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PubMedDate not supplied

Oral administration of 1 alpha hydroxyvitamin D3 inhibits tumor growth and metastasis of a murine osteosarcoma model.

We studied the effect of oral administration of 1 alpha hydroxyvitamin D3 (1-D3) on the growth and metastatic ability of Dunn murine osteosarcoma model. A solution of 1-D3 or vehicle alone was administered daily for 2 weeks to tumor-bearing mice using an esophageal tube and tumor size was serially monitored. In 1-D3-treated mice, the growth of Dunn osteosarcoma was significantly suppressed in a dose-dependent manner. Histologically, tumor cells in the control mice proliferated in marginal regions of the tumor with wide central necrosis, whereas in the 1-D3-treated mice, tumor cells were distributed as scattered islands among extensive necrotic tissue. The mean tumor necrosis area was 55.7% in the control tumors and 94.6% in 1-D3-treated tumors (p < 0.001). There were no substantial differences in the cytofluorometric cell cycle distribution or the histological mitotic index between control and 1-D3-treated tumors. When 1-D3 was administered to mice from 2 days before to 2 weeks after transplantation of the tumor, there were significantly fewer metastatic foci in the lungs in 1-D3-treated mice than in control mice. We also tested the effect of coadministration of 1-D3 and doxorubicin on the growth of Dunn osteosarcoma and found that these two drugs act additively to suppress tumor growth. These results indicated that 1-D3 given orally inhibits tumor growth and metastases in a Dunn osteosarcoma model. Although the mechanism remains unknown, oral administration of 1-D3 might be promising as a new method of treating human osteosarcoma.

Administration, Oral↗
PubMed2002

Pathologic fracture in osteosarcoma : prognostic importance and treatment implications.

BACKGROUND: The presence of a pathologic fracture in an osteosarcoma has been considered a poor prognostic factor and an indication for immediate amputation. The purpose of the present study was to determine, in the current era of neoadjuvant chemotherapy, whether a pathologic fracture in an osteosarcoma has prognostic importance and whether limb salvage can be safely performed in such patients without compromising clinical outcome. METHODS: In a cooperative effort of the Musculoskeletal Tumor Society, members from eight institutions provided retrospective data on fifty-two patients with osteosarcoma who had a pathologic fracture and on fifty-five patients with osteosarcoma who had not had a pathologic fracture and had been followed for at least two years or until disease recurrence, metastasis, or death. The two groups were matched for patient age and tumor location. Outcomes examined were survival and local recurrence. A subgroup analysis was performed to assess differences in outcome within the group with the pathologic fracture. RESULTS: The five-year estimated survival rates were 55% for the group with a pathologic fracture and 77% for the group without a fracture (p = 0.02). The rate of survival without a local recurrence at five years was 75% for the group with a fracture and 96% for the group without a fracture (p = 0.007). In the group with a fracture, seven (23%) of the thirty patients managed with limb salvage and four (18%) of the twenty-two managed with an amputation had a local recurrence (p = 0.75). Eleven (37%) of the thirty patients with a fracture who were managed with limb salvage and ten (45%) of the twenty-two patients with a fracture who were managed with an amputation died of the disease (p = 0.50). Five patients underwent open reduction and internal fixation followed by limb-salvage surgery. Two of them had a local recurrence and died at an average of eight months postoperatively. The remaining three patients were alive at an average of 6.1 years postoperatively. Local disease control and the survival of these patients were not significantly different from those for the thirty-three patients who were treated with nonoperative immobilization of the fracture followed by limb-salvage surgery. CONCLUSIONS: Patients with osteosarcoma who present with a pathologic fracture or sustain one during preoperative chemotherapy have an increased risk of local recurrence and a decreased rate of survival compared with patients who have not sustained a pathologic fracture. The performance of a limb-salvage procedure in carefully selected patients with a pathologic fracture does not significantly increase the risk of local recurrence or death. Factors predictive of improved outcome, such as the response to chemotherapy and union of the fracture, should be taken into account when limb salvage is being considered.

