Desmoplastic small round cell tumour: characteristics and prognostic factors of 41 patients and review of the literature

Single-cell multiomics profiling reveals heterogeneous transcriptional programs and microenvironment in DSRCTs

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive sarcoma driven by the EWSR1::WT1 chimeric transcription factor. Despite this unique oncogenic driver, DSRCT displays a polyphenotypic differentiation of unknown causality. Using single-cell multi-omics on 12 samples from five patients, we find that DSRCT tumor cells cluster into consistent subpopulations with partially overlapping lineage- and metabolism-related transcriptional programs. In vitro modeling shows that high EWSR1::WT1 DNA-binding activity associates with most lineage-related states, in contrast to glycolytic and profibrotic states. Single-cell chromatin accessibility analysis suggests that EWSR1::WT1 binding site variability may drive distinct lineage-related transcriptional programs, supporting some level of cell-intrinsic plasticity. Spatial transcriptomics reveals that glycolytic and profibrotic states specifically localize within hypoxic niches at the periphery of tumor cell islets, suggesting an additional role of tumor cell-extrinsic microenvironmental cues. We finally identify a single-cell transcriptomics-derived epithelial signature associated with improved patient survival, highlighting the clinical relevance of our findings.

EWSR1::WT1 Fusions in Neoplasms Other Than Conventional Desmoplastic Small Round Cell Tumor: Three Tumors Occurring Outside the Female Genital Tract

Desmoplastic small round cell tumor (DSRCT) is a high-grade, primitive round cell sarcoma classically associated with prominent desmoplastic stroma, coexpression of keratin and desmin, and a characteristic EWSR1::WT1 gene fusion. DSRCT typically arises in the abdominopelvic cavity of young males with diffuse peritoneal spread and poor overall survival. Although originally considered to be pathognomonic for DSRCT, EWSR1::WT1 gene fusions have recently been detected in rare tumors lacking the characteristic morphologic and immunohistochemical features of DSRCT. Here, we report 3 additional cases of neoplasms other than conventional DSCRCT with EWSR1::WT1 gene fusions that occurred outside the female genital tract. Two occurred in the abdominopelvic cavities of a 27-year-old man and a 12-year-old girl, whereas the third arose in the axillary soft tissue of an 85-year-old man. All cases lacked prominent desmoplastic stroma and were instead solid and cystic with peripheral fibrous pseudocapsules and occasional intervening fibrous septa. Necrosis was either absent (1/3) or rare (2/3), and mitotic activity was low (<1 to 3 per 10 hpf). In immunohistochemical studies, there was expression of smooth muscle actin (3/3) and desmin (3/3), rare to focal reactivity for EMA (2/3), and variable expression of CK AE1/AE3 (1/3). Myogenin and MyoD1 were negative, and C-terminus-specific WT1 was positive in both cases tested (2/2). All 3 tumors followed a more indolent clinical course with 2 cases demonstrating no evidence of disease at 20 and 44 months after resection. The patient from case 3 died of other causes at 14 months with no evidence of recurrence. DNA methylation profiling showed that the 3 cases clustered with DSRCT; however, they demonstrated fewer copy number variations with 2 cases having a flat profile (0% copy number variation). Differential methylation analysis with hierarchical clustering further showed variation between the 3 cases and conventional DSRCT. Although further study is needed, our results, in addition to previous reports, suggest that EWSR1::WT1 gene fusions occur in rare and seemingly distinctive tumors other than conventional DSRCT with indolent behavior. Proper classification of these unusual soft tissue tumors with EWSR1::WT1 gene fusions requires direct correlation with tumor morphology and clinical behavior, which is essential to avoid overtreatment with aggressive chemotherapy.

Desmoplastic Small Round Cell Tumor Involving Serous Fluid: Cytologic Features and Diagnostic Pitfalls: A Series of 8 Cases

OBJECTIVES

When desmoplastic small round cell tumor (DSRCT) is present in serous fluid, the cytomorphology can be diverse and can mimic metastatic carcinomas and thus present a diagnostic challenge. The aim of this study was to evaluate the cytomorphologic and immunocytochemical features of this rare tumor in serous effusion specimens.

METHODS

Demographic, clinical, radiologic, and pathologic information from patients who had a DSRCT diagnosis on body fluid specimens was collected and cytologic slides were reviewed.

RESULTS

Nine specimens were identified (5 pleural fluid and 4 ascitic fluid specimens) from 8 patients (5 male and 3 female). The mean patient age at diagnosis was 26 years. The most common symptoms were abdominal distension and pain, with 5 patients having abdominal masses. Other findings included peritoneal carcinomatosis, liver masses, ascites, and pleural nodules. The predominant cytomorphology was loose cellular clusters, followed by tight clusters of small cells with scant occasional vacuolated cytoplasm and a sphere-like pattern.

CONCLUSIONS

Serous fluid may be the first available specimen to diagnose DSRCT. In young patients with no history of malignancy and radiologic finding of peritoneal implants, DSRCT should be considered a possibility in the differential diagnosis, and sensitive markers should be used for accurate diagnosis.

Desmoplastic small round cell tumor of the liver: diagnosing a rare case on liver biopsy

Desmoplastic small round-cell tumors (DSRCT) frequently develop in the retroperitoneum, pelvis, omentum, and mesentery. Here, we present an unusual case of primary DSRCT in the liver. The patient was an 11-year-old boy with multiple solid masses in the liver parenchyma. The tumor in the needle biopsy had a histology revealing a small round cell morphology and desmoplasia. It shows the immunohistochemical features of DSRCT and documentation of EWSR1-WT1 fusion.A potential diagnostic pitfall is exerted when evaluating liver biopsy, in which DSRCT is a great mimicker and may be easily confused with more common liver malignancies of childhood, such as hepatoblastoma, calcifying nested stromal-epithelial tumor, undifferentiated embryonal sarcoma, and other small round cell tumors, as well as the fibrolamellar variant of hepatocellular carcinoma. This distinction is critical because an accurate therapeutic approach requires a correct diagnosis.

