Osteosarcoma is the most common primary bone tumour worldwide. This disease presents a formidable challenge to the orthopaedic surgeon, with a mortality rate of 30 per cent, even after surgical clearance. Aberrant Wnt signalling has been implicated in the pathogenesis osteoblastic tumours. The objective of this study is 2 fold- to investigate if osteosarcoma does indeed demonstrate aberrant Wnt signaling, and if so, does osteosarcoma respond to a novel Wnt inhibitor(ETC159). This can potentially lead to the development of a new adjuvant treatment modality for osteosarcoma. A novel Wnt signaling pathway protein antibody (YJ5) was used in immunihistochemistry staining of clinical osteosarcoma samples. A Wnt high osteosarcoma cell line(SJSA-1) was then implanted subcutaneously in a mouse model. These mice were treated with a novel PORCN inhibitor, ETC 159 for a period of 4 weeks in a two-arm randomised control study. The results of treatment were evaulated by clinical outcome parameters as well as immunohstochemistry. 100 per cent of clinical osteosarcoma samples demonstrated increased WLS expression and Wnt protein expression. SJSA-1 showed no significant decrease in tumour volume after 30 days of drug treatment (3070 SD 625 mm3 vs 3480 SD 433 mm3 p= 0.605 and 2060 SD 209 vs 1677 SD 213 mm3 p=0.219 respectively). Significantly, SJSA-1 demonstrated increased tumour necrosis in the treatment arm(30–60 percent increase across all samples p < 0 .005) Treated tumours also demonstrated markedly less angiogenesis compared to the non treatment arm. Osteosarcoma demonstrates aberrant Wnt signaling in a large percentage of cases. The use of a novel PORCN inhibitor ETC 159 for the treatment of Osteosarcoma has a marked effect on tumour necrosis. Our results suggest that ETC159 may cause tumour necrosis by inhibiting angiogenesis within the tumour. Further evaluation and understanding of the mechanism of Wnt singaling in regulating tumour pathogenesis may hold the potential for developing a curative therapeutic drug for this deadly disease

Traditional staging systems for high grade osteosarcoma (Enneking, MSTS) are based largely on gross surgical margins and were developed before the widespread use of neoadjuvant chemotherapy. It is now well known that both microscopic margins and chemotherapy are predictors of local recurrence. However, neither of these variables are used in the traditional surgical staging and the precise safe margin distance is debated. Recently, a novel staging system utilizing a 2mm margin cutoff and incorporating precent necrosis was proposed and demonstrated improved prognostic value for local recurrence free survival (LRFS) when compared to the MSTS staging system. This staging system has not been validated beyond the original patient cohort. We propose to analyze this staging system in a cohort of patients with high-grade osteosarcoma, as well as evaluate the ability of additional variables to predict the risk of local recurrence and overall survival. A retrospective review of a prospectively collected database of all sarcoma patients between 1985 and 2020 at a tertiary sarcoma care center was performed. All patients with high-grade osteosarcoma receiving neo-adjuvant chemotherapy and with no evidence of metastatic disease on presentation were isolated and analyzed. A minimum of two year follow up was used for surviving patients. A total of 225 patients were identified meeting these criteria. Univariate analysis was performed to evaluate variable that were associated with LRFS. Multivariate analysis is used to further analyze factors associated with LRFS on univariate analysis. There were 20 patients (8.9%) who had locally recurrent disease. Five-year LRFS was significantly different for patients with surgical margins 2mm or less (77.6% v. 93.3%; p=0.006) and those with a central tumor location (67.9 v. 94.4; <0.001). A four-tiered staging system using 2mm surgical margins and a percent necrosis of 90% of greater was also a significant predictor of 5-year LRFS (p=0.019) in this cohort. Notably, percent necrosis in isolation was not a predictor of LRFS in this cohort (p=0.875). Tumor size, gender, and type of surgery (amputation v. limb salvage) were also analyzed and not associated with LRFS. The MSTS surgical margin staging system did not significantly stratify groups (0.066). A 2mm surgical margin cutoff was predictive of 5-year LRFS in this cohort of patients with localized high-grade osteosarcoma and a combination of a 2mm margin and percent necrosis outperformed the prognostic value of the traditional MSTS staging system. Utilization of this system may improve the ability of surgeons to stage thier patients. Additional variables may increase the value of this system and further validation is required

Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging (BLI) and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with increased expression of Runx-2 (p = 0.009), Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in partial osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), and did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing

Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with significantly increased expression of the Osteoblast markers Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), but did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing

