Percent slope analysis of dynamic magnetic resonance imaging for assessment of chemotherapy response of osteosarcoma or Ewing sarcoma: systematic review and meta-analysis

Evaluation of response to neoadjuvant chemotherapy in osteosarcoma using dynamic contrast-enhanced MRI: development and external validation of a model

OBJECTIVE

To identify which dynamic contrast-enhanced (DCE-)MRI features best predict histological response to neoadjuvant chemotherapy in patients with an osteosarcoma.

METHODS

Patients with osteosarcoma who underwent DCE-MRI before and after neoadjuvant chemotherapy prior to resection were retrospectively included at two different centers. Data from the center with the larger cohort (training cohort) was used to identify which method for region-of-interest selection (whole slab or focal area method) and which change in DCE-MRI features (time to enhancement, wash-in rate, maximum relative enhancement and area under the curve) gave the most accurate prediction of histological response. Models were created using logistic regression and cross-validated. The most accurate model was then externally validated using data from the other center (test cohort).

RESULTS

Fifty-five (27 poor response) and 30 (19 poor response) patients were included in training and test cohorts, respectively. Intraclass correlation coefficient of relative DCE-MRI features ranged 0.81-0.97 with the whole slab and 0.57-0.85 with the focal area segmentation method. Poor histological response was best predicted with the whole slab segmentation method using a single feature threshold, relative wash-in rate <2.3. Mean accuracy was 0.85 (95%CI: 0.75-0.95), and area under the receiver operating characteristic curve (AUC-index) was 0.93 (95%CI: 0.86-1.00). In external validation, accuracy and AUC-index were 0.80 and 0.80.

CONCLUSION

In this study, a relative wash-in rate of <2.3 determined with the whole slab segmentation method predicted histological response to neoadjuvant chemotherapy in osteosarcoma. Consistent performance was observed in an external test cohort.

Imaging Assessment of the Efficacy of Chemotherapy in Primary Malignant Bone Tumors: Recent Advances in Qualitative and Quantitative Magnetic Resonance Imaging and Radiomics

Recent studies have shown that MRI demonstrates promising results for evaluating the chemotherapy efficacy in bone sarcomas. This article reviews current methods for evaluating the efficacy of malignant bone tumors and the application of MRI in this area, and emphasizes the advantages and limitations of each modality. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 2.

Ewing sarcoma of the temporal bone with aneurysmal bone cyst-like changes: A rare case report with an unusual radiological presentation

Ewing sarcoma (ES) is a malignant small round cell tumor, accounting for 10-15% of all primary bone tumors and approximately 3% of all pediatric cancers. Primary ES of the cranial bone is unusual with reported incidence from 1% to 6% of all ES cases. This report shows a rare case of primary ES of the squamous temporal bone in a 12-year-old boy with a history of swelling of the right temporal region and symptoms of increased intracranial pressure. We illustrate the extremely unusual radiological presentation of this primary ES of temporal bone associated with large aneurysmal bone cyst-like (ABC-like) changes. The boy was successfully treated according to Euro Ewing 2012 protocol. He is alive with no evidence of recurrence and metastasis after 16 months of completed treatment.

Advances in The Application and Research of Magnetic Resonance Diffusion Kurtosis Imaging in The Musculoskeletal System

Magnetic resonance diffusion kurtosis imaging (DKI) is an emerging magnetic resonance imaging (MRI) technique that can reflect microstructural changes in tissue through non-Gaussian diffusion of water molecules. Compared to traditional diffusion weighted imaging (DWI), the DKI model has shown greater sensitivity for diagnosis of musculoskeletal diseases and can help formulate more reasonable treatment plans. Moreover, DKI is an important auxiliary examination for evaluation of the motor function of the musculoskeletal system. This article briefly introduces the basic principles of DKI and reviews the application and research of DKI in the evaluation of disorders of the musculoskeletal system (including bone tumors, soft tissue tumors, spinal lesions, chronic musculoskeletal diseases, musculoskeletal trauma, and developmental disorders) as well as the normal musculoskeletal tissues. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: 1.

T2-weighted MRI radiomics in high-grade intramedullary osteosarcoma: predictive accuracy in assessing histologic response to chemotherapy, overall survival, and disease-free survival

OBJECTIVE

To analyze radiomic features obtained from pre-treatment T2-weighted MRI acquisitions in patients with histologically proven intramedullary high-grade osteosarcomas and assess the accuracy of radiomic modelling as predictive biomarker of tumor necrosis following neoadjuvant chemotherapy (NAC), overall survival (OS), and disease-free survival (DFS).