Intra-abdominal desmoplastic small round cell tumor: The European pediatric Soft tissue sarcoma Study Group (EpSSG) experience

BACKGROUND

This study describes the clinical findings of a consecutive series of pediatric and adolescent patients with a diagnosis of intra-abdominal desmoplastic small round cell tumor (DSRCT) prospectively enrolled in European pediatric Soft tissue sarcoma Study Group (EpSSG) protocols: the BERNIE study, the EpSSG MTS 2008 study, and the EpSSG NRSTS 2005 study.

METHODS

Patients aged less than 21 years with a diagnosis of DSRCT arising in the abdomen were included. All trials recommended a multimodal approach including intensive multidrug chemotherapy and loco-regional treatment with surgery and/or radiotherapy whenever possible.

RESULTS

The analysis included 32 cases (median age 13.7 years, male:female ratio 1.5:1). Three patients had localized tumors, seven had regionally disseminated disease, and 22 extraperitoneal metastases. All but one patient received multidrug chemotherapy and 11 had maintenance chemotherapy. Loco-regional treatment consisted of surgery only in seven cases, surgery plus adjuvant radiotherapy in 10, and radiotherapy only in six. Among the 17 cases who had radiotherapy, six had irradiation of the primary site, 10 had whole abdominopelvic radiotherapy plus boost to macroscopic residual disease, and one had irradiation to lung metastases only. With a median follow-up of 76 months (range: 18-124 months), 5-year event-free and overall survivals were 19.7% and 21.0%, respectively. Event-free survival was significantly worse for patients who did not receive loco-regional treatment (p-value .007).

CONCLUSIONS

The study confirmed that the outcome of patients with DSRCT remains dismal and did not improve over recent years despite an intensive multimodal treatment approach.

Desmoplastic small round cell tumor: from state of the art to future clinical prospects

INTRODUCTION

Desmoplastic small round cell tumor (DSRCT) is an extremely rare and highly aggressive soft tissue sarcoma, presenting mainly in male adolescents and young adults with multiple nodules disseminated within the abdominopelvic cavity. Despite a multimodal approach including aggressive cytoreductive surgery, intensive multi-agent chemotherapy, and postoperative whole abdominopelvic radiotherapy, the prognosis for DSRCT remains dismal. Median progression-free survival ranges between 4 and 21 months, and overall survival between 17 and 60 months, with the 5-year overall survival rate in the range of 10-20%.

AREA COVERED

This review discusses the treatment strategies used for DSRCT over the years, the state of the art of current treatments, and future clinical prospects.

EXPERT OPINION

The unsatisfactory outcomes for patients with DSRCT warrant investigations into innovative treatment combinations. An international multidisciplinary and multi-stakeholder collaboration, involving both pediatric and adult sarcoma communities, is needed to propel preclinical model generation and drug development, and innovative clinical trial designs to enable the timely testing of treatments involving novel agents guided by biology to boost the chances of survival for patients with this devastating disease.

Small round cell sarcomas

Undifferentiated small round cell sarcomas (SRCSs) of bone and soft tissue comprise a heterogeneous group of highly aggressive tumours associated with a poor prognosis, especially in metastatic disease. SRCS entities mainly occur in the third decade of life and can exhibit striking disparities regarding preferentially affected sex and tumour localization. SRCSs comprise new entities defined by specific genetic abnormalities, namely EWSR1-non-ETS fusions, CIC-rearrangements or BCOR genetic alterations, as well as EWSR1-ETS fusions in the prototypic SRCS Ewing sarcoma. These gene fusions mainly encode aberrant oncogenic transcription factors that massively rewire the transcriptome and epigenome of the as yet unknown cell or cells of origin. Additional mutations or copy number variants are rare at diagnosis and, depending on the tumour entity, may involve TP53, CDKN2A and others. Histologically, these lesions consist of small round cells expressing variable levels of CD99 and specific marker proteins, including cyclin B3, ETV4, WT1, NKX3-1 and aggrecan, depending on the entity. Besides locoregional treatment that should follow standard protocols for sarcoma management, (neo)adjuvant treatment is as yet ill-defined but generally follows that of Ewing sarcoma and is associated with adverse effects that might compromise quality of life. Emerging studies on the molecular mechanisms of SRCSs and the development of genetically engineered animal models hold promise for improvements in early detection, disease monitoring, treatment-related toxicity, overall survival and quality of life.

Selective Immunoreactivity for WT1 Carboxy-Terminus Distinguishes Desmoplastic Small Round Cell Tumor From its Histologic Mimics

Desmoplastic small round cell tumor (DSRCT) is an aggressive pediatric round cell sarcoma containing a characteristic EWSR1-WT1 gene fusion. In the absence of genetic data, distinguishing DSRCT from other small round cell tumors of childhood can be problematic due to overlapping histologic and immunohistochemical features. We studied the utility of immunohistochemistry with antibodies targeting both the amino-terminal and carboxy-terminal regions of the Wilms tumor-1 (WT1) protein in differentiating these groups of tumors. The study cohort included 33 cases of genetically confirmed pediatric round cell tumors (10 DSRCTs, 12 Wilms tumors, 10 Ewing sarcomas, and 1 CIC-rearranged sarcoma). Immunoreactivities and immunolocalization of both the WT1 amino-terminus and carboxy-terminus were scored and documented. All DSRCTs displayed selective reactivity for only the WT1 carboxy-terminus (10/10), while dual immunoreactivity for both the WT1 carboxy-terminus (12/12) and amino-terminus antibodies (12/12) were characteristic of Wilms tumors. CIC-rearranged sarcoma showed variable WT1 nuclear immunopositivity (1/1, 1/1) and Ewing sarcomas were consistently WT1-negative for both the WT1 amino-terminus (0/10) and carboxy-terminus (0/10). Dual WT1 amino-terminus and carboxy-terminus immunohistochemistry remains a helpful diagnostic tool in discriminating intraabdominal small round cell tumors, which serves as an adjunct to the genetic information in preventing misdiagnosis.

