How can survival be improved in localized osteosarcoma?

Decoding the Impact of Tumor Microenvironment in Osteosarcoma Progression and Metastasis

Osteosarcoma (OS) is a heterogeneous, highly metastatic bone malignancy in children and adolescents. Despite advancements in multimodal treatment strategies, the prognosis for patients with metastatic or recurrent disease has not improved significantly in the last four decades. OS is a highly heterogeneous tumor; its genetic background and the mechanism of oncogenesis are not well defined. Unfortunately, no effective molecular targeted therapy is currently available for this disease. Understanding osteosarcoma's tumor microenvironment (TME) has recently gained much interest among scientists hoping to provide valuable insights into tumor heterogeneity, progression, metastasis, and the identification of novel therapeutic avenues. Here, we review the current understanding of the TME of OS, including different cellular and noncellular components, their crosstalk with OS tumor cells, and their involvement in tumor progression and metastasis. We also highlight past/current clinical trials targeting the TME of OS for effective therapies and potential future therapeutic strategies with negligible adverse effects.

Sorafenib inhibits doxorubicin-induced PD-L1 upregulation to improve immunosuppressive microenvironment in Osteosarcoma

PURPOSE

Although undergoing conventional chemotherapy significantly improves the prognosis of Osteosarcoma, chemoresistance and failure of therapy is still a significant challenge. Furthermore, conventional chemotherapy, like doxorubicin, would upregulate the expression of programmed death-ligand 1 (PD-L1) which caused an immunosuppressive microenvironment and unsatisfied treatment result in Osteosarcoma. Thus, it is urgent to explore a strategy to overcome this disadvantage.

METHODS

Human Osteosarcoma cell line MG63 and mouse Osteosarcoma cell line K7 were included in this study. Subcutaneous tumor model was used by injection of K7 cells in BALB/C mice to test the effect of doxorubicin and sorafenib on tumor growth. PD-L1 expression was tested in vitro (flow cytometry, western blot and PCR) and in vivo (flow cytometry and immunohistochemistry). Proportion of immune cells (CD4, CD8, Tregs, and cytotoxic T lymphocytes) in vivo was analyzed with flow cytometry.

RESULTS

Combination of sorafenib and doxorubicin inhibited tumor growth significantly in vivo. Doxorubicin increased PD-L1 expression in vitro and in vivo, while sorafenib inhibited doxorubicin-induced PD-L1 upregulation in vitro and in vivo. Proportion of interferon-γ-secreting CD8 + T lymphocytes in tumor tissue was increased significantly when sorafenib was combined with doxorubicin, while proportion of CD4, CD8, and Tregs was not significantly changed. Extracellular signal-regulated kinases (ERK) pathway could be one of the key mechanisms by which doxorubicin induced upregulation of PD-L1 in Osteosarcoma cells.

CONCLUSION

Combination of sorafenib and conventional chemotherapeutic reagents is a potent strategy to improve treatment effectiveness by modulating tumor microenvironment in Osteosarcoma through increasing proportion of cytotoxic T lymphocytes.

Development and validation of a nomogram to predict long-term cancer-specific survival for patients with osteosarcoma

The present work aimed to establish a new model to accurately estimate overall survival (OS) as well as cancer-specific survival (CSS) of osteosarcoma. Osteosarcoma cases were collected from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2017 and randomized as training or validation sets. Then, the OS- and CSS-related variables were discovered through multivariate Cox regression analysis to develop new nomograms to predict the 1-, 3- and 5-year OS and CSS. Besides, consistency index (C-index), decision curve analysis (DCA), along with calibration curve were adopted for assessing the predicting ability of our constructed nomograms after calibrating for 1-, 3- and 5-year OS and CSS. Altogether, 1727 osteosarcoma cases were enrolled in the present study and randomly divided as training (n = 1149, 70%) or validation (n = 576, 30%) set. As shown by univariate as well as multivariate Cox regression analyses, age, grade, T stage, M stage, surgery, chemotherapy, and histological type were identified to be the adverse factors to independently predict OS and CSS among the osteosarcoma cases. Besides, based on results of multivariate Cox regression analysis, we constructed the OS and CSS prediction nomograms. The C-index in training set was 0.806 (95% CI 0.769-0.836) for OS nomogram and 0.807 (95% CI 0.769-0.836) for CSS nomogram. In the meantime, C-index value in validation set was 0.818 (95% CI 0.789-0.847) for OS nomogram, while 0.804 (95% CI 0.773-0.835) for CSS nomogram. Besides, those calibration curves regarding the 3- and 5-year CSS of our constructed nomogram were highly consistent between the predicted values and the measurements in the training set as well as the external validation set. Our constructed nomogram outperformed the TNM stage in prediction. Our constructed nomogram is facile, creditable, and feasible; it efficiently predicts OS and CSS for osteosarcoma cases and can assist clinicians in assessing the prognosis for individuals and making decisions.