Osteosarcoma (OS) is the most prevalent bone tumor in children and young adults. Most tumors arise from the metaphysis of the long bones and easily metastasize to the lungs. Current therapeutic strategies of osteosarcoma are routinely surgical resection and chemotherapy, which are limited to the patients suffering from metastatic recurrence. Therefore, to investigate molecular mechanisms that contribute to osteosarcoma progression is very important and may shed light on targeted therapeutic approach to improve the survival of patients with this disease. Several miRNAs have been found expressed differentially in osteosarcoma (OS), In this study, we found that miR-144 significantly suppresses osteosarcoma cell proliferation, migration andinvasion ability in vitro, and inhibited tumor growth and metastasisin vivo. The function and molecular mechanism of miR-144 in Osteosarcoma was further investigated. Tissue samples from fifty-one osteosarcoma patients were obtained from Shanghai Ninth People's Hospital. The in vitro function of miR-144 in Osteosarcoma was investigated by cell viability assay, wound healing assay, invasion assay, the molecular mechanism was identified by Biotin-coupled miRNA capture, Dual-luciferase reporter assays, etc. the in vivo function of miR-144 in osteosarcoma was confirmed by osteosarcoma animal model and miR-144−/− zebrafish model. Mechanically, we demonstrated that Ras homolog family member A (RhoA) and its pivotal downstream effector Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) were both identified as direct targets of miR-144. Moreover, the negative co-relation between downregulated miR-144 and upregulated ROCK1/RhoA was verified both in the osteosarcoma cell lines and clinical patients' specimens. Functionally, RhoA with or without ROCK1 co-overexpression resulted a rescue phenotype on the miR-144 inhibited cell growth, migration and invasion abilities, while individual overexpression of ROCK1 had no statistical significance compared with control in miR-144 transfected SAOS2 and U2-OS cells. This study demonstrates that miR-144 inhibited tumor growth and metastasis in osteosarcoma via dual-suppressing of RhoA and ROCK1, which could be a new therapeutic approach for the treatment ofosteosarcoma

Introduction. The use of vascularised fibula grafts is an accepted method for reconstructing the distal femur following resection of malignant childhood tumours. Limitations relate to the mismatch of the cross-sectional area of the transplanted fibula graft and thel ocal bone, instability of the construct and union difficulties. We present midterm results of a unique staged technique—an immediate defect reconstruction using a double-barrel vascularised fibula graft set in in A-frame configuration and a subsequent intramedullary femoral lengthening. Materials & Methods. We retrospectively included 10 patients (mean age 10 y)with an osteosarcoma of the distal femur, who were treated ac-cording to the above-mentioned surgical technique. All patients were evaluated with regards to consolidation of the transplanted grafts, hypertrophy at the graft-host junctions, leg length discrepancies, lengthening indices, complications as well as functional outcome. Results. The mean defect size after tumour resection was 14.5 cm, the mean length of the harvested fibula graft 22 cm, resulting in a mean (acute) shortening of 4.7 cm (in 8 patients). Consolidation was achieved in all cases, 4 patients required supplementary bone grafting. Hypertrophy at the graft-host junctions was observed in78% of the evaluable junctions. In total 11 intramedullary lengthening procedures in 9 patients had been performed at the last follow up. The mean Muskuloskeletal Society Rating Scale(MSTS) score of the evaluable 9 patients was 85% (57% to 100%)with good or excellent results in 7 patients. Conclusions. A-frame vascularised fibula reconstructions showed encouraging results with respect to defect reconstruction, length as well as function and should therefore be considered a valuable option for reconstruction of the distal femur after osteosarcoma resection. The surgical implementation is demanding though, which is emphasized by the considerable high number of com-plications requiring surgical intervention, even though most were not serious

