Disruption of the TP53 locus in osteosarcoma leads to TP53 promoter gene fusions and restoration of parts of the TP53 signalling pathway.

TP53 is the most frequently mutated gene in human cancer. This gene shows not only loss-of-function mutations but also recurrent missense mutations with gain-of-function activity. We have studied the primary bone malignancy osteosarcoma, which harbours one of the most rearranged genomes of all cancers. This is odd since it primarily affects children and adolescents who have not lived the long life thought necessary to accumulate massive numbers of mutations. In osteosarcoma, TP53 is often disrupted by structural variants. Here, we show through combined whole-genome and transcriptome analyses of 148 osteosarcomas that TP53 structural variants commonly result in loss of coding parts of the gene while simultaneously preserving and relocating the promoter region. The transferred TP53 promoter region is fused to genes previously implicated in cancer development. Paradoxically, these erroneously upregulated genes are significantly associated with the TP53 signalling pathway itself. This suggests that while the classical tumour suppressor activities of TP53 are lost, certain parts of the TP53 signalling pathway that are necessary for cancer cell survival and proliferation are retained. In line with this, our data suggest that transposition of the TP53 promoter is an early event that allows for a new normal state of genome-wide rearrangements in osteosarcoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Genetic profiling of a chondroblastoma-like osteosarcoma/malignant phosphaturic mesenchymal tumor of bone reveals a homozygous deletion of CDKN2A, intragenic deletion of DMD, and a targetable FN1-FGFR1 gene fusion.

Conventional osteosarcoma is the most common primary malignancy of bone. This group of neoplasms is subclassified according to specific histological features, but hitherto there has been no correlation between subtype, treatment, and prognosis. By in-depth genetic analyses of a chondroblastoma-like osteosarcoma, we detect a genetic profile that is distinct from those previously reported in benign and malignant bone tumors. The overall genomic copy number profile was less complex than that typically associated with conventional osteosarcoma, and there was no activating point mutation in any of H3F3A, H3F3B, IDH1, IDH2, BRAF, or GNAS. Instead, we found a homozygous CDKN2A deletion, a DMD microdeletion and an FN1-FGFR1 gene fusion. The latter alteration has been described in phosphaturic mesenchymal tumor. This tumor type shares some morphological features with chondroblastoma-like osteosarcoma and we cannot rule out that the present case actually represents an FN1-FGFR1 positive malignant phosphaturic mesenchymal tumor of bone without osteomalacia.

Drug sensitivity testing on patient-derived sarcoma cells predicts patient response to treatment and identifies c-Sarc inhibitors as active drugs for translocation sarcomas.

BACKGROUND: Heterogeneity and low incidence comprise the biggest challenge in sarcoma diagnosis and treatment. Chemotherapy, although efficient for some sarcoma subtypes, generally results in poor clinical responses and is mostly recommended for advanced disease. Specific genomic aberrations have been identified in some sarcoma subtypes but few of them can be targeted with approved drugs. METHODS: We cultured and characterised patient-derived sarcoma cells and evaluated their sensitivity to 525 anti-cancer agents including both approved and non-approved drugs. In total, 14 sarcomas and 5 healthy mesenchymal primary cell cultures were studied. The sarcoma biopsies and derived cells were characterised by gene panel sequencing, cancer driver gene expression and by detecting specific fusion oncoproteins in situ in sarcomas with translocations. RESULTS: Soft tissue sarcoma cultures were established from patient biopsies with a success rate of 58%. The genomic profile and drug sensitivity testing on these samples helped to identify targeted inhibitors active on sarcomas. The cSrc inhibitor Dasatinib was identified as an active drug in sarcomas carrying chromosomal translocations. The drug sensitivity of the patient sarcoma cells ex vivo correlated with the response to the former treatment of the patient. CONCLUSIONS: Our results show that patient-derived sarcoma cells cultured in vitro are relevant and practical models for genotypic and phenotypic screens aiming to identify efficient drugs to treat sarcoma patients with poor treatment options.

Integrative genome and transcriptome analyses reveal two distinct types of ring chromosome in soft tissue sarcomas.