Cancer-Specific Survival after Limb Salvage versus Amputation in Children and Adolescents with Osteosarcoma: A Population-Based Analysis with Propensity Score Matching

Background

The study aims to identify whether osteosarcoma patients of children and young adults will benefit from a survival profit from the choice of the operation method.

Methods

The National Cancer Institute SEER database from 2000 to 2018 was selected for a retrospective analysis of 1630 children and young adults with a primary diagnosis of osteosarcoma, 1222 who underwent limb-preserving surgery, and 408 who underwent amputation. Confounders were controlled for by propensity score matching (PSM), cancer-specific survival (CSS) was analyzed using the Kaplan-Meier method, and univariate and multivariate Cox regression was used to analyze the factors influencing the prognosis of children and young osteosarcoma patients after surgery. A nomogram plot predicted 1-, 3-, and 5- survival rate in osteosarcoma. The model's accuracy was validated by the area under the ROC and calibration curves.

Results

After PSM, multifactor Cox regression analysis found AJCC Stage III-IV (CSS : HR = 5.26, 95% CI 1.95-14.18, p=0. 001; HR = 5.54, 95% CI 2.56-12.01, p < 0. 001. Limb salvage surgery (CSS : HR = 0.58, 95% CI 0.44-0.77, p < 0. 001) has independent impact factors for CSS prognosis. The survival curve before and after PSM showed that patients with osteosarcoma of children and young adults who underwent limb salvage surgery had a survival benefit compared with those who underwent amputation surgery. Gender, chemotherapy, histology, primary tumor site, stage, and surgical modality were modeled in a total of six variables in the nomogram. The model exhibited good predictive performance. The AUC were 0.823, 0.74, and 0.757 for training set at 1, 3, and 5 years, respectively. The AUC of validation set 0.666, 0.722, and 0.699 at 1, 3, and 5 years, respectively. The model also predicted CSS with good fidelity for both datasets. This model was significantly superior to the 8^th edition of the AJCC TNM staging system, with a better net benefit in predicting CSS in children and young adults with osteosarcoma.

Conclusion

Limb salvage surgery is an option for children and young adults with osteosarcoma and cancer-specific survival rates can be improved by receiving limb salvage surgery.

Prediction of Neoadjuvant Chemotherapy Response in Osteosarcoma Using Convolutional Neural Network of Tumor Center 18F-FDG PET Images