Adolescent↗
PubMed2002

Differential expression of cytokines in rat osteosarcoma and malignant fibrous histiocytoma cell lines induced by 4-(hydroxyamino)quinoline-1-oxide.

Cytokines are considered to play an important role in tumor pathogenesis and progression, and recent studies have demonstrated that a variety of forms, including interleukins (ILs) and transforming growth factor-beta(s) (TGF-beta(s)), may regulate tumors. In the present study, the expression of TGF-beta isoforms and ILs was investigated in cell lines from a rat osteosarcoma and a malignant fibrous histiocytoma (MFH), both established from transplantable tumors induced by 4-(hydroxyamino) quinoline 1-oxide (4-HAQO) in syngeneic F344 male rats. The results of a multiprobe RNase protection assay showed TGF-beta1 expression to be remarkably elevated, with no TGF-beta2 and beta3 detectable in MFH cells, while TGF-beta1 and -beta2 were found to be moderately and TGF-beta3 weakly expressed in osteosarcoma lines. All cell lines of osteosarcomas and MFHs expressed macrophage migration inhibitory factor at similar levels. In contrast to the lack of ILs in the MFH cells, moderate IL-6 and very weak IL-1beta expression was detected in the osteosarcoma cells. These results suggest that variation in expression pattern of these cytokines in osteosarcomas and MFHs might be involved in differences in histological appearance and biological behavior, including metastatic ability, between these two mesenchyme-derived tumor types.

4-Hydroxyaminoquinoline-1-oxide↗
PubMed1998

[Pathological study of ER and PR in osteosarcoma].

OBJECTIVE: To determine the relationship between estrogen receptor (ER), progesterone receptor (PR) and pathological characteristics of osteosarcoma. METHOD: ER and PR were detected by streptavidin/peroxidase (SP) method immunohistochemically using the paraffin embedded tissues from 65 cases of osteosarcoma. The patients were typed and graded pathologically according to Liu Zijun's classification. RESULT: The positive rates of ER and PR were 40% (26/65), 32.3% (21/65) respectively. The positive particles were distributed in cytoplasm and nucleus. The positive rates of ER and PR in osteosarcoma with higher cell differentiation grade were higher than those in the tumor with lower one. The differences were statistically significant (P < 0.05). There were no relations to the pathological type. CONCLUSION: ER and PR exist in osteosarcoma and their positive rates are related to the cell differentiation of osteosarcoma.

Bone Neoplasms↗
PubMedDate not supplied

Interleukin-12 and interleukin-18 induce indoleamine 2,3-dioxygenase (IDO) activity in human osteosarcoma cell lines independently from interferon-gamma.

PURPOSE: In this study we evaluated the ability of inducing activation of the enzyme indoleamine 2,3-dioxygenase (IDO) for the development of a new adjuvant therapy of osteosarcomas. The pathway that has described in the literature states that IDO activity is elevated by IFN-gamma. This mechanism is important because the increased IDO activation induces an intracellular degradation of the essential amino acid tryptophan and thereby activates apoptosis in human osteosarcoma cells. MATERIALS AND METHODS: Four different well-established human osteosarcoma cell lines (MNNG/HOS, KHOS-240, HOS and MG-63) were investigated in vitro. Several cytokines were tested for their ability to induce IDO activity. However special emphasis was placed to evaluate the synergistic effects of Interleukin-12 (IL-12) in combination with Interleukin-18 (IL-18). In the first series of experiments IDO induction was investigated by direct application of the cytokines IFN-gamma, TNF-alpha, IL-12 and IL-18 in different concentrations. Secondly, the increase of IDO expression from osteosarcoma cell lines was analysed in the presence of activated lymphocytes with or without cytokine application. RESULTS: Our results demonstrated that the combined application of IL-12 and IL-18 enhanced IDO activity in the human osteosarcoma cell lines HOS and MG-63, in the presence of activated lymphocytes. In the absence of activated lymphocytes, no significant enhancement could be detected. In all our experiments the increase in IDO expression was only partly inhibited by blocking INF-gamma. CONCLUSION: The presented study demonstrates that IL-12 and IL-18, or even more a combined application of both cytokines, induce IDO expression besides the known pathway via IFN-gamma. These mechanisms have been shown herein for the first time in human osteosacoma cell lines. Since IDO expression could still be shown after complete blocking of IFN-gamma, we conclude that at least a second pathway is responsible for inducing IDO activity. This is in contrast to the present knowledge about IDO activation.