Intra-Abdominal Desmoplastic Small Round Cell Tumor: Current Treatment Options and Perspectives

Intra-abdominal desmoplastic small round cell tumor (IDSRCT) is a rare and highly malignant soft tissue neoplasm, which is characterized by rapid progression and poor prognosis. The mechanism underlying the development of this neoplasm remains elusive, but all cases are characterized by the chromosomal translocation t (11;22) (p13; q12), which results in a formation of EWSR1-WT1 gene fusion. The diagnosis of IDSRCT is often made with core-needle tissue biopsy specimens or laparoscopy or laparotomy. Immunohistochemical analyses have shown the co-expression of epithelial, neuronal, myogenic, and mesenchymal differentiation markers. FISH or reverse transcription polymerase chain reaction detecting EWS-WT1 fusion can be performed to assist in molecular confirmation. There is no standard of care for patients with IDSRCT currently, and majority of newly diagnosed patients received the aggressive therapy, which includes >90% resection of surgical debulking, high-dose alkylator-based chemotherapy, and radiotherapy. More recently, targeted therapy has been increasingly administered to recurrent IDSRCT patients and has been associated with improved survival in clinical conditions. Immunotherapy as a possible therapeutic strategy is being explored in patients with IDSRCT. In this review, we summarize currently available knowledge regarding the epidemiology, potential mechanisms, clinical manifestations, diagnosis, treatment, and prognosis of IDSRCT to assist oncologists in comprehensively recognizing and accurately treating this malignancy.

The Role and Clinical Effectiveness of Multiline Chemotherapy in Advanced Desmoplastic Small Round Cell Tumor

Background:

A multimodal approach is the standard treatment for desmoplastic small round cell tumor (DSRCT); however, many patients are diagnosed with inoperable disease, which leaves chemotherapy as the only treatment option. There are limited data on the effectiveness of palliative chemotherapy, especially when used after first-line treatment. Here, we evaluated the clinical outcomes of patients with DSRCT treated with multiple lines of chemotherapy.

Methods:

We reviewed medical records of 14 patients with pathologically confirmed DSRCT at Asan Medical Center between 2004 and 2018.

Results:

The median age at diagnosis was 25, with males comprising 92.9% of patients. All patients had inoperable disease at presentation and received chemotherapy as the initial treatment. Four patients (28.6%) were treated with surgery, and complete resection was achieved in 1 patient. Median overall survival (OS) was 23.9 months, and 1-, 2-, and 3-year survival rates were 92.9%, 48.6%, and 19.5%, respectively. In patients receiving first- (N = 14), second- (N = 10), and third-line (N = 8) chemotherapy, median time-to-progression was 9.9, 3.5, and 2.5 months, respectively, and the disease control rates were 100%, 88.9%, and 75.0%, respectively. Factors associated with longer OS in the univariable analysis were ⩽2 metastatic sites at presentation (27.0 vs 14.7 months; P = .024) and surgery with intended complete resection (43.5 vs 20.1 months; P = .027).

Conclusions:

Although advanced DSRCT may initially respond to chemotherapy after first-line treatment, the response becomes less durable as the disease progresses. Individualized treatment decisions focused on palliation should be made.

Hyperthermic intraperitoneal chemotherapy (HIPEC) as another treatment modality for desmoplastic round cell tumour patients: first paediatric experience from UK

We present the first young paediatric patient with desmoplastic small round cell tumour (DSRCT) treated in UK with hyperthermic intraperitoneal chemotherapy (HIPEC). A 7-year-old girl was diagnosed with abdominal DSRCT with peritoneal and liver metastases. After six cycles of chemotherapy she obtained a partial response, including almost complete resolution of the two liver metastases. It was decided to pursue cytoreductive surgery (CRS) combined with HIPEC, a procedure commonly performed in adults, but seldom in a child. The surgery was macroscopically complete and the HIPEC uncomplicated. She continued treatment without delays, including whole abdomino-pelvic radiotherapy and maintenance chemotherapy (cyclophosphamide/vinorelbine for 12 months). She is currently in complete remission 4 months after end of treatment and 26 months after diagnosis. HIPEC was made possible by successful collaboration between multiple teams. CRS-HIPEC proved to be safe and feasible and could be offered to other children with diagnoses of peritoneal malignancies across the UK.

Desmoplastic Small Round Cell Tumor: A Review of Main Molecular Abnormalities and Emerging Therapy

Simple Summary

Desmoplastic small round cell tumor is a rare neoplasm with extremely aggressive behavior. Despite the multimodal treatment for newly diagnosed patients with chemotherapy, cytoreductive surgery and radiation, the cure rate is still low. For relapsed or progressive disease, there is limited data regarding second and third-line therapies. Novel agents have shown only modest activity. Recent molecular changes have been identified in this disease and this opens opportunities to be explored in future clinical trials.