Purpose:. To assess the outcomes of osteosarcoma cases managed between January 2006 & December 2010 in a tertiary centre. Methods:. A retrospective review of patient records. Results. Twenty eight consecutive cases of osteosarcoma managed over 5 years were reviewed retrospectively. 16 patients were male, and ages ranged from 11 to 69 years, with 20 patients in their 2nd decade. The distal femur was involved in 17 cases and the proximal tibia in 4. Histologically 13 cases were osteoblastic, 4 chondroblastic and the rest other forms of osteosarcoma. Tumour size varied from 6 to 35 cm, with only 6 less than 10 cm in size. Metastases were present on admission in 14 cases, and 2 more developed metastases within 2 months. One patient was Enneking Stage IIA, 13 Stage IIB and 14 Stage III at presentation. 3 patients refused any treatment. 4 cases were considered inoperable and died within days. Chemotherapy was started in 17 patients, and 4 additional patients who were considered for chemotherapy defaulted. 17 patients were treated by amputation, achieving local control in all cases at last follow up. A single patient had a wide tumour resection and prosthetic reconstruction. 5 patients are disease free at average 16 months survival, while 3 have survived an average of 13 months with metastases. 9 patients were lost to follow up, 7 are known and 4 are presumed to be dead. Conclusion:. These results show the problems of managing osteosarcoma in the public sector. Patients are referred far too late, tumours are so large that most require amputation, half the patients have metastases at presentation and some are preterminal. Many patients refuse amputation or default from chemotherapy. Results of treatment of osteosarcoma in the public sector are discouraging mostly due to late referral. Education of medical personnel to refer suspicious bone lesions without delay is the only way to improve outcomes

The poor prognosis of patients with advanced bone and soft-tissue sarcoma has highlighted the necessity for new therapeutic approaches. T-cell based immunotherapies are a promising alternative to traditional cancer treatments due to their ability to target only malignant cells, leaving benign cells unharmed. The development of successful immunotherapy requires the identification of targetable immunogenic tumor antigens. Cancer-testis antigens (CTA) are a group of highly immunogenic tumor-associated proteins that have emerged as potential targets for CD8+ T-cell recognition. The goal of this study is to screen for CTA expression, HLA expression, and tumor T-cell infiltration in human dedifferentiated liposarcoma (DDLPS) and osteosarcoma (OS) to establish their immune profile and to identify targetable immunogenic antigens for T-cell based immunotherapy. Human tissue micro-arrays composed of 78 cores of OS and 50 cores of DDLPS were obtained, along with matched control tissues from the same patients. IHC for the cancer testis antigens NY-ESO-1, MAGE-A3, and SSX2, was performed, and the staining results were scored by two authors based on maximal staining intensity on a scale of zero to three (absent=0, weak=1, moderate=2, or strong=3) and the percentage of tumor cells that stained. IHC for CD8 and CD3 was also performed, and T-cell tumor infiltration was defined as either brisk, nonbrisk, or absent, as described in melanoma literature. Concurrently, evaluation of 38 human DDLPS specimens and 10 healthy human fat specimens by the Nanostring nCounter platform is underway for identification of novel antigen targets and to establish the immune profile of DDLPS. Immunohistochemical analysis of CTA expression showed considerable inter- and intra-tumoral heterogeneity. DDLPS showed relatively low expression of all CTAs tested, with only 22% of samples exhibiting MAGE-A3 and one sample each (3.1%) showing expression of SSX2 and NY-ESO-1 in low percentages of tumor cells. By contrast, in osteosarcoma, 74% of samples expressed MAGE-A3 and 68% expressed SSX, both with >80% of positive cases showing moderate to high expression. NY-ESO-1 was expressed in 41% of OS samples, predominantly at low levels. Brisk infiltration of CD8+ T cells was observed in over 70% of both sarcoma types tested. Furthermore, all sarcoma samples tested were positive for HLA expression. To date, these results show promising expression of CTAs MAGE-A3 and SSX in OS, which may be used as targets in the future development of an immunotherapy for sarcoma. DDLPS shows relatively low expression, highlighting the need for more exploratory study with NanoString. The data generated throughout this project will provide insight into the immune profile of DDLPS

Background. Membrane type 1 matrix metalloproteinase (MT1-MMP) plays a role in the progression of several common solid cancers. Given that osteosarcoma features extensive local invasion and haematogenous metastases, we hypothesised that osteosarcoma cells utilise MT1-MMP to drive these processes. Moreover, since hypoxia regulates MT1-MMP expression in breast cancer we investigated the effects of hypoxia on MT1-MMP expression in osteosarcoma cells. Aims. Examination of MT1-MMP expression in osteosarcoma biopsy tissue in relation to clinical outcome. Assessment of MT1-MMP, together with hypoxia inducible factors HIF-1α and HIF-2α expression in a panel of osteosarcoma cell lines under normoxia and hypoxia. Methods. Immunohistochemistry: Formalin-fixed and paraffin embedded osteosarcoma biopsy samples from 71 patients were immunostained for MT1-MMP, HIF-1α and -2α and the data correlated with patient survival. Confocal microscopy: following 24 hours culture in 20% versus 1% oxygen, a panel of osteosarcoma cell lines were analysed for the subcellular distribution of MT1-MMP, HIF-1α and -2α. Subcellular fractionation: following 48 hours culture in 20% versus 1% oxygen, the U2OS cell line was fractionated and the compartmental lysates immunoblotted for MT1-MMP, HIF-1α and -2α. Results. Immunohistochemistry showed MT1-MMP immunopositive cytoplasmic and nuclear staining. Biopsy samples with the highest MT1-MMP and HIF-2α intranuclear staining correlated with reduced patient survival: HR 16.10; (95% CI: 5.1–40.3); p< 0.0001. In vitro studies confirmed the intranuclear MT1-MMP presence with an increased nuclear fraction in hypoxia and evidence of nuclear co-localisation with HIF-2α. Conclusions. MT1-MMP expression in osteosarcoma tissue correlates with patient survival. The functional significance of the increased intranuclear presence in hypoxia warrants further investigation