Bone Neoplasms↗
PubMed2002

Primary meningeal osteosarcoma: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Primary meningeal osteosarcomas are extremely rare lesions; before this case report, only five cases had been reported in the literature. We encountered a patient with a meningeal osteosarcoma but no evidence of additional tumor at another remote site. CLINICAL PRESENTATION: A 56-year-old man presented with progressive weakness of the right leg and the right arm. Computed tomography and magnetic resonance imaging revealed an extracerebral frontoparietal tumor on the left side. INTERVENTION: The patient underwent complete resection of the tumor and subsequent radiotherapy of the tumor region. The histological examination showed evidence of the osteosarcoma, which was confined to the meninges. Postoperative adjuvant radiotherapy was administered. There was no tumor recurrence during 3 years of postoperative follow-up. Because the patient had no risk factors or further osteosarcomas, primary meningeal development was assumed. CONCLUSION: Despite their rarity, osteosarcomas must be considered in the differential diagnosis of meningeal tumors.

Cerebral Angiography↗
PubMed2002

[Establishment of biopanning model of phage display peptide library in the blood vessels of excised human osteosarcoma vasculature and its significance].

OBJECTIVE: To establish an in vivo biopanning model of phage display peptide library in the blood vessels contained in surgically removed human osteosarcoma. METHOD: In 28 patients with osteosarcoma, digital subtraction angiography (DSA) of the involved limb was performed preoperatively to understand the approximate status of the arteries in the tumors. The tumors were then surgically removed and carefully trimmed, perfused via a simulated Langendorff perfusion apparatus with the indexes as the pH value, temperature and O2 partial pressure monitored in the blood vessels. A 12-meres phage display peptide library was biopanned to isolate peptides capable of homing specifically to the excised osteosarcoma. RESULTS: In vivo biopanning models were successfully established in all the excised tumors, which could be directly used in perfusion experiment and the indexes monitored in the blood vessels in the tumors were comparable to those of living tissues. Some high-affinity peptides specific to the blood vessels in osteosarcoma were obtained with the motif of RLTR. CONCLUSION: In vivo biopanning model simulating the Langendorff perfusion apparatus can be easily established which is instrumental for the application of phage display technology in human living tissues and may facilitate the study of targeted chemotherapy of osteosarcoma.

Adolescent↗
PubMed2003

Sequence alterations in the reduced folate carrier are observed in osteosarcoma tumor samples.

