can be either primary or metastatic lesions. Retroperitoneal tumours can cause a diagnostic dilemma and present several therapeutic challenges because of their rarity, relative late presentation and anatomical location, often in close relationship with several vital structures in the retroperitoneal space.

MATERIALS AND METHODS

A comprehensive literature search was conducted using PubMed. Relevant international articles published in the last ten years were assessed. The keywords for search purposes included: retroperitoneum, benign, sarcoma, neoplasm, diagnosis and surgery, radiotherapy, chemotherapy. The search was limited to articles published in English. All articles were read in full by the authors and selected for inclusion based on relevance to this article.

RESULTS

Tumours usually present late and cause symptoms or become palpable once they have reached a significant size. Retroperitoneal tumours are best evaluated with good quality cross-sectional imaging and preoperative histology by core needle biopsy is required when imaging is non-diagnostic. Sarcomas comprise a third of retroperitoneal tumours. Other retroperitoneal neoplasms include lymphomas and epithelial tumours or might represent metastatic disease from known or unknown primary sites. The most common benign pathologies encountered in the retroperitoneum include benign neurogenic tumours, paragangliomas, fibromatosis, renal angiomyolipomas and benign retroperitoneal lipomas.

CONCLUSIONS

Complete surgical resection is the only potential curative treatment modality for retroperitoneal sarcomas and is best performed in high-volume centres by a multidisciplinary sarcoma team. The ability completely to resect a retroperitoneal sarcoma and tumour grade remain the most important predictors of local recurrence and disease-specific survival.

[Clinicopathological study of retroperitoneal sarcoma]

OBJECTIVES

The purpose of this study was to retrospectively analyze the characteristics of patients with retroperitoneal sarcoma and to examine pathological findings, first site of recurrence and recurrence free-survival after surgery.

METHODS

From June 2003 to May 2010, we performed 10 surgeries for retroperitoneal sarcomas. We chose 9 tumors after excluding 1 tumor that had already disseminated in the abdominal cavity. We examined patient characteristics, pathological findings and the first site of recurrence (local or distant metastasis). We also analyzed recurrence-free survival after surgery with the Kaplan-Meier method.

RESULTS

The patients' median age was 60 years (31-71 years), and the median tumor diameter was 10.0 cm (2.7-45 cm). Pathological diagnosis revealed 7 cases of dedifferentiated liposarcoma and 2 cases of leiomyosarcoma. En-block resection with adjacent organs was achieved in 8 of 9 patients. During follow-up, 5 of 9 patients experienced tumor local recurrence. There were no cases in which distant metastases appeared before local recurrence. The median duration between surgery and local recurrence was 13 months (3-27 months). The median duration from surgery to death was 30 months (5-78 months).

CONCLUSIONS

Although we resected adjacent organs together when we could not achieve a sufficient margin, the rate of local recurrence after surgery for retroperitoneal sarcoma was high. Given this result using treatment with surgery alone, it is necessary to prospectively establish multimodal treatments with chemotherapy and radiotherapy to reduce local tumor recurrence.