We compared the accuracy of prediction of the response to neoadjuvant chemotherapy (NAC) in osteosarcoma patients between machine learning approaches of whole tumor utilizing fluorine−¹⁸fluorodeoxyglucose (¹⁸F-FDG) uptake heterogeneity features and a convolutional neural network of the intratumor image region. In 105 patients with osteosarcoma, ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) images were acquired before (baseline PET0) and after NAC (PET1). Patients were divided into responders and non-responders about neoadjuvant chemotherapy. Quantitative ¹⁸F-FDG heterogeneity features were calculated using LIFEX version 4.0. Receiver operating characteristic (ROC) curve analysis of ¹⁸F-FDG uptake heterogeneity features was used to predict the response to NAC. Machine learning algorithms and 2-dimensional convolutional neural network (2D CNN) deep learning networks were estimated for predicting NAC response with the baseline PET0 images of the 105 patients. ML was performed using the entire tumor image. The accuracy of the 2D CNN prediction model was evaluated using total tumor slices, the center 20 slices, the center 10 slices, and center slice. A total number of 80 patients was used for k-fold validation by five groups with 16 patients. The CNN network test accuracy estimation was performed using 25 patients. The areas under the ROC curves (AUCs) for baseline PET maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and gray level size zone matrix (GLSZM) were 0.532, 0.507, 0.510, and 0.626, respectively. The texture features test accuracy of machine learning by random forest and support vector machine were 0.55 and 0. 54, respectively. The k-fold validation accuracy and validation accuracy were 0.968 ± 0.01 and 0.610 ± 0.04, respectively. The test accuracy of total tumor slices, the center 20 slices, center 10 slices, and center slices were 0.625, 0.616, 0.628, and 0.760, respectively. The prediction model for NAC response with baseline PET0 texture features machine learning estimated a poor outcome, but the 2D CNN network using ¹⁸F-FDG baseline PET0 images could predict the treatment response before prior chemotherapy in osteosarcoma. Additionally, using the 2D CNN prediction model using a tumor center slice of ¹⁸F-FDG PET images before NAC can help decide whether to perform NAC to treat osteosarcoma patients.

Impact of Secondary Aneurysmal Bone Cysts on Survival of Patients with Enneking Stage IIB Extremity Osteosarcoma: A Propensity Score Matching Analysis

BACKGROUND

The clinicopathology of aneurysmal bone cysts (ABCs) secondary to osteosarcoma has not yet been reported. We conduct a retrospective review of ABCs secondary to osteosarcoma to characterize clinicopathology and influence on the survival of patients with Enneking stage IIB extremity osteosarcoma.

PATIENTS AND METHODS

A total of 300 patients with Enneking stage IIB extremity osteosarcoma were eligible for analysis. These cases were divided, according to the pathology of biopsy and magnetic resonance imaging (MRI), into ABCs group and no ABCs group. Patients (ABCs versus no ABCs) were compared using a 1:2 propensity score analysis to best match between groups. Clinicopathology and survival data were analyzed.

RESULTS

The total occurrence rate of secondary ABCs was 10.3%. A higher prevalence of pathological fractures was observed in the ABCs group (22.6%) compared with the no ABCs group (8.6%) (p = 0.032). Patients with ABCs were more likely to undergo amputation compared with patients without ABCs (p = 0.007). Those with secondary ABCs had poorer response to chemotherapy before and after propensity score matching (p = 0.006 and p = 0.048, respectively). Kaplan-Meier survival analysis showed that EFS and OS distributions were not significantly different between the two patient groups. ABCs were not significantly different in terms of EFS or OS in the multivariate analysis model (p > 0.05).

CONCLUSIONS

The presence of secondary ABCs was associated with increased occurrence rate of pathological fracture and high percentage of amputation. Moreover, patients with secondary ABCs had poorer response to chemotherapy. However, the presence of secondary ABCs did not influence survival of patients with Enneking stage IIB extremity osteosarcoma.

The Plasma Concentration of D-Dimer is Associated with Neoadjuvant-Chemotherapy Efficacy and the Prognosis in Osteosarcoma

PURPOSE

This retrospective study explored the clinical value of the plasma D-dimer level in osteosarcoma.

MATERIALS AND METHODS

We measured the plasma D-dimer level before neoadjuvant chemotherapy (D0) and the plasma D-dimer level after four courses of neoadjuvant chemotherapy (D1) in 103 patients with stage-IIB high-grade osteosarcoma of the limb. The change in the D-dimer level (ΔD) was defined as D1 minus D0. The chi-square test was used to compare categorical variables. Analyses of receiver operating characteristic (ROC) curves were undertaken to determine the optimal cutoff points for D0, D1, and ΔD. The area under the ROC (AUC) of D0, D1, and ΔD was calculated to evaluate their discriminatory abilities in monitoring the response to neoadjuvant chemotherapy (tumor necrosis). Survival curves were generated according to Kaplan-Meier analyses and compared using the Log rank test. Univariate analyses and multivariate analyses were carried out to determine independent prognostic factors.