High-dose methotrexate is a standard component of therapy for high-grade osteosarcoma. Its effectiveness may be limited by intrinsic and acquired resistance. Decreased reduced folate carrier (RFC) expression has been shown in approximately half of osteosarcomas at diagnosis. Mutations and polymorphisms in the RFC gene have been reported in various cell lines. The purpose of this study was to investigate sequence alterations in the RFC gene in osteosarcoma tumor samples. The entire coding region of the RFC gene in samples from 162 osteosarcoma patients was screened by DNA single-stranded conformational polymorphism, followed by direct sequencing of any region with altered mobility. A previously identified polymorphism at cDNA position number 174 of RFC exon 2 was observed. Sixty-one samples (37.6%) were heterozygous with both A/G at this position (His(27)/Arg(27)), 52 samples (32.2%) were homozygous with G (Arg(27)), and 49 samples (30.2%) were homozygous with A (His(27)). Fifteen (9.2%) samples were identified with other RFC sequence variants in exon 2, none of which have been reported. The sequence variants in exon 2 included a G to A substitution at cDNA position 231, a G to A substitution at cDNA position 155, a C to T substitution at cDNA position 114, and a T to C substitution at cDNA position 104, resulting in a serine to asparagine substitution at amino acid 46, a glutamate to lysine substitution at amino acid 21, an alanine to valine substitution at amino acid 7, and a serine to proline substitution at amino acid 4, respectively. A deletion of A at cDNA position 126 resulting in a frameshift was also observed. Some of these variants were observed in multiple samples. Eight samples had altered single-stranded conformational polymorphism patterns in exon 3 that were associated with nucleotide changes that altered the amino acid sequence. All of these RFC sequence variants appeared to be heterozygous. Heterozygous C/T and homozygous C also were observed at RFC cDNA position 790 in exon 3, which does not alter the amino acid coding sequence. This study shows that RFC sequence alterations are frequent in samples from osteosarcoma patients. Additional studies are under way to determine the clinical significance of these sequence alterations and their effect on methotrexate transport and resistance.

Amino Acid Sequence↗
PubMed2001

[Relationship between vascular endothelial growth factor expression and angiogenesis in osteosarcoma].

OBJECTIVE: To determine the relationship between angiogenesis and vascular endothelial growth factor (VEGF) expression in osteosarcoma. METHODS: The expression of VEGF was evaluated by immunohistochemical staining of tumor specimens from 33 patients with osteosarcoma. The microvessel density was assessed by immunostaining with CD34 in the most neovascularized area (hot spots). RESULTS: In osteosarcoma, the mean microvessel count of VEGF strong-expression tumors was significantly higher than that of VEGF low-expression tumors (Wilcoxon rank sum test, P < 0.05). The close correlation was found between VEGF expression and microvessel density. In contrast, no association was found between Price's grade of osteosarcoma and VEGF expression, as well as microvessel density. CONCLUSION: These observations suggest that VEGF is an important angiogenic factor in osteosarcoma.

Humans↗
PubMed2003

Unstratified chemotherapy for non-metastatic osteosarcoma of the extremities in children.

BACKGROUND AND PURPOSE: The superiority of changing postoperative chemotherapy of osteosarcoma based on histological response of the primary tumor over non-tailored chemotherapy has not been confirmed. This multicenter study evaluated the effectiveness of an intensive unstratified chemotherapy regimen in Taiwanese children with osteosarcoma. METHODS: Fifty patients younger than 18 years of age with previously untreated non-metastatic osteosarcoma of the extremities were enrolled. Patients were treated with pre- and postoperative chemotherapy, and surgery. Definitive surgery was scheduled in week 7 and postoperative chemotherapy was uniform without stratification regardless of histologic response. RESULTS: Chemotherapy toxicities were considerable, but manageable. Treatment delay and decreased dose-intensity were common. There was one treatment-related mortality. Forty three patients (86%) received limb salvage surgery and 14 patients (33%) had a good histologic response to preoperative chemotherapy. With a median follow-up of 47.1 months, the 7-year event-free and overall survival rates were 51.6% and 67.6%, respectively. CONCLUSIONS: This was the first multicenter study on the treatment of osteosarcoma from Taiwan. The results suggest that a non-tailored regimen may serve as an alternative treatment strategy in the management of osteosarcoma, particularly when histologic assessment of the tumor response is not available.

Adolescent↗
PubMed2003

[Construction and characterization of osteosarcoma 9901 cell cDNA library].

AIM: To construct human osteosarcoma 9901 cell cDNA expression library for screening osteosarcoma-specific antigens. METHODS: Total RNA was extracted from human osteosarcoma cell line 9901 and mRNA was purified. cDNA was synthesized by reverse transcription, and cDNA fragments larger than 400 bp were ligated with dephosphorylated arms of lambdagt11. The recombinants were packaged in-vitro, and a small portion of packaged phage was used to infect E.coli Y1090 for titration. The size of cDNA inserts and the diversity of library were detected by PCR. RESULTS: The osteosarcoma 9901 cell line cDNA library consisting of 1.5x10(6) recombinant bacteriophages was constructed. The average length of exogenous inserts in the recombinants was about 1.4 kb. CONCLUSION: The cDNA library reported herein is suitable for screening osteosarcoma-specific antigens.

