Synovial sarcoma

Advances of SS18-SSX fusion gene in synovial sarcoma: Emerging novel functions and therapeutic potentials

Synovial sarcoma is a rare type of soft tissue sarcoma that primarily affects adolescents and young adults, featured by aggressive behavior and a high potential for metastasis. Genetically, synovial sarcoma is defined by the fusion oncogene SS18-SSX arising from the translocation of t(X;18)(p11;q11). SS18-SSX fusion gene is the major driver of the oncogenic event in synovial sarcoma. SS18-SSX fusion protein, while not containing any DNA-binding motifs, binds to the SWI/SNF (BAF) complex, a major epigenetic regulator, leading to the disruption of gene expression which results in tumor initiation and progression. Emerging studies on the molecular mechanisms of SS18-SSX associated signaling pathway hold promise for developments in diagnosis and treatments. Advanced diagnostic methods facilitate early and precise detection of the tumor, enabling disease monitoring and prognostic improvements. Treatment of synovial sarcoma typically comprises local surgery, radiotherapy and chemotherapy, while novel managements such as immunotherapy, targeted therapies and epigenetic modifiers are explored. This review focuses on the recent studies of SS18-SSX fusion gene, epigenetic landscape, signaling pathways, diagnostic techniques, and relevant therapeutic advances, aiming to inhibit the oncogenic processes and improve outcomes for patients with synovial sarcoma.

Contemporary surgical management of pediatric non-rhabdomyosarcoma soft tissue sarcoma

Non-rhabdomyosarcoma soft tissue sarcoma (STS) comprises most STS in pediatric patients. It is a diverse set of over 30 histologic subtypes. Treatment is based on risk group determined by tumor size, grade, and the presence of metastases. Surgical resection is a cornerstone of therapy, as tumors are often resistant to chemotherapy or radiation. While patients with isolated tumors less than 5 cm may undergo upfront resection, strong consideration should be given to neoadjuvant chemoradiotherapy to ensure negative margins at surgical resection and optimal outcomes. Sentinel lymph node biopsy is strongly recommended for clear cell and epithelioid sarcomas. The most common metastatic site is the lung, and metastases should be resected at the end of therapy, when feasible. Unfortunately, many high-risk patients progress on therapy, and alternative strategies including earlier metastatic control require investigation.

Unusual manifestation of synovial sarcoma: A rare case report with elevated beta HCG level

Synovial sarcoma is a rare type of soft tissue sarcoma that typically arises in the lower extremities and rarely in the upper extremities. Here, we present an unusual case of a middle-aged man who complained of dyspnea, dry cough, and chest pain and was found to have a mass-like lesion on the ulnar side of his left wrist during physical examination. The patient also exhibited gynecomastia and had elevated β-human chorionic gonadotropin (βHCG) levels. Subsequent imaging and histopathological analysis of the wrist mass confirmed the diagnosis of synovial sarcoma with disseminated lung metastasis. This article aims to provide a comprehensive overview of the clinical and pathological characteristics of synovial sarcoma, highlight the importance of considering synovial sarcoma as a differential diagnosis in patients with abnormal hormonal assays, and emphasize the need for clinicians to be vigilant about any pathologic lesions existing on the upper extremity to avoid late diagnosis and the development of advanced cancerous diseases.

Establishment and characterization of NCC-SS6-C1: a novel patient-derived cell line of synovial sarcoma

Synovial sarcoma (SS) is identified as a sarcoma with monomorphic blue spindle cells that display variable epithelial differentiation and is characterized by the SS18::SSX fusion gene. SS accounts for approximately 5-10% of all soft tissue sarcomas, making it a relatively common type within this group of tumors. Since SS is generally sensitive to chemotherapy, the standard treatment for SS includes extensive surgical resection, complemented by neoadjuvant chemotherapy with several approved anticancer drugs. However, in advanced and metastatic cases, the efficacy of these drugs is limited, resulting in poor prognoses. This underscores the need for innovative therapeutic strategies. Patient-derived cancer cell lines are essential tools for basic and preclinical research, yet only four SS cell lines are publicly available. To facilitate the studies of SS, we have developed a novel SS cell line, named NCC-SS6-C1, derived from surgically excised tumor tissue of an SS patient. NCC-SS6-C1 cells preserve the SS18::SSX1 fusion gene, consistent with the genetic characteristics of the original tumor. The cells exhibit continuous proliferation, invasiveness, and the ability to form spheroids. Additionally, we confirmed that this cell line was useful for evaluating the efficacy of anticancer drugs. Our results suggest that NCC-SS6-C1 is a useful tool for basic and pre-clinical studies of SS.

Epidemiological trends of synovial sarcoma by primary tumor sites in the US from 2000 to 2020

BACKGROUND

Synovial sarcoma (SS) is a rare soft-tissue cancer. Existing literature encompasses Surveillance, Epidemiology, and End Results (SEER) data-based research on SS explaining the incidence-prevalence in general, by subtypes, and by age at diagnosis. Therefore, this study aimed to fill in the gap of knowledge about measures of disease occurrence and burden of SS by tumor site using the SEER database.

METHODS

In this cross-sectional study, primary SS patients were selected from SEER 17 Registries, Nov. 2021 (2000-2020) using ICD-O-3 codes 9040, 9041, 9042, and 9043. Patients with additional cancers were excluded. The primary tumor site was categorized into (1) head/neck, (2) internal thorax, (3) abdomen/pelvis, (4) upper extremity, and (5) lower extremity using ICD-10CM codes. Five outcomes were analyzed: age-adjusted incidence rate, 5-year limited-duration prevalence rate, incidence-based mortality, case-fatality rate, and overall survival.

RESULTS

From 2000-2020, the overall age-adjusted incidence rate was 0.15 per 100,000; the 5-year limited duration prevalence rate was 0.56 per 100,000; and the incidence-based mortality rate was 0.06 per 100,000 people. The case-fatality and 5-year OS rates were 39.2 % and 62.9 %, respectively. Lower extremity had the highest incidence of 0.07 (estimated 1166 cases), prevalence of 0.36 (estimated 224 cases), and mortality rate of 0.025 (estimated 429 deaths) per 100,000. The other four locations had much closer rates with each other. Intrathoracic SS had the highest case-fatality rate of 71.5 % (148/207) and lowest 5-year OS of 26.0 % (95 % CI: 19.6 %, 32.9 %) than other sites.

CONCLUSION

Based on the measures of disease frequency, the most common primary tumor site is the lower extremity, followed by the upper extremity, abdomen/pelvis, internal thorax, and head/neck. The least favorable primary location is the internal thorax. Those with a primary location of the upper extremity have the longest overall survival, followed by the head/neck, lower extremity, abdomen/pelvis, and internal thorax.

Does the Primary Tumor Site Drive Biology for Patients With Synovial Sarcoma?

OBJECTIVE

We evaluated survival outcomes by primary tumor site in synovial sarcoma (SS) patients with localized and metastatic disease at diagnosis.

METHODS

We conducted a retrospective review of 504 SS patients diagnosed from 1974 to 2020. Kaplan-Meier method, log-rank test, and Cox-proportional hazards regression were used.

RESULTS

Among 504 patients, 401 (79.6%) presented with localized disease, and 103 (20.4%) with metastases. For patients with localized disease, (1) 5-year OS by tumor site was as follows: 80% (95% CI, 67%-89%) for head/neck, 30% (95% CI, 18%-42%) for intrathoracic, 51% (95% CI, 35%-65%) for abdomen/pelvis, 71% (95% CI, 62%-79%) for proximal-extremity, and 83% (71%, 91%) for distal-extremity. (2) On multivariable analysis, tumor site (compared with proximal-extremity: intrathoracic tumors [HR: 1.95; 95% CI, 1.22-3.16]; hand/foot [HR: 0.52; 95% CI, 0.28-0.97]), tumor size (compared with <5 cm, 5-10 cm [HR: 1.80; 95% CI, 1.14-2.85]; ≥10 cm [HR: 4.37; 95% CI, 2.69-7.11]), and use of neo/adjuvant radiation (HR: 0.54; 95% CI, 0.37-0.79) remained significantly associated with OS. For patients with metastatic disease, (1) 5-year OS was 12% (95% CI, 6%-21%) and (2) the only factor that remained significantly associated with OS on multivariable analysis was surgical resection for the primary tumor (HR: 0.14; 95% CI, 0.08-0.26).

CONCLUSIONS

The primary tumor location plays a significant role in predicting outcomes for patients with localized SS. Even though patients present with metastatic disease, surgical resection of the primary tumor improves their survival. These findings are critical for patient counseling and designing a personalized treatment plan that reflects the corresponding outcomes.

