Subtype specific prognostic nomogram for patients with primary liposarcoma of the retroperitoneum, extremity, or trunk

Primary intracranial dedifferentiated liposarcoma: An extremely rare site with unusual histopathological findings

Primary intracranial sarcomas constitute a rare group of tumors, with the most common types described in the literature being chondrosarcoma and fibrosarcoma. Dedifferentiated liposarcoma (DDLS) is a high-grade sarcoma that sometimes metastasizes to the brain. However, a primary intracranial DDLS is exceedingly rare. A 45-year-old patient from the Middle East came to India for treatment. His magnetic resonance imaging (MRI) scans revealed a space-occupying lesion at the level of the lateral ventricle T2/fluid attenuated inversion recovery hyperintensity with peripheral edema. A T1 perfusion map showed high relative cerebral blood volume values in the peripheral part, suggesting a high-grade neoplasm. Gross total resection was performed, and histopathology showed a high-grade tumor composed of sheets of pleomorphic lipoblasts and epithelioid tumor cells arranged in nests and cords. Immunohistochemistry showed diffuse immunopositivity for MDM2, CDK4, and p16, while GFAP and OLIG2 were negative. Fluorescence in situ hybridization showed MDM2 amplification. Final diagnosis of DDLS was rendered. The patient had no systemic lesions elsewhere on positron emission tomography computed tomography scan.

Cellular origin and clonal evolution of human dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is the most frequent high-grade soft tissue sarcoma subtype. It is characterized by a component of undifferentiated tumor cells coexisting with a component of well-differentiated adipocytic tumor cells. Both dedifferentiated (DD) and well-differentiated (WD) components exhibit MDM2 amplification, however their cellular origin remains elusive. Using single-cell RNA sequencing, DNA sequencing, in situ multiplex immunofluorescence and functional assays in paired WD and DD components from primary DDLPS tumors, we characterize the cellular heterogeneity of DDLPS tumor and micro-environment. We identify a population of tumor adipocyte stem cells (ASC) showing striking similarities with adipocyte stromal progenitors found in white adipose tissue. We show that tumor ASC harbor the ancestral genomic alterations of WD and DD components, suggesting that both derive from these progenitors following clonal evolution. Last, we show that DD tumor cells keep important biological properties of ASC including pluripotency and that their adipogenic properties are inhibited by a TGF-β-high immunosuppressive tumor micro-environment.

Recurrent Intrathoracic Liposarcoma: A Case Report and a Comprehensive Literature Review of a Rare Clinical Entity

Liposarcomas (LPSs) are rare malignant tumors of adipocytic origin, primarily occurring in the extremities and retroperitoneum, with thoracic involvement being exceptionally rare. This case report details the surgical management and outcomes of a recurrent intrathoracic LPS in a 65-year-old male with a history of previous mediastinal tumor resection. CT imaging revealed a recurrent tumor extending into the left pleura. The patient underwent a posterolateral thoracotomy for complete tumor excision and limited replacement of the descending aorta. Postoperative recovery was smooth, and histology confirmed dedifferentiated LPS (G2) with areas of highly differentiated LPS. LPSs encompass a heterogeneous group of tumors with various subtypes, including atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS), dedifferentiated liposarcoma (DDLPS), myxoid liposarcoma (MLPS), and pleomorphic liposarcoma (PLPS). Treatment primarily involves complete surgical resection, while the roles of radiotherapy and chemotherapy remain debated. Immunotherapy shows potential benefits, particularly for DDLPS patients expressing PD-L1. Prognosis varies significantly by subtype, with DDLPS and PLPS associated with poorer outcomes compared to MLPS and ALT/WDLPS. Long-term follow-up is crucial for managing LPSs due to their high recurrence rate. This case highlights the effectiveness of surgical intervention in recurrent intrathoracic LPSs and underlines the need for continued research into adjuvant therapies to improve patient outcomes.

Opportunities and Challenges in Soft Tissue Sarcoma Risk Stratification in the Era of Personalised Medicine

OPINION STATEMENT

Soft tissue sarcomas (STS) are a rare and heterogeneous group of cancers. Treatment options have changed little in the past thirty years, and the role of neoadjuvant chemotherapy is controversial. Accurate risk stratification is crucial in STS in order to facilitate clinical discussions around peri-operative treatment. Current risk stratification tools used in clinic, such as Sarculator, use clinicopathological characteristics and may be specific to anatomical site or to histology. More recently, risk stratification tools have been developed using molecular or immunological data. Combining Sarculator with other risk stratification tools may identify novel patient groups with differential clinical outcomes. There are several considerations when translating risk stratification tools into widespread clinical use, including establishing clinical utility, health economic value, being applicable to existing clinical pathways, having strong real-world performance, and being supported by investment into infrastructure. Future work may include incorporation of novel modalities and data integration techniques.

Massive, Retroperitoneal, Well-Differentiated Liposarcoma in Second-Trimester Pregnancy: A Report of a Rare Case

Retroperitoneal liposarcoma during pregnancy is rare and poses significant diagnostic challenges, even for experienced specialists. We present a case report of a 27-year-old female patient, 15 weeks pregnant, who was admitted to the hospital due to a massive retroperitoneal liposarcoma. The patient underwent surgical resection of the tumor. Postoperative pathology confirmed a diagnosis of well-differentiated liposarcoma. Although liposarcoma during pregnancy is rare and challenging to diagnose, CT or MRI plays a crucial role in its detection. The recurrence rate depends on the pathological stage, histological grade, and ability to resect the tumor.

Explainable machine learning predicts survival of retroperitoneal liposarcoma: A study based on the SEER database and external validation in China

OBJECTIVE

We have developed explainable machine learning models to predict the overall survival (OS) of retroperitoneal liposarcoma (RLPS) patients. This approach aims to enhance the explainability and transparency of our modeling results.

METHODS

We collected clinicopathological information of RLPS patients from The Surveillance, Epidemiology, and End Results (SEER) database and allocated them into training and validation sets with a 7:3 ratio. Simultaneously, we obtained an external validation cohort from The First Affiliated Hospital of Naval Medical University (Shanghai, China). We performed LASSO regression and multivariate Cox proportional hazards analysis to identify relevant risk factors, which were then combined to develop six machine learning (ML) models: Cox proportional hazards model (Coxph), random survival forest (RSF), ranger, gradient boosting with component-wise linear models (GBM), decision trees, and boosting trees. The predictive performance of these ML models was evaluated using the concordance index (C-index), the integrated cumulative/dynamic area under the curve (AUC), and the integrated Brier score, as well as the Cox-Snell residual plot. We also used time-dependent variable importance, analysis of partial dependence survival plots, and the generation of aggregated survival SHapley Additive exPlanations (SurvSHAP) plots to provide a global explanation of the optimal model. Additionally, SurvSHAP (t) and survival local interpretable model-agnostic explanations (SurvLIME) plots were used to provide a local explanation of the optimal model.

RESULTS

The final ML models are consisted of six factors: patient's age, gender, marital status, surgical history, as well as tumor's histopathological classification, histological grade, and SEER stage. Our prognostic model exhibits significant discriminative ability, particularly with the ranger model performing optimally. In the training set, validation set, and external validation set, the AUC for 1, 3, and 5 year OS are all above 0.83, and the integrated Brier scores are consistently below 0.15. The explainability analysis of the ranger model also indicates that histological grade, histopathological classification, and age are the most influential factors in predicting OS.

CONCLUSIONS

The ranger ML prognostic model exhibits optimal performance and can be utilized to predict the OS of RLPS patients, offering valuable and crucial references for clinical physicians to make informed decisions in advance.

Identification of NINJ1 as a novel prognostic predictor for retroperitoneal liposarcoma

BACKGROUND

Retroperitoneal liposarcoma (RPLS) is known for its propensity for local recurrence and short survival time. We aimed to identify a credible and specific prognostic biomarker for RPLS.