Bone Neoplasms↗
PubMed2005

Antitumor effect of nutrient synergy on human osteosarcoma cells U-2OS, MNNG-HOS and Ewing's sarcoma SK-ES.1.

Current treatment of osteosarcoma is associated with poor prognosis, especially due to the increased risk of developing other cancers with chemotherapy. Therefore, new, safe and effective treatment strategies are needed. We investigated the effect of a unique mixture of nutrients containing lysine, proline, arginine, ascorbic acid, and epigallocatechin gallate (EGCG) on human osteosarcoma cell lines U-2OS, MNNG-HOS, and Ewing's sarcoma SK-ES-1 by measuring: cell proliferation, expression of matrix metalloproteinase-2 (MMP-2), MMP-9, and invasive and angiogenesis potential. Cell proliferation was evaluated by MTT assay, matrix metalloproteinases (MMP) expression by gelatinase zymography, VEGF expression by ELISA, and invasion through Matrigel. Cells were also treated with phorbol 12-myristate 13-acetate (PMA) to study enhanced MMP and VEGF expression. The invasion of osteosarcoma U-2OS and MNNG-HOS cells through Matrigel was significantly reduced in a dose-dependent fashion, with 100% inhibition of invasion of U-2OS cells at 100 microg/ml, and MNNG cells at 50 microg/ml concentration of the synergistically acting nutrient mixture. Ewing's sarcoma SK-ES-1 cells were not invasive. Nutrient synergy (NS) exhibited a dose response antiproliferative effect on osteosarcoma U-2OS cells, reaching 67% at 1000 microg/ml of NS; no significant suppression of cell proliferation was seen with MNNG or Ewing's sarcoma cells. Zymography showed dose-dependent inhibition of MMP secretion by all three cell lines in the presence of NS. VEGF secretion by U-2OS cells was completely blocked at 500 microg/ml of NS. Our results suggest NS is an excellent candidate for therapeutic use in the treatment of osteosarcoma, by inhibiting cancer cell invasion, and secretion of MMPs and VEGF, all critical parameters for cancer control and prevention.

Arginine↗
PubMed2005

[Unusual presentation of metastatic osteosarcoma as a giant duodenal polyp. A case report].

INTRODUCTION: Osteosarcoma is a malignant bone neoplasm with an usually high metastatic potential. Besides the common metastatic sites such as lungs, bone, and pleura, metastases to unusual sites such as liver, brain and regional lymph nodes have also been reported with increasing frequency; among them, gastrointestinal metastases represent an extraordinarily rare event in the natural history of this neoplasia. MATERIALS AND METHODS: We describe a case of a 27 year old man, who was diagnosed with a grade IV osteoblastic osteosarcoma of the left tibia and submitted to 5 courses of pre-surgical chemotherapy; later he underwent tibial resection with implantation of a prosthesis, followed by 2 further courses of adjuvant chemotherapy. Five years after the patient presented with melena and acute anemia; during endoscopic examination, a large bleeding duodenal polyp was found, so a surgical resection of the gastric antrum, duodenum, head of the pancreas, main bile ducts and gallbladder was performed. The surgical specimen was formalin fixed and paraffin embedded, and sections obtained by the blocks were stained with haematoxylin-eosin; immunohistochemical and ultrastructural analysis were performed. RESULTS: Microscopically, the tumor mass showed a mostly fasciculated architecture, composed of spindle and epithelioid cells in a scarce fibromyxoid stroma, featuring large areas of coagulative necrosis and small foci of sclerohyalinosis. Tumor cells featured large vesciculous nuclei, with a few prominent nucleoli; no foci of osteoid matrix were detectable. The ultrastructural analysis revealed small calcified electron-dense depots both in the perinuclear cytoplasm and in the extracellular collagen matrix compatible with an "early osteoid formation". Due to alteration of the natural history of the tumor induced by multiagent chemotherapy, the rate of metastases of osteosarcoma to unusual sites has been increasing. We report the 9th case of a gastrointestinal metastasis of osteosarcoma reported thus far, and only the second one arising in the duodenum. Both the histological features and the immunohistochemical findings were not suggestive for osteosarcoma metastases because the tumor appeared dedifferentiated; in our case the combination of electron microscopy and clinical history played a pivotal role to establish the final diagnosis.