Abstract

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, aggressive sarcoma affecting adolescents and young adults with male predominance. Generally, it originates from the serosal surface of the abdominal cavity. The hallmark characteristic of DSRCT is the EWSR1–WT1 gene fusion. This translocation up-regulates the expression of PDGFRα, VEGF and other proteins related to tumor and vascular cell proliferation. Current management of DSRCT includes a combination of chemotherapy, radiation and aggressive cytoreductive surgery plus intra-peritoneal hyperthermic chemotherapy (HIPEC). Despite advances in multimodal therapy, outcomes remain poor since the majority of patients present disease recurrence and die within three years. The dismal survival makes DSRCT an orphan disease with an urgent need for new drugs. The treatment of advanced and recurrent disease with tyrosine kinase inhibitors, such as pazopanib, sunitinib, and mTOR inhibitors was evaluated by small trials. Recent studies using comprehensive molecular profiling of DSRCT identified potential therapeutic targets. In this review, we aim to describe the current studies conducted to better understand DSRCT biology and to explore the new therapeutic strategies under investigation in preclinical models and in early phase clinical trials.

The addition of autologous stem cell transplantation to neoadjuvant chemotherapy, radiation, and HIPEC for patients with unresectable desmoplastic small round cell tumor: a single center case series

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive malignancy primarily affecting children and young adults. Although modest improvements have been gained by intensification of chemotherapy and radiation, survival of patients with DSRCT remains poor, particularly in those with unresectable or disseminated disease. We report 3 pediatric patients who were treated with a combination of therapy including chemotherapy, surgical debulking, hyperthermic intraperitoneal chemotherapy, whole abdominal irradiation, and autologous hematopoietic stem cell transplantation following busulfan and melphalan conditioning. We find that this approach is well tolerated and may offer improved survival in patients with DSRCT.

Clinical Characteristics, Management, and Outcomes of 19 Nonpediatric Patients with Desmoplastic Small Round Cell Tumor: A Cohort of Brazilian Patients

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive mesenchymal malignancy, usually affecting young males. There is no consensus on the best therapeutic approach. We seek to characterize a cohort of nonpediatric patients with DSRCT treated at a large Brazilian cancer center. We performed a retrospective analysis of patients with histologically confirmed DSRCT referred to our institution (2007–2020). Clinical and imaging data were extracted and summarized with descriptive statistics. Survival analyses were conducted by the Kaplan–Meier method and compared with the log-rank test. We included 19 patients with DSRCT, the median age at diagnosis was 26 years (range: 15–41 years), and 68% were male. Ninety percent presented with abdominopelvic masses, and 32% had extra-abdominal metastasis at diagnosis. Eleven patients (58%) underwent surgery, four patients (21%) received whole abdominal adjuvant radiotherapy, and five patients (26%) had hyperthermic intraperitoneal chemotherapy. Median OS was 27 months (interquartile range: 18–51 m). The five-year OS rate was 12%. Our data confirm the aggressiveness of DSRCT despite intense multimodality treatment. Outcomes of patients treated in a reference cancer center in a developing country are similar to cancer centers in developed nations. Multicenter cooperation is urgent to the development of clinical trials and to improve diagnosis and treatment efficacy.

Immune profiling of pediatric solid tumors

Pediatric cancers, particularly high-risk solid tumors, urgently need effective and specific therapies. Their outlook has not appreciably improved in decades. Immunotherapies such as immune checkpoint inhibitors offer much promise, but most are only approved for use in adults. Though several hundred clinical trials have tested immune-based approaches in childhood cancers, few have been guided by biomarkers or clinical-grade assays developed to predict patient response and, ultimately, to help select those most likely to benefit. There is extensive evidence in adults to show that immune profiling has substantial predictive value, but few studies focus on childhood tumors, because of the relatively small disease population and restricted use of immune-based therapies. For instance, only one published study has retrospectively examined the immune profiles of pediatric brain tumors after immunotherapy. Furthermore, application and integration of advanced multiplex techniques has been extremely limited. Here, we review the current status of immune profiling of pediatric solid tumors, with emphasis on tumor types that represent enormous unmet clinical need, primarily in the context of immune checkpoint inhibitor therapy. Translating optimized and informative immune profiling into standard practice and access to personalized combination therapy will be critical if childhood cancers are to be treated effectively and affordably.

Mini-Review on Targeted Treatment of Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor (DSRCT) is a devastating disease which most commonly affects adolescents, with a male predominance. Despite the best multimodality treatment efforts, most patients will ultimately not survive more than 3-5 years after diagnosis. Some research trials in soft-tissue sarcoma and Ewing sarcoma include DSRCT patients but few studies have been tailored to the specific clinical needs and underlying cytogenetic abnormalities characterizing this disease such as the typical EWSR1-WT1 gene fusion. Downstream activation of EWSR1-WT1 gene fusion includes signaling pathways of platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and insulin growth factor (IGF)-1. Other biological pathways that are activated and expressed in DSRCT cells include endothelial growth factor receptor (EGFR), androgen receptor pathway, c-KIT, MET, and transforming growth factor (TGF) beta. Investigation of somatic mutations, copy number alterations (CNA), and chromosomes in DSRCT samples suggests that deregulation of mesenchymal-epithelial reverse transition (MErT)/epithelial-mesenchymal transition (EMT) and DNA damage repair (DDR) may be important in DSRCT. This mini review looks at known druggable targets in DSRCT and existing clinical evidence for targeted treatments, particularly multityrosine kinase inhibitors such as pazopanib, imatinib, and sorafenib alone or in combination with other agents such as mTOR (mammalian target of rapamycin) inhibitors. The aim is to increase shared knowledge about current available treatments and identify gaps in research to further efforts toward clinical development of targeted agents.

A national analysis of patterns of care and outcomes for adults diagnosed with desmoplastic small round cell tumors in the United States

BACKGROUND

Because of the rarity of desmoplastic small round cell tumors (DSRCT), there is a lack of data describing patterns of care and survival for these patients. Using a national tumor registry, the current study sought to describe patterns of care and clinical outcomes for patients with DSCRT.

