Effect of radiotherapy on local recurrence, distant metastasis and overall survival in 1200 extremity soft tissue sarcoma patients. Retrospective analysis using IPTW-adjusted models

BACKGROUND AND PURPOSE

Neoadjuvant (NRTX) and adjuvant radiotherapy (ARTX) reduce local recurrence (LR) risk in extremity soft tissue sarcoma (eSTS), yet their impact on distant metastasis (DM) and overall survival (OS) is less well defined. This study aimed at analysing the influence of NRTX/ARTX on all three endpoints using a retrospective, multicentre eSTS cohort.

MATERIALS AND METHODS

1200 patients (mean age: 60.7 ± 16.8 years; 44.4 % females) were retrospectively included, treated with limb sparing surgery and curative intent for localised, high grade (G2/3) eSTS. 194 (16.2 %), 790 (65.8 %), and 216 (18.0 %) patients had received NRTX, ARTX and no RTX, respectively. For the resulting three groups (no RTX vs. NRTX, no RTX vs. ARTX, NRTX vs. ARTX) Fine&Gray models for LR and DM, and Cox-regression models for OS were calculated, with IPTW-modelling adjusting for imbalances between groups.

RESULTS

In the IPTW-adjusted analysis, NRTX was associated with lower LR-risk in comparison to no RTX (SHR [subhazard ratio]: 0.236; p = 0.003), whilst no impact on DM-risk (p = 0.576) or OS (p = 1.000) was found. IPTW-weighted analysis for no RTX vs. ARTX revealed a significant positive association between ARTX and lower LR-risk (SHR: 0.479, p = 0.003), but again no impact on DM-risk (p = 0.363) or OS (p = 0.534). IPTW-weighted model for NRTX vs. ARTX showed significantly lower LR-risk for NRTX (SHR for ARTX: 3.433; p = 0.003) but no difference regarding DM-risk (p = 1.000) or OS (p = 0.639).

CONCLUSION

NRTX and ARTX are associated with lower LR-risk, but do not seem to affect DM-risk or OS. NRTX may be favoured over ARTX as our results indicate better local control rates.

Artificial Bone Graft Substitutes for Curettage of Benign and Low-Grade Malignant Bone Tumors: Clinical and Radiological Experience with Cerasorb

Background

Artificial bone graft substitutes (ABGS) for curettage of bone tumors are becoming increasingly popular. The aim of this retrospective analysis was to determine the efficacy of the ABGS Cerasorb (Curasan-AG, Kleinostheim, Germany), a beta-tricalcium phosphate (beta-TCP), concerning resorption profile, bone healing, and remodeling after surgery and to evaluate potential complications.

Methods

Forty-three patients suffering from benign and low-grade malignant bone tumors were treated with curettage and refilling of the bony cavity using the ABGS Cerasorb between 2018 and 2021 and included in the final analysis. Clinical follow-up exams with X-rays in two planes were performed 6 weeks, 3 months, 6 months, and 1 year after surgery.

Results

After a mean follow-up period of 14.6 months, radiological consolidation following curettage was observed in all patients. Total resorption was observed in 16.3% of patients; in the other 83.7%, resorption was partial. In four patients, of whom two had a tumor in the distal femur and two in the humeral diaphysis, fractures occurred within 6 weeks after primary surgery.

Conclusion

In conclusion, the beta-TCP Cerasorb seems to be a reliable bone graft substitute with low complication rates and is a suitable alternative to autologous bone grafts or allografts. Nonetheless, it shows a tendency of delayed resorption.

Level of Evidence

III; retrospective cohort study.

Datasets for reporting of soft-tissue sarcoma: recommendations from the International Collaboration on Cancer Reporting (ICCR)

AIMS

Soft-tissue tumours are rare and both accurate diagnosis and proper treatment represent a global challenge. Current treatment guidelines also recommend review by specialised pathologists. Here we report on international consensus-based datasets for the pathology reporting of biopsy and resection specimens of soft-tissue sarcomas. The datasets were produced under the auspices of the International Collaboration on Cancer Reporting (ICCR), a global alliance of international pathology and cancer organisations.

METHODS AND RESULTS

According to the ICCR's guidelines for dataset development, an international expert panel consisting of pathologists, a surgical oncologist, and a medical oncologist produced a set of core and noncore data items for biopsy and resection specimens based on a critical review and discussion of current evidence. All professionals involved were subspecialised soft-tissue sarcoma experts and affiliated with tertiary referral centres. Commentary was provided for each data item to explain the rationale for selecting it as a core or noncore element, its clinical relevance, and to highlight potential areas of disagreement or lack of evidence, in which case a consensus position was formulated. Following international public consultation, the documents were finalised and ratified, and the datasets, which included a synoptic reporting guide, were published on the ICCR website.

CONCLUSION

These first international datasets for soft-tissue sarcomas are aimed to promote high-quality, standardised pathology reporting. Their adoption will improve consistency of reporting, facilitate multidisciplinary communication, and enhance comparability of data, all of which will help to improve patient's management.

Targeting epigenetic features in clear cell sarcomas based on patient-derived cell lines

BACKGROUND

Clear cell sarcomas (CCSs) are translocated aggressive malignancies, most commonly affecting young adults with a high incidence of metastases and a poor prognosis. Research into the disease is more feasible when adequate models are available. By establishing CCS cell lines from a primary and metastatic lesion and isolating healthy fibroblasts from the same patient, the in vivo process is accurately reflected and aspects of clinical multistep carcinogenesis recapitulated.

METHODS

Isolated tumor cells and normal healthy skin fibroblasts from the same patient were compared in terms of growth behavior and morphological characteristics using light and electron microscopy. Tumorigenicity potential was determined by soft agar colony formation assay and in vivo xenograft applications. While genetic differences between the two lineages were examined by copy number alternation profiles, nuclear magnetic resonance spectroscopy determined arginine methylation as epigenetic features. Potential anti-tumor effects of a protein arginine N-methyltransferase type I (PRMT1) inhibitor were elicited in 2D and 3D cell culture experiments using cell viability and apoptosis assays. Statistical significance was calculated by one-way ANOVA and unpaired t-test.

RESULTS

The two established CCS cell lines named MUG Lucifer prim and MUG Lucifer met showed differences in morphology, genetic and epigenetic data, reflecting the respective original tissue. The detailed cell line characterization especially in regards to the epigenetic domain allows investigation of new innovative therapies. Based on the epigenetic data, a PRMT1 inhibitor was used to demonstrate the targeted antitumor effect; normal tissue cells isolated and immortalized from the same patient were not affected with the IC50 used.

CONCLUSIONS

MUG Lucifer prim, MUG Lucifer met and isolated and immortalized fibroblasts from the same patient represent an ideal in vitro model to explore the biology of CCS. Based on this cell culture model, novel therapies could be tested in the form of PRMT1 inhibitors, which drive tumor cells into apoptosis, but show no effect on fibroblasts, further supporting their potential as promising treatment options in the combat against CCS. The data substantiate the importance of tailored therapies in the advanced metastatic stage of CCS.

Implementation of Copy Number Variations-Based Diagnostics in Morphologically Challenging EWSR1/FUS::NFATC2 Neoplasms of the Bone and Soft Tissue

In the last decade, new tumor entities have been described, including EWSR1/FUS::NFATC2-rearranged neoplasms of different biologic behavior. To gain further insights into the behavior of these tumors, we analyzed a spectrum of EWSR1/FUS::NFATC2-rearranged neoplasms and discuss their key diagnostic and molecular features in relation to their prognosis. We report five patients with EWSR1/FUS::NFATC2-rearranged neoplasms, including one simple bone cyst (SBC), two complex cystic bone lesions lacking morphological characteristics of SBC, and two sarcomas. In three cases, fluorescence in situ hybridization (FISH) and in all cases copy number variation (CNV) profiling and fusion analyses were performed. All patients were male, three cystic lesions occurred in children (aged 10, 14, and 17 years), and two sarcomas in adults (69 and 39 years). Fusion analysis revealed two FUS::NFATC2 rearrangements in two cystic lesions and three EWSR1::NFATC2 rearrangements in one complex cystic lesion and two sarcomas. EWSR1 FISH revealed tumor cells with break-apart signal without amplification in one complex cystic lesion and EWSR1 amplification in both sarcomas was documented. CNV analysis showed simple karyotypes in all cystic lesions, while more complex karyotypes were found in NFATC2-rearranged sarcomas. Our study supports and expands previously reported molecular findings of EWSR1/FUS::NFATC2-rearranged neoplasms. The study highlights the importance of combining radiology and morphologic features with molecular aberrations. The use of additional molecular methods, such as CNV and FISH in the routine diagnostic workup, can be crucial in providing a correct diagnosis and avoiding overtreatment.