Adult↗
PubMed2005

[The role of CD44 in the proliferation, adhesiveness and invasiveness of osteosarcoma cell lines].

OBJECTIVE: To study the influence of CD44 a cell-matrix adhesion molecule on the proliferation, adhesiveness and invasiveness of osteosarcoma cell lines, in order to investigate the growth and invasion mechanism of osteosarcoma. METHODS: Three osteosarcoma cell lines MG-63, HOS and U2-OS were routinely cultured. Flow cytometry and Western blot analysis were used for detecting the positive rates and relative amount of CD44 protein in the three cell lines. RT-PCR method was also used to compare the differences in the expression of CD44 mRNA among the 3 cell lines. Then, MTT method, adhesion detection, and Microcon-migration assay were used to detect the changes of the cells' proliferation rate, adhesive and invasive abilities after blocking the role of CD44 by using a special neutralizing antibody. RESULTS: The results of flow cytometry showed that the percentage of CD44 positive cells were both over 99% in HOS and U2-OS, while that in MG-63 was only (2.10 +/- 0.46)%. The average fluorescence density of CD44 in HOS was significantly higher than in U2-OS. Western blot also showed that the relative content of CD44 protein in HOS was notably higher than that in U2-OS, while CD44 was negatively expressed in MG-63. The expression of CD44 mRNA was significantly lower in MG-63 than in both HOS and U2-OS, which were consistent with the expression of CD44 protein. The proliferation rates and adhesive abilities of MG-63 and HOS have no significant difference, but both were significantly higher than that of U2-OS. The invasive abilities of HOS was dramatically higher than MG-63 and U2-OS. After the role of CD44 was blocked by anti-CD44 neutralizing antibody, the proliferation rates of the 3 cell lines did not change significantly. While the HOS and MG-63 adhesion indices decreased dramatically (P < 0.05), the invasive abilities of HOS and U2-OS also decreased notably (P < 0.01). CONCLUSIONS: CD44 could promote the adhesiveness and invasiveness of osteosarcoma cell line HOS. CD44 may take part in promoting the process of U2-OS invasion and the adhesion of MG-63. On the other hand, CD44 could not affect the osteosarcoma cell proliferation rates.

Bone Neoplasms↗
PubMed2005

[Standards and Options for the use of radiation therapy in the management of patients with osteosarcoma. Update 2004].

CONTEXT: The A "Standards, Options and Recommendations A" (SOR) project, started in 1993, is a collaboration between the Federation of French Cancer Centres (FNCLCC), the 20 French regional cancer centres, and specialists from French public universities, general hospitals and private clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and the outcome of cancer patients. The methodology is based on a literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVE: To update the SOR recommendations for the use of radiation therapy in the management of patients with osteosarcoma. This work was performed in collaboration with the French society against cancers in children and adolescent (SFCE). METHODS: Data have been identified by literature search using MedlineA (from January 1992 to October 2003). In addition several Internet sites were searched in October 2003. RESULTS: The 3 mains standards are: 1) local and exclusive curative irradiation is not indicated as primary treatment for osteosarcoma or for local and operable recurrence, except for lesion in inaccessible sites or if the patient refuses surgery; 2) local and prophylactic adjuvant irradiation is not indicated for the treatment of osteosarcoma after chemotherapy (neoadjuvant and/or adjuvant) and complete macro or microscopic surgery, except for nonoperable R1 or R2 surgical resection and 3) whole-lung prophylactic irradiation is not indicated in non-metastatic osteosarcoma. Systemic metabolic radiotherapy for pain treatment, using samarium-153 ethylene diamine tetramethylene phosphonic acid (Sm-153-EDTMP) can be offered to patients with painful metastatic osteosarcoma or in case of recurrent bone sites inaccessible to local therapies (surgery, external irradiation).