METHODS

Cases from The Cancer Genome Atlas (TCGA) sarcoma dataset were included as the training group. Co-expression modules were constructed using weighted gene co-expression network analysis (WGCNA) to explore associations between modules and survival. Survival analysis of hub genes was performed using the Kaplan-Meier method. In addition, independent external validation was performed on a cohort of 135 Chinese RPLS patients from the REtroperitoneal SArcoma Registry (RESAR) study (NCT03838718).

RESULTS

A total of 19 co-expression modules were constructed based on the expression levels of 26,497 RNAs in the TCGA cohort. Among these modules, the green module exhibited a positive correlation with overall survival (OS, p = 0.10) and disease-free survival (DFS, p = 0.06). Gene set enrichment analysis showed that the green module was associated with endocytosis and soft-tissue sarcomas. Survival analysis demonstrated that NINJ1, a hub gene within the green module, was positively associated with OS (p = 0.019) in the TCGA cohort. Moreover, in the validation cohort, patients with higher NINJ1 expression levels displayed a higher probability of survival for both OS (p = 0.023) and DFS (p = 0.012). Multivariable Cox analysis further confirmed the independent prognostic significance of NINJ1.

CONCLUSIONS

We here provide a foundation for the establishment of a consensus prognostic biomarker for RPLS, which should not only facilitate medical treatment but also guide the development of novel targeted drugs.

Clinical and surgical effectiveness of the multi-disciplinary standardized management model in the treatment of retroperitoneal liposarcoma: Evidence-based clinical practice experience from Fudan Zhongshan

BACKGROUND

To assess the correlation between clinical outcomes and diagnostic accuracy of evaluations carried out by a preoperative multidisciplinary team versus standard surgical care for patients with retroperitoneal liposarcoma undergoing surgery.

METHODS

This comparative study was conducted retrospectively at a specialist assessment center within Zhongshan Hospital, Fudan University, China, between April 2011 and March 2021. Patients were assigned to a multidisciplinary team or nonmultidisciplinary team cohort based on referral to the multidisciplinary team. The primary outcome measured was long-term clinical prognosis, with other outcomes including diagnostic accuracy, 30-day reoperation, duration of stay, perioperative mortality, and medical complications. To mitigate selection bias, we conducted propensity-score matching. Uni- and multivariable Cox proportional hazard models were then used to evaluate the effect of multidisciplinary teams on postoperative survival. The previously specified questionnaire was used to measure the enhancement of awareness and treatment adherence facilitated by multidisciplinary team management. Data analysis was carried out between January 2023 and August 2023.

RESULTS

Of the 521 records that were screened, 139 patients were deemed eligible for inclusion and defined as the multidisciplinary team cohort. At the same time, 382 patients without multidisciplinary team management were also included during that period and defined as the nonmultidisciplinary team cohort. The multidisciplinary team cohort exhibited lower numbers of primary retroperitoneal liposarcoma but a higher tumor grade and a greater proportion of R2 resection. After propensity-score matching, the 1-, 3-, and 5-year overall survival rates were 89.5%, 70.5%, and 62.9%, respectively, in the multidisciplinary team cohort, and 77.1%, 49.8%, and 45.1% in the nonmultidisciplinary team cohort. The diagnostic consistency of the multidisciplinary team group was significantly superior to that of the nonmultidisciplinary cohort (92.5% vs 83.6%, P = .042). Although no significant links were shown with duration of stay (P = .232) and 30-day reoperation (P = .447), the multidisciplinary team participation was linked to a substantial decrease in perioperative mortality (P = .036) and postoperative complications (P = .002). Additionally, the multidisciplinary team group indicated stronger illness awareness and postoperative adherence among individuals with retroperitoneal liposarcoma.

CONCLUSION

The study's findings indicate that multidisciplinary team management could result in improved clinical outcomes, higher diagnostic accuracy, and reduced duration of postoperative stays, complications, and perioperative mortality. The intervention may also enhance disease awareness and postoperative compliance in retroperitoneal liposarcoma patients who undergo surgery. However, evidence quality was deemed low, and prospective studies with robust designs are required. Nonetheless, these results are worth considering.

Dedifferentiation in bone and soft tissue sarcomas: How do we define it? What is prognostically relevant?

Dedifferentiation traditionally is defined by descriptive criteria as a tumor showing an abrupt change in histology from a conventional, classic, low-grade appearing neoplasm to a tumor that is more cellular, pleomorphic and "high grade", with grading typically being performed by subjective criteria. The dedifferentiated areas range from areas with recognizable histologic differentiation which differs from the primary tumor (such as an osteosarcoma arising from a low-grade chondrosarcoma) to areas containing sarcomas without specific histologic differentiation (such as pleomorphic or spindle cell sarcoma). Many, but not all, dedifferentiated tumors are aggressive and associated with significantly shorter survival than their conventional counterparts, even grade 3 conventional tumors. As a result, dedifferentiated tumors are generally considered to be clinically aggressive and as a result, more aggressive surgery or the addition of (neo)adjuvant chemotherapy is often considered. However, long-term (greater than 20 year) survivors are reported in the most common dedifferentiated bone and soft tissue sarcomas. Moreover, use of mitotic criterion for defining dedifferentiation in dedifferentiated liposarcoma as well as grading (by the French system) have been found to be associated with survival. This paper reviews the literature on dedifferentiated chondrosarcoma, dedifferentiated liposarcoma, dedifferentiated chordoma and dedifferentiated parosteal osteosarcoma. As a result of that review, recommendations are advocated to identify evidence-based, objective diagnostic and grading criteria for dedifferentiation that are appropriate for each tumor type. Adding such criteria will improve consistency in diagnosis worldwide, allow easier comparison of clinical research performed on dedifferentiated tumors and help communicate (to patients and clinicians) the tumors with highest risk of clinically aggressive behavior, to allow appropriate and personalized treatment planning.

Gender Differences in Prognosis After Primary Resection for Retroperitoneal Liposarcoma

BACKGROUND

Current evidence regarding gender difference in retroperitoneal liposarcoma (RLPS) is scarce, so we sought to investigate whether gender may affect prognosis after primary resection of RLPS.

METHODS

We used the Surveillance, Epidemiology, and End Results (SEER) database to identify RLPS patients from January 1973 to December 2015. Multivariate cox proportional hazard analysis was adopted to generate adjusted hazard ratio (AHR) and 95% confidence intervals (CIs) of survival outcomes.

RESULTS

In total, 2108 RLPS patients, including 971 women and 1137 men, were identified, with a median follow-up of 45.0 (17.0-92.0) months. The 5-year and 10-year overall survival rates were 50.5% and 31.5% for men and 60.4% and 42.5% for women. The 5-year and 10-year disease-specific survival rates for men and women were 71.5%, 57.3% and 76.3%, 62.1%, respectively. We found men were associated with an increased risk of all-cause mortality (AHR 1.3, 95% CI 1.0-1.6, P = .017) but not disease-specific mortality (AHR 1.2, 95% CI .9-1.6, P = .246). The subgroup analyses revealed that men were associated with an increased risk of all-cause mortality in patients with low-grade tumors (AHR 1.8, 95% CI 1.3-2.5) or patients who received non-radical resection (AHR 1.6, 95% CI 1.2-2.1). In the subgroup of low-grade tumors, men were also associated with an increased risk of disease-specific mortality (AHR 2.0, 95% CI 1.2-3.3).

CONCLUSION

Men may have worse survival after primary resection of RLPS compared with women, especially in patients with low-grade tumors or patients who received non-radical resection. Gender-based disparities may deserve more attention in patients with RLPS.

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.