RESULTS

Kaplan-Meier curves showed that a high D-dimer level at D0 and tumor diameter ≥8 cm were associated significantly with worse overall survival (OS) (P<0.05). Multivariate Cox regression analyses revealed a high D-dimer level at D0 (hazard ratio, 3.92; 95% confidence interval, 1.756-5.804; P=0.000) was an independent unfavorable prognostic factor. The chi-square test showed ΔD to be associated significantly with tumor necrosis. Analyses of ROC curves showed the D-dimer level at D0 and ΔD had better ability compared to that at D1 to discriminate the response to neoadjuvant chemotherapy.

CONCLUSION

The D-dimer level was correlated with the prognosis and response to chemotherapy in patients with stage-IIB high-grade osteosarcoma of the limb. The D-dimer level may serve as a risk factor of the response to chemotherapy and prognosis of localized osteosarcoma.

Checkpoint Blockade in Combination With Doxorubicin Augments Tumor Cell Apoptosis in Osteosarcoma

The aim of this study was to provide a basis for the theory that the combination of conventional chemotherapy and immunotherapy would be an effective treatment for osteosarcoma. Here, the expression of programmed death ligand 1 (PD-L1) in 26 clinical osteosarcoma tissue samples collected before and after chemotherapy was analyzed. The effects of osteosarcoma cells treated with doxorubicin, a conventional chemotherapeutic agent, on the proliferation and apoptosis of CD8 T lymphocytes were investigated in vitro. Thereafter, the effectiveness of doxorubicin combined with an anti-PD-L1 antibody as an osteosarcoma therapy was tested in 24 subcutaneous tumor mouse models. The results showed that the expression of PD-L1 was upregulated by chemotherapy in both the clinical osteosarcoma tissue samples and the osteosarcoma cell lines. The proliferation of CD8 T lymphocytes was inhibited, and apoptosis in CD8 T lymphocytes was enhanced by the doxorubicin-pretreated osteosarcoma cells, whereas this effect was reversed by the anti-PD-L1 antibody. A more effective result was observed when doxorubicin was combined with the anti-PD-L1 antibody in vivo. In short, the combination of conventional chemotherapy and an anti-PD-L1 antibody might be an effective option for osteosarcoma treatment, as anti-PD-L1 antibody can reverse the immunosuppression induced by chemotherapy.

Sunitinib inhibits PD-L1 expression in osteosarcoma by targeting STAT3 and remodels the immune system in tumor-bearing mice

Aim: Exploring the mechanisms of the combination therapy using VEGFR-TKI and immune checkpoint inhibitors might be useful to control the development of osteosarcoma. Materials & methods: The expression of PD-L1 and STAT3 in osteosarcoma were determined with western blot. Proliferation, migration and invasion were determined with CCK-8 and Transwell assays. Lung metastases, tumor growth, survival and immune cell populations were performed in tumor-bearing mice. Results: Sunitinib reduced the expression of PD-L1 by inhibiting the activation of STAT3 and suppressed the migration and invasion in osteosarcoma cells. Combination therapy reduced lung metastases, tumor growth, improved survival and reverse tumor microenvironment in tumor-bearing mice. Conclusion: Sunitinib inhibits PD-L1 expression by targeting STAT3 and remodels the immune system in tumor-bearing mice.

Early response monitoring of neoadjuvant chemotherapy using [18F]FDG PET can predict the clinical outcome of extremity osteosarcoma

Background

To propose a personalized therapeutic approach in osteosarcoma treatment, we assessed whether sequential [¹⁸F]FDG PET/CT (PET/CT) could predict the outcome of patients with osteosarcoma of the extremities after one cycle and two cycles of neoadjuvant chemotherapy.