To set up an osteosarcoma mouse model with spontaneous lung metastasis and to identify a marker of osteosarcoma metastasis and to inhibit the marker against the invasive ability of an osteosarcoma cell line. A human osteosarcoma orthotopic mouse model was set up by injecting 143B human osteosarcoma cells into mouse tibia. Type I insulin-like growth factor receptor (IGF-1R) and its downstream signalling factors were measured in samples from the primary tumor and the lung secondaries by immunohistochemistry. Human Alu mRNA expression was tested using in situ hybridization assay. A Matrigel assay was used to assess cell invasion ability under the interference of a MEK/ERK pathway specific inhibitor, U0126. All fifteen mice showed tumour mass at the left tibia and lung metastasis. Human Alu expression in the primary and secondary tumours confirmed human origin of the tumour cells. Total IGF-1R, MEK, Akt, p38 and phosphorylated MEK (p-MEK), but not p-Akt and p-p38, were positive in both local tumours and lung secondaries. Leiomyosarcoma controls expressed p-Akt and p-MEK, but not p-p38. The 143B cells treated with U0126 had significantly lower in vitro invasion ability compared with controls. The IGF-1R-MEK signalling pathway, particularly Ras/Raf/MEK/ERK, may play an important role in osteosarcoma lung metastasis, and the targeting MEK/ERK by its specific inhibitor may have a potential use in the effective treatment of osteosarcoma

Osteosarcoma (OSA) is a rare, but disproportionately lethal cancer that predominantly affects children. Sadly, discovery of new therapies for OSA has largely been unsuccessful in the past 30 years; there is an urgent need to identify new treatments for OSA. Pet dogs with naturally-occurring OSA represent a unique comparative “model” to discover new treatments for OSA. Unlike humans, in which fewer than 1,000 cases of OSA occur each year, there are nearly 50,000 new cases each year of OSA in dogs. In addition, dogs have an intact immune system, a shared environment with humans, and more rapid progression of disease. Together these factors make dogs an important comparative model for new therapies for OSA. The purpose of this study was: 1) to validate this mouse-dog-human pipeline for drug discovery and 2) to validate CRM1 as a novel target for ostesoarcoma treatment. We developed patient-derived cell lines and xenografts of OSA from both dogs and humans and applied these models to identify new therapies for OSA using high-throughput drug screens in vitro followed by in vivo validation. Whole exome sequencing was performed on the patient-derived models and original tumors to identify potential driver mutations. A high-throughput screen in both dog and human OSA identified CRM1 inhibitors as effective at killing dog and human OSA patient-derived cell lines in vitro. In vivo, CRM1 inhibition led to significant tumor growth inhibition in patient-derived xenografts from dogs and humans. Western blotting demonstrated increased levels of CRM1 protein expression across nine different dog and human OSA cell lines compared to non-transformed human osteoblasts. CRM1 upregulation in OSA cells was further verified by immunofluorescence staining. Increased CRM1 expression was prognostic for poorer metastasis-free survival and poorer overall survival. Our cross-species personalized medicine pipeline identified CRM1 as a potential therapeutic target to treat OSA in both dogs and humans. Future studies are focused on testing CRM1 inhibitors in canine clinical trials