Bone Neoplasms↗
PubMed2006

Osteosarcoma of the talus: a case report.

The reported incidence of osteosarcoma of the foot is very low. Osteosarcoma of the talus is extremely rare and few cases have been reported in the literature. The clinical findings are not typical, and osteosarcoma of the talus can be easily misdiagnosed, resulting in a delay in proper treatment. We report the case of a patient with osteosarcoma of the talus, from a series of 120 osteosarcomas treated at our hospital between 1966 and 2002.

Adult↗
PubMed2005

The correlation of Tc-99m MIBI scintigraphy and histological response in determining the percentage of tumor necrosis in osteosarcoma after preoperative chemotherapy.

PURPOSE: The most important prognostic factor of osteosarcoma is the percentage of tumor necrosis. Only well trained and experienced musculoskeletal pathologists can count and assess the percentage of tumor necrosis from the resected specimens. The purpose of the present study was to characterize the correlation of Tc-99m MIBI scintigraphy for assessing the percentage of tumor necrosis using postoperative histology as a gold standard. MATERIAL AND METHOD: During September 2002 to August 2004, nine consecutive patients with the diagnosis of conventional osteosarcoma were included in the present study. The osteosarcoma protocol comprises 3 courses of doxorubicin and cisplatin preoperatively followed by wide resection of tumors and another 3 courses of postoperative chemotherapy. The Tc-99m MIBI scintigraphy examination was carried out before commencing chemotherapy and after completing preoperative chemotherapy. The tumor uptake was measured using the tumor to the background ratio (TBR). Comparison of TBR before and after preoperative chemotherapy was used to calculate the alteration ratio which was reported in terms of percentage. All of the resected specimens were sent to the pathological department. The histological assessment of the response to chemotherapy was performed using the standard technique according to the current practice of osteosarcoma from the Mayo Clinic. The percentages of tumor necrosis from histology were also reported. RESULTS: The analysis of the correlation between the reduction of tracer uptake and the postoperative histological response was performed. The correlation and linear regression analysis showed that the two methods had a significant correlation (R = 0.75) regression coefficient (1.172) with p = 0.020 and 0.043, respectively. CONCLUSION: The present study showed that Tc-99m MIBI scintigraphy had a significant correlation with percentage of tumor necrosis from histology. This technique can be used to predict the response of osteosarcoma after preoperative chemotherapy.

Adolescent↗
PubMedDate not supplied

[Magnetic resonance for the study of osteosarcoma].

The authors report their experience with MR imaging in the study of osteosarcoma. Two main elements were evaluated: signal characteristics and loco-regional staging. Seventy-one patients were studied: 65 of them had central long-bone osteosarcoma, and 6 had telangiectatic long-bone osteosarcoma. T1- and T2-weighted spin-echo sequences were employed and all cases were scanned on 3 planes (sagittal, coronal, and axial). In 28 patients MR imaging was performed both before and after preoperative chemotherapy. The obtained data were compared to surgical and pathological findings. With the exception of the typical signal patterns of quite-osteoblastic osteosarcoma (which presents with low signal on both T1- and T2-weighted sequences), no particular signal features were observed which could help distinguish the different types of osteosarcoma. MR imaging is the method of choice in loco-regional staging for, in our series, it allowed a rational and adequate surgical planning. For this purpose, at least a longitudinal T1- and an axial T2-weighted images are required.

Adolescent↗