Methods

A total of 73 patients with AJCC stage II extremity osteosarcoma treated with 2 cycles of neoadjuvant chemotherapy, surgery, and adjuvant chemotherapy were retrospectively analyzed in this study. All patients underwent PET/CT before (PET0), after 1 cycle (PET1), and after the completion of neoadjuvant chemotherapy (PET2), respectively. Maximum standardized uptake value (SUV_max) (corrected for body weight) and the % changes of SUV_max were calculated, and histological responses were evaluated after surgery. Receiver-operating characteristic (ROC) curve analyses and the Cox proportional hazards models were used to analyze whether imaging and clinicopathologic parameters could predict event-free survival (EFS).

Results

A total of 36 patients (49.3%) exhibited a poor histologic response and 17 patients (23.3%) showed events (metastasis in 15 and local recurrence in 2). SUV_max on PET2 (SUV2), the percentage change of SUV_max between PET0 and PET1 (Δ%SUV01), and between PET0 and PET2 (Δ%SUV02) most accurately predicted events using the ROC curve analysis. SUV2 (relative risk, 8.86; 95% CI, 2.25–34.93), Δ%SUV01 (relative risk, 5.97; 95% CI, 1.47–24.25), and Δ%SUV02 (relative risk, 6.00; 95% CI, 1.16–30.91) were independent predicting factors for EFS with multivariate analysis. Patients with SUV2 over 5.9 or Δ%SUV01 over − 39.8% or Δ%SUV02 over − 54.1% showed worse EFS rates than others (p < 0.05).

Conclusions

PET evaluation after 1 cycle of presurgical chemotherapy can predict the clinical outcome of extremity osteosarcoma. [¹⁸F]FDG PET, which shows a potential role in the early evaluation of the modification of timing of local control, can be a useful modality for early response monitoring of neoadjuvant chemotherapy.

Amputation Versus Limb-Salvage Surgery in Patients with Osteosarcoma: A Meta-analysis

BACKGROUND

This meta-analysis compared survival and function in patients with limb osteosarcoma treated with limb-salvage surgery (LSS) versus amputation or rotationplasty.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar were searched until November 30, 2015 for studies reporting Musculoskeletal Tumor Society (MSTS) scores and survival rates in osteosarcoma patients. Differences between patients undergoing LSS versus ablative surgery were analyzed based on MSTS scores and postoperative survival rates.

RESULTS

Of 1330 patients in the studies analyzed, 934 underwent LSS, and 662 were treated with amputation. A random-effects model was applied due to heterogeneity among studies (Q statistic = 1.829, I (2) = 0 %, p = 0.767). No difference was found in post-operative local recurrence rate between amputees and patients receiving LSS. The 5-year survival rate was significantly lower with amputation compared with LSS (OR 0.628; 95 % CI 0.431-0.913, p = 0.015). The 2-year survival rate was not different between amputation and LSS. In addition, amputees had lower MSTS scores than those undergoing LSS (difference in means = -4.46 %, 95 % CI 6.49-2.45 %, p < 0.001).

CONCLUSIONS

LSS results in higher 5-year survival rates and better functional outcomes as indicated by MSTS scores in patients with limb osteosarcomas.

Therapeutic effect of neoadjuvant chemotherapy combined with curettage to treat distal femoral osteosarcoma: A case report

RATIONALE

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Metastasis occurs early, the mortality rate is high, and the tumor results in a tremendous physical, mental, and economic burden on patients. Therefore, the treatment of osteosarcoma has been important for orthopedic surgeons. However, treatment has always been a difficult problem globally.

PATIENT CONCERN

We present the case of a 22-year-old girl with increasing local pain in the distal left thigh.

DIAGNOSES

The patient was initially diagnosed as bone cancer according to computed tomography (CT) and X-ray imaging. And the patient was further diagnosed as osteosarcoma via to puncture biopsy of the left distal femur.

INTERVENTIONS

Local arterial infusion chemotherapy, systemic intravenous chemotherapy, and curettage was conducted because of limb salvage program.

OUTCOMES

The patient was doing well with no evidence of local or distant recurrence 7 years after the surgery.

LESSONS

Our case indicated that limb osteosarcoma patients can undergo a limb salvage program of local arterial infusion chemotherapy, systemic intravenous chemotherapy, and curettage.