METHODS

Data from the National Cancer Database were used to identify 491 patients aged 18 years or older diagnosed with DSRCT between 2004 and 2014. Multivariable Cox proportional hazards regression analysis was used to identify factors associated with overall survival (OS).

RESULTS

Among all patients, 41.2% (n = 200), underwent surgical resection of their primary tumor, chemotherapy was administered to 86.5% (n = 415) of patients, while radiation therapy was administered to 13.0% (n = 63) of patients. Over the study, 69.7% of patients died with a median OS of 25.9 months (interquartile range [IQR]: 22.7-27.5); 1-, 3-, and 5-year OS were 78.6%, 32.3%, and 18.4%, respectively. On multivariable analysis, stage IV disease (Hazard Ratio [HR] = 2.12, 95% CI: 1.41-3.18), receipt of surgery (HR = 0.68, 95% CI: 0.50-0.91), chemotherapy (HR = 0.52, 95% CI: 0.35-0.78), or radiation therapy (HR = 0.55, 95% CI: 0.33-0.92) were independently associated with OS.

CONCLUSIONS

Although receipt of multimodality treatment may lead to improved survival, further research and clinical trials are required to establish best practices for the care of DSRCT.

Desmoplastic small round cell tumors: Multimodality treatment and new risk factors

Background

To evaluate optimal therapy and potential risk factors.

Methods

Data of DSRCT patients <40 years treated in prospective CWS trials 1997‐2015 were analyzed.

Results

Median age of 60 patients was 14.5 years. Male:female ratio was 4:1. Tumors were abdominal/retroperitoneal in 56/60 (93%). 6/60 (10%) presented with a localized mass, 16/60 (27%) regionally disseminated nodes, and 38/60 (63%) with extraperitoneal metastases. At diagnosis, 23/60 (38%) patients had effusions, 4/60 (7%) a thrombosis, and 37/54 (69%) elevated CRP. 40/60 (67%) patients underwent tumor resection, 21/60 (35%) macroscopically complete. 37/60 (62%) received chemotherapy according to CEVAIE (ifosfamide, vincristine, actinomycin D, carboplatin, epirubicin, etoposide), 15/60 (25%) VAIA (ifosfamide, vincristine, adriamycin, actinomycin D) and, 5/60 (8%) P6 (cyclophosphamide, doxorubicin, vincristine, ifosfamide, etoposide). Nine received high‐dose chemotherapy, 6 received regional hyperthermia, and 20 received radiotherapy. Among 25 patients achieving complete remission, 18 (72%) received metronomic therapies. Three‐year event‐free (EFS) and overall survival (OS) were 11% (±8 confidence interval [CI] 95%) and 30% (±12 CI 95%), respectively, for all patients and 26.7% (±18.0 CI 95%) and 56.9% (±20.4 CI 95%) for 25 patients achieving remission. Extra‐abdominal site, localized disease, no effusion or ascites only, absence of thrombosis, normal CRP, complete tumor resection, and chemotherapy with VAIA correlated with EFS in univariate analysis. In multivariate analysis, significant factors were no thrombosis and chemotherapy with VAIA. In patients achieving complete remission, metronomic therapy with cyclophosphamide/vinblastine correlated with prolonged time to relapse.

Conclusion

Pleural effusions, venous thrombosis, and CRP elevation were identified as potential risk factors. The VAIA scheme showed best outcome. Maintenance therapy should be investigated further.

The genomics of desmoplastic small round cell tumor reveals the deregulation of genes related to DNA damage response, epithelial-mesenchymal transition, and immune response

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, and poorly investigated simple sarcoma with a low frequency of genetic deregulation other than an Ewing sarcoma RNA binding protein 1 (EWSR1)-Wilm's tumor suppressor (WT1) translocation. We used whole-exome sequencing to interrogate six consecutive pre-treated DSRCTs whose gene expression was previously investigated.

METHODS

DNA libraries were prepared from formalin-fixed, paraffin-embedded archival tissue specimens following the Agilent SureSelectXT2 target enrichment protocol and sequenced on Illumina NextSeq 500. Raw sequence data were aligned to the reference genome with Burrows-Wheeler Aligner algorithm. Somatic mutations and copy number alterations (CNAs) were identified using MuTect2 and EXCAVATOR2, respectively. Biological functions associated with altered genes were investigated through Ingenuity Pathway Analysis (IPA) software.

RESULTS

A total of 137 unique somatic mutations were identified: 133 mutated genes were case-specific, and 2 were mutated in two cases but in different positions. Among the 135 mutated genes, 27% were related to two biological categories: DNA damage-response (DDR) network that was also identified through IPA and mesenchymal-epithelial reverse transition (MErT)/epithelial-mesenchymal transition (EMT) already demonstrated to be relevant in DSRCT. The mutated genes in the DDR network were involved in various steps of transcription and particularly affected pre-mRNA. Half of these genes encoded RNA-binding proteins or DNA/RNA-binding proteins, which were recently recognized as a new class of DDR players. CNAs in genes/gene families, involved in MErT/EMT and DDR, were recurrent across patients and mostly segregated in the MErT/EMT category. In addition, recurrent gains of regions in chromosome 1 involving many MErT/EMT gene families and loss of one arm or the entire chromosome 6 affecting relevant immune-regulatory genes were recorded.

CONCLUSIONS

The emerging picture is an extreme inter-tumor heterogeneity, characterized by the concurrent deregulation of the DDR and MErT/EMT dynamic and plastic programs that could favour genomic instability and explain the refractory DSRCT profile.

