The role of radiotherapy in oseosarcoma

Treatment and survival of osteosarcoma and Ewing sarcoma of the skull: a SEER database analysis

Background

Common primary bone tumors include osteosarcomas (OSC) and Ewing sarcomas (EWS). The skull is a rare site, and literature about their treatment and survival is scarce. Using the Surveillance, Epidemiology, and End Results (SEER) database, this study aims to assess the treatment and survival of skull OSC and skull EWS, as well as predictors for survival.

Methods

Skull OSC and EWS cases were obtained from the SEER database. Patient and tumor characteristics, treatment modalities, and survival were extracted. Overall survival (OS) was assessed using multivariable Cox proportional hazard regression stratified by tumor histology. Kaplan-Meier curves were constructed for OS comparing OSC and EWS, as well as histological subtypes in OSC.

Results

A total of 321 skull OSC and 80 skull EWS patients were registered from 1973 to 2013. EWS was more common in younger patients (p < 0.001). Resection was the predominant treatment strategy (80.1%), frequently in combination with adjuvant radiotherapy (30.4%). The 5-year survival rate varied significantly between OSC and EWS (51.0% versus 68.5%, p = 0.02). Kaplan-Meier curves show that EWS had a significantly better survival compared to OSC. Comparing histological subtypes of skull OSC, chondroblastic OSC had the best OS, Paget OSC the worst. Older age, tumor advancement, no surgical treatment, and the use of radiotherapy were identified as independent predictors of decreased OS in skull OSC.

Conclusion

Overall prognosis is better for EWS compared to OSC. Chondroblastic OSC have the best overall survival, while OSC associated with Paget’s disease of the bone has the poorest overall survival.

Simvastatin exerts anticancer effects in osteosarcoma cell lines via geranylgeranylation and c-Jun activation

Osteosarcoma is the leading primary bone cancer in young adults and exhibits high chemoresistance rates. Therefore, characterization of both alternative treatment options and the underlying mechanisms is essential. Simvastatin, a cholesterol-lowering drug, has among its pleiotropic effects anticancer potential. Characterizing this potential and the underlying mechanisms in osteosarcoma is the subject of the present study. Human osteosarcoma cells (SaOS-2 and U2OS) were treated with simvastatin (4-66 µM) for 48 or 72 h. The effects of downstream substrate mevalonate (MA) or substrates for isoprenylation farnesyl pyrophosphate (FPP) and geranylgeranyl-pyrophosphate (GGPP) were evaluated using add-back experiments. Tumour growth using MTT assay, apoptosis, cell cycle and signalling cascades involved in simvastatin-induced manipulation were analysed. The results revealed that simvastatin dose-dependently inhibited cell growth. Simvastatin significantly induced apoptosis, increased the Bax/Bcl-2 ratio, and cleavage of caspase-3 and PARP protein. Simvastatin impaired cell cycle progression as shown by significantly increased percentages of cells in the G0/G1 phase and lower percentages of cells in the S phase. Gene expression levels of cell cycle-regulating genes (TP53, CDKN1A and CDK1) were markedly altered. These effects were not completely abolished by FPP, but were reversed by MA and GGPP. JNK and c-Jun phosphorylation was enhanced after simvastatin treatment, while those were abolished when either MA or GGPP were added. In conclusion, simvastatin acts primarily by reducing prenylation to induce apoptosis and reduce osteosarcoma cell growth. Particularly enhanced activation of c-Jun seems to play a pivotal role in osteosarcoma cell death.

Zoledronic acid is an effective radiosensitizer in the treatment of osteosarcoma

To overcome radioresistance in the treatment of osteosarcoma, a primary malignant tumor of the bone, radiotherapy is generally combined with radiosensitizers. The purpose of this study was to investigate a third-generation bisphosphonate, zoledronic acid (ZOL), as a radiosensitizer for osteosarcoma. We found that exposure of KHOS/NP osteosarcoma cells to 20 μM ZOL decreased the γ-radiation dose needed to kill 90% of cells. This radiosensitizing effect of ZOL was mediated through decreased mitochondrial membrane potential, increased levels of reactive oxygen species, increased DNA damage (as assessed by counting γ-H2AX foci), decreased abundance of proteins involved in DNA repair pathways (ATR, Rad52, and DNA-PKcs), and decreased phosphorylation of PI3K-Akt and MAPK pathway proteins (Raf1, MEK1/2, ERK1/2, and Akt), as compared to γ-irradiation alone. Cells treated with ZOL plus γ-irradiation showed impaired cell migration and invasion and reduced expression of epithelial-mesenchymal transition markers (vimentin, MMP9, and Slug). In Balb/c nude mice, the mean size of orthotopic osteosarcoma tumors 2 weeks post-inoculation was 195 mm³ following γ-irradiation (8 Gy), while it was 150 mm³ after γ-irradiation plus ZOL treatment (0.1 mg/kg twice weekly for 2 weeks). These results provide a rationale for combining ZOL with radiotherapy to treat osteosarcoma.

Osteosarcoma of the Pelvis: A Monoinstitutional Experience in Patients Younger than 41 Years

Aims and background

Information is scarce on systemic treatment of pelvic osteosarcoma because most chemotherapy protocols for osteosarcoma include patients with extremity tumors and aged up to 30–40 years.

Methods

Data on patients <41 years of age with high-grade pelvic osteosarcoma were prospectively collected. Patients received two chemotherapy protocols consisting of methotrexate, cisplatin, doxorubicin (MAP) and standard-dose or high-dose ifosfamide.

Results

Forty patients between 11 and 36 years were included. The most frequent histological subtype was osteoblastic followed by chondroblastic (37.5%). Complete surgical remission was achieved in 65% of patients. Eighteen patients had MAP/standard-dose ifosfamide, 22 MAP/high-dose ifosfamide. Primary chemotherapy was given to 25 patients and 6 (24%) of them had a good histological response. Median follow-up was 32 months (range, 4–134). Five-year overall survival was 27.5%: 33% in localized and 0 in metastatic patients (P = 0.02); 45% in patients with complete surgical remission and 0 for patients without complete surgical remission (P = 0.001). Local recurrence rate was 46%. In patients with complete surgical remission, 5-year overall survival was 32% with MAP/standard-dose ifosfamide and 59% with MAP/high-dose ifosfamide regimen (P = 0.3).