P16 protein expression as a useful predictive biomarker for neoadjuvant chemotherapy response in patients with high-grade osteosarcoma: A systematic meta-analysis under guideline of PRISMA

BACKGROUND

Neoadjuvant chemotherapy for patients with high-grade osteosarcoma has highly improved the clinical survival. However, the prognostic and predictive role of P16 expression after neoadjuvant chemotherapy remains unclear. We first determined whether P16 expression can become a potential prognostic and predictive biomarker in high-grade osteosarcoma.

METHODS

This meta-analysis was conducted based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline. Eligible studies were pooled and the overall odds ratios (ORs) and hazard ratios (HRs) with the corresponding 95% confidence intervals (95% CIs) were calculated in this analysis.

RESULTS

Four studies involving a total of 527 patients with high-grade osteosarcoma receiving neoadjuvant chemotherapy were identified. We did not find that P16 expression was correlated with sex status, histologic subtype, and tumor site (P > .1). P16 expression was found to be significantly associated with a "good" response to neoadjuvant chemotherapy (OR = 4.69, P < .001). A significant relationship was observed between p16 expression and pathologic complete response after neoadjuvant chemotherapy using multivariate analysis (OR = 9.63, P = .001). The expression of the P16 was not associated with clinical outcomes in overall survival (OS) and disease-free survival (DFS) by multivariate analysis (OS: P = .448; DFS: P = .263).

CONCLUSIONS

The use of P16 expression could become a promising predictive biomarker of the response to neoadjuvant chemotherapy in the white population with high-grade osteosarcoma. However, it was not correlated with the prognosis of patients in OS and DFS. More clinical researches are very essential in Asians in the future.

Serum C-reactive protein and overall survival of patients with osteosarcoma

Increased level of serum C-reactive protein (CRP) has been identified as an important prognostic factor in several types of cancers. However, the prognostic significance of serum CRP levels in patients with osteosarcoma was still unclear. A retrospective cohort study of 85 patients was performed to assess the prognostic significance of serum CRP level in osteosarcoma. Both log-rank test and multivariable analysis by Cox regression model were used to assess the impact of serum CRP levels on the overall survival in patients with osteosarcoma. Among those 85 patients, 28 (32.9 %) had high serum CRP level (>1 mg/dL), while the other 57 (67.1 %) patients had normal serum CRP level (≤ 1 mg/dL). There was no obvious difference in the baseline characteristics between high CRP group and normal CRP group. Kaplan-Meier product-limit method showed that patients with high serum CRP levels had significantly poorer overall survival than those patients with normal serum CRP levels (log-rank test P = 0.0008). Multivariable analysis by Cox regression model further showed that high serum CRP level was an independent predictor of poor overall survival (hazard ratio [HR] = 2.39; 95 % confidence interval [95 % CI] 1.22-4.67, P = 0.01). Thus, serum CRP level has an important prognostic significance in patients with osteosarcoma, and high CRP level is associated with worse overall survival.

Postoperative nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma

BACKGROUND

Metastasis is the most crucial prognostic factor in osteosarcoma. The goal of this study was to develop a new nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma after neoadjuvant chemotherapy and limb salvage surgery.

METHODS

We examined medical records of 91 patients who had undergone surgery between March 1994 and March 2007. A nomogram was developed using multivariate logistic regression. The nomogram was validated internally by bootstrapping-method (200 repetitions) and externally in independent validation set (n = 34). A Youden-derived cutoff value was assigned to the nomogram to predict dichotomous outcomes for metastasis.

RESULTS

The nomogram was built from four predictors of tumor site, serum alkaline phosphatase, intracapsular extension, and Huvos grade, and an additional clause that the cutoff value should be added to the total points in the cases of incomplete surgical resection. P-value of Hosmer and Lemshow Goodness-of-fit test of this model was 0.649. Area under receiver operating curve values of 0.83 (95% confidence interval [CI], 0.75 to 0.92) in the training set and 0.80 (95% CI, 0.63 to 0.96) in the validation set were obtained. The accuracy of dichotomous outcomes was 79.1% (95% CI, 0.69 to 0.86) and 82.4% (95% CI, 0.63 to 0.92) in the training and validation sets.