Pleomorphic Liposarcoma Initially Presenting with Multiple Organ Involvement Including the Heart

A 42-year-old man visited our hospital due to a gradually swelling subcutaneous mass on the back of the right shoulder. The biopsy specimen was diagnosed pathologically as pleomorphic liposarcoma. Systemic computed tomography and 18F-fluorodeoxyglucose positron emission tomography revealed multiple organ metastases, including involvement of the heart, skin, liver, bone, and lung. Six cycles of doxorubicin plus ifosfamide initially controlled the disease. However, newly developed lung metastases grew rapidly during subsequent cycles of chemotherapy, and the patient died 10 months after the initial diagnosis. The initial presentation of multiple organ involvement, including the heart, is a rare clinical manifestation of pleomorphic liposarcoma.

Extremity and Truncal Soft Tissue Sarcoma: Risk Assessment and Multidisciplinary Management

Extremity and truncal soft tissue sarcomas are a heterogeneous group of rare cancers that arise from mesenchymal tissues. Hence, the adoption of tailored risk assessment and prognostication tools plays a crucial role in optimizing the decision-making for which of the many possible treatment strategies to select. Management of these tumors requires a multidisciplinary strategy, which has seen significant development in recent decades. Surgery has emerged as the primary treatment approach, with the main goal of achieving microscopic negative tumor margins. To reduce the likelihood of local recurrence, loco-regional treatments such as radiation therapy and isolated limb perfusion are often added to the treatment regimen in combination with surgery. This approach also enables surgeons to perform limb-sparing surgery, particularly in cases where a positive tumor margin is expected. Chemotherapy may also provide a further benefit in decreasing the probability of local recurrence or reducing distant metastasis in selected patients. Selecting the optimal treatment strategy for these rare tumors is best accomplished by an experienced multi-disciplinary team.

Toward the use of diffuse reflection spectroscopy for intra-operative tissue discrimination during sarcoma surgery

Significance

Accurately distinguishing tumor tissue from normal tissue is crucial to achieve complete resections during soft tissue sarcoma (STS) surgery while preserving critical structures. Incomplete tumor resections are associated with an increased risk of local recurrence and worse patient prognosis.

Aim

We evaluate the performance of diffuse reflectance spectroscopy (DRS) to distinguish tumor tissue from healthy tissue in STSs.

Approach

DRS spectra were acquired from different tissue types on multiple locations in 20 freshly excised sarcoma specimens. A k -nearest neighbors classification model was trained to predict the tissue types of the measured locations, using binary and multiclass approaches.

Results

Tumor tissue could be distinguished from healthy tissue with a classification accuracy of 0.90, sensitivity of 0.88, and specificity of 0.93 when well-differentiated liposarcomas were included. Excluding this subtype, the classification performance increased to an accuracy of 0.93, sensitivity of 0.94, and specificity of 0.93. The developed model showed a consistent performance over different histological subtypes and tumor locations.

Conclusions

Automatic tissue discrimination using DRS enables real-time intra-operative guidance, contributing to more accurate STS resections.

Genetic, Epigenetic and Transcriptome Alterations in Liposarcoma for Target Therapy Selection

Liposarcoma (LPS) is one of the most common adult soft-tissue sarcomas (STS), characterized by a high diversity of histopathological features as well as to a lesser extent by a spectrum of molecular abnormalities. Current targeted therapies for STS do not include a wide range of drugs and surgical resection is the mainstay of treatment for localized disease in all subtypes, while many LPS patients initially present with or ultimately progress to advanced disease that is either unresectable, metastatic or both. The understanding of the molecular characteristics of liposarcoma subtypes is becoming an important option for the detection of new potential targets and development novel, biology-driven therapies for this disease. Innovative therapies have been introduced and they are currently part of preclinical and clinical studies. In this review, we provide an analysis of the molecular genetics of liposarcoma followed by a discussion of the specific epigenetic changes in these malignancies. Then, we summarize the peculiarities of the key signaling cascades involved in the pathogenesis of the disease and possible novel therapeutic approaches based on a better understanding of subtype-specific disease biology. Although heterogeneity in liposarcoma genetics and phenotype as well as the associated development of resistance to therapy make difficult the introduction of novel therapeutic targets into the clinic, recently a number of targeted therapy drugs were proposed for LPS treatment. The most promising results were shown for CDK4/6 and MDM2 inhibitors as well as for the multi-kinase inhibitors anlotinib and sunitinib.

Retroperitoneal Soft Tissue Sarcoma: Emerging Therapeutic Strategies

Retroperitoneal soft tissue sarcoma (RPS) is a rare and heterogenous disease for which surgery is the cornerstone of treatment. However, the local recurrence rate is much higher than in soft tissue sarcoma of the extremities since wide resection is usually unfeasible in RPS due to its large size, indistinct tumour borders, anatomical constraints and the thinness of the overlying peritoneum. Local recurrence is the leading cause of death for low-grade RPS, whereas high-grade tumours are prone to distant metastases. In recent decades, the role of emerging therapeutic strategies, such as more extended surgery and (neo)adjuvant treatments to improve oncological outcome in primary localised RPS, has been extensively investigated. In this review, the recent data on the evolving multidisciplinary management of primary localised RPS are comprehensively discussed. The heterogeneity of RPS, with their different histological subtypes and biological behaviour, renders a standard therapeutic 'one-size-fits-all' approach inappropriate, and treatment should be modified according to histological type and malignancy grade. There is sufficient evidence that frontline extended surgery with compartmental resection including all ipsilateral retroperitoneal fat and liberal en bloc resection of adjacent organs and structures, even if they are not macroscopically involved, increases local tumour control in low-grade sarcoma and liposarcoma, but not in leiomyosarcoma for which complete macroscopic resection seems sufficient. Additionally, preoperative radiotherapy is not indicated for all RPSs, but seems to be beneficial in well-differentiated liposarcoma and grade I/II dedifferentiated liposarcoma, and probably in solitary fibrous tumour. Whether neoadjuvant chemotherapy is of benefit in high-grade RPS remains unclear from retrospective data and is subject of the ongoing randomised STRASS 2 trial, from which the results are eagerly awaited. Personalised, histology-tailored multimodality treatment is promising and will likely further evolve as our understanding of the molecular and genetic characteristics within RPS improves.

TNM classification of malignant tumors: Eighth edition for retroperitoneal liposarcoma. Ways to improve

AIM

This study was aimed at assessing the prognostic significance of the "TNM: Classification of Malignant Tumors" eighth edition (TNM8) in the most common retroperitoneal tumors - liposarcoma.

METHODS

The study included 192 patients with retroperitoneal liposarcoma (RLPS). The distribution of patients by stages and survival in accordance with the TNM8 were studied.

RESULTS

In the TNM8, only the degree of malignancy of the tumor has a prognostic value. The T-category does not reflect the actual size of the RLPS and is considered as T4 in 93%, which leads to inadequate staging. During the 15-year period, there were no cases with stages II and IIIA, and the survival rate was estimated only in patients with stages I and IIIB. The tumor node metastasis (TNM) classification with new values of the T-category was proposed by us, which demonstrated a more adequate distribution of patients by stages and the reliability of intergroup differences in the survival rate.

CONCLUSION

It is advisable to create a special TNM classification for RLPS, which makes up more than half of all retroperitoneal sarcomas. The TNM8 does not accurately reflect the prevalence of the tumor and the prognosis in RLPS. Revision of the T-staging is necessary to improve the accuracy of the prognosis in RLPS. The modified by us TNM classification demonstrated a more adequate distribution of patients by stages.

A century of retroperitoneal soft-tissue sarcoma research: From single center experience to precision oncology? A bibliometric analysis of past, present, and future perspectives

BACKGROUND

Increasing publication numbers in the biomedical field led to an improvement of patient care in many aspects but are challenging for scientists when integratively processing data of their fields. Using bibliometric analyses, the present study assesses the productivity and predominant topics in retroperitoneal soft-tissue sarcoma (RPS) research across the past 122 years, thereby identifying crucial questions to address in future RPS research.

METHODS

Using the Web of Science Core Collection, 1018 RPS-associated publications from 1900 to 2022 were identified and analyzed regarding key bibliometric variables using the Bibliometrix R package and the VOSviewer software.