Genotyping of Circulating Free DNA Enables Monitoring of Tumor Dynamics in Synovial Sarcomas

Simple Summary

Synovial sarcomas (SS) are rare soft tissue tumors of mesenchymal origin. Following resection of the primary tumor, about one third to half of the patients suffer from recurrence. Detection of local and distant recurrence during follow-up is commonly accomplished by imaging. There are no biomarkers available for routine diagnostics. We employ a highly sensitive targeted next-generation sequencing approach to monitor tumor dynamics by genotyping of circulating free DNA (cfDNA) in SS patients. cfDNA which harbors tumor-specific mutations (circulating tumor-DNA; ctDNA) correlated with the presence of viable tumor tissue. This enables timely and non-invasive detection of tumor recurrence and monitoring of treatment response independent of the anatomic location.

Abstract

Background: Synovial sarcoma (SS) is a malignant soft tissue tumor of mesenchymal origin that frequently occurs in young adults. Translocation of the SYT gene on chromosome 18 to the SSX genes on chromosome X leads to the formation of oncogenic fusion genes, which lead to initiation and proliferation of tumor cells. The detection and quantification of circulating tumor DNA (ctDNA) can serve as a non-invasive method for diagnostics of local or distant tumor recurrence, which could improve survival rates due to early detection. Methods: We developed a subtype-specific targeted next-generation sequencing (NGS) approach specifically targeting SS t(X;18)(p11;q11), which fuses SS18 (SYT) in chromosome 18 to SSX1 or SSX2 in chromosome x, and recurrent point mutations. In addition, patient-specific panels were designed from tumor exome sequencing. Both approaches were used to quantify ctDNA in patients’ plasma. Results: The subtype-specific assay allowed detection of somatic mutations from 25/25 tumors with a mean of 1.68 targetable mutations. The minimal limit of detection was determined at a variant allele frequency of 0.05%. Analysis of 29 plasma samples from 15 tumor patients identified breakpoint ctDNA in 6 patients (sensitivity: 40%, specificity 100%). The addition of more mutations further increased assay sensitivity. Quantification of ctDNA in plasma samples (n = 11) from one patient collected over 3 years, with a patient-specific panel based on tumor exome sequencing, correlated with the clinical course, response to treatment and tumor volume. Conclusions: Targeted NGS allows for highly sensitive tumor profiling and non-invasive detection of ctDNA in SS patients, enabling non-invasive monitoring of tumor dynamics.

Clinical implementation of plasma cell-free circulating tumor DNA quantification by digital droplet PCR for the monitoring of Ewing sarcoma in children and adolescents

BACKGROUND

Treatment stratification and response assessment in pediatric sarcomas has relied on imaging studies and surgical/histopathological evidence of vital tumor cells. Such studies and evidence collection processes often involve radiation and/or general anesthesia in children. Cell-free circulating tumor DNA (ctDNA) detection in blood plasma is one available method of so-called liquid biopsies that has been shown to correlate qualitatively and quantitatively with the existence of vital tumor cells in the body. Our clinical observational study focused on the utility and feasibility of ctDNA detection in pediatric Ewing sarcoma (EWS) as a marker of minimal residual disease (MRD).

PATIENTS AND METHODS

We performed whole genome sequencing (WGS) to identify the exact breakpoints in tumors known to carry the EWS-FLI1 fusion gene. Patient-specific fusion breakpoints were tracked in peripheral blood plasma using digital droplet PCR (ddPCR) before, during, and after therapy in six children and young adults with EWS. Presence and levels of fusion breakpoints were correlated with clinical disease courses.

RESULTS

We show that the detection of ctDNA in the peripheral blood of EWS patients (i) is feasible in the clinical routine and (ii) allows for the longitudinal real-time monitoring of MRD activity in children and young adults. Although changing ctDNA levels correlated well with clinical outcome within patients, between patients, a high variability was observed (inter-individually).

CONCLUSION

ctDNA detection by ddPCR is a highly sensitive, specific, feasible, and highly accurate method that can be applied in EWS for follow-up assessments as an additional surrogate parameter for clinical MRD monitoring and, potentially, also for treatment stratification in the near future.

The clinicopathologic spectrum and genomic landscape of de-/trans-differentiated melanoma

Dedifferentiation and transdifferentiation are rare and only poorly understood phenomena in cutaneous melanoma. To study this disease more comprehensively we have retrieved 11 primary cutaneous melanomas from our pathology archives showing biphasic features characterized by a conventional melanoma and additional areas of de-/trans-differentiation as defined by a lack of immunohistochemical expression of all conventional melanocytic markers (S-100 protein, SOX10, Melan-A, and HMB-45). The clinical, histologic, and immunohistochemical findings were recorded and follow-up was obtained. The patients were mostly elderly (median: 81 years; range: 42-86 years) without significant gender predilection, and the sun-exposed skin of the head and neck area was most commonly affected. The tumors were deeply invasive with a mean depth of 7 mm (range: 4-80 mm). The dedifferentiated component showed atypical fibroxanthoma-like features in the majority of cases (7), while additional rhabdomyosarcomatous and epithelial transdifferentiation was noted histologically and/or immunohistochemically in two tumors each. The background conventional melanoma component was of desmoplastic (4), superficial spreading (3), nodular (2), lentigo maligna (1), or spindle cell (1) types. For the seven patients with available follow-up data (median follow-up period of 25 months; range: 8-36 months), two died from their disease, and three developed metastases. Next-generation sequencing of the cohort revealed somatic mutations of established melanoma drivers including mainly NF1 mutations (5) in the conventional component, which was also detected in the corresponding de-/trans-differentiated component. In summary, the diagnosis of primary cutaneous de-/trans-differentiated melanoma is challenging and depends on the morphologic identification of conventional melanoma. Molecular analysis is diagnostically helpful as the mutated gene profile is shared between the conventional and de-/trans-differentiated components. Importantly, de-/trans-differentiation does not appear to confer a more aggressive behavior.

Drug combination screening as a translational approach toward an improved drug therapy for chordoma

Purpose

Drug screening programmes have revealed epidermal growth factor receptor inhibitors (EGFR_is) as promising therapeutics for chordoma, an orphan malignant bone tumour, in the absence of a known genetic driver. Concurrently, the irreversible EGFR_i afatinib (Giotrif®) is being evaluated in a multicentric Phase II trial. As tyrosine kinase inhibitor (TKI) monotherapies are invariably followed by resistance, we aimed to evaluate potential therapeutic combinations with EGFR_is.

Methods

We screened 133 clinically approved anticancer drugs as single agents and in combination with two EGFR_is (afatinib and erlotinib) in the clival chordoma cell line UM-Chor1. Synergistic combinations were analysed in a 7 × 7 matrix format. The most promising combination was further explored in clival (UM-Chor1, MUG-CC1) and sacral (MUG-Chor1, U-CH1) chordoma cell lines. Secretomes were analysed for receptor tyrosine kinase ligands (EGF, TGF-α, FGF-2 and VEGF-A) upon drug treatment.

Results

Drugs that were active as single agents (n = 45) included TKIs, HDAC and proteasome inhibitors, and cytostatic drugs. Six combinations were analysed in a matrix format: n = 4 resulted in a significantly increased cell killing (crizotinib, dabrafenib, panobinostat and doxorubicin), and n = 2 exhibited no or negligible effects (regorafenib, venetoclax). Clival chordoma cell lines were more responsive to combined EGFR-MET inhibition. EGFR-MET cross-talk (e.g. via TGF-α secretion) likely accounts for the synergistic effects of EGFR-MET inhibition.

Conclusion

Our screen revealed promising combinations with EGFR_is, such as the ALK/MET-inhibitor crizotinib, the HDAC-inhibitor panobinostat or the topoisomerase-II-inhibitor doxorubicin, which are part of standard chemotherapy regimens for various bone and soft-tissue sarcomas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-021-00632-x.

T-regulatory cells predict clinical outcome in soft tissue sarcoma patients: a clinico-pathological study

BACKGROUND

Soft tissue sarcomas (STS) are generally considered non-immunogenic, although specific subtypes respond to immunotherapy. Antitumour response within the tumour microenvironment relies on a balance between inhibitory and activating signals for tumour-infiltrating lymphocytes (TILs). This study analysed TILs and immune checkpoint molecules in STS, and assessed their prognostic impact regarding local recurrence (LR), distant metastasis (DM), and overall survival (OS).