CONCLUSIONS

We have developed a new high-performance nomogram to predict the probability of metastasis in Enneking stage IIB extremity osteosarcoma after limb salvage surgery.

Early response monitoring to neoadjuvant chemotherapy in osteosarcoma using sequential ¹⁸F-FDG PET/CT and MRI

PURPOSE

We evaluated the potential of sequential fluorine-18 fluorodeoxyglucose ((18) F-FDG) positron emission tomography (PET)/computed tomography (CT) and MRI (PET/MRI) after one cycle of neoadjuvant chemotherapy to predict a poor histologic response in osteosarcoma.

METHODS

A prospective study was conducted on 30 patients with osteosarcoma treated with two cycles of neoadjuvant chemotherapy and surgery. All patients underwent PET/MRI before, after one cycle, and after the completion of neoadjuvant chemotherapy, respectively. Imaging parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor volume based on magnetic resonance (MR) images (MRV)] and their % changes were calculated on each PET/MRI data set, and histological responses were evaluated on the postsurgical specimen.

RESULTS

A total of 17 patients (57%) exhibited a poor histologic response after two cycles of chemotherapy. Unlike the little volumetric change in MRI, PET parameters significantly decreased after one and two cycles of chemotherapy, respectively. After one cycle of chemotherapy, SUVmax, MTV, and TLG predicted the poor responders. Among these parameters, either MTV ≥ 47 mL or TLG ≥ 190 g after one cycle of chemotherapy was significantly associated with a poor histologic response on multivariate logistic regression analysis (OR 8.98, p = 0.039). The sensitivity, specificity, and accuracy of these parameters were 71%, 85% and 77%; and 71%, 85% and 77 %, respectively.

CONCLUSION

The histologic response to neoadjuvant chemotherapy in osteosarcoma can be predicted accurately by FDG PET after one course of chemotherapy. Among PET parameters, MTV and TLG were independent predictors of the histologic response.

Initial metabolic tumor volume measured by 18F-FDG PET/CT can predict the outcome of osteosarcoma of the extremities

We evaluated the ability of metabolic and volumetric parameters measured by pretreatment (18)F-FDG PET/CT to predict the survival of patients with osteosarcoma of the extremities.

METHODS

The records of 83 patients with American Joint Committee on Cancer stage II extremity osteosarcoma treated with surgery and chemotherapy were retrospectively reviewed. Imaging parameters (maximum standardized uptake value, metabolic tumor volume [MTV], total lesion glycolysis, and tumor volume based on MR images) were measured before treatment, and histologic responses to neoadjuvant chemotherapy were assessed by examination of postsurgical specimens. Receiver-operating-characteristic curve analyses and the Cox proportional hazards model were used to analyze whether imaging and clinicopathologic parameters could predict metastasis-free survival.

RESULTS

Of the imaging parameters, MTV at the fixed standardized uptake value threshold of 2.0 (MTV(2.0)) most accurately predicted metastasis by receiver-operating-characteristic curve analysis (area under the curve = 0.679, P = 0.011). By multivariate analysis, MTV(2.0) > 105 mL (relative risk, 3.93; 95% confidence interval, 1.55-9.92) and poor response to neoadjuvant chemotherapy (relative risk, 4.83; 95% confidence interval, 1.64-14.21) independently shortened metastasis-free survival (P = 0.004 for both parameters). The stratification of patients by the combined criteria of MTV(2.0) and histologic response predicted outcome in more detail.

CONCLUSION

MTV is an independent predictor of metastasis in patients with osteosarcoma of the extremities. The combination of MTV and histologic response predicts survival more accurately than the chemotherapeutic response alone.

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.