Conclusions

Local control is the major issue in the treatment of pelvic osteosarcoma. Poor pathological response and high incidence of chondroblastic variant indicate different characteristics between pelvic and extremity osteosarcoma. Chemotherapy with MAP and high-dose ifosfamide might be beneficial in patients with pelvic osteosarcoma and warrants further investigation.

Local Control of Soft Tissue and Bone Sarcomas

Sarcomas of soft tissue and bone are mesenchymal malignancies that can arise in any anatomic location, most commonly the extremity, retroperitoneum, and trunk. Even for lower grade histologic subtypes, local recurrence can cause significant morbidity and even disease-related death. Although surgery remains the cornerstone of local control, perioperative radiation and systemic therapy are often important adjuvants. This review will summarize the current therapeutic approaches for local control of soft tissue and bone sarcomas.

Malignant bone tumors (other than Ewing's): clinical practice guidelines for diagnosis, treatment and follow-up by Spanish Group for Research on Sarcomas (GEIS)

Primary malignant bone tumors are uncommon and heterogeneous malignancies. This document is a guideline developed by the Spanish Group for Research on Sarcoma with the participation of different specialists involved in the diagnosis and treatment of bone sarcomas. The aim is to provide practical recommendations with the intention of helping in the clinical decision-making process. The diagnosis and treatment of bone tumors requires a multidisciplinary approach, involving as a minimum pathologists, radiologists, surgeons, and radiation and medical oncologists. Early referral to a specialist center could improve patients' survival. The multidisciplinary management of osteosarcoma, chondrosarcoma, chordoma, giant cell tumor of bone and other rare bone tumors is reviewed in this guideline. Ewing's sarcoma will be the focus of a separate guideline because of its specific biological, clinical and therapeutic features. Each statement has been accompanied by the level of evidence and grade of recommendation on the basis of the available data. Surgical excision is the mainstay of treatment of a localized bone tumor, with various techniques available depending on the histologic type, grade and location of the tumor. Chemotherapy plays an important role in some chemosensitive subtypes (such as high-grade osteosarcoma). In other subtypes, historically considered chemoresistant (such as chordoma or giant cell tumor of bone), new targeted therapies have emerged recently, with a very significant efficacy in the case of denosumab. Radiation therapy is usually necessary in the treatment of chordoma and sometimes of other bone tumors.

miR‑328‑3p enhances the radiosensitivity of osteosarcoma and regulates apoptosis and cell viability via H2AX

Osteosarcoma is a kind of high-risk sarcoma of the skeleton typically observed in people under 25 years old. Currently, radiotherapy is widely applied in cancer treatment. However, osteosarcoma is radioresistant and accordingly new, more effective radiosensitizers are needed. miRNAs have been reported to play an important role in osteosarcoma radiosensitivity. We examined the modulating effect of miR-328-3p in vivo and in vitro. miR-328-3p was downregulated in HOS-2R cells. The overexpression of miR-328-3p enhanced the radiosensitivity of osteosarcoma cells. miR-328-3p inhibited proliferation and promoted apoptosis in osteosarcoma cells under radiation conditions. In cells overexpressing miR-328-3p, H2AX expression was downregulated. We found that miR-328-3p targets H2AX and inhibits its expression. It was concluded, that miR-328-3p enhances the radiosensitization of osteosarcoma following X-ray irradiation, and determined that it directly targets H2AX to regulate radiosensitization.

Radiosensitivity of human ovarian cancer cells is enhanced by pseudolaric acid B due to the inhibition of the Ras/Raf/ERK signaling pathway

Ovarian cancer has the highest mortality rate among gynecological cancers; the most effective therapy for this cancer is a combination of radiation treatment and chemotherapy. However, radiation resistance is the leading factor associated with treatment failure. The present study aimed to investigate pseudolaric acid B (PAB) as a potential radiosensitizer for the treatment of ovarian cancer. The present study performed MTT and clonogenic assays, and demonstrated that PAB could induce a radiosensitizing effect on SKOV-3 cells. An Annexin V/propidium iodide staining assay revealed that PAB exerted a radiosensitizing effect by inducing SKOV-3 cell apoptosis. In addition, western blot analysis demonstrated that the activity of the Ras/RAF proto-oncogene serine/threonine-protein kinase/extracellular signal-regulated kinase signaling pathway was reduced by combination therapy with PAB and irradiation. In conclusion, the present study establishes PAB as a radiosensitizer, and provides a rational basis for the use of PAB and irradiation as a combination therapy to treat ovarian cancer.

Natural product β-thujaplicin inhibits homologous recombination repair and sensitizes cancer cells to radiation therapy

Investigation of natural products is an attractive strategy to identify novel compounds for cancer prevention and treatment. Numerous studies have shown the efficacy and safety of natural products, and they have been widely used as alternative treatments for a wide range of illnesses, including cancers. However, it remains unknown whether natural products affect homologous recombination (HR)-mediated DNA repair and whether these compounds can be used as sensitizers with minimal toxicity to improve patients' responses to radiation therapy, a mainstay of treatment for many human cancers. In this study, in order to systematically identify natural products with an inhibitory effect on HR repair, we developed a high-throughput image-based HR repair screening assay and screened a chemical library containing natural products. Among the most interesting of the candidate compounds identified from the screen was β-thujaplicin, a bioactive compound isolated from the heart wood of plants in the Cupressaceae family, can significantly inhibit HR repair. We further demonstrated that β-thujaplicin inhibits HR repair by reducing the recruitment of a key HR repair protein, Rad51, to DNA double-strand breaks. More importantly, our results showed that β-thujaplicin can radiosensitize cancer cells. Additionally, β-thujaplicin sensitizes cancer cells to PARP inhibitor in different cancer cell lines. Collectively, our findings for the first time identify natural compound β-thujaplicin, which has a good biosafety profile, as a novel HR repair inhibitor with great potential to be translated into clinical applications as a sensitizer to DNA-damage-inducing treatment such as radiation and PARP inhibitor. In addition, our study provides proof of the principle that our robust high-throughput functional HR repair assay can be used for a large-scale screening system to identify novel natural products that regulate DNA repair and cellular responses to DNA damage-inducing treatments such as radiation therapy.