METHODS

One-hundred and ninety-two surgically treated STS patients (median age: 63.5 years; 103 males [53.6%]) were retrospectively included. Tissue microarrays were constructed, immunohistochemistry for PD-1, PD-L1, FOXP3, CD3, CD4, and CD8 performed, and staining assessed with multispectral imaging. TIL phenotype abundance and immune checkpoint markers were correlated with clinical and outcome parameters (LR, DM, and OS).

RESULTS

Significant differences between histology and all immune checkpoint markers except for FOXP3+ and CD3-PD-L1+ cell subpopulations were found. Higher levels of PD-L1, PD-1, and any TIL phenotype were found in myxofibrosarcoma as compared to leiomyosarcoma (all p < 0.05). The presence of regulatory T cells (Tregs) was associated with increased LR risk (p = 0.006), irrespective of margins. Other TILs or immune checkpoint markers had no significant impact on outcome parameters.

CONCLUSIONS

TIL and immune checkpoint marker levels are most abundant in myxofibrosarcoma. High Treg levels are independently associated with increased LR risk, irrespective of margins.

Molecular profiling of soft-tissue sarcomas with FoundationOne® Heme identifies potential targets for sarcoma therapy: a single-centre experience

Background:

Molecular diagnosis has become an established tool in the characterisation of adult soft-tissue sarcomas (STS). FoundationOne^® Heme analyses somatic gene alterations in sarcomas via DNA and RNA-hotspot sequencing of tumour-associated genes.

Methods:

We evaluated FoundationOne^® Heme testing in 81 localised STS including 35 translocation-associated and 46 complex-karyotyped cases from a single institution.

Results:

Although FoundationOne^® Heme achieved broad patient coverage and identified at least five genetic alterations in each sample, the sensitivity for fusion detection was rather low, at 42.4%. Nevertheless, potential targets for STS treatment were detected using the FoundationOne^® Heme assay: complex-karyotyped sarcomas frequently displayed copy-number alterations of common tumour-suppressor genes, particularly deletions in TP53, NF1, ATRX, and CDKN2A. A subset of myxofibrosarcomas (MFS) was amplified for HGF (n = 3) and MET (n = 1). PIK3CA was mutated in 7/15 cases of myxoid liposarcoma (MLS; 46.7%). Epigenetic regulators (e.g. MLL2 and MLL3) were frequently mutated.

Conclusions:

In summary, FoundationOne^® Heme detected a broad range of genetic alterations and potential therapeutic targets in STS (e.g. HGF/MET in a subset of MFS, or PIK3CA in MLS). The assay’s sensitivity for fusion detection was low in our sample and needs to be re-evaluated in a larger cohort.

Quantification of increased MUC5AC expression in airway mucus of smoker using an automated image-based approach

Microscopic analysis of mucus quantity and composition is crucial in research and diagnostics on muco-obstructive diseases. Currently used image-based methods are unable to extract concrete numeric values of mucosal proteins, especially on the expression of the key mucosal proteins MUC5AC and MUC5B. Since their levels increase under pathologic conditions such as extensive exposure to cigarette smoke, it is imperative to quantify them to improve treatment strategies of pulmonary diseases. This study presents a simple, image-based, and high-processing computational method that allows determining the ratio of MUC5AC and MUC5B within the overall airway mucus while providing information on their spatial distribution. The presented pipeline was optimized for automated downstream analysis using a combination of bright field and immunofluorescence imaging suitable for tracheal and bronchial tissue samples, and air-liquid interface (ALI) cell cultures. To validate our approach, we compared tracheal tissue and ALI cell cultures of isolated primary normal human bronchial epithelial cells derived from smokers and nonsmokers. Our data indicated 18-fold higher levels of MUC5AC in submucosal glands of smokers covering about 8% of mucosal areas compared to <1% in nonsmoking individuals, confirming results of previous studies. We further identified a subpopulation of nonsmokers with slightly elevated glandular MUC5AC levels suggesting moderate exposure to second-hand smoke or fine particulate air pollution. Overall, this study demonstrates a novel, user-friendly and freely available tool for digital pathology and the analysis of therapeutic interventions tested in ALI cell cultures.

YAP1-TFE3 gene fusion variant in clear cell stromal tumour of lung: report of two cases in support of a distinct entity

AIMS

Clear cell (haemangioblastoma-like) stromal tumour of the lung is a newly described, rare pulmonary neoplasm. Recurrent YAP1-TFE3 gene fusions have recently been reported in three cases. We describe two additional cases and confirm the characteristic YAP1-TFE3 gene fusion.

METHODS AND RESULTS

Two mesenchymal tumours of lung were identified from our soft tissue pathology consultation services and RNA sequencing was performed. Both cases were in male patients, aged 35 and 77 years. Both presented as solitary lung nodules measuring 3.9 and 7.5 cm in greatest dimension. Histopathologically, the tumours were composed of epithelioid to plump spindle cells arranged in packets and solid sheets. The cells showed fusiform to ovoid nuclei with open chromatin, variably prominent nucleoli and scant to moderate, clear to eosinophilic cytoplasm. Cytological atypia and significant mitotic activity were minimal. None of the tumours expressed lineage-specific immunophenotypical markers. Both cases were diffusely positive for nuclear TFE3. Unlike YAP1-TFE3-fused epithelioid haemangioendothelioma, for which the fusion breakpoint occurs in YAP1 exon 1 and TFE3 exons 4 or 6, the fusion breakpoints of these tumours were located in YAP1 exon 4 and TFE3 exon 7. Following complete surgical resection, neither of the tumours has recurred or metastasised (follow-up period 6-7 months).

CONCLUSIONS

We validate the presence of YAP1-TFE3 gene fusion in a unique primary mesenchymal tumour of lung, adding additional support for clear cell stromal tumour of the lung as a distinct entity.

Applicability of pan-TRK immunohistochemistry for identification of NTRK fusions in lung carcinoma

In the last two decades, various therapies have been introduced for lung carcinoma patients, including tyrosine-kinase inhibitors for different mutations. While some of them are specific to specific tumor types, others, like NTRK1-3 fusions, are found in various solid tumors. The occurrence of an NTRK1,2 or 3 fusion acts as a biomarker for efficient treatment with NTRK inhibitors, irrespectively of the tumor type. However, the occurrence of the NTRK1-3 fusions in lung carcinomas is extremely rare. We performed a retrospective analysis to evaluate the applicability of immunohistochemistry with the pan-TRK antibody in the detection of NTRK fusions in lung carcinomas. The study cohort included 176 adenocarcinomas (AC), 161 squamous cell carcinomas (SCC), 31 large-cell neuroendocrine carcinomas (LCNEC), and 19 small cell lung carcinomas (SCLC). Immunohistochemistry (IHC) was performed using the pan-TRK antibody (clone EPR17341, Ventana) on tissue microarrays, while confirmation for all positive cases was done using RNA-based Archer FusionPlex MUG Lung Panel. On IHC staining, 12/387 samples (3.1%) demonstrated a positive reaction. Ten SCC cases (10/161, 6.2%), and two LCNEC cases (2/31, 6.5%) were positive. Positive cases demonstrated heterogeneous staining of tumor cells, mostly membranous with some cytoplasmic and in one case nuclear pattern. RNA-based sequencing did not demonstrate any NTRK1-3 fusion in our patients' collective. Our study demonstrates that pan-TRK expression in lung carcinoma is very low across different histologic types. NTRK1-3 fusions using an RNA-based sequencing approached could not be detected. This stresses the importance of confirmation of immunohistochemistry results by molecular methods.

Comparison of the 7th and 8th version of the AJCC classification system for soft tissue sarcomas of extremities and trunk in patients with localised, intermediate or high-grade disease treated at European tertiary sarcoma centres

BACKGROUND

The updated 8th version of the AJCC-staging system for soft tissue sarcomas (STS) has been criticised for omitting tumour depth as category-defining variable and eventually not improving prognostic accuracy in comparison to the 7th version. This study aimed at investigating the prognostic accuracy of both AJCC-versions in STS-patients treated at European tertiary sarcoma centres.

METHODS

1032 patients (mean age: 60.7 ± 16.3 years; 46.0% [n = 475] females; median follow-up: 38.6 months), treated at five tertiary sarcoma centres for localised, intermediate or high-grade STS of extremities and trunk were retrospectively included. Uni- and multivariate Cox-regression models and Harrell's C-indices were calculated to analyse prognostic factors for overall survival (OS) and assess prognostic accuracy.