Gene amplification is a common phenomenon in malignant neoplasms of all types. One mechanism behind increased gene copy number is the formation of ring chromosomes. Such structures are mitotically unstable and during tumor progression they accumulate material from many different parts of the genome. Hence, their content varies considerably between and within tumors. Partly due to this extensive variation, the genetic content of many ring-containing tumors remains poorly characterized. Ring chromosomes are particularly prevalent in specific subtypes of sarcoma. Here, we have combined fluorescence in situ hybridization (FISH), global genomic copy number and gene expression data on ring-containing soft tissue sarcomas and show that they harbor two fundamentally different types of ring chromosome: MDM2-positive and MDM2-negative rings. While the former are often found in an otherwise normal chromosome complement, the latter seem to arise in the context of general chromosomal instability. In line with this, sarcomas with MDM2-negative rings commonly show complete loss of either CDKN2A or RB1 -both known to be important for genome integrity. Sarcomas with MDM2-positive rings instead show co-amplification of a variety of potential driver oncogenes. More than 100 different genes were found to be involved, many of which are known to induce cell growth, promote proliferation or inhibit apoptosis. Several of the amplified and overexpressed genes constitute potential drug targets.

RNA sequencing of sarcomas with simple karyotypes: identification and enrichment of fusion transcripts.

Gene fusions are neoplasia-associated mutations arising from structural chromosomal rearrangements. They have a strong impact on tumor development and constitute important diagnostic markers. Malignant soft tissue tumors (sarcomas) constitute a heterogeneous group of neoplasms with >50 distinct subtypes, each of which is rare. In addition, there is considerable morphologic overlap between sarcomas and benign lesions. Several subtypes display distinct gene fusions, serving as excellent biomarkers. The development of methods for deep sequencing of the complete transcriptome (RNA-Seq) has substantially improved the possibilities for detecting gene fusions. With the aim of identifying new gene fusions of biological and clinical relevance, eight sarcomas with simple karyotypes, ie, only one or a few structural rearrangements, were subjected to massively parallel paired-end sequencing of mRNA. Three different algorithms were used to identify fusion transcripts from RNA-Seq data. Three novel (KIAA2026-NUDT11, CCBL1-ARL1, and AFF3-PHF1) and two previously known fusions (FUS-CREB3L2 and HAS2-PLAG1) were found and could be verified by other methods. These findings show that RNA-Seq is a powerful tool for detecting gene fusions in sarcomas but also suggest that it is advisable to use more than one algorithm to analyze the output data as only two of the confirmed fusions were reported by more than one of the gene fusion detection software programs. For all of the confirmed gene fusions, at least one of the genes mapped to a chromosome band implicated by the karyotype, suggesting that sarcomas with simple karyotypes constitute an excellent resource for identifying novel gene fusions.

Prognostic factors and follow-up strategy for superficial soft-tissue sarcomas: Analysis of 622 surgically treated patients from the scandinavian sarcoma group register.

BACKGROUND AND OBJECTIVES: Our study aimed to describe the clinical outcome of patients with superficial soft-tissue sarcomas (SSTS), define prognostic factors and provide evidence for a rational surveillance scheme. METHODS: Data for 622 consecutive, surgically treated SSTS patients were retrieved from the Scandinavian Sarcoma Group Register. We assessed the rates of local recurrence (LR) and metastasis (M), as well as overall survival (OS), local recurrence free-survival (LRFS) and metastasis-free survival (MFS) of the cohort. RESULTS: The incidence of LR and M was 9% and 12%, respectively. OS at 5 years was 79%, LRFS was 74% and MFS 76%. Factors that affected OS, LRFS, and MFS were tumor size and patient age. Additionally, tumor grade was an independent prognostic factor for LRFS. The majority of LR and M events were observed the first 2 years of follow-up. Clear surgical margins were correlated to lower risk for LR. Selected patients benefited from adjuvant radiotherapy. CONCLUSIONS: SSTS have a favourable prognosis, which is mainly determined by tumour-associated factors. Adequate surgical margins are important for local control, whereas radiotherapy has a secondary role. The data support current surveillance schemes, with a closer follow-up the first 2 years after surgery.

Reconstruction of metastatic acetabular defects using a modified Harrington procedure.