TNF-related apoptosis-inducing ligand (TRAIL) for bone sarcoma treatment: Pre-clinical and clinical data

Bone sarcomas are rare, highly malignant mesenchymal tumours that affect teenagers and young adults, as well as older patients. Despite intensive, multimodal therapy, patients with bone sarcomas have poor 5-year survival, close to 50%, with lack of improvement over recent decades. TNF-related apoptosis-inducing ligand (TRAIL), a member of the tumour necrosis factor (TNF) ligand superfamily (TNFLSF), has been found to induce apoptosis in cancer cells while sparing nontransformed cells, and may therefore offer a promising new approach to treatment. We cover the existing preclinical and clinical evidence about the use of TRAIL and other death receptor agonists in bone sarcoma treatment. In vitro studies indicate that TRAIL and other death receptor agonists are generally potent against bone sarcoma cell lines. Ewing's sarcoma cell lines present the highest sensitivity, whereas osteosarcoma and chondrosarcoma cell lines are considered less sensitive. In vivo studies also demonstrate satisfactory results, especially in Ewing's sarcoma xenograft models. However, the few clinical trials in the literature show only low or moderate efficacy of TRAIL in treating bone sarcoma. Potential strategies to overcome the in vivo resistance reported include co-administration with other drugs and the potential to deliver TRAIL on the surface of primed mesenchymal or immune cells and the use of targeted single chain antibodies such as scFv-scTRAIL.

Effect of low- and high-linear energy transfer radiation on in vitro and orthotopic in vivo models of osteosarcoma by activation of caspase-3 and -9

Osteosarcoma (OS) is a malignant tumor of the bone derived from primitive transformed cells of the mesenchymal origin. Local low-linear energy transfer (LET) radiotherapy has limited benefits on OS owing to its radioresistance. Thus, this study aimed to investigate the effects of high-LET radiation on human OS. Therefore, the human OS cell lines, U2O2 and KHOS/NP, were examined in vitro, or an orthotopic mouse xenograft model was studied in vivo after treatment with low-LET (gamma-ray) and high-LET (neutron) radiation. Notably, OS cells were significantly more sensitive to high-LET radiation in vitro and in the orthotopic xenograft tumor model. Specifically, neutron radiation treatment increased the relative percentage of apoptotic sub-G1 phase cells via caspase-3/9 activation; increased intracellular reactive oxygen species, autophagy, and DNA damage; and decreased invasion and migration. Similarly, the mean size of gamma-irradiated (8 Gy) orthotopic KHOS/NP OS was 195 mm³ at 6 weeks after gamma-irradiation (8 Gy), but it was only 150 mm³ in mice treated with high-LET neutron radiotherapy. Significantly, our results provide a rationale for the use of high-LET radiotherapy to treat patients with OS.

Understanding the potentiality of accelerator based-boron neutron capture therapy for osteosarcoma: dosimetry assessment based on the reported clinical experience

BACKGROUND

Osteosarcoma is the most frequent primary malignant bone tumour, and its incidence is higher in children and adolescents, for whom it represents more than 10% of solid cancers. Despite the introduction of adjuvant and neo-adjuvant chemotherapy that markedly increased the success rate in the treatment, aggressive surgery is still needed and a considerable percentage of patients do not survive due to recurrences or early metastases. Boron Neutron Capture Therapy (BNCT), an experimental radiotherapy, was investigated as a treatment that could allow a less aggressive surgery by killing infiltrated tumour cells in the surrounding healthy tissues. BNCT requires an intense neutron beam to ensure irradiation times of the order of 1 h. In Italy, a Radio Frequency Quadrupole (RFQ) proton accelerator has been designed and constructed for BNCT, and a suitable neutron spectrum was tailored by means of Monte Carlo calculations. This paper explores the feasibility of BNCT to treat osteosarcoma using this neutron source based on accelerator.

METHODS

The therapeutic efficacy of BNCT was analysed evaluating the dose distribution obtained in a clinical case of femur osteosarcoma. Mixed field dosimetry was assessed with two different formalisms whose parameters were specifically derived from radiobiological experiments involving in vitro UMR-106 osteosarcoma cell survival assays and boron concentration assessments in an animal model of osteosarcoma. A clinical case of skull osteosarcoma treated with BNCT in Japan was re-evaluated from the point of view of dose calculation and used as a reference for comparison.

RESULTS

The results in the case of femur osteosarcoma show that the RFQ beam would ensure a suitable tumour dose painting in a total irradiation time of less than an hour. Comparing the dosimetry between the analysed case and the treated patient in Japan it turns out that doses obtained in the femur tumour are at least as good as the ones delivered in the skull osteosarcoma. The same is concluded when the comparison is carried out taking into account osteosarcoma irradiations with photon radiation therapy.

CONCLUSIONS

The possibility to apply BNCT to osteosarcoma would allow a multimodal treatment consisting in neo-adjuvant chemotherapy, high-LET selective radiation treatment and a more conservative surgery.

Management of Bone Sarcoma

Treatment of bone sarcoma requires careful planning and involvement of an experienced multidisciplinary team. Significant advancements in systemic therapy, radiation, and surgery in recent years have contributed to improved functional and survival outcomes for patients with these difficult tumors, and emerging technologies hold promise for further advancement.