RESULTS

In univariate analysis, prognostic accuracy for OS was comparable for both AJCC-versions (C-index: 0.620 [8th] vs. 0.614 [7th]). By adding margins, age, gender, and histology to the multivariate models, prognostic accuracy of both versions could be likewise improved (C-index: 0.714 [8th] vs. 0.705 [7th]). Moreover, tumour depth did not significantly contribute to prognostic accuracy of the 8th version's multivariate model (C-index for both models: 0.714). Stratification into four main T-stages based on tumour size only, as implemented in the 8th version, significantly improved prognostic accuracy between each category. However, T-stages as defined in the 7th version had poorer discriminatory power (C-index: 0.625 [8th] vs. 0.582 [7th]).

CONCLUSION

Both AJCC-versions perform equally well regarding prognostic accuracy. Yet, simplification of the 8 ^th version by omitting tumour depth as T-stage-defining parameter, whilst emphasizing the importance of tumour size, should be considered advantageous.

Influence of tumor-infiltrating immune cells on local control rate, distant metastasis, and survival in patients with soft tissue sarcoma

Soft tissue sarcomas (STS) are considered non-immunogenic, although distinct entities respond to anti-tumor agents targeting the tumor microenvironment. This study’s aims were to investigate relationships between tumor-infiltrating immune cells and patient/tumor-related factors, and assess their prognostic value for local recurrence (LR), distant metastasis (DM), and overall survival (OS).

One-hundred-eighty-eight STS-patients (87 females [46.3%]; median age: 62.5 years) were retrospectively analyzed. Tissue microarrays (in total 1266 cores) were stained with multiplex immunohistochemistry and analyzed with multispectral imaging. Seven cell types were differentiated depending on marker profiles (CD3+, CD3+ CD4+ helper, CD3+ CD8+ cytotoxic, CD3+ CD4+ CD45RO+ helper memory, CD3+ CD8+ CD45RO+ cytotoxic memory T-cells; CD20 + B-cells; CD68+ macrophages). Correlations between phenotype abundance and variables were analyzed. Uni- and multivariate Fine&Gray and Cox-regression models were constructed to investigate prognostic variables. Model calibration was assessed with C-index. IHC-findings were validated with TCGA-SARC gene expression data of genes specific for macrophages, T- and B-cells.

B-cell percentage was lower in patients older than 62.5 years (p = .013), whilst macrophage percentage was higher (p = .002). High B-cell (p = .035) and macrophage levels (p = .003) were associated with increased LR-risk in the univariate analysis. In the multivariate setting, high macrophage levels (p = .014) were associated with increased LR-risk, irrespective of margins, age, gender or B-cells. Other immune cells were not associated with outcome events.

High macrophage levels were a poor prognostic factor for LR, irrespective of margins, B-cells, gender and age. Thus, anti-tumor, macrophage-targeting agents may be applied more frequently in tumors with enhanced macrophage infiltration.

Update on Molecular Genetics of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The majority are sporadic, solitary tumors that harbor mutually exclusive KIT or PDGFRA gain-of-function mutations. The type of mutation in addition to risk stratification corresponds to the biological behavior of GIST and response to treatment. Up to 85% of pediatric GISTs and 10–15% of adult GISTs are devoid of these (KIT/PDGFRA) mutations and are referred to as wild-type GISTs (wt-GIST). It has been shown that these wt-GISTs are a heterogeneous tumor group with regard to their clinical behavior and molecular profile. Recent advances in molecular pathology helped to further sub-classify the so-called “wt-GISTs”. Based on their significant clinical and molecular heterogeneity, wt-GISTs are divided into a syndromic and a non-syndromic (sporadic) subgroup. Recently, the use of succinate dehydrogenase B (SDHB) by immunohistochemistry has been used to stratify GIST into an SDHB-retained and an SDHB-deficient group. In this review, we focus on GIST sub-classification based on clinicopathologic, and molecular findings and discuss the known and yet emerging prognostic and predictive genetic alterations. We also give insights into the limitations of targeted therapy and highlight the mechanisms of secondary resistance.

Interdisciplinary Radical "En-Bloc" Resection of Ewing Sarcoma of the Chest Wall and Simultaneous Chest Wall Repair Achieves Excellent Long-Term Survival in Children and Adolescents

Introduction: Ewing sarcomas of the chest wall, historically known as "Askin tumors" represent highly aggressive pediatric malignancies with a reported 5-year survival ranging only between 40 and 60% in most studies. Multimodal oncological treatment according to specific Ewing sarcoma protocols and radical "en-bloc" resection with simultaneous chest wall repair are key factors for long-term survival. However, the surgical complexity depends on tumor location and volume and potential infiltrations into lung, pericardium, diaphragm, esophagus, spine and major vessels. Thus, the question arises, which surgical specialties should join their comprehensive skills when approaching a child with Ewing sarcoma of the chest wall. Patients and Methods: All pediatric patients with Ewing sarcomas of the chest wall treated between 1990 and 2020 were analyzed focusing on complete resection, chest wall reconstruction, surgical complications according to Clavien-Dindo (CD) and survival. Patients received neo-adjuvant chemotherapy according to the respective Ewing sarcoma protocols. Depending on tumor location and organ infiltration, a multi-disciplinary surgical team was orchestrated to perform radical en-bloc resection and simultaneous chest wall repair. Results: Thirteen consecutive patients (seven boys and six girls) were included. Median age at presentation was 10.9 years (range 2.2-21 years). Neo-adjuvant chemotherapy (n = 13) and irradiation (n = 3) achieved significant reduction of the median tumor volume (305.6 vs. 44 ml, p < 0.05). En-bloc resection and simultaneous chest wall reconstruction was achieved without major complications despite multi-organ involvement. Postoperatively, one patient with infiltration of the costovertebral joint and laminectomy required surgical re-intervention (CD IIIb). 11/13 patients were treated with clear resections margins (R1 resection in one patient with infiltration of the costovertebral joint and marginal resection <1 mm in one child with multiple pulmonary metastases). All patients underwent postoperative chemotherapy; irradiation was performed in four children. Two deaths occurred 18 months and 7.5 years after diagnosis, respectively. Median follow-up for the remaining patients was 8.8 years (range: 0.9-30.7 years). The 5-year survival rate was 89% and the overall survival 85%. Conclusion: EWING specific oncological treatment and multi-disciplinary surgery performing radical en-bloc resections and simultaneous chest wall repair contribute to an improved survival of children with Ewing sarcoma of the chest wall.

Assessing Prognostic and Predictive Biomarkers of Regorafenib Response in Patients with Advanced Soft Tissue Sarcoma: REGOSARC Study

: Regorafenib significantly prolonged progression-free survival (PFS) in pretreated patients with advanced non-adipocytic sarcoma (HR = 0.46; p < 0.001) in a placebo-controlled, randomized, phase-II trial (NCT01900743). Thus, here, we assessed the prevalence of 57 biomarkers and their prognostic and predictive values for PFS and overall survival (OS). We analyzed 134/182 patients included in this trial, treated with regorafenib (n = 71, 53%) or placebo (n = 63, 47%). Mutational analyses were performed via full coding sequence analysis for 10 genes, and mutation hotspot panel for 50 genes (four genes in common). H19 was studied with RNA in-situ hybridization. The prognostic and predictive biomarkers' values were studied only for biomarkers found positive/mutated in at least 10 patients. Overall, 25 out of 57 studied biomarkers, including five out of seven genes involved in angiogenesis, were found mutated/positive in at least one patient, of which 23 biomarkers had low prevalence (fewer than eight out of 134 patients), contrasting with H19 (n = 24, 18%), and TP53 (n = 35, 26%). However, in multivariable models of PFS and OS, including treatment effects and interactions, no significant prognostic or predictive values of the tested biomarkers were observed. Though several promising biomarkers were found to be positive/mutated, none of them were identified as viable predictive and prognostic biomarkers.

Bone marrow aspirations in Ewing sarcomas: Are they still necessary? A single-center retrospective analysis and review of the literature

Background and Objectives

Currently, one of the most useful prognostic indicators in Ewing sarcomas (ES) is the presence of metastatic disease at diagnosis. According to various clinical guidelines, the assessment of bone marrow (BM) metastases, using light microscopy examination of bone marrow aspirates and biopsies (BMAB) is mandatory. However, the prognostic value of BM positivity is discussed controversially. Therefore, the primary aim of this study was to retrospectively review BM samples from patients with ES.