Multimodality Treatment of Desmoplastic Small Round Cell Tumor: Chemotherapy and Complete Cytoreductive Surgery Improve Patient Survival

Purpose: Desmoplastic small round cell tumor (DSRCT), which harbors EWSR1-WT1 t(11;22)(p13:q12) chromosomal translocation, is an aggressive malignancy that typically presents as intra-abdominal sarcomatosis in young males. Given its rarity, optimal treatment has not been defined.Experimental Design: We conducted a retrospective study of 187 patients with DSRCT treated at MD Anderson Cancer Center over 2 decades. Univariate and multivariate regression analyses were performed. We determined whether chemotherapy, complete cytoreductive surgery (CCS), hyperthermic intraperitoneal cisplatin (HIPEC), and/or whole abdominal radiation (WART) improve overall survival (OS) in patients with DSRCT. Critically, because our institutional practice limits HIPEC and WART to patients with less extensive, potentially resectable disease that had benefited from neoadjuvant chemotherapy, a time-variant analysis was performed to evaluate those adjunct treatment modalities.Results: The pre-2003 5-year OS rate of 5% has substantially improved to 25% with the advent of newer chemotherapies and better surgical and radiotherapy techniques (HR, 0.47; 95% CI, 0.29-0.75). Chemotherapy response (log rank P = 0.004) and CCS (log rank P < 0.0001) were associated with improved survival. Although WART and HIPEC lacked statistical significance, our study was not powered to detect their potential impact upon OS.Conclusions: Improved 3- and 5-year OS were observed following multidisciplinary treatment that includes Ewing sarcoma (ES)-based chemotherapy and complete tumor cytoreductive surgery, but few if any patients are cured. Prospective randomized studies will be required to prove whether HIPEC or WART are important. In the meantime, chemotherapy and CCS remain the cornerstone of treatment and provide a solid foundation to evaluate new biologically targeted therapies. Clin Cancer Res; 24(19); 4865-73. ©2018 AACR.

Whole abdominopelvic radiotherapy in desmoplastic small round cell tumour of abdomen: a challenge for radiation oncologists

An adolescent patient diagnosed with disseminated abdominal desmoplastic small round cell tumour (DSRCT) was taken up for systemic chemotherapy, debulking surgery, stem cell transplant followed by whole abdominopelvic radiotherapy using intensity-modulated radiotherapy. Following this, the patient developed multiple episodes of small bowel obstruction, a known complication of abdominal surgery and radiotherapy. The patient expired due to the complications of bowel obstruction 13 months after the completion of radiotherapy. Though we managed to achieve a complete response at the disease sites with an aggressive therapeutic approach, the patient eventually succumbed to treatment-induced morbidity. Large prospective trials to define management guidelines taking into account quality of life issues may not be feasible for a rare and aggressive scenario such as DSRCT. Therefore, case reports and series reporting not just the treatment techniques and survival, but also the resultant toxicities, will make us vigilant when choosing the intensity of its treatment.

Desmoplastic Small Round Blue Cell Tumor: A Review of Treatment and Potential Therapeutic Genomic Alterations

Desmoplastic small round blue cell tumors (DSRCTs) originate from a cell with multilineage potential. A molecular hallmark of DSRCT is the EWS-WT1 reciprocal translocation. Ewing sarcoma and DSRCT are treated similarly due to similar oncogene activation pathways, and DSRCT has been represented in very limited numbers in sarcoma studies. Despite aggressive therapy, median survival ranges from 17 to 25 months, and 5-year survival rates remain around 15%, with higher survival reported among those undergoing removal of at least 90% of tumor in the absence of extraperitoneal metastasis. Almost 100% of these tumors contain t(11;22) (p13;q12) translocation, and it is likely that EWS-WT1 functions as a transcription factor possibly through WT1 targets. While there is no standard protocol for this aggressive disease, treatment usually includes the neoadjuvant HD P6 regimen (high-dose cyclophosphamide, doxorubicin, and vincristine (HD-CAV) alternating with ifosfamide and etoposide (IE) chemotherapy combined with aggressively attempted R0 resection). We aimed to review the molecular characteristics of DSRCTs to explore therapeutic opportunities for this extremely rare and aggressive cancer type.

Desmoplastic small round cell tumors of the pleura: a review of the clinical literature

Desmoplastic small round cell tumor of the pleura is a rare malignancy, with only a few cases reported in the scientific literature. The aim of the present review is to discuss the demographic, pathological, clinical, and therapeutic features of this rare tumor. English-language articles published since 1989, when the first case of desmoplastic small round cell tumor of the pleura was described, were retrieved, and fifteen cases included in fourteen articles were revised. The mean age of the patients was 25.5 years, out of them 60% were males. Chest pain, pleural effusion, and dyspnea were the most common clinical manifestations, while chest roentgenogram and computed tomography were the imaging techniques most commonly used. Surgical biopsy was employed in 80% of the cases for diagnosis. A multidisciplinary approach consisting in a combination of surgery with chemotherapy and radiation therapy was adopted in most cases. Only two patients (13.3%) were alive at 3 years from diagnosis, reflecting the aggressiveness of the disease, and the poor outcomes of the treatments currently available. Desmoplastic small round cell tumors of the pleura are extremely aggressive and challenging to diagnose, because of their rarity and unspecific demographic, clinical, and radiological features. An in-depth knowledge of such features is necessary for the optimal management of patients with this rare malignancy.

Imatinib mesylate in desmoplastic small round cell tumors

AIM

To investigate the possible role of imatinib, an inhibitor of the tyrosine kinase activity of PDGF-R, in desmoplastic small round cell tumor (DSRCT).