Introduction. We conducted a retrospective study of 61 patients, suffering from osteosarcoma, who presented to the CMJAH tumour Unit between 2007 and 2011. Results. The average time to presentation to the unit, post-onset of symptoms, was 4.5 months. Most patients, 43/61 (70%), presented initially to a hospital or clinic; only 3/61patients (5%) presented first to traditional healers and 15/61 (25%) to a GP. 16 patients (26%) came from other South African provinces and 3 patients (5%) were international. 3 Patients (5%) presented with a pathological fracture. 3/61 (5%) patients were HIV positive, 8 unknown and the rest were HIV negative. A standard osteosarcoma work-up was performed. 4 patients (7%) were Enneking Stage 2A, 41 patients (67%) were Stage 2B and 16 patients (26%) presented with metastases (Stage 3). Biopsy was performed on average of 3 weeks post-presentation (delay largely due to MRI). Surgery was undertaken in 46 patients (75%), with the aim of achieving wide local resection margins: 13 (21%) limb salvage procedures and 33 (79%) limb ablations were performed. 4 patients refused further treatment. 54/57 patients (95%) underwent chemotherapy and, of these, 44 (81%) underwent a neo-adjuvant chemotherapy protocol and 2 patients (4%) received post-adjuvant chemotherapy only. 19/61 patients (31%) defaulted follow-up: of these 19 patients, 15 (79%) were amputees, 1 (5%) was a limb salvage patient and 4 (16%) were un-operated. Two patients developed local recurrence: 1 was treated with amputation & the other with further excision. Palliative Radiotherapy was administered to 2 patients. In March 2013, 41 patients were contactable. Of these, 17/41 (41%) were alive and of the surviving 17 patients, 9 (81%) were limb salvage patients and 6 (38%) were amputees. Of the 12 patients, who had initially presented with metastases, only I patient (8%) was alive. Only 1 of the 3 patients, who initially presented with pathological fracture, was traceable and alive. NO DISCLOSURES

Background. Decisions about local treatment are important in osteosarcoma treatment. The purpose of this study was to review decisions about local treatment in one centre. Methods. This was a retrospective review of the records of all patients with high-grade extremity osteosarcoma presenting to our centre between 1997 and 2008. Particular attention was paid to local control decisions. Results. 54 patients were included, 37 were male. Median age was 18 (4.1 to 71.3 years). The anatomical location was distal femur in 33, tibia in 8, humerus in 7, ankle/foot in 3, fibula in 2 and clavicle in 1. 8 (14.8%) patients had metastases at presentation. 13 (24.1%) patients underwent primary amputation, predominantly in the early years of the series. The remaining 41 patients had limb-sparing surgery, 5 of whom had microscopically positive margins. 21 of 54 (38.8%) had >90% necrosis in the resected tumour. 3 patients had poor necrosis and positive margins. These were a 70 yo intolerant of chemotherapy, who refused amputation, developed LR and metastatic disease; a 15 yo with metastatic disease, who had a secondary amputation and metastatectomy and survived and a 43 yo who developed metastases and LR on chemotherapy. 4 further patients had local recurrence after LSS. All had poor necrosis after chemotherapy but adequate margins. All developed metastatic disease and 3 have died. Overall survival was 60%. 5-year survival without metastatic disease at presentation was 65%. Conclusion. Our series is similar to other centres. Challenges include older patients, poor response to chemotherapy and metastases