Advances in the management of osteosarcoma

Osteosarcoma, a bone cancer most commonly seen in adolescents and young adults, is usually a high-grade malignancy characterized by a very high risk for the development of pulmonary metastases. High-grade osteosarcomas are usually treated by preoperative and postoperative chemotherapy and surgery, with a very limited number of active agents available. Rarer lower-grade variants such as parosteal and periosteal osteosarcoma or low-grade central osteosarcoma are treated by surgery only. Imaging to search for possible metastases focuses on the lung. Computed tomography is the most sensitive method but cannot reliably distinguish small metastases from benign lesions. Advances of local imaging and surgical reconstruction now allow the use of limb-salvage in an ever-increasing proportion of patients. While still troubled by complications, non-invasive endoprosthesis-lengthening mechanisms have led to an increased uptake of limb-salvage, even for young, skeletally immature patients. Radiotherapy is employed when osteosarcomas cannot be removed with clear margins, but very high doses are required, and both proton and carbon-ion radiotherapy are under investigation. Unfortunately, the past 30 years have witnessed few, if any, survival improvements. Novel agents have not led to universally accepted changes of treatment standards. In patients with operable high-grade osteosarcomas, the extent of histological response to preoperative chemotherapy is a significant predictive factor for both local and systemic control. Attempts to improve prognosis by adapting postoperative treatment to response, recently tested in a randomized, prospective setting by the European and American Osteosarcoma Study Group, have not been proven to be beneficial. Many agree that only increased knowledge about osteosarcoma biology will lead to novel, effective treatment approaches and will be able to move the field forward.

Multimodal treatment of craniofacial osteosarcoma with high-grade histology. A single-center experience over 35 years

High-grade craniofacial osteosarcoma (CFOS) is an aggressive malignancy with a poor prognosis. Our goals were to evaluate treatment outcomes in those treated at a single referral institution over 35 years and to compare our results to the available literature. A retrospective analysis of all 42 patients treated between 1980 and 2015 at Oslo University Hospital, Norway, identified in a prospectively collected database, was conducted. Mean follow-up was 79.6 months. Overall survival at 2 and 5 years was 70.5 and 44.7%, respectively. The corresponding disease-specific survival rates were 73.0 and 49.8%. Treatment was surgery only in eight cases. Additional therapy was administered in 34 patients: chemotherapy in nine, radiotherapy in seven, and a combination of these in 18 cases. Stratified analysis by resection margins demonstrated significantly better survival at 2 and 5 years after radical surgical treatment. Neoadjuvant chemotherapy and subsequent adequate surgery resulted in better survival than surgery alone. Half of the patients either had a primary or familial cancer predisposition. This is the largest single-center study conducted on high-grade CFOS to date. Our experience indicates that neoadjuvant chemotherapy with complete surgical resection significantly improved survival, compared to surgery alone.

miR-513a-5p regulates radiosensitivity of osteosarcoma by targeting human apurinic/apyrimidinic endonuclease

Radiotherapy in osteosarcoma patients is problematic due to radioresistance; therefore, understanding the mechanism of radioresistance is integral to providing effective radiotherapeutic regimens for osteosarcoma. We now report the activity of an miRNA, miR-513a-5p, in stimulating radiosensitivity of osteosarcoma cells in vitro and in vivo. MiR-513a-5p expression is decreased in osteosarcoma tissue from patients and cultured osteosarcoma cell lines. However, exogenous re-expression of this miRNA in osteosarcoma cell lines, including HOS, U2OS and 9901, can induce sensitization to ionizing radiation. We also confirm that miR-513a-5p suppresses APE1 expression, and that both the redox and DNA repair activity of APE1 were decreased in miR-513a-5p expressing cell lines. By suppressing APE1, miR-513a-5p induces the DNA damage response which stimulates apoptosis after irradiation. Our report establishes miR-513a-5p as a radiosensitizing miRNA and identifies its activity in the suppression of APE1, which could directly lead to radiosensitization.

Targeted therapy of osteosarcoma with radiolabeled monoclonal antibody to an insulin-like growth factor-2 receptor (IGF2R)

INTRODUCTION

Osteosarcoma overall survival has plateaued around 70%, without meaningful improvements in over 30years. Outcomes for patients with overt metastatic disease at presentation or who relapse are dismal. In this study we investigated a novel osteosarcoma therapy utilizing radioimmunotherapy (RIT) targeted to IGF2R, which is widely expressed in OS.

METHODS

Binding efficiency of the Rhenium-188(¹⁸⁸Re)-labeled IGF2R-specific monoclonal antibody (mAb) to IGF2R on OS17 OS cells was assessed with Scatchard plot analysis. Biodistribution studies were performed in heterotopic murine osteosarcoma xenografts. Tumor growth was compared over a 24-day period post-treatment between mice randomized to receive ¹⁸⁸Re-labeled IGF2R-specific murine mAb MEM-238 (¹⁸⁸Re-MEM-238) or one of three controls: ¹⁸⁸Re-labeled isotype control mAb, unlabeled MEM-238, or no treatment.

RESULTS

Results demonstrate that the radioimmunoconjugate had a high binding constant to IGF2R. Both ¹⁸⁸Re-MEM-238 and the isotype control had similar initial distribution in normal tissue. After 48h ¹⁸⁸Re-MEM-238 exhibited a 1.8 fold selective uptake within tumor compared to the isotype control (p=0.057). Over 24days, the tumor growth ratio was suppressed in animals treated with RIT compared to unlabeled and untreated controls (p=0.005) as demonstrated by a 38% reduction of IGF2R expressing osteosarcoma cells in the RIT group (p=0.002).

CONCLUSIONS

In conclusion, given the lack of new effective therapies in osteosarcoma, additional investigation into this target is warranted.

ADVANCES IN KNOWLEDGE

High expression of IGF2R on osteosarcoma tumors, paired with the specificity and in vivo anti-cancer activity of ¹⁸⁸Re-labeled IGF2R-specific mAb suggests that IGF2R may represent a novel therapeutic target in the treatment of osteosarcoma.

IMPLICATIONS FOR PATIENT CARE

This targeted approach offers the benefits of being independent of a specific pathway, a resistance mechanism, and/or an inherent biologic tumor trait and therefore is relevant to all OS tumors that express IGF2R.