BACKGROUND AND PURPOSE: Metastases engaging the acetabulum result in significant disability. We investigated the outcome after curettage and reconstruction of the defect with a protrusio cage, retrograde screws, and a cemented total hip arthroplasty. PATIENTS AND METHODS: We retrospectively identified 70 consecutive patients who were surgically treated for metastatic disease of the acetabulum between 1995 and 2012 using the above technique. The type of primary tumor, extent of the disease, degree of acetabular erosion, and type of implant used were identified. Patient and implant survival, complications, and functional outcome were recorded. RESULTS: There were no mortalities in the perioperative period (30 days after surgery). Median overall patient survival was 12 months. Prosthesis survival was 92% at 1 year and 89% at 5 years. One third of the patients suffered a complication, the most frequent one being dislocation. The functional outcome was good. Multiple skeletal or visceral metastases and specific types of cancer were associated with poor patient survival. INTERPRETATION: Reconstruction of metastatic acetabular defects using a protrusio cage stabilized with retrograde screws and a cemented total hip arthroplasty is a safe procedure that provides efficient relief of symptoms. Patients with extensive disease, especially when diagnosed with specific types of cancer, have a very poor prognosis. The complication rate is substantial, the most frequent being dislocation. However, revision surgery is seldom required and prosthesis survival is high.

Comprehensive genetic analysis identifies a pathognomonic NAB2/STAT6 fusion gene, nonrandom secondary genomic imbalances, and a characteristic gene expression profile in solitary fibrous tumor.

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm displaying variable morphologic and clinical features. To identify pathogenetically important genetic rearrangements, 44 SFTs were analyzed using a variety of techniques. Chromosome banding and fluorescence in situ hybridization (FISH) showed recurrent breakpoints in 12q13, clustering near the NAB2 and STAT6 genes, and single nucleotide polymorphism array analysis disclosed frequent deletions affecting STAT6. Quantitative real-time PCR revealed high expression levels of the 5'-end of NAB2 and the 3'-end of STAT6, which at deep sequencing of enriched DNA corresponded to NAB2/STAT6 fusions. Subsequent reverse-transcriptase PCR (RT-PCR) analysis identified a NAB2/STAT6 fusion in 37/41 cases, confirming that this fusion gene underlies the pathogenesis of SFT. The hypothesis that the NAB2/STAT6 fusions will result in altered properties of the transcriptional co-repressor NAB2--a key regulator of the early growth response 1 (EGR1) transcription factor - was corroborated by global gene expression analysis; SFTs showed deregulated expression of EGR1 target genes, as well as of other, developmentally important genes. We also identified several nonrandom secondary changes, notably loss of material from 13q and 14q. As neither chromosome banding nor FISH analysis identify more than a minor fraction of the fusion-positive cases, and because multiple primer combinations are required to identify all possible fusion transcripts by RT-PCR, alternative diagnostic markers might instead be found among deregulated genes identified at global gene expression analysis. Indeed, using immunohistochemistry on tissue microarrays, the top up-regulated gene, GRIA2, was found to be differentially expressed also at the protein level.

[Most musculoskeletal soft tissue tumors are benign]. / Fetthaltiga mjukdelstumörer i rörelseapparaten ofta godartade.

Most musculoskeletal soft tissue tumors are benign, lipoma being the most common. Malignant soft tissue tumors may be difficult to clinically distinguish from benign. Scandinavian recommendations are that all lesions suspicious for sarcoma be referred to a sarcoma center. This has led to improved tumor control and less post-operative functional deficits. Magnetic resonance imaging (MRI) can reliably diagnose lipomas, and further work-up is not necessary. Lipomas can be treated at the local hospital. All deep seated musculoskeletal tumors (under the muscle fascia) not unequivocally lipomas should be referred to a sarcoma center. All superficial (subcutaneous) musculoskeletal tumors larger than 5 cm and not unequivocally lipomas should be referred to a sarcoma center.

Megaprosthetic reconstruction for periprosthetic or highly comminuted fractures of the hip and knee.

OBJECTIVES: To present the experience of a tertiary referral hospital in the management of a case series with hip or knee fractures by using modular megaprosthesis. PATIENTS AND METHODS: Seventeen consecutive patients with highly comminuted fractures of the knee (n = 2), periprosthetic fractures of knee (n = 10) or hip (n = 5) were included. Fractures were managed with modular megaprosthesis (including total hip in 2 cases). Postoperative complications like infection and instability and outcome measures like return to previous mobility and living were recorded. RESULTS: The mean age at time of surgery was 77 years (25-91), and mean follow-up was 44 months (13-98). We had no intra-operative complications. There were 3 deep periprosthetic infections, 1 hip and 2 knee. In the hip group, including total femur patients, we had 2 dislocations (2/7), both managed with closed reduction. No aseptic loosening was seen. 15/17 patients regained walking ability, and 16 were discharged to independent living. Nine patients have died at the time of follow-up. CONCLUSIONS: In these often old and physically compromised patients with highly comminuted fractures or complicated periprosthetic fractures, modular megaprosthesis could be a good surgical option. It can provide immediate stability and allow early mobilization.