Introduction. Due to its remarkable stoichiometric flexibility and surface chemistry, hydroxyapatite (HAp) is the fundamental structural material in all vertebrates. Natural HAp's properties inspired an investigation into silicon nitride (Si. 3. N. 4. ) to see if similar functionality could be engineered into this bioceramic. Biological and in situ spectroscopic analyses were used to monitor the response of osteosarcoma cells (SaOS-2) to surface-modulated Si. 3. N. 4. and a titanium alloy after long-term in vitro exposure. Materials and Methods. Four groups of Si. 3. N. 4. discs, Ø12.7×1.0mm, (Amedica Corporation, Salt Lake City, UT USA) were subjected to surface treatments: (i) “As-fired;” (ii) HF-etched (5% HF solution for 45 s); (iii) Oxidized (1070°C for 7 h); and (iv) Nitrogen-annealed (1400°C for 30 min, 1.1 bar N. 2. gas). 1. Titanium alloy discs (Ti6Al4V, ASTM F136) were used as a control group. SaOS-2 cells cultured for 24 h at 37. °. C were deposited (5×10. 5. cells/ml) and incubated on the UV sterilized discs in an osteogenic medium for 7 days at 37°C. Cell proliferation was monitored using scanning electron and laser microscopy. The Receptor Activator of NF-kB Ligand (sRANKL) and the insulin growth factor 1 (IGF-1) were used to evaluate osteoclast formation and cell proliferation efficiency, respectively. In situ Raman spectroscopy was employed to monitor metabolic cell activity. Statistics (n≥3) were analyzed using the Student's t-test or one-way Analysis of Variance with p<0.05 considered significant. Results. Results are presented in Figure 1(a)∼(c) for HAp formation, free sRANKL, and IGF-1, respectively. These data indicate that the N. 2. -annealed Si. 3. N. 4. samples had the highest amount of HAp formation followed by the as-fired, oxidized, and HF samples. The Ti-alloy showed moderate HAp formation; but it had a higher amount of free sRANKL as compared to all Si. 3. N. 4. samples. These data suggest that the Si. 3. N. 4. represented a friendlier environment for SaOS-2 cell differentiation. The IGF-1 concentration did not differ among the Si. 3. N. 4. samples, but they were all higher than the Ti-alloy. Higher IGF-1 stimulates cells to proliferate and differentiate. 2. In Figure 2, in situ collected Raman spectra confirmed enhanced formation of HAp on the Si. 3. N. 4. samples, especially the N. 2. -annealed material. Discussion. Enhanced apatite formation was found to originate from a high density of positively charged surface groups, including nitrogen vacancies (V. N. 3+. ) and nitrogen N-N bonds (N. 4+. ). 3. These surface charges promoted binding of proteins onto the negatively charged Si. 3. N. 4. surface. A dipole-like-charge of V. N. 3+. /N. 4+. and SiO. −. defective sites is proposed as a mechanism to explain the attraction between proteins and the COO. −. and NH. 2+. terminus, respectively. This is analogous to the mechanism occurring in hydroxyapatite where protein groups are displaced by positively charged calcium loci (Ca. +. ) and off-stoichiometry phosphorus sites (PO. 4. 2−. ). Conclusion. Osteoblast proliferation and apatite-growth are important properties in regenerative bone therapies. In general, these properties were pronounced on all of the Si. 3. N. 4. substrates; but achieved maximum values on the N. 2. -annealed Si. 3. N. 4.

Ewing sarcoma (ES) and Osteosarcoma (OS) are the 2 most common malignant primary bone tumors. A patient's response to neoadjuvant chemotherapy has important implications in subsequent patient management and prognosis, as a favourable response to chemotherapy allows orthopedic oncologists to be more aggressive in pursuing limb-sparing surgery. An accurate and non-invasive pre-operative marker of response would be ideal for planning surgical margins and as a prognostic tool. ES and OS have differing biological characterisitcs and respond differently to chemotherapy. We reviewed 18F-FDG PET imaging characteristics of ES and OS patients at baseline and following treatment to determine whether this biological variation is reflected in their imaging phenotype. A retrospective review of ES and OS patients treated with neoadjuvant chemotherapy and surgery was done, correlating PET results with histologic response to chemotherapy. Change in the maximum standardized Uptake Value (SUVmax) between baseline and post-treatment scanning was not significantly associated with histologic response for either ES or OS. Metabolic tumor volume (MTV) and the percentage of injected 18F-FDG dose (%ID) in the primary tumor were found to be different for ES and OS response subgroups. A 50% reduction in MTV (MTV2:1 < 0.5) was found to be significantly associated with histologic response in OS. Using the same criteria for ES incorrectly predicted good responders. Increasing the cut-offs for ES to a 90% reduction in MTV (MTV 2:1 < 0.1) resulted in association with histologic response. Response to neoadjuvant chemotherapy as reflected by changes in PET characteristics should be interpreted differently for ES and OS

Purpose. Ewings Sarcoma (ES) and Osteosarcoma (OS) behave and respond differently to chemotherapy and any interpretation of diagnostics tests to predict a patients response to treatment must consider this. We reviewed 18F-FDG PET imaging characteristics of consecutive series of ES and OS patients to determine if any differences in PET imaging existed between them. Method. A retrospective review was performed of 31 patients with ES and OS who received all their treatment by our group and who had pre- and post-chemotherapy 18F-FDG PET scans at the Peter MacCallum Cancer Centre from Jan 1, 1999 to December 1, 2009 (Table 1). Patients who did not have both their pre- and post-chemotherapy PET scans done at Peter MacCallum Cancer Centre were excluded from the study to remove bias from having different PET scanning protocols. Patients received neoadjuvant chemotherapy according to standard protocols, all starting within 2 weeks after the initial pre-chemotherapy PET scans (PET1). The PET scan taken after the last cycle of chemotherapy prior to surgery was considered as the post-chemotherapy scan (PET2). The ratio between pre and post-chemotherapy for each PET parameter was then associated with the histology response for both ES and OS, and positive (PPV) and negative predicting values (NPV) of each parameter were calculated. Results. Standardized Uptake Values (SUV) was not significantly associated with histologic response for both ES and OS. Metabolic tumor volume (MTV) and accumulation percentage of 18F-FDG (%ID) was found to be different for ES and OS. A 50% reduction in MTV (MTV2:1 < 0.5) was found to be significantly associated with histologic response in OS. Using the same criteria for ES incorrectly predicted good responders. Increasing the cut-offs for ES to a 90% reduction in MTV (MTV 2:1 < 0.1) resulted in association with histologic response. Conclusion. Response to neoadjuvant chemotherapy as reflected by changes in PET characteristics should be interpreted differently for ES and OS