Discovery of CW-3308 as a Potent, Selective, and Orally Efficacious PROTAC Degrader of BRD9

The bromodomain-containing protein BRD9 has emerged as an attractive therapeutic target. In the present study, we successfully identified a number of highly potent BRD9 degraders by using two different cereblon ligands developed in our laboratory. Further optimization led to the discovery of CW-3308 as a potent, selective, and orally bioavailable BRD9 degrader. It displayed degradation potency (DC50) < 10 nM and efficiency (Dmax) > 90% against BRD9 in the G401 rhabdoid tumor and HS-SY-II synovial sarcoma cell lines and had a high degradation selectivity over BRD7 and BRD4 proteins. CW-3308 achieved 91% of oral bioavailability in mice. A single oral dose efficiently reduced the BRD9 protein by >90% in the synovial sarcoma HS-SY-II xenograft tumor tissue. Oral administration effectively inhibited HS-SY-II xenograft tumor growth in mice. CW-3308 is a promising lead compound for further optimization and extensive evaluation for the treatment of synovial sarcoma, rhabdoid tumor, and other BRD9-dependent human diseases.

Biological and therapeutic insights from animal modeling of fusion-driven pediatric soft tissue sarcomas

Survival for children with cancer has primarily improved over the past decades due to refinements in surgery, radiation and chemotherapy. Although these general therapies are sometimes curative, the cancer often recurs, resulting in poor outcomes for patients. Fusion-driven pediatric soft tissue sarcomas are genetically defined by chromosomal translocations that create a chimeric oncogene. This distinctive, almost 'monogenic', genetic feature supports the generation of animal models to study the respective diseases in vivo. This Review focuses on a subset of fusion-driven pediatric soft tissue sarcomas that have transgenic animal tumor models, which includes fusion-positive and infantile rhabdomyosarcoma, synovial sarcoma, undifferentiated small round cell sarcoma, alveolar soft part sarcoma and clear cell sarcoma. Studies using the animal models of these sarcomas have highlighted that pediatric cancers require a specific cellular state or developmental stage to drive tumorigenesis, as the fusion oncogenes cause different outcomes depending on their lineage and timing of expression. Therefore, understanding these context-specific activities could identify targetable activities and mechanisms critical for tumorigenesis. Broadly, these cancers show dependencies on chromatin regulators to support oncogenic gene expression and co-opting of developmental pathways. Comparative analyses across lineages and tumor models will further provide biological and therapeutic insights to improve outcomes for these children.

Clinicopathological Profile and Survival Outcomes in Patients with Localised Extremity Synovial Sarcomas

AIMS

Synovial sarcoma is a rare but aggressive variant of soft-tissue sarcoma. Literature is sparse and reported mostly from the West. We analysed the clinical profiles and prognostic factors of extremity synovial sarcoma patients in order to study their clinical journey.

MATERIALS AND METHODS

This was a retrospective analysis. All patients with extremity synovial sarcoma treated between 1992 and 2020 were included. Patients with metastases at presentation were excluded. A descriptive analysis of demographic and clinicopathological features of patients undergoing limb salvage surgery (LSS) or amputation was carried out. Overall survival and disease-free survival were calculated for the entire cohort as well as for the LSS and amputation groups. Factors prognostic for survival were identified.

RESULTS

In total, 157 patients had localised extremity synovial sarcoma. Predominantly, young adults (median 31 years) and males (61%) were affected. Over 70% of patients presented after recurrence or unplanned surgeries. Sixty-seven per cent of tumours were >5 cm, 69% were deep and 23% involved bone. The limb salvage rate was 64%. In the LSS group, adjuvant radiotherapy and chemotherapy were given to 72% and 68% of patients, respectively. In the amputation group, 72% of patients received adjuvant chemotherapy. In a median follow-up of 59 months, 39.4% of patients had recurrences, the majority (61.2%) were systemic. Five-year overall survival and disease-free survival were 53.4% and 49.8%, respectively. Overall survival was 63.9% and 29.7% in the LSS and amputation groups, respectively. On multivariate analysis, tumour size, depth, omission of radiotherapy and bone invasion were found to be the adverse prognostic factors.

CONCLUSION

This is one of the largest studies on extremity synovial sarcoma. Mostly males and young adults were affected. The limb salvage rate was 64%, despite most being referred after unplanned surgery. Almost 70% of patients received radiotherapy and chemotherapy. Overall survival was inferior in the amputation group. Tumour size >5 cm, depth and bone invasion were negative, whereas adjuvant radiotherapy was a positive prognostic factor for survival. Chemotherapy had no impact on survival.

Team Approach: Extremity Soft Tissue Sarcoma

» Synovial sarcoma is a soft tissue sarcoma that most commonly presents in the extremity in a periarticular location.» As the history and physical examination of patients with synovial sarcoma can overlap considerably with those of patients with non-oncologic orthopedic conditions, it is important that orthopedic surgeons maintain a high level of suspicion when caring for patients with extremity masses.» Soft tissue sarcomas are best treated using a team approach. Early recognition and referral to a multidisciplinary sarcoma team are crucial to ensure the best clinical outcome for the patient.

Synovial sarcoma: characteristics, challenges, and evolving therapeutic strategies

Synovial sarcoma (SS) is a rare and aggressive disease that accounts for 5%-10% of all soft tissue sarcomas. Although it can occur at any age, it typically affects younger adults and children, with a peak incidence in the fourth decade of life. In >95% of cases, the oncogenic driver is a translocation between chromosomes X and 18 that leads to the formation of the SS18::SSX fusion oncogenes. Early and accurate diagnosis is often a challenge; optimal outcomes are achieved by referral to a specialist center for diagnosis and management by a multidisciplinary team as soon as SS is suspected. Surgery with or without radiotherapy and/or chemotherapy can be effective in localized disease, especially in children. However, the prognosis in the advanced stages is poor, with treatment strategies that have relied heavily on traditional cytotoxic chemotherapies. Therefore, there is an unmet need for novel effective management strategies for advanced disease. An improved understanding of disease pathology and its molecular basis has paved the way for novel targeted agents and immunotherapies that are being investigated in clinical trials. This review provides an overview of the epidemiology and characteristics of SS in children and adults, as well as the patient journey from diagnosis to treatment. Current and future management strategies, focusing particularly on the potential of immunotherapies to improve clinical outcomes, are also summarized.

Tumor size and surgical margins are important prognostic factors of synovial sarcoma - A retrospective study

Background

Synovial Sarcoma (SS) is a rare soft tissue sarcoma. Mean time to get a SS diagnosis from the onset of symptoms is 10 years, furthermore, SS is associated with late metastasis. Surgery is the main treatment option, whose quality deeply affects SS outcomes, and it can be associated to preoperative or post-operative radiotherapy. Chemotherapy is considered very effective in Children, while in adults its efficacy is still under debate. The aim of this study was to investigate the oncologic results in SS treatment and to identify the risk factors for local and systemic control of the disease.

Methods

From 1994 to 2018, 211 patients affected by SS were treated in 3 Referral Centres of Orthopaedic Oncology. One hundred seventy-seven patients were included in the study, the median follow-up length was 96 months (5-374).

Results

Overall Survival on the Kaplan Meier Analyses was 80%, 70% and 56% at 5, 10 and 20 years. In multivariate analyses, OS correlated with tumour size and negative surgical margins. Chemotherapy use wasn't associated with better survival although patients who underwent CT had bigger and more aggressive tumours.

Conclusions

Our findings suggests that surgery with negative margins is the most important factor in Synovial Sarcoma. Adjuvant treatments as chemotherapy and radiation therapy didn't change the disease's course.

A phase II study of gemcitabine and docetaxel combination in relapsed metastatic or unresectable locally advanced synovial sarcoma

Synovial sarcoma (SS) is one of the commonest non-rhabdomyosarcoma soft tissue sarcoma with limited treatment options in the relapsed and advanced settings. The combination of gemcitabine and docetaxel has demonstrated its role predominantly in leiomyosarcoma and pleomorphic sarcomas but has not been prospectively studied in SS. This trial assesses the efficacy, tolerability and quality of life (QoL) with this regimen in metastatic/unresectable locally advanced relapsed SS.Patients and methods This was a single-arm, two-stage, phase II, investigator-initiated interventional study among patients with metastatic or unresectable locally advanced SS who had progressed after at least one line of chemotherapy. Gemcitabine 900 mg/m2 on days 1 and 8 and docetaxel 75 mg/m2 on day 8 were administered intravenously every 21 days. The primary endpoint was 3-month progression-free rate (PFR); overall survival (OS), progression-free survival (PFS), overall response rate (ORR), safety and quality of life (QoL) constituted the secondary endpoints.Results Twenty-two patients were enrolled between March 2020 and September 2021 and the study had to be closed early due to slow accrual. The study population comprised of 18 (81.8%) patients with metastatic disease and 4 (18.2%) patients with locally advanced, unresectable disease. The most common primary sites of disease were extremity in 15 (68%) and the median number of lines of prior therapies received was 1 (range 1-4). 3-month PFR was 45.4% (95% CI 24.8-66.1) and ORR was 4.5%. Median progression-free survival (PFS) was 3 months (95% CI 2.3-3.6) and median OS was 14 months (95% CI 8.9-19.0). 7 (31.8%) patients experienced grade 3 or worse toxicities, including anemia (18%), neutropenia (9%) and mucositis (9%). QoL analysis demonstrated significant decline in certain functional and symptom scales, while financial and global health scales remained stable.Conclusion This is the first prospective study on the combination of gemcitabine and docetaxel performed specifically in patients with advanced, relapsed SS. Although the accrual of patients could not be completed as planned, the therapy did produce clinically meaningful outcomes and met its primary endpoint of 3-month PFR. This result, along with the manageable toxicity profile and stable global health status on QoL analysis, should encourage further studies.Trial registration This trial was prospectively registered under the Clinical Trials Registry of India on 26/02/2020 (Registration number: CTRI/2020/02/023612).