Recurrent rearrangement of the PHF1 gene in ossifying fibromyxoid tumors.

Ossifying fibromyxoid tumor (OFMT) is a soft tissue tumor of unknown lineage. Although most cases are histologically and clinically benign, some show malignant morphological features and local recurrences are not uncommon; a few may even metastasize. In the present study, cytogenetic analysis identified different structural rearrangements of chromosome band 6p21 in tumor cells from three cases of OFMT, including one with typical, one with atypical, and one with malignant morphological features. Mapping of the 6p21 breakpoint by fluorescence in situ hybridization (FISH) indicated that the PHF1 gene was rearranged in all three cases. Further FISH, 5'-rapid amplification of cDNA ends, and RT-PCR analyses disclosed an EP400/PHF1 fusion transcript in one of the cases. Interphase FISH on tumor sections from 13 additional cases of OFMT showed rearrangement of the PHF1 locus in four of four typical, two of three atypical, and one of six malignant lesions. Thus, the PHF1 gene, previously shown to be the 3'-partner of fusion genes in endometrial stromal tumors, is also recurrently involved in the pathogenesis of OFMTs, irrespective of whether they are diagnosed as typical, atypical, or malignant lesions. The PHF1 protein interacts with the polycomb-repressive complex 2 (PRC2), which, in turn, regulates the expression of a variety of developmental genes. Thus, the results indicate that deregulation of PRC2 target genes is crucial for OFMT development.

Sclerotherapy with polidocanol for treatment of aneurysmal bone cysts.

BACKGROUND AND PURPOSE: Recent data suggest that percutaneous sclerotherapy is a safe alternative to surgery for treatment of aneurysmal bone cysts (ABCs). We present our experience of this method. METHODS: We retrospectively analyzed data from 38 consecutive patients treated with repeated injections of polidocanol. Each injection consisted of 2-4 mg polidocanol per kg body weight. Radiological and clinical assessments were performed until healing. RESULTS: All cycts except 1 healed after a median of 4 (1-11) injections. A lesion failed to heal in 1 patient, who was operated. 3 patients experienced minor local inflammatory reactions. INTERPRETATION: Our results show that percutaneus sclerotherapy with polidocanol has high efficacy in the treatment of ABCs, with a low frequency of side effects. Our findings corroborate data presented in previous publications. We believe that the method will be especially valuable in ABCs of the pelvis and sacrum, where surgery is associated with considerable morbidity.

Mesenchymal stromal cells from primary osteosarcoma are non-malignant and strikingly similar to their bone marrow counterparts.

Mesenchymal stromal cells (MSC) are multipotent cells that can be isolated from a number of human tissues. In cancer, MSC have been implicated with tumor growth, invasion, metastasis, drug resistance and were even suggested as possible tumor-initiating cells in osteosarcoma (OS). However, MSC from OS and their possible tumor origin have not yet been thoroughly investigated. Therefore, primary OS mesenchymal progenitors and OS-derived MSC were studied. OS samples contained very high frequencies of mesenchymal progenitor cells as measured by the colony-forming unit fibroblast (CFU-F) assay (median: 1,117 colonies per 10(5) cells, range: 133-3,000, n = 6). This is considerably higher compared to other human tissues such as normal bone marrow (BM) (1.3 ± 0.2 colonies per 10(5) cells, n = 8). OS-derived MSC (OS-MSC) showed normal MSC morphology and expressed the typical MSC surface marker profile (CD105/CD73/CD90/CD44/HLA-classI/CD166 positive, CD45/CD34/CD14/CD19/HLA-DR/CD31 negative). Furthermore, all OS-MSC samples could be differentiated into the osteogenic lineage, and all but one sample into adipocytes and chondrocytes. Genetic analysis of OS-MSC as well as OS-derived spheres showed no tumor-related chromosomal aberrations. OS-MSC expression of markers related to tumor-associated fibroblasts (fibroblast surface protein, alpha-smooth muscle actin, vimentin) was comparable to BM-MSC and OS-MSC growth was considerably affected by tyrosine kinase inhibitors. Taken together, our results demonstrate that normal, non-malignant mesenchymal stroma cells are isolated from OS when MSC culture techniques are applied. OS-MSC represent a major constituent of the tumor microenvironment, and they share many properties with BM-derived MSC.