Fifty-six patients with stage II-B osteosarcoma around the knee were followed-up for a minimum of 92 months. The percentage of tumour cells expressing VEGF/MMP-9 was assessed using immunohistochemistry. The relationship between VEGF/MMP-9 expression and survival was assessed using Kaplan-Meier and Cox regression models. Patients with tumours expressing VEGF in >25% of their cells had shorter overall (p=0.019) and disease-free survival (p=0.009). Patients with tumours expressing MMP-9 had shorter overall (p=0.0042) and disease-free survival (p=0.0004). There was an association between VEGF and MMP-9 expression (p=0.021). The negative effects of VEGF/MMP-9 expression on survival were independent of traditional prognostic factors

Radiation induced sarcoma of bone is a rare but challenging disease process associated with a poor prognosis. To date, series are limited by small patient numbers; data to inform prognosis and the optimal management for these patients is needed. We hypothesized that patients with radiation-induced pelvic bone sarcomas would have worse surgical, oncologic, and functional outcomes than patients diagnosed with primary pelvic bone sarcomas. This was a multi-institution, comparative cohort analysis. A retrospective chart review was performed of all patients diagnosed with a radiation-induced pelvic and sacral bone sarcoma between January 1st, 1985 and January 1st, 2020 (defined as a histologically confirmed bone sarcoma of the pelvis in a previously irradiated field with a minimum 3-year interval between radiation and sarcoma diagnosis). We also identified a comparison group including all patients diagnosed with a primary pelvic osteosarcoma/spindle cell sarcoma of bone (i.e. eligible for osteosarcoma-type chemotherapy) during the same time interval. The primary outcome measure was disease-free and overall survival. We identified 85 patients with primary osteosarcoma of the pelvis (POP) and 39 patients with confirmed radiation induced sarcoma of the bony pelvis (RISB) undergoing surgical resection. Patients with RISB were older than patients with POP (50.5 years vs. 36.5 years, p67.7% of patients with POP underwent limb salvage as compared to 77% of patients with RISB; the type of surgery was not different between groups (p=.0.24). There was no difference in the rate of margin positive surgery for RISB vs. POP (21.1% vs. 14.1%, p=0.16). For patients undergoing surgical resection, the rate of surgical complications was high, with more RISB patients experiencing complications (79.5%) than POP patients (64.7%); this approached statistical significance (p=0.09). 15.4% of patients with RISB died perioperative period (within 90 days of surgery) as compared to 3.5% of patients with POP (p= 0.02). For patients undergoing surgical resection, 5-year OS was significantly worse for patients with RISB vs. POP (27.3% vs. 47.7%, p=0.02). When considering only patients without metastatic disease at presentation, a significant difference in 5-year survival remains for patients with RISB vs. POP (28.6% vs. 50%, p=0.03) was a trend towards poorer 5-year DFS for patients with RISB vs. POP (30% vs. 47.5%), though this did not achieve statistical significance (p=0.09). POP and RISB represent challenging disease processes and the oncologic outcomes are similarly poor between the two; however, the disease course for patients with RISB appears to be worse overall. While surgery can result in a favorable outcome for a small subset of patients, surgical treatment is fraught with complications