RESULTS

A continuous increase in RPS-associated publication numbers can be noticed over the time, which is strongly pronounced from 2005 onwards, and is characterized by a multinationally driven collaborative clinical research focus. The research primarily reflects progression regarding surgical techniques, histology-based therapy, radiotherapy regimens, and identification of prognostic clinicopathological factors. This progression is accompanied with improved overall survival of RPS patients. However, a paucity of RPS-specific basic/translational research indicates that such research might be additionally needed to better understand the pathophysiology of RPS and with that to enable the development of personalized therapies and to further improve patient outcome.

CONCLUSION

Increasing publication numbers of multinationally driven clinical RPS research are accompanied with improved overall survival of RPS patients, highlighting the importance of international collaborations to facilitate future clinical trials. However, this bibliometric analysis reveals a lack of RPS-specific basic/translational research which is needed to further improve patient outcome in the context of precision oncology.

Surgical excision of a giant retroperitoneal liposarcoma with renal cell carcinoma: A case report of the largest retroperitoneal sarcoma

INTRODUCTION

Retroperitoneal liposarcomas are rare malignant tumors known for their slow growth and challenging management, particularly due to their substantial size upon diagnosis. This case report highlights a remarkable instance of a massive retroperitoneal sarcoma concomitant with synchronous renal cell carcinoma.

CASE PRESENTATION

We report a 57-year-old male patient with a huge abdominal mass hampering his daily activities and on further investigation, CECT abdomen and pelvis revealed a large Retroperitoneal Scarcoma (RPS) occupying his entire abdominal cavity displacing the visceral organs. In accordance with the final decision of the multi-disciplinary team meeting, he was subjected for surgery and the tumor was excised enbloc. He is kept under surveillance.

DISCUSSION

Surgery remains the main modality of treatment for RPS. Hence careful preoperative surgical planning and execution with meticulous dissection aids in achieving a good clinical outcome and to reduce recurrence in future.

CONCLUSION

Despite the huge size of the tumor, surgical intervention remains the primary treatment option whenever feasible, often complemented by additional therapeutic approaches.

Laparoscopic resection of a metastatic myxoid liposarcoma in the mesentery of the small intestine: a case report

BACKGROUND

Myxoid liposarcoma (MLS), with its risk factors, tends to spread to the lungs and extraperitoneally, with intraperitoneal metastases occurring rarely. We present an unusual case of a myxoid liposarcoma that metastasized to the abdominal organs.

CASE PRESENTATION

A 60-year-old female patient was referred to our hospital for the evaluation of a right upper limb tumor that had been growing for 7 years. The patient refused surgery, and during follow-up, tumor hemorrhage resulted in hemorrhagic shock. The patient's right upper limb was immediately amputated. MLS was diagnosed histopathologically. Subsequently, the patient underwent adjuvant chemotherapy. Computed tomography (CT) revealed a right buttock mass, a pelvic mass, and left cardiophrenic angle lymph nodes 3 years after the initial surgery. Contrast-enhanced abdominal CT revealed a relatively low-density, lobulated pelvic tumor. Contrast-enhanced pelvic magnetic resonance imaging (MRI) revealed a low-intensity, lobulated mass on T1-weighted images and a high-intensity mass on T2-weighted images. The pelvic mass showed no significant fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)-CT. On clinical examination, gynecological malignancies were ruled out as the origin of the pelvic lesions. After resection of the right buttock mass, pelvic mass, and left cardiophrenic angle lymph nodes, the patient underwent laparoscopic surgery for a preoperative diagnosis of small intestinal mesenteric metastasis of MLS. A tumor was found in the mesentery of the small intestine and removed with a margin of 5 cm on both the proximal and distal sides. The specimen measured 10 × 8 × 5 cm and contained a multifocal mass. The tumor was found in the mesentery of the small intestine, with no mucosal or submucosal invasion. The patient was diagnosed with MLS with small mesenteric intestinal metastases. On postoperative day 8, the patient was discharged after an uneventful postoperative course. Twelve months after the surgery, there was no evidence of local or distant recurrence.

CONCLUSIONS

Small intestinal mesenteric metastases of MLSs are rare. Moreover, there are few reports on laparoscopic resection. In this case, the laparoscopic approach was useful in detecting the tumor location and determining the range of resection.

A case of retroperitoneal liposarcoma extending through the inguinal canal to the thigh and lesser trochanter

Introduction

Liposarcoma is the most common retroperitoneal soft tissue tumor. Liposarcomas are often asymptomatic and are discovered after they become huge. Surgical resection is the first-line treatment for retroperitoneal liposarcoma, but the surrounding organs are often resected with the liposarcoma.

Case presentation

A man saw a hospital with a complaint of left lower abdominal distention, and a left retroperitoneal mass was noted on imaging examination. The patient was referred to our hospital. The mass extended from the retroperitoneum through the inguinal canal to the thigh and involved the femoral nerve and psoas major muscle. A well-differentiated liposarcoma was suspected, and an open surgical resection was performed. Complete resection of a retroperitoneal liposarcoma extending to the thigh was achieved without postoperative complications.

Conclusion

Treatment strategies for huge retroperitoneal liposarcomas are important to balance antitumor efficacy and postoperative quality of life.

The Role of Surgery in Oligometastatic Retroperitoneal Sarcoma

Retroperitoneal sarcomas are extremely rare, comprising <15% of primary sarcomas. Distant metastasis occurs in about 20% of cases, with pulmonary and hepatic metastasis as the most common sites of hematogenous spread. Although surgical resection is well established as the main treatment of localized primary disease, there are limited guidelines for the surgical treatment of intra-abdominal and distant metastases. There are inadequate systemic treatment options for patients with metastatic sarcoma, thereby necessitating the consideration of surgical options in carefully selected patients. Key points to consider include tumor biology, patient fitness and co-morbidities, overall prognosis, and goals of care. Multidisciplinary sarcoma tumor board discussion for each case is an essential practice in order to deliver the best care to these patients. The purpose of this review is to summarize the published literature on the past and present role of surgery in the treatment of oligometastatic retroperitoneal sarcoma in order to inform the management of this difficult disease.

Lack of radiosensitivity predicts poor disease specific survival in myxoid liposarcoma

BACKGROUND

Compared to other sarcomas, myxoid liposarcoma (ML) is known to be radiosensitive, with improved oncologic outcomes. Although these tumors "shrink" following radiotherapy, there is a paucity of data examining the degree of radiosensitivity and oncologic outcome. The purpose of the study was to evaluate pre- and postradiotherapy tumor volume to determine if size reduction impacts outcome.

METHODS

We reviewed 62 patients with ML undergoing surgical resection combined with preoperative radiotherapy, with pre- and postradiotherapy MRI. This included 34 (55%) males, with a mean age of 47 ± 14 years. All tumors were deep to the fascia, and 12 (19%) patients had tumors with a >5% round-cell component.

RESULTS

The mean volume reduction was 54% ± 29%. Compared to patients with >25% volume reduction, patients with reduction ≤25% had worse 10-year disease specific survival (86% vs. 37%, p < 0.01), in addition to an increased risk of metastatic disease (HR 4.63, p < 0.01) and death due to disease (HR 4.52, p < 0.01).

CONCLUSION

Lack of volume reduction is a risk factor for metastatic disease and subsequent death due to disease in patients with extremity ML treated with combined preoperative radiotherapy and surgery. This data could be used to stratify patients for adjuvant therapies and follow-up intervals.