Results of the Scandinavian Sarcoma Group XIV protocol for classical osteosarcoma: 63 patients with a minimum follow-up of 4 years.

BACKGROUND AND PURPOSE: The Scandinavian Sarcoma Group (SSG) XIV protocol is based on experience from previous SSG trials and other osteosarcoma intergroup trials, and has been considered the best standard of care for patients with extremity localized, non-metastatic osteosarcoma. We analyzed the outcome in 63 consecutive patients. Patients and methods From 2001 through 2005, 63 patients recruited from centers in Sweden, Norway, and Finland were included. They received preoperative chemotherapy consisting of 2 cycles of paired methotrexate (12 g/m²), cisplatin (90 mg/m²), and doxorubicin (75 mg/m²). 3 cycles were administered postoperatively, and poor histological responders were given 3 additional cycles of ifosfamide (10-12 g/m²) as a salvage strategy. RESULTS: With a median follow-up of 77 months for survivors, the estimated metastasis-free and sarcoma-related survival at 5 years was 70% and 76%, respectively. 53 patients were treated with limb salvage surgery or rotationplasty and 2 patients experienced a local recurrence. 3 toxic deaths were recorded, all related to acute toxicity from chemotherapy. The 5-year metastasis-free survival of poor histological responders receiving add-on treatment with ifosfamide was 47%, as compared to 89% for good histological responders. INTERPRETATION: Outcome from the SSG XIV protocol compares favorably with the results of previous SSG trials and other published osteosarcoma trials. However, salvage therapy given to poor responders did not improve outcome to a similar degree as for good responders. In a multi-institutional setting, more than four-fifths of the patients were operated with limb salvage surgery or rotationplasty, with few local recurrences.

Outcome in dedifferentiated chondrosarcoma for patients treated with multimodal therapy: Results from the EUROpean Bone Over 40 Sarcoma Study.

INTRODUCTION: The role of chemotherapy for patients with dedifferentiated chondrosarcoma (DDCS) is still under discussion. Here, we present the outcome in patients with DDCS treated with intensive chemotherapy from the EUROpean Bone Over 40 Sarcoma Study. MATERIALS AND METHODS: The chemotherapy regimen included doxorubicin, ifosfamide and cisplatin. Postoperative methotrexate was added in case of poor histological response. Toxicity was graded based on the National Cancer Institute expanded common toxicity criteria, version 2.0, and survival was analysed using Kaplan-Meier curves, log-rank tests and univariate Cox regression models. RESULTS: Fifty-seven patients with DDCS (localised, 34 [60%]; metastatic, 23 [40%]) aged 42-65 years were included. Surgical complete remission (SCR) was achieved in 36 (63%) patients. The median overall survival (OS) was 24 months (95% confidence interval, 22-25), and the 5-year OS was 39%. Patients with extremity localisation had a 5-year OS of 49% compared with 29% in patients with a central tumour (P = 0.08). Patients with localised disease had a 5-year OS of 46%, whereas patients with metastatic disease had a 5-year OS of 29% (P = 0.12). Patients in SCR had a 5-year OS of 49%, whereas patients not in SCR had a 5-year OS of 23% (P = 0.004). Chemotherapy toxicity was considerable but manageable. There was no treatment-related death, and 39 (70%) patients received ≥6 cycles of the planned nine chemotherapy cycles. CONCLUSIONS: Adding intensive chemotherapy to surgery for treatment of DDCS is feasible and shows favourable survival data compared with previous reports. With the limitations of data from a non-controlled trial, we conclude that chemotherapy could be considered in the management of patients aged >40 years.

Genomic profiling of chondrosarcoma: chromosomal patterns in central and peripheral tumors.