Inhibition of the Wnt-β-catenin and Notch signaling pathways sensitizes osteosarcoma cells to chemotherapy

Osteosarcoma (OS) is one of the most common malignant bone tumors in early adolescence. Multi-drug chemotherapy has greatly increased the five year survival rate from 20% to 70%. However, the rate has been staggering for 30 years and the prognosis is particularly poor for patients with recurrence and metastasis. Our study aimed to investigate the role of Wnt-β-catenin, Notch and Hedgehog pathway in OS development because all these pathways are involved in skeletal development, tumorigenesis and chemoresistance. Our results showed that the major components in Wnt-β-catenin pathway, e.g. Wnt3a, β-catenin and Lef1, were consistently upregulated in human osteosarcoma cell line Saos2 cells compared to human fetal osteoblasts (hFOB), whereas the changes in the expression levels of Notch and Hh signaling molecules were not consistent. Knocking down β-catenin increased the Saos2 sensitivity to methotrexate (MTX) induced cell death. Consistently, the expression level of β-catenin protein correlated with the invasiveness of OS, as evidenced by more intensive β-catenin immunoreactivity in higher grade OS samples. Chemical inhibition of the Wnt-β-catenin signaling enhanced MTX mediated death of Saos2 cells. A synergistic effect with MTX was observed when both inhibitors for Wnt-β-catenin and Notch pathways were simultaneously used, while the addition of the Hh inhibitor did not further improve the efficacy. Our findings provide some novel insight to OS pathogenesis and lay a foundation for future application of Wnt-β-catenin and Notch inhibitors together with the currently used chemotherapeutic drugs to improve the outcome of OS treatment.

Suboptimal chemotherapy is an adverse prognostic factor in osteosarcoma

BACKGROUND

We sought to determine whether suboptimal chemotherapy compromised the prognosis of osteosarcoma patients.

METHODS

A total of 132 eligible patients who underwent chemotherapy between 1998 and 2008 were identified in our database. Information regarding patient demographics, clinical characteristics, and survival status were extracted for analysis. Optimal chemotherapy was defined as receipt of ≥80% of the planned dose intensity of prescribed agents within the planned durations.

RESULTS

The use of optimal chemotherapy resulted in an overall survival benefit with P = 0.006. Patients who failed to complete the optimal chemotherapy protocol had a dismal prognosis of 30.8% overall survival over five years, whereas those who completed the optimal chemotherapy had an overall survival rate over five years of 65.3%. Based on multivariate analysis, patients who were treated with a suboptimal protocol had a higher risk of relapse, metastasis and mortality. The hazard ratio (HR) of recurrence or death for the suboptimal chemotherapy group was as high as 2.512 over that of the optimal chemotherapy group (HR = 2.512, 95% confidence interval = 1.242 to 3.729).

CONCLUSIONS

Chemotherapy is a significant independent prognostic variable, and suboptimal chemotherapy was found to have a detrimental effect on the outcome of patients with osteosarcoma.

Analysis of the efficacy and prognosis of limb-salvage surgery for osteosarcoma around the knee

AIM

Limb-salvage surgery has become the standard of care for extremity osteosarcoma. In this study, we investigated the survival and functional outcomes of patients with osteosarcoma around the knee who were treated with limb-salvage surgery.

METHODS

We retrospectively reviewed the clinical data for 120 patients with osteosarcoma around the knee who were treated with limb-salvage surgery between 1998 and 2008. The sample included 75 males and 45 females. The mean age of the patients was 18.9 years. Osteosarcoma was diagnosed in the distal femur in 78 patients and in the proximal tibia in 42 patients. Statistical analyses were conducted to process and record the patient data and analyse the surgery's efficacy, prognosis and survival rates.

RESULTS

All patients were followed for 6-144 months (mean of 56.8 months). The overall 5-year survival rate was 61.8%. Lung metastasis developed in 31 patients. Local recurrence developed in 9 patients. The average Musculoskeletal Tumor Society Score (MSTS) was 25.5 points on a 30-point scale. Sixteen patients underwent prosthesis revision and twelve patients underwent amputation. The overall survivorship of the prosthesis based on Kaplan-Meier estimates was 77% at five years and 71% at ten years. There was a higher incidence of extensor lag for the patients with osteosarcoma in the proximal tibia than for those with osteosarcoma in the distal femur (P < 0.01).

CONCLUSIONS

Treating osteosarcoma around the knee with limb-salvage surgery can preserve most of the knee's functionality. Attention must be paid to prevent the relatively high incidence of postoperative complications.