Genistein sensitizes sarcoma cells in vitro and in vivo by enhancing apoptosis and by inhibiting DSB repair pathways

The aim of this work was to investigate the radiosensitization effects of genistein on mice sarcoma cells and the corresponding biological mechanisms in vitro and in vivo Using the non-toxic dosage of 10 μM genistein, the sensitizer enhancement ratios after exposure to X-rays at 50% cell survival (IC50) was 1.45 for S180 cells. For mice cotreated with genistein and X-rays, the excised tumor tissues had reduced blood vessels and decreased size and volume compared with the control and irradiation-only groups. Moreover, a significant increase in apoptosis was accompanied by upregulation of Bax and downregulation of Bcl-2 in the mitochondria, and lots of cytochrome c being transferred to the cytoplasm. Furthermore, X-rays combined with genistein inhibited the activity of DNA-PKcs, so DNA-injured sites were dominated by Ku70/80, leading to incompleteness of homologous recombination (HR) and non-homologous end-joining (NHEJ) repairs and the eventual occurrence of cell apoptosis. Our study, for the first time, demonstrated that genistein sensitized sarcoma cells to X-rays and that this radiosensitizing effect depended on induction of the mitochondrial apoptosis pathway and inhibition of the double-strand break (DSB) repair pathways.

Adjuvant radiation therapy in resected high-grade localized skeletal osteosarcomas treated with neoadjuvant chemotherapy: Long-term outcomes

PURPOSE

To assess long-term outcomes and toxicity of adjuvant radiotherapy in the post-surgical management of patients with resected high-grade skeletal osteosarcomas.

METHODS AND MATERIALS

Seventy-two patients with primary resected osteosarcomas underwent adjuvant radiotherapy after neoadjuvant chemotherapy from December 1984 to December 2008. Local control (LC), overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier methods. For survival outcomes potential associations were assessed in univariate and multivariate analyses using the Cox proportional hazards model.

RESULTS

After a median follow-up of 174months (range, 33-363months), 10-year LC, DFS, and OS rates were 82%, 58%, and 73%, respectively. In the multivariate analysis only R1 margin status (p=0.02) remained significantly associated with LC. Patients with tumor necrosis <90% (p=0.04) and R1 resection margin (p=0.05) remained at a significantly higher risk of mortality on multivariate analysis. Six patients (8%) developed grade ⩾3 treatment-related chronic toxicity events. No grade 5 toxicities were reported.

CONCLUSIONS

A multimodal radiotherapy-containing approach is a well-tolerated component of treatment for patients with osteosarcomas undergoing programed resection, allowing low toxicity rates while maintaining high local control rates.

Radiotherapy and gemcitabine-docetaxel chemotherapy in children and adolescents with unresectable recurrent or refractory osteosarcoma

OBJECTIVE

Few reports have described the treatment outcome of osteosarcoma using radiotherapy. We evaluated the efficacy of radiotherapy and gemcitabine and docetaxel chemotherapy for patients with unresectable recurrent or refractory osteosarcoma.

METHODS

Data from six patients (five male, one female) who received radiotherapy and gemcitabine and docetaxel chemotherapy at the Korea Cancer Center Hospital were retrospectively reviewed. Tumor response was evaluated according to metabolic changes using (18)F-fluorodeoxy-D-glucose-positron emission tomography.

RESULTS

The median age of the patients was 15.0 years (range, 14.0-15.8 years). Two patients had single bone lesions, and four had multiple metastatic bone lesions. Patients received a median 3.5 courses of gemcitabine and docetaxel chemotherapy (range, 2-6 courses). The median dose of radiotherapy was 50.0 Gy (range, 46-84 Gy). There were two complete metabolic responses and one partial metabolic response. The objective response rate was 50.0% (3/6). Responses were maintained for 4.6, 6.1 and 13.7 months, respectively. Patients were followed up for a median of 5.8 months (range, 2.7-84.6 months), and the median progression-free survival after this treatment was 3.6 months (range, 1.1-13.7 months). At the time of analysis, two patients were alive, one was lost to follow-up and three had died.

CONCLUSION

Radiotherapy with gemcitabine and docetaxel chemotherapy showed some improvement in cases of refractory tumors or multiple bone metastases. Further studies are needed to investigate the efficacy of newer radiotherapy modalities, as well as to identify new radiosensitizing chemotherapy regimens.

Clinical Epidemiology of Low-Grade and Dedifferentiated Osteosarcoma in Norway during 1975 and 2009

Purpose. To describe epidemiological, clinical characteristics and treatment outcomes of low-grade osteosarcoma (LGOS), including dedifferentiated osteosarcoma (DLGOS). Method. We analysed a nationwide cohort comprised of patients with histologically verified LGOS and DLGOS between 1975 and 2009, based on registry sources supplemented with clinical records from hospitals involved in sarcoma management. Results. Fifty-four patients were identified, 12 of whom had DLGOS. The annual incidence for all patients was 0.3 per million, with the peak incidence in the third decade of the life. Fifteen patients experienced local relapses during follow-up and ten developed metastatic diseases, including three at primary diagnosis. Patients with DLGOS dominated the metastatic relapse group. The five-year sarcoma-specific survival rate was 91%, with no documented improvement over time. Free margin following surgical resection of the primary tumour had a positive impact on survival. As expected, both local relapse and metastasis during follow-up were associated with an unfavourable outcome. Radiotherapy predicted poor survival due to the selection of high-risk patients in need of such treatment. Neither higher age nor axial tumour localisation was adverse prognostic factors. Conclusion. LGOS has an excellent prognosis when surgically resected with a free margin; however, LGOS has the potential to dedifferentiate and metastasize with a poor outcome.

Inhibition of hypoxia-inducible factor-1 alpha radiosensitized MG-63 human osteosarcoma cells in vitro

AIMS AND BACKGROUND

Hypoxia is a fundamental microenvironmental component of osteosarcoma which induces activation of the hypoxia-inducible factor-1 (HIF-1) pathway. Overexpression of HIF-1α has been linked to tumor resistance to radio- or chemotherapy. However, little is known about the effects of HIF-1α inhibition on hypoxic radioresistance of human osteosarcoma cells. Here, we investigated the effects of HIF-1α inhibition on cell survival and radiosensitivity in the MG-63 human osteosarcoma cell line.

METHODS

HIF-1α inhibition was achieved by small interfering RNA (siRNA) targeting of HIF-1α or via chetomin. Inhibition of the HIF-1 pathway was determined by monitoring the expression levels of HIF-1α, carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) using quantitative real-time PCR and Western blot analyses. Clonogenic assay was performed after irradiation (2-10 Gy) to investigate the effect of HIF-1α inhibition on the radiosensitivity of human osteosarcoma cells under normoxic and hypoxic conditions.