Axillary synovial sarcoma recurrence involving brachial plexus, a rare case report from Pakistan

INTRODUCTION

Synovial sarcomas are rare tumors, and the incidence of axillary synovial sarcoma involving the brachial plexus has been reported as 2.9 % among all axillary soft tissue tumors. However, the recurrence of axillary synovial sarcomas has not been reported in literature.

CASE PRESENTATION

A 36-years-old Afghan female presented in Karachi, Pakistan with a history of persistently increasing, recurrent, right axillary mass for 6 months. Initially diagnosed as a spindle-cell tumor on excision in Afghanistan, she had received ifosfamide and doxorubicin, but the lesion recurred. On examination, it was a 5 × 6 cm, hard mass palpable in right axilla. After radiological work-up and a multidisciplinary team discussion, she underwent complete excision of the tumor with successful preservation of brachial plexus. The final diagnosis was reported as monophasic synovial sarcoma FNCLCC Grade 3.

DISCUSSION

Our patient presented with a recurrent right axillary synovial sarcoma that was involving the axillary neurovascular bundle and brachial plexus, which was initially diagnosed as a spindle cell sarcoma. Pre-operative core-needle biopsy was unable to provide a definitive diagnosis. MRI scan was useful in delineating the proximity of the neurovascular structures. Re-excision of the tumor was performed which is the mainstay of treatment for axillary synovial sarcomas, combined with radiotherapy depending on the disease grading, staging and patient factors.

CONCLUSION

Axillary synovial sarcoma recurrence with involvement of the brachial plexus is an extremely rare presentation. Our patient was successfully managed through a multidisciplinary approach with complete surgical excision and preservation of the brachial plexus followed by adjuvant radiotherapy.

Treatment patterns and outcomes in patients with metastatic synovial sarcoma in France, Germany, Italy, Spain and the United Kingdom

Aim: Describing the treatment patterns, outcomes by line of treatment (LOT), and healthcare resource utilization (HCRU) in patients with metastatic synovial sarcoma (mSS). Patients & methods: In this descriptive, non-interventional, retrospective cohort study, physicians from five European countries reported on patients with recent pharmacological treatment for mSS. Results: Among 296 patients with mSS, 86.1, 38.9 and 8.4% received 1 LOT (1L), 2 LOTs (2L) and 3+ LOTs (L3+), respectively. Common regimens were doxorubicin/ifosfamide-based (37.4%) for 1L and trabectedin-based for 2L (29.7%). For 1L, median time to next treatment was 13.1 and 6.0 months for living and deceased patients, respectively. Median OS was 22.0, 6.0 and 4.9 months in all patients, 2L and 3L, respectively. HCRU data showed median one inpatient hospital admission, 3 days in hospital and four outpatient visits yearly. Conclusion: This large-scale study documents high unmet needs in patients previously treated for mSS and for more effective therapies.

Emerging targeted and cellular therapies in the treatment of advanced and metastatic synovial sarcoma

Synovial sarcoma is a soft tissue sarcoma accounting for approximately 1,000 cases per year in the United States. Currently, standard treatment of advanced and metastatic synovial sarcoma is anthracycline-based chemotherapy. While advanced synovial sarcoma is more responsive to chemotherapy compared to other soft tissue sarcomas, survival rates are poor, with a median survival time of less than 18 months. Enhanced understanding of tumor antigen expression and molecular mechanisms behind synovial sarcoma provide potential targets for treatment. Adoptive Cell Transfer using engineered T-cell receptors is in clinical trials for treatment of synovial sarcoma, specifically targeting New York esophageal squamous cell carcinoma-1 (NY-ESO-1), preferentially expressed antigen in melanoma (PRAME), and melanoma antigen-A4 (MAGE-A4). In this review, we explore the opportunities and challenges of these treatments. We also describe artificial adjuvant vector cells (aAVCs) and BRD9 inhibitors, two additional potential targets for treatment of advanced synovial sarcoma. This review demonstrates the progress that has been made in treatment of synovial sarcoma and highlights the future study and qualification needed to implement these technologies as standard of care.

Synovial Sarcoma Preclinical Modeling: Integrating Transgenic Mouse Models and Patient-Derived Models for Translational Research

Synovial sarcomas (SyS) are rare malignant tumors predominantly affecting children, adolescents, and young adults. The genetic hallmark of SyS is the t(X;18) translocation encoding the SS18-SSX fusion gene. The fusion protein interacts with both the BAF enhancer and polycomb repressor complexes, and either activates or represses target gene transcription, resulting in genome-wide epigenetic perturbations and altered gene expression. Several experimental in in vivo models, including conditional transgenic mouse models expressing the SS18-SSX fusion protein and spontaneously developing SyS, are available. In addition, patient-derived xenografts have been estab-lished in immunodeficient mice, faithfully reproducing the complex clinical heterogeneity. This review focuses on the main molecular features of SyS and the related preclinical in vivo and in vitro models. We will analyze the different conditional SyS mouse models that, after combination with some of the few other recurrent alterations, such as gains in BCL2, Wnt-β-catenin signaling, FGFR family, or loss of PTEN and SMARCB1, have provided additional insight into the mechanisms of synovial sarcomagenesis. The recent advancements in the understanding of SyS biology and improvements in preclinical modeling pave the way to the development of new epigenetic drugs and immunotherapeutic approaches conducive to new treatment options.

Synovial sarcoma of the vulva: A case report and literature review with discussion on fertility sparing approaches

•Vulvar synovial sarcoma is a rare malignancy with unclear treatment guidelines but usually includes surgical resection.•Our literature review demonstrates additional survival benefit from addition of radiotherapy to surgical resection.•There is no specific guidance in the literature for the addition of systemic agents to treat vulvovaginal disease.•Our patient received wide surgical excision and IMRT radiotherapy with no signs of recurrence 2 years from treatment.•She conceived after treatment. This has only been documented once before with different, less accessible treatments.

Clinical analysis of multimodal treatment for localized synovial sarcoma: A multicenter retrospective study

INTRODUCTION

Several prognostic factors for survival in synovial sarcoma have been proposed, but the role of adjuvant chemotherapy and radiotherapy is a matter of debate. The study aim was to clarify the effect of high-dose ifosfamide-containing chemotherapy and adjuvant radiotherapy for patients with localized synovial sarcoma.

MATERIALS AND METHODS

Five tertiary musculoskeletal oncology hospitals participated in this retrospective study. The records of the patient diagnosed with synovial sarcoma without metastasis at diagnosis from 1990 to 2011 have been collected and reviewed. Overall, distant failure-free, and local failure-free survivals were calculated, and prognostic factors for each survival were evaluated by performing univariate and multivariate analyses.

RESULTS

A total of 162 patients were enrolled in this study with a median follow-up period of 67 months (range, 5-267 months) for all surviving patients. The 5-year overall, distant failure-free, and local failure-free survival rates were 79.7%, 66.3%, and 98.4%, respectively. Univariate analyses demonstrated that high-dose ifosfamide-containing chemotherapy was significantly associated with better overall (p = 0.014) and distant failure-free survival (p = 0.0043) than that of low-dose or no ifosfamide-containing chemotherapy if we analyzed only patients with tumors >5 cm in size. Addition of radiotherapy was not a significant prognostic factor for overall survival in the univariate and multivariate analyses, but it did improve the overall survival of the patients with R1 resection (p = 0.053).

CONCLUSION

Patients with localized synovial sarcoma >5 cm in size had better overall and distant failure-free survival after receiving adjuvant chemotherapy containing high-dose ifosfamide comparing to low-dose or no ifosfamide-containing chemotherapy. The addition of adjuvant radiotherapy was beneficial for the patients who received R1 resection. Alternatively, adjuvant radiotherapy could be avoided for patients who achieved an R0 margin.