PATIENTS & METHODS

From August 2005 to June 2009, DSRCT patients refractory to conventional treatment were enrolled. Patients received imatinib 400 mg daily. Primary end point of this open label, prospective, Phase II trial was objective response rate.

RESULTS

Of the 13 enrolled patients, eight were evaluable for response. Median age was 20 years (range: 9-32). Objective responses at 3 months were: stable disease in one patient and progressive disease in seven patients.

CONCLUSION

Imatinib showed no efficacy in the treatment of DSRCT unresponsive to conventional therapy, despite molecular-based selection of patients.

The RENAPE observational registry: rationale and framework of the rare peritoneal tumors French patient registry

Background

Rare peritoneal cancers represent complex clinical situations requiring a specific and multidisciplinary management. Because of their rarity, lack of awareness and knowledge often leads to diagnostic delays and misdiagnosis. And patients are not systematically referred to expert centers as they should be. Clinicians and researchers also face unique challenges with these rare cancers, because it is hard to conduct adequately powered, controlled trials in such small patient population. This is how an observational patient registry constitutes a key instrument for the development of epidemiological and clinical research in the field of these rare cancers. It is the appropriate tool to pool scarce data for epidemiological research and to assess the impact of diagnostic and therapeutic strategies. We aimed to provide the outlines and the framework of the RENAPE observational registry and share our experience in the establishment of a national patient registry.

Results

The RENAPE observational registry has been launched in 2010 thanks to institutional supports. It concerns only patients with a histological diagnosis confirming a peritoneal surface malignancy. A web secured clinical database has been implemented based on data management procedures according to the principles of international recommendations and regulatory statements. A virtual tumor bank is linked in order to the conduct translational studies. Specialized working groups have been established to continuously upgrade and evolve the common clinical and histological data elements following the last classifications and clinical practices. They contribute also to standardize clinical assessment and homogenize practices.

Conclusions

The RENAPE Registry may improve awareness and understanding of the rare peritoneal tumors into the incidence, prevalence, recurrence, survival and mortality rates, as well as treatment practices thereby enabling therapeutic intervention to be evaluated and ultimately optimized.

Trial registration

ClinicalTrials.gov Identifier: NCT02834169

Clinical features and outcomes of 20 patients with abdominopelvic desmoplastic small round cell tumor

INTRODUCTION

Desmoplastic small round cell tumor (DSRCT) is a rare mesenchymal malignancy. We describe our experience with treating DSRCT at a large sarcoma referral center.

METHODS

A retrospective chart review was performed on DSRCT patients referred to our institution (1998-2014). Pathology specimens were reviewed to confirm the diagnosis. Clinical and imaging were extracted and summarized with descriptive statistics. Univariate analysis was performed to evaluate the association between patient, tumor, and treatment variables and overall survival (OS).

RESULTS

In this study cohort of 20 patients, median age at presentation was 29 y (range 18-43) and 90% were male. Fifty-five percent presented with metastasis. Patients underwent chemotherapy (n = 20), radiation therapy (n = 3), and cytoreductive surgery (CRS) (n = 5). Median OS was 22 m (interquartile range: 12-28 m). Five-year OS rate was 20%. Extra-abdominal metastasis was associated with a higher hazard ratio (HR) of mortality (HR: 3.1, 95% C.I. 1.0-9.4, p = 0.04), while CRS improved OS (HR: 0.1, 95% C.I. 0.03-0.7, p = 0.02).

CONCLUSIONS

Despite aggressive treatment, less than half of the patients were dead of DSRCT within 2 years of presentation. Although a select group of patients who underwent CRS had improved OS, novel treatments are urgently needed.

Extensive Abdominopelvic Desmoplastic Small Round Cell Tumor — Case Report and Review of the Literature

Desmoplastic small round cell tumor (DSRCT) is a rare malignant tumor, which affects mostly young males and has a poor prognosis. Since 1991, when it was first described as a distinct clinical entity by Gerald WL and Rosai J, some 200 cases were reported. DSRCT arises mainly from the abdominal and pelvic cavity, causes abdominal pain or discomfort, weight loss, urinary, bowel or bile obstruction due to compression. Metastases appear most frequently in the liver and lungs. Multimodal therapy is usually indicated with chemotherapy, surgery, radiotherapy and autologous stem cell transplantation. DSRCT should be differentiated from other small, blue round cell tumors, especially hematopoietic malignancies (leukemia, lymphoma), neuroblastoma, Ewing sarcoma, PNET, rhabdomyosarcoma, malignant mesothelioma, small cell carcinoma and Wilms tumors. We report the case of a patient with an extensive abdominopelvic desmoplastic small round cell tumor, with liver metastases, in an adolescent male patient, highlighting the alert deterioration of the clinical status of the patient after the biopsy, the need for a second review of the histopathological material in order to obtain a correct diagnosis, the chemoresistance of the tumor despite an apparently good clinical status, and the severe prognosis of this type of tumor.

Desmoplastic Small Round Cell Tumor of the Pleura Successfully Treated with a Lower Dose of Pazopanib

Desmoplastic small round cell tumor (DSRCT) is an aggressive mesenchymal tumor which primarily affects the abdomen. Even a multimodal approach rarely achieves durable remission and the optimal therapy for extended disease is unknown. We herein describe a rare case of DSRCT arising from the pleura in a 32-year-old man. Initial therapy, which included chemotherapy, surgery and radiotherapy, achieved a partial response for only two months. Although salvage chemotherapies had no effect, pazopanib treatment shrank the tumors and was well-tolerated on an outpatient basis. From the viewpoint of quality of life, pazopanib may therefore be a good therapeutic option for this aggressive disease.

Survival and toxicity following sequential multimodality treatment including whole abdominopelvic radiotherapy for patients with desmoplastic small round cell tumor

BACKGROUND AND PURPOSE

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive malignancy. We report survival rates and toxicity associated with sequential multimodality treatment including whole abdominopelvic radiation therapy (WART).