Materials and Methods

This retrospective single centre study included 31 patients that were newly diagnosed with ES between 2000 and 2014. Twenty-seven patients had skeletal ES and in 4 patients the tumour was localized in the soft tissue only. Metastases at diagnosis were present in 5 out of 31 patients. BM samples were morphologically and immunohistochemically searched and screened for the presence or absence of BM metastases. Furthermore, in 15 of the 31 patients BM samples were still available and were reanalysed, using nested-polymerase chain reaction.

Results

All BM samples of our 31 ES patients, including the 5 metastatic patients, were, morphologically and immunohistochemically tested negative for tumour cell appearance. The nested-PCR results were also negative in all of our 15 retested patients, including two patients with metastatic disease.

Conclusions

Based on our results and on the contradictory results reported in the literature we recommend a re-evaluation of the necessity and the prognostic value of BMAB in the initial staging process of newly diagnosed ES patients.

Tumor-associated mortality and prognostic factors in myxofibrosarcoma - A retrospective review of 109 patients

BACKGROUND

Myxofibrosarcoma (MFS) is one of the most common sarcoma subtype in elderly patients. They are reported to recur locally independently of the tumour grade in 30-40% of cases and metastases are reported to develop in high-grade tumours in 20-35% cases. As MFS is a rare diagnosis, data investigating specific survival and independent risk factors are lacking and have mostly been limited to single orthopaedic oncology centre studies so far. Thus we set up a pathology-based retrospective study and analyzed all MFS diagnosed in our institution with the following aims: (1) analysis of independent risk factors for overall survival, disease specific survival, local recurrence-free survival and distant metastasis free survival following resection of MFS; (2) analysis of resection margin status.

HYPOTHESIS

High-grade MFS have a low survival distant metastasis free survival and local recurrence free survival is dependent on surgical margin status.

PATIENTS AND METHODS

We retrospectively analysed 109 patients (median 66 years [range, 21-96]) diagnosed with MFS and a median follow-up of 42 months at one centre between 1990 and 2014. Tumor-associated survival, including competing risk analysis, and prognostic factors for local recurrence, metastatic disease and death from disease were investigated and included in a multivariate analysis.

RESULTS

Overall survival was 79% [95%CI: 71.9-87.5] at 3 years and 76% [95%CI: 67.4-84.6] at 5 years. Disease specific survival was 85% [95%CI: 78.4-92.2] at 3 years and 80% [95%CI: 72.2-88.2] at 5 years. There were local recurrences in 11/109 patients (10%). Local recurrence free survival (LRFS) was 95% [95%CI: 92.0-99.8] at 3 and 88% [95%CI: 84.3-96.4] at 5 years. Metastatic disease (n=25; 23%) occurred after a median follow-up of 10 months. Distant metastasis free survival was 78% [95%CI: 69.9-85.9] at 3 and 77% [95%CI: 68.4-84.8] at 5 years. R1 status at primary resection was an independent risk factor for decreased Local Recurrence-free survival (OR: 8.5, 95%CI: 1.59-49.79 [p=0.01]). Grading was an independent risk factor for decreased Disease specific survival (OR 13.4, 95%CI: 1.65-1734.84 [p=0.01]) and Distant metastasis free survival (OR 16.2, 95%CI: 2.0-2110.5 [p=0.004]). Primary resection achieved R0 margins in 63 (58%) of 109 patients. Margins were adequate significantly more often (p<0.001) in patients treated primarily at a sarcoma centre (R0=58/68, 85%) than in those treated primarily at non-sarcoma centres (R0= 5/41, 12%), whereby the latter significantly more often treated superficial tumours (p=0.001) with a size of less than 5cm (p<0.001).

DISCUSSION

Patients with high-grade MFS had a poorer prognosis with respect to Disease specific survival/Distant metastasis free survival than low-grade MFS. Local recurrence did not significantly affect disease specific survival.

LEVEL OF EVIDENCE

IV.

β,β-Dimethylacrylshikonin Induces Apoptosis in Melanoma Cell Lines by NOXA Upregulation

Melanoma is the most aggressive form of skin cancer, with high metastasis rates and poor prognosis. Survival rates and possible therapies depend on the state of the tumor and its mutational profile. BRAF and NRAS are the most frequent driver mutations. Currently, there is no efficient therapy for NRAS-mutated or late-stage melanoma. In this study, the therapeutic potential of β,β-dimethylacrylshikonin (DMAS) was investigated on melanoma. The influence of DMAS was determined in five different melanoma cell lines with different mutational profiles. The effects of this compound on cell viability, apoptosis, and gene and protein expression were examined. The results obtained were validated in vivo. DMAS significantly reduced the viability of several melanoma cell lines in a concentration- and time-dependent manner. Furthermore, DMAS induced caspase-3-dependent apoptosis via NOXA upregulation, as confirmed by NOXA knockdown experiments. This is the first time that NOXA-dependent apoptosis was shown with respect to a shikonin derivative and melanoma. Additionally, tumor regression and necrosis under DMAS treatment were demonstrated in vivo. Importantly, BRAF as well as NRAS-mutated metastatic human melanoma cell lines were treated successfully in vitro and in vivo. Taken together, DMAS showed promising results and is worthy of further study.

Intraarticular Nodular Fasciitis of the Knee With MHY9-USP6 Fusion: A Case Report

Background. Nodular fasciitis (NF) is a self-limiting, benign mesenchymal neoplasm of fibroblastic/myofibroblastic origin. Due to the fast growth, cellularity, and frequently observed high mitotic count, it is commonly misdiagnosed as a sarcoma, often resulting in overtreatment. Intraarticular examples of NF are extremely rare. Radiologically, NF can mimic fibroma of the tendon sheath, tenosynovial giant cell tumor, and synovial chondromatosis. Histology can vary from hypercellular, mitotically active lesions to fibrotic, less cellular ones, and can, therefore, mimic other benign and low-grade malignant neoplasms. Recently, the MYH9-USP6 fusion has been found in up to 92% of NF. Case Presentation. In this article, we report a case of a 38-year-old patient with an intraarticular lesion, radiologically suspicious of tenosynovial giant cell tumor. Histology demonstrated a spindle cell lesion composed of fibroblasts/myofibroblasts embedded in a highly collagenous/hyalinized stroma, partly arranged in short fascicles. Extravasated erythrocytes and rare mitotic figures were present. Immunohistochemically, tumor cells expressed smooth muscle actin and were negative for desmin, β-catenin, CD34, and SOX10. These findings rendered the diagnosis of NF. Molecular analysis using next-generation sequencing (Archer FusionPlex Sarcoma Panel) revealed gene rearrangement involving USP6 and MYH9 supporting the diagnosis of NF in the knee joint. Conclusions. Radiological and histological features of NF can overlap with other benign and low-grade malignant lesion. Identification of the USP6 gene rearrangements or finding of the MYH9-USP6 fusion, especially in core needle biopsies and in the lesions occurring at unusual sites, can result in adequate therapeutic approach avoiding overtreatment.

Incidence, treatment and outcome of abdominal metastases in extremity soft tissue sarcoma: Results from a multi-centre study

Background and Objectives

Abdominal metastases (AM) from soft tissue sarcoma (STS) are rare and prognosis is poor. The aims of the study were to (a) identify risk factors for the development of AM and to (b) investigate the outcome of AM‐patients.

Methods

Seven‐hundred‐sixty‐nine STS‐patients with localised disease at diagnosis treated at three tumour centres (2000‐2016) were retrospectively included (409 males; mean age, 55.6 years [range, 8‐96 years]; median follow‐up, 4.1 years [interquartile‐range, 2.5‐6.6 years]).

Results

Two‐hundred‐two patients (26.3%) developed secondary metastases, and 24 of them AM (3.1%). Ten patients developed first AM (FAM) after a mean of 2.4 years and 14 patients late AM (LAM, after being diagnosed with metastases to other sites) after a mean of 2.0 years. Patients with liposarcoma had a significantly higher risk of developing AM (P = .007), irrespective of grading. There was no difference in post‐metastasis‐survival (PMS) between patients with AM at any time point and those with metastases to other sites (P = .585). Patients with LAM or FAM showed no difference in post‐abdominal‐metastasis‐survival (P = .884).

Conclusions

Survival in patients with AM is poor, irrespective of whether they develop secondarily to other metastases or not. Patients at high‐risk of AM (ie, liposarcoma) may be followed‐up regularly by abdominal‐ultrasound/CT.