Staging Systems and Nomograms for Soft Tissue Sarcoma

Reliable tools for prognosis prediction are crucially needed by oncologists so they can tailor individual treatments. However, the wide spectrum of histologies and prognostic behaviors of sarcomas challenges their development. In this field, nomograms could definitely better account for their granularity compared to the more widely used AJCC/UICC TNM staging system. Nomograms are predictive tools that incorporate multiple risk factors and return a numerical probability of a clinical event. Since the development of the first nomogram in 2002, several other nomograms have been built, either general, site-specific, histology-specific, or both. Recently, some new “dynamic” nomograms and prognostic tools have been developed, allowing doctors to “recalculate” a patient’s prognosis by taking into account the time since primary surgery, the event history, and the potential time-dependent effect of covariates. Due to these new tools, prognosis prediction is no longer limited to the time of the first computation but can be adapted and recalculated based on the occurrence (or not) of any event as time passes from the first computation. In this review, we aimed to give an overview of the available nomograms for STS and to help clinicians in the process of selecting the best tool for each patient.

Brightline-1: phase II/III trial of the MDM2-p53 antagonist BI 907828 versus doxorubicin in patients with advanced DDLPS

Dedifferentiated liposarcoma (DDLPS) is a rare, aggressive liposarcoma associated with poor prognosis. First-line treatment for advanced/metastatic DDLPS is systemic chemotherapy, but efficacy is poor and toxicities substantial. Most DDLPS tumors have amplification of the MDM2 gene, which encodes a negative regulator of the p53 suppressor protein. BI 907828 is a highly potent, oral MDM2-p53 antagonist that inhibits the interaction between p53 and MDM2, thereby restoring p53 activity. BI 907828 has shown promising activity in preclinical studies and in a phase Ia/Ib study in patients with solid tumors, particularly those with DDLPS. This manuscript describes the rationale and design of an ongoing multicenter, randomized, phase II/III trial (Brightline-1; NCT05218499) evaluating BI 907828 versus doxorubicin as first-line treatment for advanced DDLPS.

Clinical Impact of External Beam Radiotherapy for Surgically Resected Primary Retroperitoneal Liposarcoma

INTRODUCTION

EORTC-62092 (STRASS) was a phase 3, randomized study that compared surgery alone versus surgery plus neoadjuvant radiotherapy (RT) for retroperitoneal sarcomas. RT was not associated with improved abdominal recurrence-free survival, the primary outcome measure, although on subanalysis, there may have been benefit for well-differentiated (WD) liposarcoma. This study investigated the real-world use and outcomes of RT (neoadjuvant and adjuvant) for the management of retroperitoneal liposarcoma.

METHODS

We queried the National Cancer Database (NCDB) (2004-2017) for patients with nonmetastatic, primary retroperitoneal liposarcoma treated with resection with or without RT (n = 3911). Patients were stratified by treatment type and histology [WD (n = 2252), dedifferentiated (DD) (n = 1659)]. Propensity score (PS) matching was used before comparison of treatment groups. Overall survival (OS) was the primary outcome measure.

RESULTS

Median follow-up time was 4.1 years, and median OS was 10.7 years. There was no association between RT and OS for either WDLPS or DDLPS cohorts. We performed a subgroup analysis of neoadjuvant RT only, similar to STRASS. For WDLPS after PS matching (n = 208), neoadjuvant RT was not associated with OS (hazard ratio [HR] 1.01, p = 0.0523) but was associated with longer postoperative hospital stay (p = 0.012). For DDLPS after PS matching (n = 290), neoadjuvant RT was not associated with OS (HR 1.02, p = 0.889). For both WD-LPS and DD-LPS, utilization of neoadjuvant RT was associated with treatment at high-volume (≥ 10 cases/year) and academic/network facilities.

CONCLUSIONS

For primary retroperitoneal liposarcoma treated with surgical resection, radiotherapy was not associated with an overall survival benefit in this propensity-matched, adjusted analysis of the NCDB.

Paratesticular Dedifferentiated Liposarcoma with Rhabdomyoblastic Differentiation: A Case Report and Review of the Literature

Liposarcomas of the paratesticular tissue is a rare pathological entity. The symptoms are similar to inguinal hernias or hydroceles. We present the case of an 84-year-old man with a rare paratesticular liposarcoma that manifested as painless right hemiscrotal swelling. Testicular tumour markers were negative. Imaging revealed a heterogeneous mass with a fat component. He underwent a radical orchiectomy on the left side to remove the associated mass. This revealed dedifferentiated liposarcoma (DDLS) with rhabdomyoblastic differentiation and MDM2 amplification. The surgical margins were negative, and the patient had a metastatic workup that included magnetic resonance imaging (MRI) of the abdomen and pelvis. Because of the disease's rarity, there is no clear agreement on radiotherapy and chemotherapy roles.

Lifelong Imaging Surveillance is Indicated for Patients with Primary Retroperitoneal Liposarcoma

BACKGROUND

Surveillance imaging of patients with retroperitoneal liposarcoma (RP-LPS) after surgical resection is based on a projected risk of locoregional and distant recurrence. The duration of surveillance is not well defined because the natural history of RP-LPS after treatment is poorly understood. This study evaluated the long-term risk of recurrence and disease-specific survival (DSS) for a cohort of patients with at least 10 years of progression-free survival (10yr-PFS) from their primary resection.

METHODS

The prospective University of California, Los Angeles (UCLA) Sarcoma Database identified RP-LPS patients with 10yr-PFS after initial resection. The patients in the 10yr-PFS cohort were subsequently evaluated for recurrence and DSS. The time intervals start at date of initial surgical resection. Cox proportional hazards models were used to determine factors associated with recurrence and DSS.

RESULTS

From 1972 to 2010, 76 patients with RP-LPS had at least 10 years of follow-up evaluation. Of these 76 patients, 39 (51%) demonstrated 10yr-PFS. The median follow-up period was 15 years (range 10-33 years). Among the 10yr-PFS patients, 49% (19/39) experienced a recurrence at least 10 years after surgery. Of those who experienced recurrence, 42% (8/19) died of disease. Neither long-term recurrence nor DSS were significantly associated with age, sex, tumor size, LPS subtype, surgical margin, or perioperative treatment with radiation or chemotherapy.

CONCLUSION

Patients who have primary RP-LPS treated with surgical resection ± multimodality therapy face a long-term risk of recurrence and disease-specific death unacknowledged by current surveillance imaging guidelines. Among the patients with 10yr-PFS, 49% experienced a recurrence, and 42% of those died of disease. These findings suggest a need for lifelong surveillance imaging for patients with RP-LPS.

Retroperitoneal liposarcoma with pancreatic metastasis and gastric cancer: a case report

On computed tomography scanning, a 63-year-old man with vomiting and anorexia was discovered to have a mass in the pancreatic body and a retroperitoneal mass extending to the right lobe of the liver. An esophagogastroduodenoscopy revealed an advanced gastric carcinoma in the middle gastric body, and a biopsy specimen revealed a poorly differentiated adenocarcinoma. The pancreatic and retroperitoneal masses were considered metastatic lesions of gastric cancer, and a biopsy was taken from the pancreatic lesion using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). The histology of the EUS-FNA pancreatic specimen revealed atypical spindle-shaped cells and increased stromal collagen fibrosis, and liposarcoma was considered. Conversely, a percutaneous ultrasound-guided biopsy was taken for the retroperitoneal lesion, and the histology revealed that it was a dedifferentiated liposarcoma. On the basis of histopathological and imaging findings, the retroperitoneal liposarcoma was identified as the primary lesion, the pancreatic lesion as a metastasis of the primary liposarcoma, and the gastric carcinoma as an independent tumor. As far as we know, there have only been three reports of metastatic pancreatic liposarcoma diagnosed via EUS-FNA. In this case, the patient also had gastric cancer, and EUS-FNA was helpful in differentiating metastatic pancreatic tumors from gastric cancer.