MATERIAL AND METHODS

Medical records of 32 patients with DSRCT treated at our institution were reviewed. Patients underwent chemotherapy, cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (HIPEC), followed by WART with intensity-modulated radiation or volumetric-modulated arc therapy.

RESULTS

Median overall survival (OS) was 60months. After 18months of follow-up, 20 patients (62.5%) had disease recurrence and median disease-free survival (DFS) was 10months. Median time to extrahepatic abdominal failure was 19.4months. Factors affecting time to local progression included liver metastases at diagnosis, and an interval of greater than 5.6months between diagnosis and HIPEC or greater than 2.1months between HIPEC and WART. None of these factors altered OS. Grade 3 or higher toxicities occurred in 84% of patients.

CONCLUSIONS

WART following chemotherapy, surgical cytoreduction and HIPEC is an aggressive treatment for DSRCT patients and can result in severe side effects. Our median OS of 5years is favorable compared to prior studies, despite a median DFS of only 10months, which may be due to improved salvage therapies.

DESMOPLASTIC SMALL ROUND BLUE CELL TUMOUR OF THE ABDOMEN - A CASE REPORT

Desmoplastic Small Round Cell Tumour (DSRCT) is an uncommon malignant type of Small Round Blue Cell tumours with less than 200 cases reported in literature. Notorious for its aggressiveness, its commonest site of affectation is the abdomen, with a predilection for peritoneal cavity and prone to spread to multiple organs. We report a case of a 26-year old male undergraduate who presented with a 6-month history of progressive abdominal swelling associated with abdominal pain, weight loss, and change in bowel habits. He was cachectic with dyspnoea, bilateral pitting pedal oedema, a grossly distended and a palpable huge firm mass measuring 20 x 15cm. Immunohistochemisttry confirmed a diagnosis of DSRCT. An abdominopelvic Computed Tomography (CT) scan showed extensive abdominal and pelvic disease with pulmonary and liver metastases. He could only tolerate one course of chemotherapy due to deteriorating renal function. It ran an aggressive course of 9 months from onset of symptoms to eventual demise of the patient.

CONCLUSION

Desmoplastic Small Round Blue Cell Tumour is an uncommon and fatal disease, with no significant improvement in survival despite aggressive multimodality therapy. A high index of suspicion and Immunohistochemistry for accurate diagnosis as well as prompt and effective treatment will improve outcome.

[Intra-abdominal soft tissue tumors. What needs to be known to reach the diagnosis with the help of immunohistochemistry, FISH and molecular biology]

Connective tissue tumors located inside the abdomen are a rare heterogeneous group of tumors, except for gastro-intestinal stromal tumors. They may be benign, malignant, or intermediate in terms of biologic potential. Pathologists have to remember the list of all the lesions possibly involved, with their immunohistochemical characteristics, and to know which molecular analyses are needed, with which expected results, and by which team they can be performed. The main tumor types are discussed with diagnostic tools and treatment consequences.

Pazopanib in advanced desmoplastic small round cell tumours: a multi-institutional experience

Background

We retrospectively reviewed data from nine pre-treated metastatic desmoplastic small round cell tumour (DSRCT) patients who received pazopanib.

Patients and methods

Three patients received pazopanib within the EORTC phase II 62043, three in the EORTC phase III 62072, and three in the context of UK named patient program.

Results

Nine patients were retrieved from the databases, the median age was 30 years (range: 21–47), they were all males. All had received prior chemotherapy. At the time of treatment start, 4 patients (44%) had ECOG PS 0, 4 (44%) PS 1, 1 (11%) PS 2. Best response was partial response (PR) in 2/9 (22%) patients, stable disease (SD) in 5/9 (56%) and progressive disease (PD) in 2/9 (22%) with a clinical benefit rate (PR + SD > 12 weeks) of 78%. Median PFS and OS were 9.2 (95%CI: 0–23.2) and 15.4 (95%CI: 1.5-29.3) months respectively. With a median follow-up of 20 months, 2/9 (22%) patients are still alive, all progressed. The most common toxicities included neutropenia (G1-2 45%; G3-4 11%), anaemia (G1-2 45%), fatigue (G1-2 67%), diarrhoea (G1-2 45%; G3-4 11%), nausea (G1-2 45%), hypertension (G1-2 45%) and increase in liver enzymes (G1-2 34%; G3-4 11%). Three patients (34%) required a dose reduction. One of the patients discontinued treatment because of persistent increase in total bilirubin level, one due to patient’s choice.

Conclusion

In this series, pazopanib showed interesting activity in DSRCT patients who progressed after prior chemotherapy without major toxicity.

Suspected hydatid cyst of liver harbouring an aggressive desmoplastic small round cell tumour

Among the group of small round cell tumours, there is a distinct and rare tumour known as desmoplastic small round cell tumour (DSRCT). DSRCT presents as multiple, widespread masses in the abdomen and pelvis and may be accompanied by extensive tumour implants throughout the peritoneum as the tumour is known to spread diffusely along serosal surfaces. We discuss a case of DSRCT in a 16-year-old boy who presented with abdominal pain since 2 years, a non-tender mass was palpable on the right upper quadrant of the abdomen, ultrasonographic and CT findings suggested hydatid cyst of liver. Laparotomy revealed multiple small peritoneal deposits along with a single mass in the liver. On histopathology, the lesion was found to be neoplastic and composed of predominantly clusters of small round blue cells, in a desmoplastic stroma; tumour cells were diffusely positive for cytokeratin, vimentin and neuron-specific enolase, thus confirming the diagnosis of DSRCT.