RESULTS

Compared to the control groups, treatment with HIF-1α siRNA or chetomin significantly reduced the hypoxia-inducible radioresistance of MG-63 cells. However, siRNA and chetomin showed different effects on the radiosensitivity under normoxic conditions.

CONCLUSIONS

Our results indicate that inhibition of HIF-1α effectively decreases hypoxia-induced transcription and radiosensitizes hypoxic MG-63 human osteosarcoma cells in vitro.

Osteosarcoma in Korean children and adolescents

Osteosarcoma is the most frequent primary bone tumor. Advances in combination chemotherapy and surgical technique have greatly improved the survival of patients with osteosarcoma. In Korea, improvements in osteosarcoma treatment have been made over the past two decades. The 5-year event-free survival rate of Korean children and adolescents with localized disease is 64.6%, comparable to that of American or European patients. This article provides an overview of current therapies for osteosarcoma in Korea.

Prognostic factors and treatment results of high-grade osteosarcoma in norway: a scope beyond the "classical" patient

Purpose. A retrospective study of prognostic factors and treatment outcome of osteosarcoma (OS) during modern chemotherapy era with focus on patients with primary metastatic disease, nonextremity localisation, or age >40 years (nonclassical OS). Methods. A nationwide cohort, comprising 424 high-grade Norwegian bone OS patients, was based on registry sources supplemented with clinical records from hospitals involved in sarcoma management between 1975 and 2009. Results. Only 48% were younger patients with tumour in the extremities and without metastasis at diagnosis (classical OS). A considerable discrepancy in survival between classical and nonclassical OS was observed: 61% versus 26% 10-year sarcoma specific survival. Twice as many of the former received both adequate surgery and chemotherapy compared to the latter. This could only partly explain the differences in survival due to inherent chemoresistance in primary metastatic disease and a higher rate of local relapse among patients with axial tumours. Metastasis at diagnosis, increased lactate dehydrogenase, age > 40 years, and tumour size above median value were all adverse prognostic factors for overall survival. Conclusion. We confirm a dramatic difference in outcome between classical and nonclassical high-grade OS patients, but treatment variables could only partly explain the dismal outcome of the latter.

Dosimetry of a (90)Y-hydroxide liquid brachytherapy treatment approach to canine osteosarcoma using PET/CT

A new treatment strategy based on direct injections of (90)Y-hydroxide into the tumor bed in dogs with osteosarcoma was studied. Direct injections of the radiopharmaceutical into the tumor bed were made according to a pretreatment plan established using (18)F-FDG images. Using a special drill, cannulas were inserted going through tissue, tumor and bone. Using these cannulas, direct injections of the radiopharmaceutical were made. The in vivo biodistribution of (90)Y-hydroxide and the anatomical tumor bed were imaged using a time-of-flight (TOF) PET/CT scanner. The material properties of the tissues were estimated from corresponding CT numbers using an electron-density calibration. Radiation absorbed dose estimates were calculated using Monte Carlo methods where the biodistribution of the pharmaceutical from PET images was sampled using a collapsing 3-D rejection technique. Dose distributions in the tumor bed and surrounding tissues were calculated, showing significant heterogeneity with multiple hot spots at injection sites. Dose volume histograms showed that approximately 33.9% of bone and tumor and 70.2% of bone marrow and trabecular bone received an absorbed dose over 200Gy; approximately 3.2% of bone and tumor and 31.0% of bone marrow and trabecular bone received a total dose of over 1000Gy.

The importance of standardized treatment in high-grade osteosarcoma: 30 years of experience from a hospital-based database

BACKGROUND

Treatment of high-grade osteosarcoma remains a major challenge in orthopedic oncology as no major breakthrough in overall survival has occurred in the past 20 years. Due to the rarity of the disease, comparing the results of a single institution to best standard practice needs the establishment of clinical databases. The aim of this study was to report the cumulative 30-years' experience of a single institution and to assess the incidence, survival and prognostic factors of high-grade osteosarcoma using a recently validated, hospital-based database, representing all citizens living in western Denmark, the Aarhus Sarcoma Registry.

MATERIAL AND METHODS

Between 1979 and 2008, 169 patients were treated at the Sarcoma Centre of Aarhus University Hospital for high-grade osteosarcoma. The incidence was calculated as a WHO age-standardized incidence per million per year. The endpoint was overall survival, analyzed by the Kaplan-Meier method and log-rank. Possible prognostic factors were analyzed by the uni- and multivariate Cox proportional hazard method.

RESULTS

The incidence of high-grade osteosarcoma in western Denmark from 1979 to 2008 was 2.7/million inhabitants/year. The five-year overall survival was 42% (95% CI 34; 49) for the whole cohort of patients with high-grade osteosarcoma and 54% (95% CI 43; 64) for patients with localized disease treated with wide excision and chemotherapy. For patients treated with curative intent, no soft tissue extension, treatment with sufficient surgical margin and standard chemotherapy, as well as a high degree of necrosis after chemotherapy were all independent prognostic factors for overall survival.

CONCLUSION

The data from this hospital-based, validated database confirms the relevance of the known prognostic factors of high-grade osteosarcoma and emphasizes the importance of adequate surgical margins and chemotherapy.

Palliative approach in advanced pelvic osteosarcoma: a single centre experience of a rare disease

Background:

Pelvic osteosarcoma is a rare and aggressive malignant neoplasm with poor outcomes. It represents only 5% of all osteosarcomas. The authors present our institute's experience in management and outcomes of five successive patients of pelvic osteosarcoma.

Materials and Methods:

We retrospectively reviewed five patients of pelvis osteosarcoma treated in our institute from September 2008 to December 2010. Clinical characteristics and treatment (CCT) modality in form of surgery and chemotherapy were noted. Statistical analysis was done with regards to progression-free survival (PFS) using Kaplan-Meier survival analysis.