Individualizing Follow-Up Strategies in High-Grade Soft Tissue Sarcoma with Flexible Parametric Competing Risk Regression Models

Currently, patients with extremity soft tissue sarcoma (eSTS) who have undergone curative resection are followed up by a heuristic approach, not covering individual patient risks. The aim of this study was to develop two flexible parametric competing risk regression models (FPCRRMs) for local recurrence (LR) and distant metastasis (DM), aiming at providing guidance on how to individually follow-up patients. Three thousand sixteen patients (1931 test, 1085 validation cohort) with high-grade eSTS were included in this retrospective, multicenter study. Histology (9 categories), grading (time-varying covariate), gender, age, tumor size, margins, (neo)adjuvant radiotherapy (RTX), and neoadjuvant chemotherapy (CTX) were used in the FPCRRMs and performance tested with Harrell-C-index. Median follow-up was 50 months (interquartile range: 23.3–95 months). Two hundred forty-two (12.5%) and 603 (31.2%) of test cohort patients developed LR and DM. Factors significantly associated with LR were gender, size, histology, neo- and adjuvant RTX, and margins. Parameters associated with DM were margins, grading, gender, size, histology, and neoadjuvant RTX. C-statistics was computed for internal (C-index for LR: 0.705, for DM: 0.723) and external cohort (C-index for LR: 0.683, for DM: 0.772). Depending on clinical, pathological, and patient-related parameters, LR- and DM-risks vary. With the present model, implemented in the updated Personalised Sarcoma Care (PERSARC)-app, more individualized prediction of LR/DM-risks is made possible.

Undifferentiated round cell sarcomas with CIC-DUX4 gene fusion: expanding the clinical spectrum

Round cell sarcomas are a heterogeneous group of mesenchymal neoplasms with overlapping morphology and immunohistochemical profile. Ewing sarcoma is the most well-known tumour in this group characterised by EWSR1/FUS rearrangements with members of the ETS family of transcription factors. Undifferentiated round cell sarcomas lacking these rearrangements, known as 'Ewing-like' sarcomas, usually show atypical clinical presentation and focal CD99 positivity. This group of tumours can be subdivided into: capicua transcriptional repressor (CIC)-rearranged sarcomas, Bcl6 corepressor (BCOR)-rearranged sarcomas, sarcomas with EWSR1 fusion to non-ETS family members and unclassified round cell sarcomas. We describe seven new cases of CIC-DUX4 rearranged sarcomas with their clinicopathological features, two of which presented in unusual locations (skin and lymph node). Patient age ranged between 23 and 54 years, three of whom were female. In five cases, aggressive behaviour was observed with rapid disease progression and lethal outcome within 15 months. One patient achieved a complete response after chemotherapy. The last patient whose tumour was located purely in the dermis demonstrated no residual tumour in the re-resection specimen, was not given any further treatment and showed no sign of disease after 24 months. Immunohistochemically, tumour cells in all cases showed focal membranous CD99 positivity, while WT1 N-/C-terminus were positive in all 5/5 cases (nuclear and/or cytoplasmic). NGS analysis revealed a CIC-DUX4 fusion in all cases. This study expands the spectrum of anatomical locations of CIC-DUX4 rearranged sarcomas, highlighting the inclusion of this rare entity in the differential diagnosis of undifferentiated tumours in various anatomical locations outside of soft tissues.

High-resolution large-area imaging of nanoscale structure and mineralization of a sclerosing osteosarcoma in human bone

Osteosarcoma is the most common primary bone cancer type in humans. It is predominantly found in young individuals, with a second peak later in life. The tumour is formed by malignant osteoblasts and consists of collagenous, sometimes also mineralized, bone matrix. While the morphology of osteosarcoma has been well studied, there is virtually no information about the nanostructure of the tumour and changes in mineralization on the nanoscale level. In the present paper, human bone tissue inside, next to and remote from a sclerosing osteosarcoma was studied with small angle x-ray scattering, x-ray diffraction and electron microscopy. Quantitative evaluation of nanostructure parameters was combined with high resolution, large area mapping to obtain microscopic images with nanostructure parameter contrast. It was found that the tumour regions were characterized by a notable reduction in mineral particle size, while the mineral content was even higher than that in normal bone. Furthermore, the normal preferential orientation of mineral particles along the longitudinal direction of corticalis or trabeculae was largely suppressed. Also the bone mineral crystal structure was affected: severe crystal lattice distortions were detected in mineralized tumour tissue pointing to a different ion substitution of hydroxyl apatite in tumorous tissue than in healthy tissue.

KIT mutation in a naïve succinate dehydrogenase-deficient gastric GIST

Up to 85% of gastrointestinal stromal tumors (GIST) harbor mutually exclusive mutations in the KIT or the PDGFRA gene. Among others, known as wild type GIST, succinate dehydrogenase (SDH)‐deficient tumors develop due to genetic or epigenetic alterations in any of four SDH genes. Herein, we present a unique case of SDH‐deficient GIST with an unusual heterogeneous SDHA and SDHB staining pattern and mutations detected in the SDHA and KIT gene. A 50‐year‐old patient presented with a 5 cm large gastric tumor with a multinodular/plexiform growth pattern, mixed epithelioid and spindle cell morphology, and focal pronounced nuclear atypia with hyperchromasia and high mitotic activity. Immunohistochemically, CD117 and DOG‐1 were positive. SDHB and SDHA stains showed loss of expression in some of the nodules, whereas others presented with an unusually weak patchy positivity. Molecular analysis revealed a point mutation in exon 5 of the SDHA gene and a mutation in exon 11 of the KIT gene. We hypothesize that based on the allele frequency of SDHA and KIT mutations the tumor is best regarded as SDH‐deficient GIST in which the SDHA mutation represents the most likely driver mutation. The identified KIT mutation raises the distinct possibility that the KIT mutation is a secondary event reflecting clonal evolution. This is the first case of a treatment naïve GIST harboring a somatic SDHA and a KIT mutation, challenging the dogma that oncogenic mutations in treatment naïve GIST are mutually exclusive.

Detection of GNAS mutations in intramuscular / cellular myxomas as diagnostic tool in the classification of myxoid soft tissue tumors

BACKGROUND

Intramuscular / cellular myxomas and low-grade myxofibrosarcomas are two different tumor entities with a significant histological overlap, especially if dealing with small biopsies. Despite the morphological similarities, they differ considerably in their biological behaviour. Intramuscular / cellular myxoma rarely shows signs of recurrence and never metastasizes, in contrast to myxofibrosarcoma that tends to recur more aggressively and to metastasize haematologically. Therefore, it is of great importance to distinguish these lesions - evaluation of GNAS mutation status could be of tremendous help.

METHODS

We reviewed 13 cases with intramuscular / cellular myxomas. The 13 cases included 5 men and 8 women, aged from 33 to 71 years (mean age 55.5 years). Immunohistochemistry was performed as well as next generation sequencing. Ten cases were located in the lower extremities and three cases were located in the upper extremities. Two lesions were initially misdiagnosed as a low-grade myxofibrosarcoma.

RESULTS

Performing next generation sequencing 12 out of 13 specimens showed a GNAS mutation.

CONCLUSIONS

Our findings demonstrate that GNAS mutations are more common in intramuscular / cellular myxomas, than had been reported in literature in the past. Next generation sequencing for determining GNAS mutation status on small biopsies or diagnostically challenging cases facilitates the diagnosis of intramuscular / cellular myxoma and separates this tumor entity from its mimics.

Surgery for metachronous metastasis of soft tissue sarcoma - A magnitude of benefit analysis using propensity score methods

INTRODUCTION

Metastasectomy is hypothesised to improve OS in metastatic STS, but evidence in favour of this approach derives from non-controlled single-arm cohorts affected by selection bias. The objective was to quantify the effect of metastasectomy vs. non-surgical management on overall survival (OS) in patients with metachronous metastases from extremity- and trunk soft tissue sarcoma (STS).

MATERIALS AND METHODS

From a population of 1578 STS patients, 135 patients who underwent surgery for localised STS at two European centres between 1998 and 2015 and developed metachronous STS metastases were included. Propensity score analyses with inverse-probability-of-treatment-weights (IPTW) and landmark analyses were performed to control for selection and immortal time bias, respectively.

RESULTS

OS was significantly longer in the 68 patients undergoing metastasectomy than in the 67 patients who were treated non-invasively for their metastasis (10-year OS: 23% vs. 4%; hazard ratio (HR) = 0.34, 95% CI: 0.22-0.53, p < 0.0001). This association prevailed after IPTW-weighting of the data to control for the higher prevalence of favourable prognostic factors in the surgery group (adjusted 10-year OS: 17% vs. 3%, log-rank p < 0.0001; HR = 0.33, 95% CI: 0.20-0.52, p < 0.0001). Five-year OS estimates were 27.8% in patients who had and 14.5% in patients who had not undergone metastasectomy within the first 3 months after diagnosis of a metastasis (p < 0.0001).