Meta-analysis of pazopanib and trabectedin effectiveness in previously treated metastatic synovial sarcoma (second-line setting and beyond)

Background: This study examined the efficacy/effectiveness of pazopanib and trabectedin in previously treated metastatic synovial sarcoma (mSS). Materials & methods: A literature search identified studies (2002-2019) reporting outcomes of pazopanib and trabectedin in previously treated mSS, including median overall survival (mOS) and overall response rate (ORR). A meta-analysis was conducted and sensitivity analyses examined outcomes by agent (pazopanib/trabectedin), study type (clinical trial [CT] or real-world [RW]) and sample size. Results: Sixteen studies were included (pazopanib: n = 7; trabectedin: n = 9). Pooled mOS was 10.4 months and was consistent across agents and in RW and CT (pazopanib: 10.3; trabectedin: 10.4; CT: 10.8; RW: 9.9). ORR results were more variable (pooled ORR: 14.7%). ORR was consistently higher for RW (17.7%) than for CT (9.5%) and for pazopanib (18.9%) compared with trabectedin (12.3%). Conclusion: Poor outcomes across agents and settings highlight a need for novel treatments with improved efficacy. This study serves as a benchmark for efficacy estimates in this rare disease.

Characterisation of a Novel Cell Line (ICR-SS-1) Established from a Patient-Derived Xenograft of Synovial Sarcoma

Synovial sarcoma is a rare translocation-driven cancer with poor survival outcomes, particularly in the advanced setting. Previous synovial sarcoma preclinical studies have relied on a small panel of cell lines which suffer from the limitation of genomic and phenotypic drift as a result of being grown in culture for decades. Patient-derived xenografts (PDX) are a valuable tool for preclinical research as they retain many histopathological features of their originating human tumour; however, this approach is expensive, slow, and resource intensive, which hinders their utility in large-scale functional genomic and drug screens. To address some of these limitations, in this study, we have established and characterised a novel synovial sarcoma cell line, ICR-SS-1, which is derived from a PDX model and is amenable to high-throughput drug screens. We show that ICR-SS-1 grows readily in culture, retains the pathognomonic SS18::SSX1 fusion gene, and recapitulates the molecular features of human synovial sarcoma tumours as shown by proteomic profiling. Comparative analysis of drug response profiles with two other established synovial sarcoma cell lines (SYO-1 and HS-SY-II) finds that ICR-SS-1 harbours intrinsic resistance to doxorubicin and is sensitive to targeted inhibition of several oncogenic pathways including the PI3K-mTOR pathway. Collectively, our studies show that the ICR-SS-1 cell line model may be a valuable preclinical tool for studying the biology of anthracycline-resistant synovial sarcoma and identifying new salvage therapies following failure of doxorubicin.

The Role of Surgery for Primary Pulmonary Synovial Sarcoma: A Population-Based Study

INTRODUCTION

The rarity of primary pulmonary synovial sarcoma (PPSS) and the lack of prospective clinical trials resulted in poorly understood treatment modality and clinical outcomes. This study aimed to better understand PPSS based on patients from the Surveillance, Epidemiology, and End Results database.

MATERIALS AND METHODS

Clinical and survival data of PPSS patients who were diagnosed during 1989 through 2016 and retrieved from the Surveillance, Epidemiology, and End Results database were studied. Kaplan-Meier analyses and Cox proportional hazards model were applied to evaluate the overall survival (OS) and disease-specific survival (DSS) of PPSS patients.

RESULTS

A total of 122 patients with PPSS were included (median age: 50 y). PPSS accounted for 4.5% (122/2741) of total primary synovial sarcoma. Most of the patients were diagnosed as poor or undifferentiated grade (52.0% and 34.0%). Cancer-directed surgery was performed for 74.4% of PPSS patients and 28.2% of patients received radiotherapy. The 1-year, 3-year, 5-year, and 10-year OS rates of PPSS patients were 75.4%, 50.8%, 41.8%, and 39.3%, respectively. Cancer-directed surgery was shown to improve the survival of PPSS patients with localized or regional stage (P < 0.05), yet surgical resection did not prolong the OS and DSS of patients with distant stage (P > 0.1). Postoperational radiotherapy was associated with shortened survival time (P < 0.05). PPSS patients who received lobectomy had statistically prolonged OS and DSS than those with pneumonectomy (P < 0.001).

CONCLUSIONS

PPSS is a rare and special subtype of synovial sarcoma. Treatment with lobectomy or sublobar resection alone may contribute to a superior prognosis compared with other managements.

Establishment and characterization of NCC-SS5-C1: a novel patient-derived cell line of synovial sarcoma

Synovial sarcoma (SS) is a rare and aggressive mesenchymal malignancy driven by a unique chromosomal translocation that generates the expression of the SS18:SSX fusion protein. It occurs at almost any anatomical site and most commonly in young adults. The standard curative treatment for primary SS is a wide surgical resection combined with radiotherapy and/or neoadjuvant chemotherapy. The prognosis of SS varies among patients, with the 5 years survival rate ranging from 50 to 60% in adults and 90% in children. Although patient-derived cell lines are a useful resource for the development of new therapies, only a few are available from public cell banks. Therefore, this study aimed to establish and characterize a novel SS cell line. We successfully established a novel cell line, NCC-SS5-C1, harboring an SS18-SSX1 fusion gene. NCC-SS5-C1 cells demonstrated constant growth and invasion ability. We performed integrative drug screening using eight SS cell lines, including NCC-SS5-C1 cells, and examined the response spectrum of existing anticancer agents. We conclude that NCC-SS5-C1 is a useful resource for studying SS.

A Large Primary Retroperitoneal Synovial Sarcoma: A Case Report of a Huge Malignant Tumor

Synovial Sarcoma (SS) is a rare soft-tissue malignancy. Only about 15% of SS originates from the retroperitoneum. Retroperitoneal SS (RSS) is usually diagnosed incidentally due to the anatomy of the retroperitoneum. The most common complaints of patients are abdominal and low back pain. Other common symptoms of RSS are palpable abdominal mass, weight loss, and anemia. In this study, we will describe a 29-year-old white Asian man with a diagnosis of RSS after radical nephrectomy. He was admitted to the Urology Department of Shohada-e Tajrish hospital, Tehran, Iran in March 2019. The distinguishing feature of this case is the size of the mass, which has never been reported so much for retroperitoneal synovial sarcoma. Radiologic imaging showed a huge retroperitoneal mass originating from the kidney. Based on the pathologic features and immunohistochemistry (IHC) study, the diagnosis was consistent with synovial sarcoma. Accurate diagnosis of RSS is usually based on the pathological findings. Therefore, in case of doubt, a biopsy can be employed. Surgical resection of the tumor and lymph nodes dissection is the main and most important part of the treatment. Aggressive resection with free margin is recommended. The role of adjuvant and neoadjuvant chemotherapy in RSS is not certain to date, but it is recommended according to the patient's condition.

Neoadjuvant Therapy for Primary Resectable Retroperitoneal Sarcomas-Looking Forward

The cornerstone of therapy for primary retroperitoneal sarcomas (RPS) is complete surgical resection, best achieved by resecting the tumor en bloc with adherent structures even if not overtly infiltrated. Until recently, trials designed to elucidate the role of neoadjuvant radiation or chemotherapy for RPS have been unable to achieve sufficient enrollment. The completion of the STRASS trial, which explored neoadjuvant radiotherapy for primary resectable RPS, is a major milestone in RPS research, but has prompted further questions about histology-driven treatment paradigms for RPS. Though it was ultimately a negative trial with respect to its primary endpoint of abdominal recurrence-free survival, STRASS produced a signal that suggested improved abdominal recurrence-free survival with neoadjuvant radiotherapy (RT) for patients with liposarcoma (LPS). No effect was seen for leiomyosarcoma (LMS) or high-grade dedifferentiated (DD) LPS, consistent with recent literature suggesting LMS and high-grade DD-LPS have a predominant pattern of distant rather than local failure. These results, along with those from other recent studies conducted at the bench and the bedside, emphasize the importance of a histology-specific approach to RPS research. Recent evidence for patterns of distant failure in LMS and high-grade DD-LPS has prompted the initiation of STRASS2, a study of neoadjuvant chemotherapy for these histologies. As this study unfolds, evidence may emerge for novel systemic therapy options in specific sarcoma histotypes given the explosion in targeted and immunotherapeutic applications over the last decade. This article reviews current and recent evidence around neoadjuvant radiation and chemotherapy as well as avenues for future study to optimize these treatment approaches.