Results:

The median age of the patients was 16.0 years. The median duration of symptoms was 9 months. One patient had lung metastases at presentation. All patients received systemic chemotherapy. One patient underwent surgery in the form of limb sparing approach. Three patients had partial response to treatment, one had complete response, and one had progressive disease. Median duration of PFS was 7 months only.

Conclusions:

Pelvic osteosarcomas are rare neoplasms with aggressive growth patterns. Survival results are poor in view of advanced stage of presentation and difficult surgical approaches. The combined modality approach is needed to improve the results.

Repair of radiation damage of U2OS osteosarcoma cells is related to DNA-dependent protein kinase catalytic subunit (DNA-PKcs) activity

The present study was to investigate the effects of DNA-PKcs deficiencies on radiation sensitivity of human osteosarcoma U2OS cells to γ-ray and to explore the underlying molecular mechanism. In vitro, U2OS cells were transfected with different DNA-PKcs siRNAs or control siRNAs to establish stably siRNA-transfected cell lines U2OS-Si and U2OS-Sc, respectively. Cell viability and apoptosis after irradiation were analyzed using cell counting kit (CCK-8) and flow cytometric assay, respectively. Expressions of apoptosis-related and oxidative stress-responded proteins were assessed using Western blot. The tumorigenesis activity was examined in nude mice xenograft osteosarcoma mode. Results showed that DNA-PKcs siRNA significantly could inhibit U2OS viability and cell proliferation after exposure to irradiation. Compared with the U2OS and U2OS-Sc cells, the U2OS-Si cells induced higher apoptosis rate and loss of mitochondrial membrane potentials, accompanying with more reactive oxygen species (ROS) and malondialdehyde (MDA) production, increased DNA double-strand breaks (DSBs) induced by irradiation. Protein levels of the anti-apoptotic Bcl-2 were downregulated most obviously in U2OS-Si cells after irradiation, while pro-apoptotic factor Bax and caspase-3 upregulated. Moreover, the antioxidants protein expression levels of Nuclear factor-erythroid 2-related factor 2 (Nrf2) and its target heme oxygenase-1 (HO-1) were also significantly reduced in parallel to DNA-PKcs inhibition in U2OS-Si cells. In nude mice xenograft model, DNA-PKcs siRNA remarkably inhibited tumor growth and dissemination. In conclusion, DNA-PKcs siRNA might have a potential for osteosarcoma treatment by sensitizing osteosarcoma cells to γ-ray through modulation on oxidative stress-mediated DNA DSBs repair and mitochondrial pathway apoptosis.

Bone-seeking radiopharmaceuticals as targeted agents of osteosarcoma: samarium-153-EDTMP and radium-223

Osteosarcoma is a cancer characterized by formation of bone by malignant cells. Routine bone scan imaging with Tc-99m-MDP is done at diagnosis to evaluate primary tumor uptake and check for bone metastases. At time of relapse the Tc-99m-MDP bone scan also provides a specific means to assess formation of bone by malignant osteosarcoma cells and the potential for bone-seeking radiopharmaceuticals to deliver radioactivity directly into osteoblastic osteosarcoma lesions. This chapter will review and compare a bone-seeking radiopharmaceutical that emits beta-particles, samarium-153-EDTMP, with an alpha-particle emitter, radium-223. The charged alpha particles from radium-223 have far more mass and energy than beta particles (electrons) from Sm-153-EDTMP. Because radium-223 has less marrow toxicity and more radiobiological effectiveness, especially if inside the bone forming cancer cell than samarium-153-EDTMP, radium-223 may have greater potential to become widely used against osteosarcoma as a targeted therapy. Radium-223 also has more potential to be used with chemotherapy against osteosarcoma and bone metastases. Because osteosarcoma makes bone and radium-223 acts like calcium, this radiopharmaceutical could possibly become a new targeted means to achieve safe and effective reduction of tumor burden as well as facilitate better surgery and/or radiotherapy for difficult to resect large, or metastatic tumors.

Osteosarcoma treatment - where do we stand? A state of the art review

Long-term outcome for patients with high-grade osteosarcoma has improved with the addition of systemic chemotherapy, but subsequent progress has been less marked. Modern, multiagent, dose-intensive chemotherapy in conjunction with surgery achieves a 5-year event-free survival of 60-70% in extremity localized, non-metastatic disease. A major, as yet unsolved, problem is the poor prognosis for metastatic relapse or recurrence, and for patients with axial disease. This article reviews the current state of the art of systemic osteosarcoma therapy by focusing on the experiences of cooperative osteosarcoma groups. Also, we shed light on questions and challenges posed by the aggressiveness of the tumor, and we consider potential future directions that may be critical to progress in the prognosis of high-grade osteosarcoma.

Current therapeutic strategies and novel approaches in osteosarcoma

Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies.

The Current and Future Therapies for Human Osteosarcoma

Osteosarcoma (OS) is the most common non-hematologic malignant tumor of bone in adults and children. As sarcomas are more common in adolescents and young adults than most other forms of cancer, there are a significant number of years of life lost secondary to these malignancies. OS is associated with a poor prognosis secondary to a high grade at presentation, resistance to chemotherapy and a propensity to metastasize to the lungs. Current OS management involves both chemotherapy and surgery. The incorporation of cytotoxic chemotherapy into therapeutic regimens escalated cure rates from <20% to current levels of 65-75%. Furthermore, limb-salvage surgery is now offered to the majority of OS patients. Despite advances in chemotherapy and surgical techniques over the past three decades, there has been stagnation in patient survival outcome improvement, especially in patients with metastatic OS. Thus, there is a critical need to identify novel and directed therapy for OS. Several Phase I trials for sarcoma therapies currently ongoing or recently completed have shown objective responses in OS. Novel drug delivery mechanisms are currently under phase II and III clinical trials. Furthermore, there is an abundance of preclinical research which holds great promise in the development of future OS-directed therapeutics. Our continuously improving knowledge of the molecular and cell-signaling pathways involved in OS will translate into more effective therapies for OS and ultimately improved patient survival. The present review will provide an overview of current therapies, ongoing clinical trials and therapeutic targets under investigation for OS.