CONCLUSION

In this observational bi-centre study, metastasectomy was associated with prolonged survival in patients with metachronous STS metastases. In the absence of randomized studies, our results indicate that metastasectomy should be considered as an important treatment option for metachronous STS metastases.

Characterization of the endolysosomal system in human chordoma cell lines: is there a role of lysosomes in chemoresistance of this rare bone tumor?

Chordoma is a rare tumor of the bone derived from remnants of the notochord with pronounced chemoresistance. A common feature of the notochord and chordoma cells is distinct vacuolization. Recently, the notochord vacuole was described as a lysosome-related organelle. Since lysosomes are considered as mediators of drug resistance in cancer, we were interested whether they may also play a role in chemoresistance of chordoma. We characterized the lysosomal compartment in chordoma cell lines by cytochemistry, electron microscopy (ELMI) and mutational analysis of genes essential for the physiology of lysosomes. Furthermore, we tested for the first time the cytotoxicity of chloroquine, which targets lysosomes, on chordoma. Cytochemical stainings clearly demonstrated a huge mass of lysosomes in chordoma cell lines with perinuclear accumulation. Also vacuoles in chordoma cells were positive for the lysosomal marker LAMP1 but showed no acidic pH. Genetic analysis detected no apparent mutation associated with known lysosomal pathologies suggesting that vacuolization and the huge lysosomal mass of chordoma cell lines is rather a relict of the notochord than a result of transformation. ELMI investigation of chordoma cells confirmed the presence of large vacuoles, lysosomes and autophagosomes with heterogeneous ultrastructure embedded in glycogen. Interestingly, chordoma cells seem to mobilize cellular glycogen stores via autophagy. Our first preclinical data suggested no therapeutically benefit of chloroquine for chordoma. Even though, chordoma cells are crammed with lysosomes which are according to their discoverer de Duve "cellular suicide bags". Destabilizing these "suicide bags" might be a promising strategy for the treatment of chordoma.

Diagnosis and treatment of soft-tissue sarcomas of the extremities and trunk

The relatively low incidence and often atypical clinical presentation of soft-tissue sarcomas (STS) impedes early and adequate diagnosis. Patients may report on recently enlarged soft-tissue swellings, infrequently complain of painful lesions, or even have no symptoms at all.

A thorough diagnostic work-up is essential in order to distinguish between benign soft-tissue tumours and STSs. Patient history, clinical features and radiological findings all help in assessing the underlying pathology. ‘Worrying’ features such as recent increase in size, deep location relative to the fascia, a tumour exceeding 4 cm in size, and invasive growth patterns seen on imaging should prompt verification by biopsy.

Even though acquisition of biopsy material may be incomplete, one should bear in mind some essential rules. Regardless of the biopsy technique applied, the most direct route to the lump in question should be identified, contamination of adjacent structures should be avoided and a sufficient amount of tissue acquired.

Treatment of STS is best planned by a multidisciplinary team, involving experts from various medical specialities. The benchmark therapy consists of en bloc resection of the tumour, covered by a safety margin of healthy tissue. Depending on tumour histology, grade, local extent and anatomical stage, radiotherapy, chemotherapy and isolated hyperthermic limb perfusion may be employed.

Due to the complexity of treatment, any soft-tissue swelling suspected of malignancy is best referred directly to a sarcoma centre, where therapeutic management is carefully planned by an experienced multidisciplinary team.

Cite this article: EFORT Open Rev 2017;2:421-431. DOI: 10.1302/2058-5241.2.170005

Benefit of Adjuvant Radiotherapy for Local Control, Distant Metastasis, and Survival Outcomes in Patients with Localized Soft Tissue Sarcoma: Comparative Effectiveness Analysis of an Observational Cohort Study

Background

This study aimed to quantify the benefit of adjuvant radiotherapy (AXRT) for local control, distant metastasis, and long-term survival outcomes in patients with localized soft tissue sarcoma (STS).

Methods

This single-center retrospective observational study enrolled 433 STS patients who underwent surgery with curative intent. An inverse probability of treatment-weighted (IPTW) analysis was implemented to account rigorously for imbalances in prognostic variables between the adjuvant treatment groups.

Results

During a median follow-up period of 5.5 years, the study observed 38 local recurrences (9%), 73 occurrences of distant metastasis (17%), 63 STS-related deaths (15%), and 57 deaths from other causes (13%). As expected, patients receiving AXRT (n = 258, 60%) were more likely to have high-grade G3 tumors (p < 0.0001) than patients not receiving AXRT. A crude analysis showed that AXRT was not associated with improved recurrence-free survival [hazard ratio (HR) 1.00; 95% confidence interval (CI) 0.72–1.38; p = 0.98]. However, after IPTW, AXRT was associated with a 38% relative reduction in the risk of recurrence or death (HR 0.62; 95% CI 0.39–1.00; p = 0.05). This benefit was driven by a strong reduction in the risk of local recurrence (HR 0.42; 95% CI 0.19–0.91; p = 0.03), whereas the relative risk of distant metastasis (HR 0.69; 95% CI 0.39–1.25; p = 0.22) and overall survival (HR 0.76; 95% CI 0.44–1.30; p = 0.32) were only nonsignificantly in favor of AXRT. An exploratory analysis showed an overall survival benefit of AXRT for patients with high-grade G3 tumors (HR 0.51; 95% CI 0.33–0.78; p = 0.002). However, this finding may have been attributable to residual confounding.

Conclusion

In this observational cohort, AXRT was associated with a 58% reduction in the relative risk of local recurrence. No consistent association between AXRT and lower risks of distant metastasis or death was observed.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-017-6080-3) contains supplementary material, which is available to authorized users.

Rarity among benign gastric tumors: Plexiform fibromyxoma - Report of two cases

Plexiform fibromyxoma is a very rare mesenchymal tumor of the stomach, found almost exclusively in the antrum/pylorus region. The most common presenting symptoms are anemia, hematemesis, nausea and unintentional weight loss, without sex or age predilection. We describe here two cases of plexiform fibromyxoma, involving a 16-year-old female and a 34-year-old male. Both patients underwent complete resection (R0) by distal gastrectomy and retrocolic gastrojejunostomy (according to Billroth 2); for both, the postoperative course was uneventful. Histology showed multiple intramural and subserosal nodules with characteristic plexiform growth, featuring bland spindle cells situated in an abundant myxoid stroma with low mitotic activity. Immunohistochemistry showed α-smooth muscle actin-positive spindle cells, focal positivity for CD10, and negative staining for KIT, DOG1, CD34, S100, β-catenin, STAT-6 and anaplastic lymphoma kinase. One of the cases showed focal positivity for h-caldesmon and desmin. Upon follow-up, no sign of disease was found. In the differential diagnosis of plexiform fibromyxoma, it is important to exclude the more common gastrointestinal stromal tumors as they have greater potential for aggressive behavior. Other lesions, like neuronal and vascular tumors, inflammatory fibroid polyps, abdominal desmoid-type fibromatosis, solitary fibrous tumors and smooth muscle tumors, must also be excluded.

Role of Next-Generation Sequencing as a Diagnostic Tool for the Evaluation of Bone and Soft-Tissue Tumors

Bone and soft-tissue tumors are in general rare. Diagnosing these tumors is challenging based on the significant number of different tumor entities, the rareness of these tumors, and the considerable morphological heterogeneity which can be found within a single tumor entity. Considering that more than half of the described soft-tissue tumors and approximately 25% of the bone tumors harbor recurrent genetic alterations, the use of auxiliary molecular examinations should be strongly considered. Molecular analyses are important to confirm the diagnosis, to guide treatment, to provide information about prognosis, and to allow patient recruitment for basket trials based on the molecular signature of a tumor. In addition, novel molecular alterations detected by next-generation sequencing (NGS) obtain further insights into the pathogenesis of these rare tumors and allow a more detailed genetic classification. Based on our single-center results of NGS using the Ion AmpliSeq Cancer Hotspot Panel v2 and the Ion AmpliSeq Comprehensive Cancer Panel (Thermo Fisher Scientific) for mutational analyses as well as the Archer FusionPlex Sarcoma Kit (ArcherDX, Inc) to detect gene fusions in 26 genes since early 2016, we have experienced NGS as a very sensitive method to detect genetic alterations. In our experience, the use of the Archer FusionPlex Sarcoma Kit is superior to fluorescent in situ hybridization as an auxiliary tool in the routine workup of soft-tissue and bone tumors.