PURPOSE: Histologic grade is currently the best predictor of clinical course in chondrosarcoma patients. Grading suffers, however, from extensive interobserver variability and new objective markers are needed. Hence, we have investigated DNA copy numbers in chondrosarcomas with the purpose of identifying markers useful for prognosis and subclassification. EXPERIMENTAL DESIGN: The overall pattern of genomic imbalances was assessed in a series of 67 chondrosarcomas using array comparative genomic hybridization. Statistical analyses were applied to evaluate the significance of alterations detected in subgroups based on clinical data, morphology, grade, tumor size, and karyotypic features. Also, the global gene expression profiles were obtained in a subset of the tumors. RESULTS: Genomic imbalances, in most tumors affecting large regions of the genome, were found in 90% of the cases. Several apparently distinctive aberrations affecting conventional central and peripheral tumors, respectively, were identified. Although rare, recurrent amplifications were found at 8q24.21-q24.22 and 11q22.1-q22.3, and homozygous deletions of loci previously implicated in chondrosarcoma development affected the CDKN2A, EXT1, and EXT2 genes. The chromosomal imbalances in two distinct groups of predominantly near-haploid and near-triploid tumors, respectively, support the notion that polyploidization of an initially hyperhaploid/hypodiploid cell population is a common mechanism of chondrosarcoma progression. Increasing patient age as well as tumor grade were associated with adverse outcome, but no copy number imbalance affected metastasis development or tumor-associated death. CONCLUSION: Despite similarities in the overall genomic patterns, the present findings suggest that some regions are specifically altered in conventional central and peripheral tumors, respectively.

[Synovial sarcoma - a rare and highly malignant, tumor with an ambiguous clinical picture at times]. / Synovialt sarkom ­ en högmalign tumörsjukdom som kan ha egendomligt kliniskt förlopp.

A characteristic feature of soft tissue sarcomas is the absence of alarm symptoms such as pain or abnormal laboratory findings. We present two patients where the diagnostic difficulties delayed the definitive diagnosis, in one case with lethal outcome. The two patients highlight the difficulties a clinician may encounter with this particular disease. Even though synovial sarcoma represents around 0,1 % of all cancer forms, we recommend a high degree of awareness and - when in doubt - prompt contact with a Sarcoma center for consultation.

Loss of NF2 defines a genetic subgroup of non-FOS-rearranged osteoblastoma.

Osteoblastoma is a locally aggressive tumour of bone. Until recently, its underlying genetic features were largely unknown. During the past two years, reports have demonstrated that acquired structural variations affect the transcription factor FOS in a high proportion of cases. These rearrangements modify the terminal exon of the gene and are believed to stabilise both the FOS transcript and the encoded protein, resulting in high expression levels. Here, we applied in-depth genetic analyses to a series of 29 osteoblastomas, including five classified as epithelioid osteoblastoma. We found recurrent homozygous deletions of the NF2 gene in three of the five epithelioid cases and in one conventional osteoblastoma. These events were mutually exclusive from FOS mutations. Structural variations were determined by deep whole genome sequencing and the number of FOS-rearranged cases was less than previously reported (10/23, 43%). One conventional osteoblastoma displayed a novel mechanism of FOS upregulation; bringing the entire FOS gene under the control of the WNT5A enhancer that is itself activated by FOS. Taken together, we show that NF2 loss characterises a subgroup of osteoblastomas, distinct from FOS-rearranged cases. Both NF2 and FOS are involved in regulating bone homeostasis, thereby providing a mechanistic link to the excessive bone growth of osteoblastoma.

Preoperative radiotherapy of soft-tissue sarcomas: surgical and radiologic parameters associated with local control and survival.

BACKGROUND: Preoperative radiotherapy is often used to facilitate excision of soft-tissue sarcomas. We aimed define factors that affect local tumour control and patient survival. METHODS: A single institution registry study of 89 patients with non-metastatic soft-tissue sarcomas having preoperative radiotherapy between 1994 and 2014. Radiologic (presence of peritumoural oedema and volume change following radiotherapy) and histopathologic (tumour volume, grade and surgical margin) parameters were recorded. Outcomes were the events of local recurrence, amputation, metastasis and death. RESULTS: Local recurrence rate was low (12%) and marginal excision gave equal local control to wide excision. Pelvic localization was associated with a higher risk for amputation. The absence of peritumoural oedema on MRI defined a subgroup of tumours with more favourable oncologic outcome. Reduction of tumour volume following radiotherapy was also associated with better patient survival. Both these radiologic parameters were associated with lower tumour grade. Tumour necrosis was not significant for patient survival. The local complication rate, mainly wound healing problems and infection, was high (40%), but did not lead to any amputation. CONCLUSION: Preoperative radiotherapy of high-risk soft-tissue sarcomas allows for good local control rate at the expense of local wound complications, which are however manageable. Marginal excision is sufficient for local control. Absence of peritumoural oedema on MRI, as well as tumour size reduction following radiotherapy are associated to superior patient survival and can be used ass early prognostic factors.