Case Report: Primary Intraosseous Poorly Differentiated Synovial Sarcoma of the Femur

Primary intraosseous poorly differentiated synovial sarcoma is exceedingly rare. Here, we present a case of primary intraosseous poorly differentiated synovial sarcoma from the proximal femur in a 16-year-old girl. The case was initially misdiagnosed, but the correct diagnosis of synovial sarcoma was eventually confirmed by fluorescence in situ hybridization and next-generation sequencing. We review the literature pertaining to synovial sarcoma and show that this case is the second molecularly proven intraosseous poorly differentiated synovial sarcoma in the literature. Recognition of intraosseous synovial sarcoma composed of small round cells is imperative in order to avoid misdiagnosis of the tumor as Ewing sarcoma and other small round-cell tumors, all of which have markedly different clinical management.

Patterns of care and outcomes of 417 patients with METAstatic SYNovial sarcoma (METASYN): real-life data from the French Sarcoma Group (FSG)

Background

Synovial sarcoma (SS) occurs in both adult and pediatric patients. The primary aim of this study is to describe the outcomes, prognostic factors, and treatment of patients with metastatic SS within a nationwide cohort.

Patients and methods

All pediatric and adult patients with metastatic SS are registered in the French Sarcoma Group database. Data were collected from the national database https://conticabase.sarcomabcb.org/ up to March 2020. Descriptive and comparative analyses were conducted using SAS 9.4 and Stata Special Edition 16.1 software.

Results

Between January 1981 and December 2019, 417 patients with metastatic SS from 17 French sarcoma centers were included, including 64 (15.3%) under the age of 26 years. Median age was 42.5 years (range 9-87 years). The metastases were synchronous (cohort 1) or metachronous (cohort 2) in 18.9% (N = 79) and 81.1% (N = 338) patients, respectively. Median overall survival (OS) from the date of metastasis was 22.3 months (95% confidence interval 19.7-24.1 months). First-line chemotherapy without ifosfamide and/or doxorubicin was unfavorable for progression-free survival and OS (P < 0.001). Concerning cohort 1, young age, surgery of the primary tumor, and single metastatic site were independent favorable prognostic factors for OS. In cohort 2, surgery within an expert French Sarcoma Group center, absence of chemotherapy in the perioperative setting, the lungs as a single metastatic site, time to first metastasis >12 months, local therapy, and ifosfamide in the first metastatic line were independent favorable prognostic factors.

Conclusions

The outcome of patients with metastatic SS is influenced by local treatment, management in reference centers, and cytotoxic treatments given in the perioperative and metastatic setting.

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METASYN is the largest retrospective study on metastatic adult and pediatric SS.

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This study confirms that surgery remains the mainstay for improving OS in reference centers.

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METASYN emphasizes the importance of focal treatment of metastases for OS.

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This study offers real-life results in a metastatic setting and is a useful support for developing new strategies.

Clinical Significance and Risk Factors of Local Recurrence in Synovial Sarcoma: A Retrospective Analysis of 171 Cases

Objective: To investigate risk factors of local recurrence of synovial sarcoma and the impact of local recurrence on survival.

Methods: We retrospectively reviewed clinical data of patients with II to IIIB (AJCC8) synovial sarcoma who underwent surgery at our center between March 2005 and December 2016. Data relating clinicopathological factors, treatment and prognosis were collected. The impact of local recurrence on overall survival (OS), local recurrence-free survival (LRFS), and distant relapse-free survival (DRFS) were analyzed. The prognostic factors associated with local recurrence were also analyzed using Kaplan-Meier Curves and Cox regression analysis.

Results: A total of 171 patients were included in this analysis. After a median follow-up of 48 months, 66 patients (38.6%) experienced local recurrence. The 5-year OS, LRFS, and DRFS rates of patients with local recurrence were 37.6, 6.1, and 24.1%, respectively. Multivariate analysis showed that larger initial tumors, multiple recurrences, positive resection margins, marginal resection, and lack of adjuvant therapy were associated with higher local recurrence.

Conclusion: Local recurrence of synovial sarcoma is associated with distant metastasis and poor survival. Chemoradiation improves the prognosis of patients with local recurrence, in particular those for which recurrence occurs shortly after initial treatment.

Nomogram to Predict Overall and Cancer-Specific Survival in Patients with Synovial Sarcoma in the Extremities: A Population-Based Study

Background

Synovial sarcoma is a rare disease, and synovial sarcoma that first appears in the extremities accounts for more than 80% of cases. We established two nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) rates of patients with synovial sarcoma.

Methods

A total of 227 patients diagnosed with synovial sarcoma in the extremities between 2010 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate Cox analyses were performed to explore independent prognostic factors and to create two separate nomograms for OS and CSS. The C-index, the area under the curve (AUC), calibration curve, decision curve analysis (DCA), and Kaplan-Meier (KM) curve were used to evaluate the column line graphs and analyze prognostic factors.

Results

Age, Stage M, and surgery were identified as independent prognostic factors for OS and CSS. The ROC curve showed good discriminative power for the nomogram. Calibration curves and DCA curves showed that the nomogram had a satisfactory ability to predict OS and CSS. The KM curve showed that chemotherapy alone did not affect patient survival.

Conclusion

Age, Stage M, and surgery are variables that affect OS and CSS in patients with synovial sarcoma in the extremities. Two nomograms were established based on the above variables to provide patients with more accurate individual survival predictions and to help physicians make appropriate clinical decisions.

Monophasic Synovial Sarcoma in the Elbow Misclassified but Successfully Treated as Ewing's Sarcoma with Chemotherapy

To the best of the authors’ knowledge, this is the first published case of monophasic synovial sarcoma (SS) initially diagnosed as Ewing’s sarcoma (ES), yet successfully treated with chemotherapy in a 24-year-old patient. The initial diagnosis showed a monotonous round cell tumor and positivity for CD99, characteristic of ES; however, the cytology was negative for the classic EWSR1 rearrangement of ES. The patient was treated with the standard chemotherapy protocol of ES – COG AEWS1031 Regimen A with vincristine, doxorubicin, cyclophosphamide, and mesna – as well as with wide resection. Post-resection tissue submission showed additional morphologic features which led to a re-evaluation of the classification of the tumor as well as additional molecular studies; these revealed positivity for translocations of SS18 (18q11.1) in 100% of the nuclei, which is most characteristic of SS, thus, reclassifying the neoplasm as a SS tumor. This case underscores the importance of considering several pathologic entities in the differential diagnosis of small, round blue cell tumors, including ES, SS, and lymphoma. It also demonstrates the importance of using chromosomal identification for a more definitive diagnosis, rather than relying on histological features and markers which are found in more than one tumor classification. There is conflicting evidence of the impact of chemotherapy on survival in SS, as it is primarily treated with radiation therapy. Since SS is rare, prospective studies on the effect of chemotherapy on survival are limited in number. However, our case study demonstrates that chemotherapy is another modality that can be used in the treatment of SS neoplasms.

Primary synovial sarcoma of bone: A retrospective analysis of 25 patients

AIMS

To evaluate diagnostic accuracy of SSX and SSX-SS18 antibodies in decalcified surgical specimens and outcome of synovial sarcomas (SS) of bone.

METHODS AND RESULTS

Twenty-five cases were classified as bone SS (prevalence 0.32% among malignant primary bone sarcoma). Median age was 34 years (range 9 -79) . 24/25 patients presented with non-metastatic tumors, one with lung metastases. The majority of tumors involved the long bones of extremities with metaphyseal origin. Mean size of the tumor was 7.1 cm. 20 cases (80%) were monophasic and 5 (20%) biphasic. SS18-SSX fusion-specific antibody had 92% sensitivity and 99% specificity for primary bone SS, whereas SSX C-terminus antibody had 100% sensitivity and 94% specificity. FISH analysis was feasible in 9 (36%) cases and detected SS18 rearrangement in all 9 cases. All patients underwent surgical removal of their primary tumor, with adequate margins in 18 (72%) patients. Chemotherapy with metothrexate, cisplatin, doxorubicin, ifosfamide was used in the 7 patients. Two patients with inadequate surgical margins received radiotherapy. With a median follow-up of 80 months (range 6-428), 5-year and 10-year overall survival (OS) were 66.6% and 47.9% respectively and 5-and 10-years disease-free survival (DFS) were 36.8% (95% C.I.: 18.0-55.7%), and 32.2% (95% C.I.: 14.6-51.2%) respectively A significant improvement in 10-years DFS in patients undergoing chemotherapy as compared with patients who did not was observed (p 0.039).

CONCLUSIONS

Our series highlights the utility of SS18-SSX fusion-specific and SSX C-terminus antibodies to support the diagnosis of SS, Adjustment chemotherapy was associated with improved prognosis in this series.