MUG-Mel2, a novel highly pigmented and well characterized NRAS mutated human melanoma cell line

NRAS mutation in melanoma has been associated with aggressive tumor biology and poor prognosis. Although targeted therapy has been tested for NRAS mutated melanoma, response rates still appear much weaker, than in BRAF mutated melanoma. While plenty of cell lines exist, however, only few melanogenic cell lines retain their in vivo characteristics. In this work we present an intensively pigmented and well-characterized cell line derived from a highly aggressive NRAS mutated cutaneous melanoma, named MUG-Mel2. We present the clinical course, unique morphology, angiogenic properties, growth characteristics using in vivo experiments and 3D cell culture, and results of the exome gene sequencing of an intensively pigmented melanogenic cell line MUG-Mel2, derived from a cutaneous metastasis of an aggressive NRAS p. Q61R mutated melanoma. Amongst several genetic alterations, mutations in GRIN2A, CREBP, PIK3C2G, ATM, and ATR were present. These mutations, known to reinforce DNA repair problems in melanoma, might serve as potential treatment targets. The aggressive and fast growing behavior in animal models and the obtained phenotype in 3D culture reveal a perfect model for research in the field of NRAS mutated melanoma.

In vitro and in vivo cytotoxic activity of human lactoferricin derived antitumor peptide R-DIM-P-LF11-334 on human malignant melanoma

Di-peptides derived from the human host defense peptide lactoferricin were previously described to specifically interact with the negatively charged lipid phosphatidylserine exposed by cancer cells. In this study one further derivative, namely R-DIM-P-LF11-334 is shown to exhibit even increased cancer toxicity in vitro and in vivo while non-neoplastic cells are not harmed.

In liposomal model systems composed of phosphatidylserine mimicking cancerous and phosphatidylcholine mimicking non-cancerous membranes the specific interaction with the cancer marker PS was confirmed by specific induction of membrane perturbation and permeabilization in presence of the peptide. In vitro studies with cell lines of human malignant melanoma, such as A375, or primary cells of human melanoma metastases to the brain, as MUG Mel1, and non-neoplastic human dermal fibroblasts NHDF revealed high cytotoxic effect of R-DIM-P-LF11-334 on melanoma cells of A375 and MUG Mel1, whereas only minor effect on the dermal fibroblasts NHDF was observed, yielding an about 20-fold killing-specificity for A375 and MUG-Mel1. The LC₅₀ values for melanoma A375 and MUG Mel1 were about 10 μM. Analysis of secondary structure of the peptide revealed an increase in the proportion of β-sheets exclusively in presence of the cancer mimic. Stability studies further indicated a potential adequate stability in blood or under stringent conditions. Importantly the cytotoxic effect on cancer cells was also proven in vivo in mouse xenografts of human melanoma, where peptide treatment induced strong tumor regression and in average a tumor area reduction of 85% compared to tumors of control mice without peptide treatment.

Can Multistate Modeling of Local Recurrence, Distant Metastasis, and Death Improve the Prediction of Outcome in Patients With Soft Tissue Sarcomas?

BACKGROUND

Exploration of the complex relationship between prognostic indicators such as tumor grade and size and clinical outcomes such as local recurrence and distant metastasis in patients with cancer is crucial to guide treatment decisions. However, in patients with soft tissue sarcoma, there are many gaps in our understanding of this relationship. Multistate analysis may help us in gaining a comprehensive understanding of risk factor-outcome relationships in soft tissue sarcoma, because this methodology can integrate multiple risk factors and clinical endpoints into a single statistical model. To our knowledge, no study of this kind has been performed before in patients with soft tissue sarcoma.

QUESTIONS/PURPOSES

We implemented a multistate model of localized soft tissue sarcoma to statistically evaluate the relationship among baseline risk factors, recurrence, and death in patients with localized soft tissue sarcoma undergoing curative surgery.

METHODS

Between 1998 and 2015, our center treated 539 patients for localized soft tissue sarcoma with surgery as curative intent. Of those, 96 patients (18%) were not included in this single-center retrospective study owing to missing baseline histopathology data (n = 3), not yet observed followup (n = 80), or because a neoadjuvant treatment approach in the presence of synchronous distant metastasis was used (n = 13), leaving 443 patients (82%) for the current analysis, of which 40 were lost to followup during the first year after surgery. All patients had tumors of the stages I to III according to the American Joint Committee on Cancer Stages. The median age of the patients was 62 years (range, 16-96 years), and 217 patients (49%) were female. Three hundred-forty-six patients (78%) had tumors of high grade (Grades 2 and 3), and 310 (70%) tumors were greater than 5 cm in maximum diameter. Patients who had died during the first year of followup were included in this analysis. Median followup for the 443 study patients was 6 years, with 84%, 52%, and 23% of patients being followed for more than 1, 5, and 10 years, respectively. The 15-year cumulative incidences of local recurrence, distant metastasis, and death from any cause, using a competing risk analysis, were 16% (95% CI, 11%-22%), 21% (95% CI, 17%-26%), and 55% (95% CI, 44%-67%), respectively. Wide resection with a margin of 1 mm was the preferred treatment for all patients, except for those with Grade 1 liposarcoma where a marginal resection was considered adequate. Multistate models were implemented with the mstate library in R.

RESULTS

In multistate analysis, patients who experienced a local recurrence were more likely to have distant metastasis develop (hazard ratio [HR] = 8.4; 95% CI, 4.3-16.5; p < 0.001), and to die (HR = 3.4; 95% CI, 2.1-5.6; p < 0.001). The occurrence of distant metastasis was associated with a strong increase in the risk of death (HR = 12.6; 95% CI, 8.7-18.3; p < 0.001). Distant metastasis occurring after a long tumor-free interval was not associated with a more-favorable prognosis with respect to mortality than distant metastasis occurring early after surgery (estimated relative decrease in the adverse effect of distant metastasis on mortality for 1-year delay in the occurrence of distant metastasis = 0.9; 95% CI, 0.7-1.1; p = 0.28). High-grade histology (Grades 2 and 3) was associated with a higher risk of overall recurrence (defined as a composite of local recurrence and distant metastasis, HR = 3.8; 95% CI, 1.8-7.8; p = 0.0003) and a higher risk of death after recurrence developed (HR = 4.4; 95% CI, 1.1-18.2; p = 0.04). Finally, the multistate model predicted distinct outcome patterns depending on baseline covariates and how long a patient has remained free from recurrence after surgery.

CONCLUSIONS

In patients with localized soft tissue sarcoma undergoing resection, the occurrence of local recurrence and distant metastasis contributes to a dramatically impaired long-term survival outcome. Local recurrences are a substantial risk factor for distant metastasis. Multistate modeling is a very powerful approach for analysis of sarcoma cohorts, and may be used in the future to obtain highly personalized, dynamic predictions of outcomes in patients with localized soft tissue sarcoma.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Langerhans-cell histiocytosis of the cervical spine in an adult patient: Case report and review of the literature

Langerhans-cell histiocytosis (LCH) is a rare, benign bone tumor, usually occurring in children and younger adults under 20 years old. Only a few cases of solitary bone lesions of the adult spine are reported in literature, therapeutic guidelines or treatment regimens for lesions of the adult spine are not established yet to our knowledge.

DNA methylation heterogeneity defines a disease spectrum in Ewing sarcoma

Developmental tumors in children and young adults carry few genetic alterations, yet they have diverse clinical presentation. Focusing on Ewing sarcoma, we sought to establish the prevalence and characteristics of epigenetic heterogeneity in genetically homogeneous cancers. We performed genome-scale DNA methylation sequencing for a large cohort of Ewing sarcoma tumors and analyzed epigenetic heterogeneity on three levels: between cancers, between tumors, and within tumors. We observed consistent DNA hypomethylation at enhancers regulated by the disease-defining EWS-FLI1 fusion protein, thus establishing epigenomic enhancer reprogramming as a ubiquitous and characteristic feature of Ewing sarcoma. DNA methylation differences between tumors identified a continuous disease spectrum underlying Ewing sarcoma, which reflected the strength of an EWS-FLI1 regulatory signature and a continuum between mesenchymal and stem cell signatures. There was substantial epigenetic heterogeneity within tumors, particularly in patients with metastatic disease. In summary, our study provides a comprehensive assessment of epigenetic heterogeneity in Ewing sarcoma and thereby highlights the importance of considering nongenetic aspects of tumor heterogeneity in the context of cancer biology and personalized medicine.