Lipidomics and Transcriptomics Differ Liposarcoma Differentiation Characteristics That Can Be Altered by Pentose Phosphate Pathway Intervention

Liposarcoma (LPS) is a rare and heterogeneous malignancy of adipocytic origin. Well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS) are two of the most common subtypes, showing similar genetic characterizations but distinct biological behaviors and clinical prognosis. Compared to WDLPS, DDLPS is more aggressive and has the potential of metastasis, as the malignant adipocytic tumor's metabolic changes may have taken place during the tumorigenesis of LPSs. Therefore, to investigate the lipid alterations between the two subtypes, high-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS) based untargeted lipidomic analysis was performed onto LPS tissues from 6 WDLPS and 7 DDLPS patients. The lipidomic analysis showed the upregulated phosphatidylcholines and phosphoethanolamines in DDLPS, and the upregulated triglycerides and diglycerides in WDLPS, which might be due to the uncompleted adipocytic dedifferentiation leading to such tumorigenesis. Such a finding was also confirmed by the similarity comparison of two LPS subtypes to the transcriptome of stromal vascular fraction at different differentiation stages. Transcriptomic analysis also demonstrated that metabolic pathways including the pentose phosphate pathway (PPP) were upregulated in WDLPS compared to DDLPS. Therefore, the cell line LPS853 was treated with the PPP inhibitor 6-aminonicotinamide ex vivo and the proliferation and invasion of LPS853 was significantly promoted by PPP inhibition, suggesting the potential role of PPP in the development and differentiation of LPS. In conclusion, this study described the altered lipid profiles of WDLPS and DDLPS for the first time, revealing the different differentiation stages of the two subtypes and providing a potential metabolic target for LPS treatment.

Five decades of sarcoma care at Memorial Sloan Kettering Cancer Center

Early studies of the management of soft tissue sarcoma at Memorial Sloan Kettering Cancer Center were influenced by development of robust prospective long-term databases. Increasing capacity for molecular diagnostics has identified a myriad of subtypes with definable natural history. Accurate identification of tissue-specific risk of recurrence and disease-specific survival have increasingly allowed selective use of surgery, radiation therapy, and target-specific cytotoxic and immune therapies.

Hallazgos incidentales en cirugía abdominal: masas y sarcomas retroperitoneales

Introducción. El retroperitoneo es una estructura que se extiende desde el diafragma hasta la pelvis, está delimitado adelante por el peritoneo parietal, atrás y a los lados por la fascia transversalis y se divide en 9 compartimientos. Se pueden encontrar lesiones primarias o secundarias, cuya evolución clínica varía desde un curso indolente hasta rápidamente progresivo, tanto local como a distancia. Su enfoque, desde el hallazgo hasta el tratamiento, es fundamental para el desenlace oncológico. Objetivo. Analizar la evaluación, el diagnóstico y el tratamiento de las masas retroperitoneales halladas incidentalmente y brindar un algoritmo de manejo. Métodos. Se hizo búsqueda en bases de datos como PubMed y MedicalKey de literatura referentes a tumores retroperitoneales, su diagnóstico y enfoque terapéutico, con el fin de presentar una revisión sobre el abordaje de las masas retroperitoneales y dar nuestras opiniones. Resultados. Se revisaron 43 referencias bibliográficas internacionales y nacionales, y se seleccionaron 20 de ellas, de donde se obtuvieron datos actualizados, recomendaciones de guías internacionales y experiencias nacionales, con lo cual se estructuró este manuscrito. Conclusiones. Las masas retroperitoneales abarcan un espectro de patologías que establecen un reto diagnóstico por su origen embriológico, localización y baja frecuencia. El diagnostico histológico es de vital importancia desde el inicio, para conocer la evolución natural de la enfermedad, y el manejo multidisciplinario en centros de referencia es fundamental para impactar en los desenlaces oncológicos. Existen variadas modalidades terapéuticas, como quimioterapia, radioterapia y resección quirúrgica con estándares oncológicos.

Management of pelvic sarcoma

Pelvic sarcomas are a rare and heterogenous group of tumors divided into two groups: soft tissue sarcomas and bone sarcomas. Soft tissue sarcomas of the pelvis include most commonly liposarcoma, leiomyosarcoma, gastrointestinal stromal tumors, malignant peripheral nerve sheath tumors, and solitary fibrous tumors. Bone sarcomas of the pelvis most commonly include osteosarcoma and chondrosarcoma. Multidisciplinary treatment at a center experienced in the treatment of sarcoma is essential. Management is dictated by histologic type and grade. Surgical resection with wide margins is the cornerstone of treatment for pelvic sarcomas, although this is often challenging due to anatomic constraints of the pelvis. Multimodal treatment is critical due to the high risk of local recurrence in the pelvis.

Lipoma and Its Doppelganger: The Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma

Lipomatous tumors are among the most common soft tissue lesions encountered by the general surgeon. Shared history and clinical presentation make differentiation between benign lipomas and low-grade liposarcomas a diagnostic dilemma. This article reviews the epidemiology, clinical history, diagnostic workup, management, natural history, and surveillance of benign lipomas and atypical lipomatous tumors/well-differentiated liposarcomas. Although it is important that aggressive, potentially malignant atypical lipomatous tumors and liposarcomas be managed in a multidisciplinary, preferably high-volume setting, it is equally as important for the nonspecialist general surgeon to be familiar with lipoma and its doppelganger-the well-differentiated liposarcoma.

Retroperitoneal and Mesenteric Liposarcomas

Retroperitoneal liposarcomas are a rare entity and are comprised mostly of the well-differentiated and dedifferentiated subtypes. Eight-year survival ranges from 30% to 80% depending on histologic subtype and grade. Surgery is the cornerstone of treatment and compartment resection is the current standard. Mesenteric liposarcomas are extremely rare and comprise more high-grade lesions, with poorer prognosis of 50% 5-year overall survival. They are managed with a similar aggressive surgical approach. This review presents the current management of retroperitoneal and mesenteric liposarcomas.

Primary gastric dedifferentiated liposarcoma resected endoscopically: A case report

BACKGROUND

Liposarcoma is one of the most common adult mesenchymal tumors but is uncommon in the gastrointestinal tract and extremely rare in the stomach. Furthermore, the histological subtypes of liposarcoma usually reported in the stomach are well-differentiated or myxoid, and few reports have been issued on small-sized gastric liposarcomas resected endoscopically and followed up. Herein, we report a case of primary gastric dedifferentiated liposarcoma (DL) that was resected endoscopically.

CASE SUMMARY

A 67-year-old female Korean patient was referred to our institution for further evaluation of a gastric submucosal tumor (SMT) located in the lesser curvature of the gastric body by esophagogastroduodenoscopy. Endoscopic ultrasound revealed a well-circumscribed, slightly heterogeneous, isoechoic, 17 mm × 10 mm sized mass originating from the third sonographic layer. Computed tomography showed no evidence of significant lymph node enlargement or distant metastasis. Endoscopic resection was undertaken using the snare resection technique after mucosal precutting to provide a definitive histopathologic diagnosis, which proved to be consistent with DL, based on its morphology and the immunoexpressions of MDM2 and CDK4. The patient was planned for surgery because the deep resection margin was positive for malignancy. After declining any invasive procedure or adjuvant treatment, the patient was placed under close follow-up, and at one year after endoscopic resection, remained disease free.

CONCLUSION

This is the first reported case of a small primary gastric DL resected endoscopically and followed up. This report demonstrates that when diagnosis of a SMT is uncertain, the use of invasive techniques, including endoscopic resection, should be considered.

Primary High-Grade Myxoid Liposarcoma of the Extremities: Prognostic Factors and Metastatic Pattern

(1) Background: This retrospective study aimed to analyze the history and treatment outcomes of localized, high-grade MLS of the extremities. (2) Methods: We retrospectively reviewed 82 patients with primary high-grade MLS of the extremities. OS, LRFS, MFS, PRS, and DFS were analyzed. (3) Results: Five-year OS and LRS were 96% (95% CI: 86-98) and 94% (95% CI: 85-98), respectively. Statistical analysis indicated no risk factors for OS and LFRS. MFS was 77% (65-85) at 5-year follow-up. Size (p = 0.0337) was the only risk factor statistically significant for MFS (HR = 0.248, 95% CI: 0.07-0.84). Median PRS after distant metastasis was 34 months (range: 1-127 months). Five-year PRS was 79% (48-93). Overall, the 5-year DFS was 76% (65-85). (4) Conclusions: Patients with MLS were found to have a good prognosis. In high-grade deep-seated tumors, common risk factors for MLS do not correlate with survival. Tumor size appears to be the only predictor of long-term DSF and MSF.