The management of primary malignant bone tumors with metastatic disease at presentation remains a challenge. While surgical resection has been shown to improve overall survival among patients with non-metastatic malignant bone tumors, current evidence regarding the utility of surgery in improving overall survival in metastatic patients remains limited. The 2004–2016 National Cancer Database (NCDB) was queried using International Classification of Diseases 3rd Edition (ICD-O-3) topographical codes to identify patients with primary malignant bone tumors of the extremities (C40.0-C40.3, C40.8 and C40.9) and/or pelvis (C41.4). Patients with malignant bone tumors of the axial skeleton (head/skull, trunk and spinal column) were excluded, as these cases are not routinely encountered and/or managed by orthopaedic oncologists. Histological codes were used to categorize the tumors into the following groups - osteosarcomas, chondrosarcomas, and Ewing sarcomas. Patients who were classified as stage I, II or III, based on American Joint Commission of Cancer (AJCC) guidelines, were excluded. Only patients with metastatic disease at presentation were included in the final study sample. The study sample was divided into two distinct groups – those who underwent surgical resection of the primary tumors vs. those who did not receive any surgery of the primary tumor. Kaplan-Meier survival analysis was used to report unadjusted 5-year overall survival rates between patients who underwent surgical resection of the primary tumor, compared to those who did not. Multi-variate Cox regression analyses were used to assess whether undergoing surgical resection of the primary tumor was associated with improved overall survival, after controlling for differences in baseline demographics, tumor characteristics (grade, location, histological type and tumor size), and treatment patterns (underwent metastatectomy of distal and/or regional sites, positive vs. negative surgical margins, use of radiation therapy and/or chemotherapy). Additional sensitivity analyses, stratified by histologic type for osteosarcomas, chondrosarcomas and Ewing sarcomas, were used to assess prognostic factors for overall survival. A total of 2,288 primary malignant bone tumors (1,121 osteosarcomas, 345 chondrosarcomas, and 822 Ewing sarcomas) with metastatic disease at presentation were included – out of which 1,066 (46.0%) underwent a surgical resection of the primary site. Overall 5-year survival rates, on unadjusted Kaplan-Meier log-rank analysis, were significantly better for individuals who underwent surgical resection vs. those who did not receive any surgery (31.7% vs. 17.3%; p<0.001). After controlling for differences in baseline demographics, tumor characteristics and treatment patterns, undergoing surgical resection of primary site was associated with a reduced overall mortality (HR 0.42 [95% CI 0.36–0.49]; p<0.001). Undergoing metastectomy (HR 0.92 [95% CI 0.81–1.05]; p=0.235) was not associated with a significant improvement in overall survival. On stratified analysis, radiation therapy was associated with improved overall survival for Ewing Sarcoma (HR 0.71 [95% CI 0.57–0.88]; p=0.002), but not for osteosarcoma (HR 1.14 [95% CI 0.91–1.43]; p=0.643) or chondrosarcoma (HR 1.08 [95 % CI 0.78–1.50]; p=0.643). Chemotherapy was associated with improved overall survival for osteosarcoma (HR 0.50 [95% CI 0.39–0.64]; p<0.001) and chondrosarcoma (HR 0.62 [95% CI 0.45–0.85]; p=0.003), but not Ewing sarcoma (HR 0.79 [95% CI 0.46–1.35]; p=0.385). Surgical resection of the primary site significantly improves overall survival for primary malignant bone tumors with metastatic disease at presentation. Physicians should strongly consider surgical resection of the primary tumor, with adjunct systemic and/or radiation therapy (dependent on tumor histology), in patients presenting with metastatic disease at presentation

Primary malignant bone tumours are a scarce entity with limited population-based data from developing countries. The aim of the study is to investigate the frequency and anatomical distribution of primary malignant bone tumours in a local South African population. This will be an epidemiological retrospective study. Data will be used of patients that were diagnosed with primary malignant bone tumours over a period of nine years spanning from 1 January 2014 to 31 December 2022. This data will be received from private and government laboratories. Data to be considered are type of primary malignant bone tumours diagnosed, incidence of primary malignant bone tumours over a period of nine years and the most common anatomical sites of primary malignant bone tumours. The rationale behind our study is to assess the frequency of different primary malignant bone tumours in another geographic area of South Africa and to compare these findings to local and international literature. With a projected increase in diagnosis of primary malignant bone tumours in developing countries it is important to have more available data about primary malignant bone tumours from these areas to have a better understanding of these conditions and to understand the impact of the burden they impose on healthcare systems so that management of these conditions can also be improved. Preliminary results show that 23.83% of primary malignant bone tumours occurred in the age group 0–24 years of age, 49.22% in the 25–59 age group and 26.95% in the 60+ age group. The most common tumour that occurred was chondrosarcoma (49.21%) followed by osteosarcoma (41.80%) then Ewing's sarcoma (4,69%) and lastly chordoma (4.30%). From the 256 samples that met the inclusion criteria the five most common anatomical sites were distal femur (63), proximal tibia (41), proximal humerus (38), pelvis (34) and proximal femur (20)