Common musculoskeletal tumors of childhood and adolescence

Osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma are the most common malignant musculoskeletal tumors in children and adolescents. Today, most patients can be cured. Numerous factors have contributed to improved outcome for these patients over the past several decades. These include multidisciplinary care involving oncologists, radiation oncologists, surgeons, pathologists, and radiologists and enrollment of patients in clinical trials. Better understanding of molecular mechanisms of disease have resulted in studies using molecular targets in addition to standard chemotherapeutic agents, which hopefully will lead to better outcomes in the future. Moreover, new orthopedic techniques and devices as well as new technologies in radiation oncology hold promise for better local control of primary tumors and the potential for fewer late adverse effects. Despite this progress, patients must undergo lifelong follow-up for possible late effects of intense chemotherapy and radiation therapy. We review the diagnosis, prognosis, staging, multidisciplinary therapy, new directions in therapy, and long-term complications of treatment for these tumors. For this review, we searched MEDLINE using the terms rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, biology, and humans and limited the search to articles from 2000 to September 2011. Additional references found in these articles were utilized as appropriate, as well as references from the background information in current therapeutic studies of the Children's Oncology Group. The same database and time frame were searched for articles written by leading authorities in the field.

Incidence and survival of malignant bone sarcomas in England 1979-2007

Primary malignant bone sarcomas (MBS) are rare and there are few studies examining their incidence and outcome. Here, the incidence and survival of all subtypes of MBS registered in England between 1979 and 2007 were analysed from patient registry data held by the National Cancer Intelligence Network (NCIN). Over 11,002 new cases of MBS were registered, an average of 379 per year. There was no change in incidence demonstrated over the study period (p = 0.08). Although a peak incidence is observed in adolescence, approximately half of MBS are diagnosed in patients over 50 years. An improvement in outcome of MBS was observed between those patients registered from 1979 to 1983 and 1983 to 1987 (p < 0.0001), but there has been no improvement since. In the most recent period studied (patients diagnosed 1998-2002) 5-year survival was 55% in Ewing sarcoma, 70% in chondrosarcoma, 56% in chordoma and 43% in osteosarcoma. Patients diagnosed with osteosarcoma over the age of 40 years or with a non-extremity tumour have a significantly inferior outcome; 22% 5-year survival >40 years compared with 53% <40 years (p < 0.0001) and 16% non-extremity tumour compared to 48% extremity tumour (p < 0.0001). This population-based study has allowed us to confidently define the English incidence and survival rates of both the commoner bone tumours such as osteosarcoma, and rarer entities such as chordoma as well as groups with inferior outcome. The lack of significant improvement over recent decades for these diseases is cause for concern and further research.

Solitary skeletal osteosarcoma recurrence. Findings from the Cooperative Osteosarcoma Study Group

BACKGROUND

Solitary skeletal osteosarcoma (OS) manifestations distant from the site of the primary tumor rarely arise as only sign of disease recurrence.

METHODS

This report reviews 38 patients with high-grade central OS of the limbs or axial skeleton and initial complete surgical remission (CR) who developed first recurrences as solitary osseous lesions distant from the primary tumor. The Cooperative Osteosarcoma Study Group (COSS) database was used to evaluate patient-, tumor-, and treatment-related variables and outcomes.

RESULTS

Thirty-eight patients (27 males and 11 females; 36 limb and 2 axial primaries) developed solitary osseous recurrences a median of 2.1 years (range: 0.5-14.3) from primary diagnosis. Relapses involved axial (24), extremity (10), or craniofacial bones (4). Treatment for recurrence included surgery (28), radiotherapy (10), and chemotherapy (27). After a median follow-up of 1.9 years (range: 0.1-21.2) from first recurrence for all 38 patients and 5.5 years (0.3-21.2) for 16 survivors (10 in continuous second CR), 2- and 5-year overall and event-free survival (EFS) probabilities were 55% and 34% and 34% and 27%, respectively. A long interval to recurrence (>1.5 years) predicted for better overall (P < 0.001) and EFS (P = 0.005). For 21 patients achieving a second CR, 2- and 5-year overall and EFS probabilities were 81% and 61% and 52% and 49%, respectively, while only 1/17 others survived beyond 5 years (P < 0.001). Survivors (14/16) had also received second-line chemotherapy.

CONCLUSION

First solitary skeletal recurrences of OS should be treated with curative intent. Some presumed bone metastases may represent second primary OSs.

WEE1 inhibition sensitizes osteosarcoma to radiotherapy

Background

The use of radiotherapy in osteosarcoma (OS) is controversial due to its radioresistance. OS patients currently treated with radiotherapy generally are inoperable, have painful skeletal metastases, refuse surgery or have undergone an intralesional resection of the primary tumor. After irradiation-induced DNA damage, OS cells sustain a prolonged G₂ cell cycle checkpoint arrest allowing DNA repair and evasion of cell death. Inhibition of WEE1 kinase leads to abrogation of the G₂ arrest and could sensitize OS cells to irradiation induced cell death.

Methods

WEE1 expression in OS was investigated by gene-expression data analysis and immunohistochemistry of tumor samples. WEE1 expression in OS cell lines and human osteoblasts was investigated by Western blot. The effect of WEE1 inhibition on the radiosensitivity of OS cells was assessed by cell viability and caspase activation analyses after combination treatment. The presence of DNA damage was visualized using immunofluorescence microscopy. Cell cycle effects were investigated by flow cytometry and WEE1 kinase regulation was analyzed by Western blot.

Results

WEE1 expression is found in the majority of tested OS tissue samples. Small molecule drug PD0166285 inhibits WEE1 kinase activity. In the presence of WEE1-inhibitor, irradiated cells fail to repair their damaged DNA, and show higher levels of caspase activation. The inhibition of WEE1 effectively abrogates the irradiation-induced G₂ arrest in OS cells, forcing the cells into premature, catastrophic mitosis, thus enhancing cell death after irradiation treatment.

Conclusion

We show that PD0166285, a small molecule WEE1 kinase inhibitor, can abrogate the G₂ checkpoint in OS cells, pushing them into mitotic catastrophe and thus sensitizing OS cells to irradiation-induced cell death. This suggests that WEE1 inhibition may be a promising strategy to enhance the radiotherapy effect in patients with OS.