Clinicopathologic Characteristics and Clinical Outcome of Localized Liposarcoma: A Single-Center Experience over 25 Years and Evaluation of PD-L1 Expression

PURPOSE

For liposarcoma (LPS), clinical course and proper treatment strategies have not been well-established. Recently, immune-checkpoint inhibitors have shown potential efficacy in LPS. We aimed to describe the clinical course of LPS and evaluate the clinical impact of programmed death-ligand 1 (PD-L1).

MATERIALS AND METHODS

We reviewed all consecutive patients (n=332) who underwent curative-intent surgery for localized LPS at Asan Medical Center between 1989 and 2017. PD-L1 testing was performed in well-differentiated and dedifferentiated LPS.

RESULTS

The median age was 56 years with males comprising 60.8%. Abdomen-pelvis (47.6%) and well-differentiated (37.7%) were the most frequent primary site and histologic subtype, respectively. During a median follow-up of 81.2 months, recurrence was observed in 135 (40.7%), and 86.7% (117/135) were loco-regional. Well-differentiated subtype (hazard ratio [HR], 0.38), abdomen-pelvis origin (HR, 2.43), tumor size larger than 5 cm (HR, 1.83), positive resection margin (HR, 2.58), and postoperative radiotherapy (HR, 0.36) were significantly related with recurrence-free survival as well as visceral involvement (HR, 1.84) and multifocality (HR, 3.79) in abdomen-pelvis LPS. PD-L1 was positive in 31.5% (23/73) and 51.3% (39/76) of well-differentiated and dedifferentiated LPS, respectively, but had no impact on survival outcomes.

CONCLUSION

Clinical course of LPS was heterogeneous according to histology and anatomic location. Clear resection margin was important to lower recurrence and postoperative radiotherapy might have additional benefit. A decent portion of well-differentiated and dedifferentiated LPS were positive for PD-L1, but its prognostic role was unclear. Further research is needed to determine clinical implications of PD-L1, especially for advanced-stage LPS with unmet needs for effective systemic treatment.

Expression of the preadipocyte marker ZFP423 is dysregulated between well-differentiated and dedifferentiated liposarcoma

Background

Well-differentiated and dedifferentiated liposarcomas are rare soft tissue tumors originating in adipose tissue that share genetic abnormalities but have significantly different metastatic potential. Dedifferentiated liposarcoma (DDLPS) is highly aggressive and has an overall 5-year survival rate of 30% as compared to 90% for well-differentiated liposarcoma (WDLPS). This discrepancy may be connected to their potential to form adipocytes, where WDLPS is adipogenic but DDLPS is adipogenic-impaired. Normal adipogenesis requires Zinc Finger Protein 423 (ZFP423), a transcriptional coregulator of Perixosome Proliferator Activated Receptor gamma (PPARG2) mRNA expression that defines committed preadipocytes. Expression of ZFP423 in preadipocytes is promoted by Seven-In-Absentia Homolog 2 (SIAH2)-mediated degradation of Zinc Finger Protein 521 (ZFP521). This study investigated the potential role of ZFP423, SIAH2 and ZFP521 in the adipogenic potential of WDLPS and DDLPS.

Methods

Human WDLPS and DDLPS fresh and paraffin-embedded tissues were used to assess the gene and protein expression of proadipogenic regulators. In parallel, normal adipose tissue stromal cells along with WDLPS and DDLPS cell lines were cultured, genetically modified, and induced to undergo adipogenesis in vitro.

Results

Impaired adipogenic potential in DDLPS was associated with reduced ZFP423 protein levels in parallel with reduced PPARG2 expression, potentially involving regulation of ZFP521. SIAH2 protein levels did not define a clear distinction related to adipogenesis in these liposarcomas. However, in primary tumor specimens, SIAH2 mRNA was consistently upregulated in DDLPS compared to WDLPS when assayed by fluorescence in situ hybridization or real-time PCR.

Conclusions

These data provide novel insights into ZFP423 expression in adipogenic regulation between WDLPS and DDLPS adipocytic tumor development. The data also introduces SIAH2 mRNA levels as a possible molecular marker to distinguish between WDLPS and DDLPS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09379-6.

Retroperitoneal Liposarcoma: An Unusual Presentation of a Rare Cancer

Retroperitoneal liposarcomas (RLPS) are rare tumors that have variable clinical behavior and complex treatment strategies based on presentation, histopathology, and genomics. Early identification is critical, and complete surgical resection remains the primary treatment, although chemotherapy and radiation are used on individual bases. Presenting symptoms are often nonspecific; therefore, a high degree of suspicion is essential for early diagnosis. In this report, the management of a 37-year-old otherwise healthy male with a large RLPS causing right groin/testicular pain is presented. After three evaluations in the emergency department, the patient was diagnosed and received two cycles of doxorubicin/ifosfamide/mesna (AIM) neoadjuvant chemotherapy. His physical exam on presentation for second opinion demonstrated a large palpable abdominal mass and fullness around the right spermatic cord. There was no appreciable change in tumor size or distant metastases on repeat scanning. Given some obstructive symptoms, a multidisciplinary team advised neoadjuvant radiation followed by radical resection of RLPS. Final pathology demonstrated a 31-cm grade II well-differentiated (WD) liposarcoma with low-grade dedifferentiation. Scattered foci of microscopic positive WD margins were noted, and the remainder of margins were negative. Genomic evaluation showed amplification of CDK4, MDM2, and FRS2. A concise literature review of common presentations, histopathology, genomics, and treatment information is discussed herein. Thorough physical exams, attention to subtle findings, appropriate medical imaging studies, and a high index of suspicion when evaluating vague symptomatology can lead to earlier diagnosis and treatment of RLPS, and ultimately better patient outcomes.

Different HSP90 Inhibitors Exert Divergent Effect on Myxoid Liposarcoma In Vitro and In Vivo

The therapeutic options for patients with relapsed or metastatic myxoid liposarcoma (MLS) remain scarce and there is currently no targeted therapy available. Inhibition of the HSP90 family of chaperones has been suggested as a possible therapeutic option for patients with MLS. However, the clinical effect of different HSP90 inhibitors vary considerably and no comparative study in MLS has been performed. Here, we evaluated the effects of the HSP90 inhibitors 17-DMAG, AUY922 and STA-9090 on MLS cell lines and in an MLS patient-derived xenograft (PDX) model. Albeit all drugs inhibited in vitro growth of MLS cell lines, the in vivo responses were discrepant. Whereas 17-DMAG inhibited tumor growth, AUY922 surprisingly led to increased tumor growth and a more aggressive morphological phenotype. In vitro, 17-DMAG and STA-9090 reduced the activity of the MAPK and PI3K/AKT signaling pathways, whereas AUY922 led to a compensatory upregulation of downstream ERK. Furthermore, all three tested HSP90 inhibitors displayed a synergistic combination effect with trabectidin, but not with doxorubicin. In conclusion, our results indicate that different HSP90 inhibitors, albeit having the same target, can vary significantly in downstream effects and treatment outcomes. These results should be considered before proceeding into clinical trials against MLS or other malignancies.

Prognostic Factor Analysis and Nomogram Construction of Primary Retroperitoneal Liposarcoma: A Review of 10 Years of Treatment Experience in a Single Asian Cohort of 211 Cases

Objective

This study intended to retrospectively analyze the data of patients with primary retroperitoneal liposarcoma in a single Asian large-volume sarcoma center and to establish nomograms focused on PRLPS for predicting progression-free survival (PFS) and overall survival (OS).