Prognostic implication of desmoplastic stroma in synovial sarcoma: A histological review

Synovial sarcoma (SS) is a malignant soft tissue neoplasm harboring SS18-SSX fusion gene and is histologically characterized by spindle cells and epithelial components. Some investigations have demonstrated that desmoplastic reaction (DR) is an independent prognostic factor of cancers. However, it remains unknown whether DR is of predictive value for the prognosis of synovial sarcoma patients. Here, we reviewed the clinical and histological findings of 88 patients with SS. We defined DR as hyalinized collagenous structures and classified the degree of DR as follows: none, mild, moderate, and severe. Overall, 23 SS cases (24%) showed moderate or severe DR histologically. Statistically, the cases with moderate or severe degree of DR showed poorer prognosis than those with no or mild DR (local recurrence: P = 0.0059, distant metastasis: P = 0.0002, tumor death: P = 0.0382). The findings of the study suggest that the DR of synovial sarcoma could be an important prognostic factor.

The Biology of Synovial Sarcoma: State-of-the-Art and Future Perspectives

New molecular insights are being achieved in synovial sarcoma (SS) that can provide new potential diagnostic and prognostic markers as well as therapeutic targets. In particular, the advancement of research on epigenomics and gene regulation is promising. The concrete hypothesis that the pathogenesis of SS might mainly depend on the disruption of the balance of the complex interaction between epigenomic regulatory complexes and the consequences on gene expression opens interesting new perspectives. The standard of care for primary SS is wide surgical resection combined with radiation in selected cases. The role of chemotherapy is still under refinement and can be considered in patients at high risk of metastasis or in those with advanced disease. Cytotoxic chemotherapy (anthracyclines, ifosfamide, trabectedin, and pazopanib) is the treatment of choice, despite several possible side effects. Many possible drug-able targets have been identified. However, the impact of these strategies in improving SS outcome is still limited, thus making current and future research strongly needed to improve the survival of patients with SS.

Efficacy of perioperative chemotherapy for synovial sarcoma: a retrospective analysis of a Nationwide database in Japan

BACKGROUND

Synovial sarcoma is an aggressive but chemosensitive soft-tissue tumor. We retrospectively analyzed the efficacy of perioperative chemotherapy for synovial sarcoma with data from the nationwide database, Bone and Soft Tissue Tumor Registry in Japan.

METHODS

This study included 316 patients diagnosed with synovial sarcoma between 2006 and 2012. Oncologic outcomes were analyzed using a Cox-hazard regression model. Moreover, the effects of perioperative chemotherapy on outcomes were evaluated using a matched-pair analysis. The oncologic outcomes of patients who did or did not receive chemotherapy were compared (cx + and cx-).

RESULTS

Multivariate analysis revealed significant correlations of age (over 40, hazard ratio [HR] = 0.61, p = 0.043), margin status (marginal resection, HR = 0.18, p < 0.001 and intralesional resection, HR = 0.30, p = 0.013 versus wide resection) with overall survival; surgical margin type (marginal resection, HR = 0.14, p = 0.001 and intralesional resection, HR = 0.09, p = 0.035 versus wide resection) with local recurrence; and postoperative local recurrence (HR = 0.30, p = 0.027) and surgical margin (marginal resection, HR = 0.31, p = 0.023 versus wide resection) with distant relapse-free survival. Before propensity score matching, perioperative chemotherapy was mainly administered for young patients and patients with deeper tumor locations, larger tumors, more advanced-stage disease, and trunk location. The 3-year overall survival, local control, and distant relapse-free survival rates were 79.8%/89.3% (HR = 0.64, p = 0.114), 89.6%/93.0% (HR = 0.37, p = 0.171) and 71.4%/84.5% (HR = 0.60, p = 0.089) in the cx+/cx- groups, respectively. After propensity score matching, 152 patients were selected such that the patient demographics were nearly identical in both groups. The 3-year overall survival, local control, and distant relapse-free survival rates were 71.5%/86.0% (HR = 0.48, p = 0.055), 92.5%/93.3% (HR = 0.51, p = 0.436) and 68.4%/83.9% (HR = 0.47, p = 0.046) in the cx+/cx- groups, respectively.

CONCLUSION

This large-sample study indicated that the margin status and postoperative disease control were associated directly or indirectly with improved oncologic outcomes. However, the efficacy of perioperative chemotherapy for survival outcomes in synovial sarcoma patients was not proven in this Japanese database analysis.

Synovial Sarcoma of the Hand and Foot: An Institutional Review

OBJECTIVES

Synovial sarcomas (SS) arising in distal extremities are rare and have been studied using mostly case reports and small series. We aimed to evaluate clinical presentation and survival outcomes for patients with hand or foot SS.

MATERIALS AND METHODS

We conducted a retrospective review of 84 patients diagnosed with primary hand (n=20) and foot (n=64) SS between 1979 and 2019. Progression-free survival (PFS), overall survival (OS), local recurrence-free survival and metastasis-free survival were estimated using the Kaplan-Meier method and log-rank test. Cox-proportional hazards regression was used to estimate the hazard ratios.

RESULTS

Of 84 patients, 63 (75%) presented with localized disease with 36 years median age at diagnosis (range: 4 to 76) and 21 (25%) with metastasis with 30 years median age at diagnosis (range: 15 to 64). Among patients presenting with localized disease, (1) 5 years-PFS, OS, local recurrence-free survival, and metastasis-free survival rates were 82%, 88%, 100%, and 86%, respectively. (2) Tumor size <3.0 cm corresponded to 95% 5 years-PFS (vs. 84% for 3.0 to 4.9 cm, 53% for ≥5.0 cm; P=0.007) and 100% 5 years-OS (vs. 77% for ≥3.0 cm; P=0.04). (3) Patients with ≥5.0 cm (vs. <3.0 cm) tumor size had 7.99 (95% confidence interval: 1.68, 37.91) times higher hazard of progression. Remarkably, patients presenting with metastasis had 50% 5 years-OS rate. Also, younger age (15 to 39 vs. 40 y and above) predicted better OS among patients presenting with localized disease (P=0.04) and with metastasis (P=0.03).

CONCLUSIONS

Survival outcomes are favorable for younger patients with <3.0 cm hand or foot SS. Local control is excellent, but we observed larger tumor size to be associated with poorer outcomes. Therefore, we recommend consideration of systemic therapy for patients with ≥3.0 cm hand or foot SS.

Long non-coding RNA HOTAIR promotes the progression of synovial sarcoma through microRNA-126/stromal cell-derived factor-1 regulation

The long non-coding RNA (lncRNA) HOTAIR is an oncogene, that has been reported to be aberrantly expressed in multiple types of malignant tumor tissues. However, its expression and association with synovial sarcoma (SS) remains unclear. The present study aimed to elucidate the expression level of HOTAIR in SS tissues and also identify its role. Reverse transcription-quantitative PCR was used to detect the expression level of HOTAIR and microRNA (miR)-126 in 54 tissue samples from patients with SS, in 10 tissue samples from synovium tissues of normal patients, and in SW982 cells. The protein expression level was measured using western blot analysis and cellular immunofluorescence. Cellular proliferation, invasion and migration were assessed using MTT, Transwell and wound healing assays, respectively. HOTAIR was expressed at high levels in SS tissues. In contrast, miR-126 was expressed at low levels in SS tissues, and was negatively correlated with HOTAIR expression. HOTAIR knockdown in SW982 cells inhibited cellular proliferation in vitro, but also significantly increased the ratio of cells in the G1/G0 phase of the cell cycle, and decreased the ratio of cells in the G2/S phase. In addition, HOTAIR knockdown inhibited the invasion and migration of the SW982 cells, as observed in the Transwell and wound healing assays. Furthermore, HOTAIR knockdown increased miR-126 expression level and decreased the expression level of stromal cell-derived factor-1 (SDF-1) at the protein level. On the other hand, while miR-126-mimic decreased the protein expression level of SDF-1, miR-126-inhibitor increased its expression level in SW982 cells. Notably, HOTAIR knockdown or SDF-1 knockout significantly decreased the protein expression levels of CDK1, CDK2, cyclin D1, MMP-9, vimentin and N-cadherin, and significantly increased the protein expression levels of p21, p53 and E-cadherin in SW982 cells. HOTAIR was highly expressed in SS tissues, wherein it could promote the proliferation, invasion and migration of SS cells by increasing the expression of SDF-1 via miR-126 inhibition.

Giant hemorrhagic trochanteric bursitis mimicking a high-grade soft tissue sarcoma: report of two cases

BACKGROUND

The giant haemorrhagic bursitis of the hip joint is a rare clinical condition that requires evidence-based guidelines for adequate diagnosis and management. Usually, this pathology requires conservative treatment; however, when abnormal size or clinical symptoms of compression of the surrounding noble structures are reported, an accurate differential diagnosis is required, in order to exclude other malignant conditions that can be included into differential diagnosis, and a surgical approach should be considered. The purpose of this work is to provide an appropriate description of the diagnostic and therapeutic path, providing an accurate analysis of the possible differential diagnoses.