Methods

A total of 211 patients treated surgically for primary, non-metastatic retroperitoneal liposarcoma during 2009–2021 were identified, and clinicopathologic variables were analyzed. PFS and OS nomograms were built based on variables selected by multivariable analysis. The discriminative and predictive ability of the nomogram was assessed by concordance index and calibration curve.

Results

The median follow-up time was 25 months. A total of 117 (56%) were well-differentiated, 78 (37%) were dedifferentiated, 13 (6%) were myxoid, and 3 (1%) were pleomorphic morphology. Compared to the western population cohort reported by the Memorial Sloan-Kettering Cancer Center, the median age of patients in this cohort was younger (57 vs. 63 years), the tumor burden was lower (20 vs. 26 cm), and the proportion of patients with R0 or R1 resection was higher (97% vs. 81%). The 5-year PFS rate was 49%, and factors independently associated with PFS were symptoms at visit, preoperative needle biopsy, histologic subtypes, and postoperative hospital stay. The 5-year OS rate was 72%. American Society of Anesthesiologists Physical Status and Clavien-Dindo classification were independently associated with OS. The concordance indexes for PFS and OS nomograms were 0.702 and 0.757, respectively. The calibration plots were excellent.

Conclusions

The proposed nomogram provided a favorable reference for the treatment of primary retroperitoneal liposarcoma patients.

A patient with large retroperitoneal liposarcoma - a challenge for an anesthesiologist

Retroperitoneal liposarcoma is a rare type of tumor characterized by slow growth and nonspecific symptoms, and is usually diagnosed at an advanced stage. Patients with huge retroperitoneal liposarcoma have a high risk of developing perioperative complications, and require special preoperative preparation and a carefully planned anesthetic approach. We present the case of a 57-year-old man, who was diagnosed with a huge retroperitoneal liposarcoma, 70 cm in diameter, weighing 30.4 kg and planned for surgical resection of the tumor under general anesthesia. Perioperative treatment and anesthesia for this patient were a great challenge for the anesthesiologist. However, due to preoperative preparation, monitoring and fluid replacement, hemodynamic and respiratory stability of the patient was maintained perioperatively.

Co-Targeting of MDM2 and CDK4/6 with Siremadlin and Ribociclib for the Treatment of Patients with Well-Differentiated or Dedifferentiated Liposarcoma: Results From a Proof-of-Concept, Phase Ib Study

PURPOSE

Well-differentiated (WDLPS) and dedifferentiated (DDLPS) liposarcoma are characterized by co-amplification of the murine double minute-2 (MDM2) and cyclin-dependent kinase-4 (CDK4) oncogenes. Siremadlin, a p53-MDM2 inhibitor, was combined with ribociclib, a CDK4/6 inhibitor, in patients with locally advanced/metastatic WDLPS or DDLPS who had radiologically progressed on, or despite, prior systemic therapy.

METHODS

In this proof-of-concept, phase Ib, dose-escalation study, patients received siremadlin and ribociclib across different regimens until unacceptable toxicity, disease progression, and/or treatment discontinuation: Regimen A (4-week cycle: siremadlin once daily [QD] and ribociclib QD, [2 weeks on, 2 weeks off]); Regimen B (3-week cycle: siremadlin once every 3 weeks; ribociclib QD [2 weeks on, 1 week off]); Regimen C (4-week cycle: siremadlin once every 4 weeks; ribociclib QD [2 weeks on, 2 weeks off]). The primary objective was to determine the maximum tolerated dose and/or recommended dose for expansion (RDE) of siremadlin plus ribociclib in one or more regimens.

RESULTS

As of 16 October 2019 (last patient last visit), 74 patients had enrolled. Median duration of exposure was 13 (range, 1-174) weeks. Dose-limiting toxicities occurred in 10 patients, most of which were Grade 3/4 hematologic events. The RDE was siremadlin 120 mg every 3 weeks plus ribociclib 200 mg QD (Regimen B). Three patients achieved a partial response, and 38 achieved stable disease. One patient (Regimen C) died as a result of treatment-related hematotoxicity.

CONCLUSION

Siremadlin plus ribociclib demonstrated manageable toxicity and early signs of antitumor activity in patients with advanced WDLPS or DDLPS.

Risk factors for the development of local recurrence in extremity soft-tissue sarcoma

INTRODUCTION

Local recurrence (LR) is one of the main pitfalls in surgery for extremities soft tissue sarcoma (eSTS). Achieving clear histopathological margins is the most important factor to reduce the risk of LR, but the ability to do so depends on not only surgical technique but also the interplay between tumor biology, anatomical location and surgical approach. The balance between postoperative morbidity and oncological benefits in reducing the risk of LR needs to be considered.

AREAS COVERED

This review will cover which etiological factors for the development of eSTS lead to an increased risk of LR and discuss histological subtypes that have a high risk of LR and which surgical and neoadjuvant therapeutic strategies can minimize the risk of LR.

EXPERT OPINION

The traditional view that surgical radicality always results in low rates of LR, while marginality alone always leads to high rates of relapse, is outdated. In the modern era of surgical oncology, limb salvage and high-level function after resectional surgery are the key surgical goals. The best results are achieved by combining effective neoadjuvant treatments with planned bespoke oncological operations that consider the biological and anatomical factors of each individual sarcoma.

Targeting abundant survivin expression in liposarcoma: subtype dependent therapy responses to YM155 treatment

Purpose

Liposarcoma (LPS) represent the largest group of malignant soft tissue tumours comprising a heterogeneous group of subtypes in which the degrees of chemoresistance and radiosensitivity strongly vary. Consequently, it is of utmost interest to establish novel therapeutic regimens based on molecular targets.

Methods

Immunohistochemical staining of survivin was performed in tissue microarrays comprising 49 primary LPS specimens. LPS cell lines were treated with survivin antagonist YM155 and doxorubicin or etoposide alone as well as in combination. Changes in cell viability were investigated and the synergistic effect of a combined therapy analysed.

Results

Immunohistochemistry revealed an abundant expression of survivin in LPS that significantly concurred with less-differentiated tumour subtypes and grading. In vitro, we demonstrated the impact of the survivin inhibitor YM155 on dedifferentiated LPS (DDLPS) and, even more imposing, pleomorphic LPS (PLS) tumour cell viability with a strong induction of apoptosis. A combined treatment of doxorubicin or etoposide with YM155 augmented the cytotoxic effects on DDLPS and PLS cells.

Conclusion

These findings support the significant role of survivin in the oncogenesis and progression of LPS subtypes providing a rationale to target survivin in eligible in-vivo models and to pioneer clinical applications of survivin-specific substances unfolding their therapeutic potential in LPS patients prospectively.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03871-5.

Development and Validation of a Nomogram for Predicting Recurrence-Free Survival of Surgical Resected Retroperitoneal Liposarcoma

Background and Objectives

Surgical treatment is still the mainstay of curative therapy for retroperitoneal liposarcoma (RLPS), but often recurs after surgical resection. We aimed to establish a nomogram for postoperative recurrence of RLPS based on the Asian population.

Methods

Patients after surgical resection at the South Hospital of Zhongshan Hospital/Shanghai Public Health Clinical Center between August 2011 and December 2020 were included. The enrolled patients are randomly divided into training set and test set according to the ratio of 7:3. Prognostic factors were chosen based on Akaike Information Criterion, and the nomogram was built based on Cox regression and then internally validated through calibration plots and concordance index (C-index).

Results

A total of 447 patients were included. Gender, age, presentation status, organ invasion and FNCLCC grade were used to build nomogram. The calibration plots showed that RFS predicted probabilities are identical to the actual RFS rates. The C-index of the nomogram was 0.703 (95% CI 0.623–0.783) in the training set and 0.695 (95% CI 0.565–0.825) in test set.

Conclusion

The nomogram we established can accurately predict postoperative recurrence of RLPS patients for Asian population.