METHODS

We report 2 cases of symptomatic haemorrhagic bursitis of the hip joint, confirmed by histological investigation. In both cases, the patients complained a peripheral nerve deficit of a single limb: one patient presented paresthesia of lateral femoral cutaneous nerve while the second peripheral edema due to compression of the proximal venous and lymphatic circulation.

RESULTS

Both cases were successfully managed by complete surgical excision of the mass, with no  recurrence. There were no major complications, but in first case the nerve deficit was permanent.

CONCLUSIONS

Giant hemorrhagic trochanteric bursitis is a rare condition, but it should be included in the differential diagnosis of soft tissue masses arising from the hip joint. Due to the rarity of this entity, a cautious exclusion process of all plausible differential diagnosis must be undertaken, in order to not miss the possibility of soft-tissue tumors, primarily malignant high-grade sarcomas.

Synovial Sarcoma: A Series of Small Tumors in Active Duty Service Members

Synovial Sarcoma is a soft tissue sarcoma with a propensity to imitate a benign neoplasm. It is most common in males 15-40 years old, typically presents as a slow growing painful mass, and often arises insidiously without alarm to the patient. Three patients with synovial sarcomas who had each undergone an index procedure to treat a small presumedly benign mass that was later identified as synovial sarcoma were reviewed. All three patients required re-excision of the tumor and tumor bed and are currently undergoing routine surveillance. All patients exhibited the classic translocation t(X;18) (p11.2; q11.2) and all were of the monophasic type. All lesions were less than 35 mm in greatest longitudinal dimension on MRI. None have experienced recurrences of synovial sarcoma to date. Healthcare providers should be aware of the synovial sarcoma's propensity to masquerade as a benign disease and the characteristic clinical and radiological findings. We advocate for a low threshold to obtain advanced imaging and consideration of a tissue diagnosis prior to excision. A referral to an orthopedic oncologist should be considered and biopsy should only be performed where the definitive treatment will take place if malignancy is identified.

Management of Synovial Sarcoma in a Tertiary Referral Center: A Retrospective Analysis of 134 Patients

BACKGROUND

Synovial sarcomas (SS) are malignant mesenchymal neoplasms that account for about 10% of all sarcomas. Complete surgical excision is the mainstay of primary treatment for localized disease, but SS have a high tendency for local relapse and metastases. Metastatic disease is commonly treated with systemic chemotherapy.

METHODS

We designed a retrospective analysis to describe the clinical presentation, course of treatment, outcome, and prognosis of patients with SS. Univariate and multivariate analyses were performed for potential prognostic factors.

RESULTS

We identified 134 patients treated between 1987 and 2018, with a cutoff date of December 2018. Demographics, disease characteristics, treatment, and survival rates were collected and analyzed. The median overall survival (mOS) from the date of diagnosis was 96.7 months. The median progression-free survival was 6.37 months. Disease-free survival was 26 months. Age over 65 years was found to be a prognostic factor with statistically significant value in the univariate analysis regarding mOS (p = 0.015) and mOS after local relapse (p = 0.0228).

CONCLUSIONS

Even though our study is limited by the retrospective nature of the analysis, it adds an important amount of clinical data regarding the treatment and outcome of SS.

Soft-tissue Sarcoma of the Hand: Patient Characteristics, Treatment, and Oncologic Outcomes

INTRODUCTION

The aim of this study was to describe patient characteristics, treatment, and oncologic outcomes of soft-tissue sarcomas (STSs) of the hand.

METHODS

Sixty-nine STSs of the hand in adult patients treated at a tertiary referral center were retrospectively included. We describe patient and tumor characteristics along with oncologic outcomes.

RESULTS

Epithelioid sarcoma (23%) was the most common histologic subtype, followed by synovial sarcoma (15%). Of all tumors, 17 (25%) were grade I, 22 (32%) were grade II, and 30 (44%) were grade III. The 5-year disease-free survival for epithelioid sarcomas was 75% with a disease survival of 100%, along with a metastatic rate of 15%. Of the patients with a synovial sarcoma, 40% developed metastases, and the 5-year disease-free survival was 68% and the 5-year disease survival was 73%.

CONCLUSION

Hand STSs are aggressive tumors with a high metastatic potential. Even with adequate oncologic treatment, long-term clinical follow-up (10 years) in these tumors is advised. The treating surgical oncologist should not be deceived by their smaller size.

Establishment and characterization of NCC-SS4-C1: a novel patient-derived cell line of synovial sarcoma

Synovial sarcoma (SS) is defined as a monomorphic blue spindle cell sarcoma showing variable epithelial differentiation, and is characterized by a specific fusion gene, SS18-SSX. Although SS is rare, it accounts for approximately 8% of all soft tissue sarcomas, which occupies a significant proportion of soft tissue tumors. The prognosis of SS is unfavorable, with 5-year survival rate of 50-60%, and only a few anti-cancer agents are recommended for its treatment. Thus, we need to urgently establish novel treatment methods. Patient-derived cell lines are essential tools in basic research and pre-clinical studies. However, there are only 4 publicly available SS cell lines. Therefore, we established a novel SS cell line, NCC-SS4-C1, using surgically resected tumor tissues of a patient with SS. The cell line maintained the characteristic fusion gene, SS18-SSX1, and copy number alteration, in concordance with the original tumor. The cells also exhibited moderate cell proliferation, invasion ability, and spheroid formation ability. Moreover, a drug-screening test using 4 SS cell lines, including NCC-SS4-C1, demonstrated the significant anti-proliferative effects of ALK and HDAC inhibitors. Thus, we concluded that the NCC-SS4-C1 cell line is a useful tool for basic and pre-clinical studies of SS.

Marine Antimicrobial Peptide TP4 Exerts Anticancer Effects on Human Synovial Sarcoma Cells via Calcium Overload, Reactive Oxygen Species Production and Mitochondrial Hyperpolarization

Synovial sarcoma is a rare but aggressive soft-tissue sarcoma associated with translocation t(X;18). Metastasis occurs in approximately 50% of all patients, and curative outcomes are difficult to achieve in this group. Since the efficacies of current therapeutic approaches for metastatic synovial sarcoma remain limited, new therapeutic agents are urgently needed. Tilapia piscidin 4 (TP4), a marine antimicrobial peptide, is known to exhibit multiple biological functions, including anti-bacterial, wound-healing, immunomodulatory, and anticancer activities. In the present study, we assessed the anticancer activity of TP4 in human synovial sarcoma cells and determined the underlying mechanisms. We first demonstrated that TP4 can induce necrotic cell death in human synovial sarcoma AsKa-SS and SW982 cells lines. In addition, we saw that TP4 initiates reactive oxygen species (ROS) production and downregulates antioxidant proteins, such as uncoupling protein-2, superoxide dismutase (SOD)-1, and SOD-2. Moreover, TP4-induced mitochondrial hyperpolarization is followed by elevation of mitochondrial ROS. Calcium overload is also triggered by TP4, and cell death can be attenuated by a necrosis inhibitor, ROS scavenger or calcium chelator. In our experiments, TP4 displayed strong anticancer activity in human synovial sarcoma cells by disrupting oxidative status, promoting mitochondrial hyperpolarization and causing calcium overload.

The value of multidisciplinary team (MDT) management in the diagnosis and treatment of primary intrathoracic synovial sarcomas: a single-center experience

Background

Synovial sarcoma (SS) is a rare malignant soft tissue tumor. Primary intrathoracic SS is extremely rare, with limited diagnosis and treatment experiences. The aim of our study was to retrospectively study the clinicopathological characteristics, treatment and prognosis of primary intrathoracic SS and the impact of multidisciplinary team (MDT) management in diagnosis and treatment on patient prognosis.

Methods

The clinical and pathological characteristics, treatment, survival and prognosis of patients with primary intrathoracic SS admitted to the National Cancer Center from January 1999 to December 2018, as well as MDT intervention during diagnosis and treatment, were retrospectively analyzed.

Results

Thirteen patients were enrolled, including 7 (53.8%) males and 6 (46.3%) females, with primary intrathoracic SS in the lung (8/13, 61.5%), mediastinum (4/13, 30.8%) and pleura (1/13, 7.7%) as confirmed by morphological observation, immunohistochemical (IHC) staining and fluorescence in situ hybridization (FISH). Overall, 10/13 (76.9%) patients underwent surgery, and 6/10 (60.0%) received postoperative adjuvant therapy. Only 23.1% of patients received nonsurgical therapy. The MDT discussed and managed seven patients before and/or after surgery and one patient who did not undergo surgery. The estimated 3- and 5-year overall survival (OS) rates were 50.0% and 30.0%, respectively. Patients who were managed by an MDT had a longer median OS time than those who were not (46.0 vs. 18.0 months). Age (P=0.018), tumor location (P=0.029), and Ki-67 (P=0.020) were found to be significantly related to OS.

Conclusions

Monophasic morphology and fusion gene characteristics are the main features for the diagnosis of primary intrathoracic SS. MDT management can help obtain accurate diagnoses and provide reasonable therapeutic options.

Effect of anthracyclines/ifosfamide-based adjuvant chemotherapy for soft tissue sarcoma: a conventional and network Meta-analysis

The objective of this study is to assess the effect of anthracyclines/ifosfamide-based adjuvant chemotherapy for soft tissue sarcoma (STS) and provide a relative ranking of regimens for STS. We pooled the hazard ratios of overall survival (OS) and relapse free survival (RFS) by conventional meta-analysis to appraise whether adjuvant chemotherapy benefits STS and performed a network meta-analysis using a Bayesian model to establish the relative ranking of regimens. Nine studies were included in our meta-analysis. The pooled hazard ratios were 0.68 (95%CI: 0.53-0.86) and 0.65 (95%CI: 0.52-0.83) for OS and RFS, respectively. Doxorubicin was indicated as best regimen to benefit OS (probability: 30.2%), while cyclophosphamide + vincristine + doxorubicin + dactinomycin was indicated as the best regimen for RFS (probability: 37.1%). This meta-analysis confirms the positive effect of anthracyclines/ifosfamide-based adjuvant chemotherapy in STS for both OS and RFS.

Multimodal Risk-Adapted Treatment in Surgical Patients With Synovial Sarcoma: A Preoperative Nomogram-Guided Adjuvant Treatment Strategy

Background: Synovial sarcoma is characterized by heterogeneous clinical manifestations, making it difficult to evaluate individual patients' prognoses and design personal treatment schemes. We established an effective preoperative nomogram to predict cancer-specific survival (CSS) and present a risk-adapted adjuvant treatment strategy in surgical patients with synovial sarcoma. Methods: This retrospective study included patients from the Surveillance, Epidemiology, and End Results (SEER) database who were diagnosed with synovial sarcoma between 1996 and 2015. The patients were randomly divided into training and validation groups. The predictors were selected using univariate and multivariate Cox hazards models. The nomogram performance was verified for its discriminatory ability and calibration. We further stratified the patients into different risk groups according to the nomogram scores and compared the efficacy of chemotherapy, radiotherapy, and combination of radiotherapy and chemotherapy. Results: There were 915 patients enrolled in our study, with 874 patients either alive or dead due to synovial sarcoma. We established a nomogram to predict 5-year CSS based on independent factors, including sex, age, grade, tumor size, location, and extent (all p < 0.05). Our model showed a consistently good discriminatory ability and calibration for predicting 5-year CSS in both the training (c-index = 0.78, 95% CI 0.75-0.81) and validation (c-index = 0.73, 95% CI 0.68-0.78). Based on their nomogram scores, we divided patients into 5 groups. Compared to patients without adjuvant treatment, nomogram I patients with adjuvant treatment had no improvements in 5-year CSS (100.0% vs. 100.0%), nomogram II patients had higher 5-year CSS with radiotherapy or chemotherapy (92.9% vs. 72.2%, p = 0.015), nomogram III patients had higher 5-year CSS with combination of chemotherapy and radiotherapy (70.1% vs. 47.2%, p = 0.004), nomogram IV patients had higher 5-year CSS with radiotherapy (41.3% vs. 15.6%, p = 0.015), and nomogram V patients had no improvements in 5-year CSS rates with adjuvant treatment (28.9% vs. 16.9%, p = 0.18). Conclusion: The nomogram showed a satisfactory discriminatory ability and calibration for predicting 5-year CSS in synovial sarcoma patients. Based on this nomogram, we stratified synovial sarcoma patients according to risk levels, which enabled us to provide a useful grouping scheme that can inform multimodal risk-adapted treatment in synovial sarcoma.

Rare Primary Malignant Bone Sarcomas

Simple Summary

Primary malignant bone tumors are infrequent cancers. More than 90% of these neoplasms are classified as osteosarcomas, Ewing sarcomas or chondrosarcomas, and their clinical presentation, diagnosis, and treatment principles are well-established. The entities described in this article, are ultra-rare varieties of bone sarcomas, and there clinical and histological characteristics are not well known. Therefore, they are very difficult to be diagnosed and there is a lot of uncertainty on their treatment. Because of their rarity, it is also extremely difficult to perform clinical research on these cancers. This article creates more awareness of these very rare bone tumors. It explains how to recognize and diagnose each entity and it summarizes the medical scientific literature that is available on these cancers. Increasing awareness and clinical research for these cancers are key elements to improve the prognosis for patients with these diseases in the long term.

Abstract

Rare primary malignant bone sarcomas (RPMBS), other than osteosarcoma, chondrosarcoma, chordoma, and Ewing sarcoma, account for about 5–10% of primary bone tumors and represent a major diagnostic challenge. These tumors include spindle cell and round cell sarcoma entities, hemangiopericytoma-like and vascular tumors. Additionally, several histotypes, traditionally described in the soft tissues, such as myxofibrosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor of bone, have been reported in patients with primary bone tumors. While wide surgical resection is the mainstay of local treatment, systemic therapy of these rare entities is controversial. Patients with undifferentiated spindle cell or pleomorphic high-grade tumors of bone, are usually treated with osteosarcoma-like chemotherapy, while patients with round cell and undifferentiated round cell tumors (URCTs), may respond to sarcoma treatment regimens for Ewing sarcoma patients. Studies on analogies and differences among these ultra-rare tumors have seldom been reported. This review describes relevance, clinical aspects, diagnostic procedures, staging, treatment recommendations, and current research in this composite tumor group.

An Unusual Case of Synovial Sarcoma with Breast Metastasis: Findings on Positron Emission Tomography-Computed Tomography

Synovial sarcomas are aggressive soft-tissue tumors with the propensity for metastases at presentation or later course of disease. The most common site of metastases is lung, followed by lymph node and bone. It rarely metastasizes to the liver and to the brain. Breast metastases from extramammary tissue are extremely rare, more so from synovial sarcoma. ¹⁸F-fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET/CT) plays a very important role in diagnosing occult metastasis in sarcomas. Histopathological diagnosis and translocation studies are important to confirm the diagnosis. We present a case of synovial sarcoma who underwent ¹⁸FDG PET/CT which showed occult metastasis to the breast.

The Long-Term Outcomes of Intensive Combined Therapy of Adult Patients with Localised Synovial Sarcoma

Introduction: Synovial sarcoma (SaSy) is a high-grade, malignant soft tissue sarcoma (STS) accounting for 5–9% of STS. The aim of this study was to analyse outcomes of patients with localised SaSy treated in a single institution with a uniform neo- and adjuvant-combined therapy protocol. Methods: 171 patients with stage II/III SaSy were treated between 1997 and 2014. Chemotherapy consisted of 4 cycles of ifosfamide 12 g/m² and two cycles of a doxorubicin-based regimen 75 mg/m². With the exception of patients who underwent amputation, all patients received neoadjuvant radiotherapy. Results: Median age was 33 years (range 17–69). Tumours larger than 5 cm in size were found in 70% of patients. The 5-year overall survival (OS), local relapse-free survival (LRFS) and metastasis-free survival (MFS) rates were 75%, 80% and 60%, respectively. In multivariate Cox’s regression, age > 35 years, male sex, larger tumour size and histology other than monophasic were associated with worse OS. Conclusions: In adult patients with localised SaSy, long-term survival can be achieved in a significant proportion of cases with intensive combined therapy. The multivariate analysis identified age, sex, disease stage and histology subtype as independent prognostic factors of OS.

The survival and prognosis analysis of synovial sarcoma subtypes: a Surveillance, Epidemiology, and End Results population-based analysis

PURPOSE

By comparing epidemiologic and prognostic data of synovial sarcoma subtypes, this study aims to clarify the difference in prognosis and risk factors among different synovial sarcoma subtypes.

METHODS

In total, 1692 patients with synovial sarcoma in the USA who were diagnosed during 1975 through 2016 and retrieved from the Surveillance, Epidemiology, and End Results (SEER) program were studied.

RESULTS

There were statistically significant differences in the distribution of age and race among three synovial sarcoma subtypes, while no major differences in the distribution of sex, tumor stage, and tumour size were found. The highest five and ten year survival rates were found in the biphasic subtype (69%, 60%), followed by the monophasic subtype (59%, 49%), and lowest in the epithelioid subtype (32%, 26%). Age and SEER historic stage were the two demographic factors that found to have statistically significant impact on survival in all subtypes. Radiation was found to be protective in the monophasic subtype (HR 0.61, p < 0.001).

CONCLUSION

Among different synovial sarcoma subtypes, the biphasic subtype favoured the best survival, while the epithelioid cell subtype was associated with the worst. Male and black race were independently associated with worse survival only in the monophasic subtype. Radiotherapy could provide significant benefit for patients with the monophasic synovial sarcoma.