MATERIALS AND METHODS

Pre-treatment MRI exams in 105 consecutive patients who underwent NAC and resection of high-grade intramedullary osteosarcoma were evaluated. Histologic necrosis following NAC, and clinical outcome-survival data was collected for each case. Radiomic features were extracted from segmentations performed by two readers, with poorly reproducible features excluded from further analysis. Cox proportional hazard model and Spearman correlation with multivariable modelling were used for assessing relationships of radiomics features with OS, DFS, and histologic tumor necrosis.

RESULTS

Study included 74 males, 31 females (mean 32.5yrs, range 15-77 years). Histologic assessment of tumor necrosis following NAC was available in 104 cases, with good response (≥ 90% necrosis) in 41, and poor response in 63. Fifty-three of 105 patients were alive at follow-up (median 40 months, range: 2-213 months). Median OS was 89 months. Excluding 14 patients with metastases at presentation, median DFS was 19 months. Eleven radiomics features were employed in final radiomics model predicting histologic tumor necrosis (mean AUC 0.708 ± 0.046). Thirteen radiomic features were used in model predicting OS (mean concordance index 0.741 ± 0.011), and 12 features retained in predicting DFS (mean concordance index 0.745 ± 0.010).

CONCLUSIONS

T2-weighted MRI radiomic models demonstrate promising results as potential prognostic biomarkers of prospective tumor response to neoadjuvant chemotherapy and prediction of clinical outcomes in conventional osteosarcoma.

3D vs. 2D MRI radiomics in skeletal Ewing sarcoma: Feature reproducibility and preliminary machine learning analysis on neoadjuvant chemotherapy response prediction

OBJECTIVE

The extent of response to neoadjuvant chemotherapy predicts survival in Ewing sarcoma. This study focuses on MRI radiomics of skeletal Ewing sarcoma and aims to investigate feature reproducibility and machine learning prediction of response to neoadjuvant chemotherapy.

MATERIALS AND METHODS

This retrospective study included thirty patients with biopsy-proven skeletal Ewing sarcoma, who were treated with neoadjuvant chemotherapy before surgery at two tertiary sarcoma centres. 7 patients were poor responders and 23 were good responders based on pathological assessment of the surgical specimen. On pre-treatment T1-weighted and T2-weighted MRI, 2D and 3D tumour segmentations were manually performed. Features were extracted from original and wavelet-transformed images. Feature reproducibility was assessed through small geometrical transformations of the regions of interest mimicking multiple manual delineations, and intraclass correlation coefficient >0.75 defined feature reproducibility. Feature selection also consisted of collinearity and significance analysis. After class balancing in the training cohort, three machine learning classifiers were trained and tested on unseen data using hold-out cross-validation.

RESULTS

1303 (77%) 3D and 620 (65%) 2D radiomic features were reproducible. 4 3D and 4 2D features passed feature selection. Logistic regression built upon 3D features achieved the best performance with 85% accuracy (AUC=0.9) in predicting response to neoadjuvant chemotherapy.

CONCLUSION

Compared to 2D approach, 3D MRI radiomics of Ewing sarcoma had superior reproducibility and higher accuracy in predicting response to neoadjuvant chemotherapy, particularly when using logistic regression classifier.

Prediction of Histologic Neoadjuvant Chemotherapy Response in Osteosarcoma Using Pretherapeutic MRI Radiomics

Histologic response to chemotherapy for osteosarcoma is one of the most important prognostic factors for survival, but assessment occurs after surgery. Although tumor imaging is used for surgical planning and follow-up, it lacks predictive value. Therefore, a radiomics model was developed to predict the response to neoadjuvant chemotherapy based on pretreatment T1-weighted contrast-enhanced MRI. A total of 176 patients (median age, 20 years [range, 5-71 years]; 107 male patients) with osteosarcoma treated with neoadjuvant chemotherapy and surgery between January 2007 and December 2018 in three different centers in France (Centre Léon Bérard in Lyon, Centre Hospitalier Universitaire de Nantes in Nantes, and Hôpital Cochin in Paris) were retrospectively analyzed. Various models were trained from different configurations of the data sets. Two different methods of feature selection were tested with and without ComBat harmonization (ReliefF and t test) to select the most relevant features, and two different classifiers were used to build the models (an artificial neural network and a support vector machine). Sixteen radiomics models were built using the different combinations of feature selection and classifier applied on the various data sets. The most predictive model had an area under the receiver operating characteristic curve of 0.95, a sensitivity of 91%, and a specificity 92% in the training set; respective values in the validation set were 0.97, 91%, and 92%. In conclusion, MRI-based radiomics may be useful to stratify patients receiving neoadjuvant chemotherapy for osteosarcomas. Keywords: MRI, Skeletal-Axial, Oncology, Radiomics, Osteosarcoma, Pediatrics Supplemental material is available for this article. © RSNA, 2022.

Multiparametric MRI evaluation of bone sarcomas in children

Osteosarcoma and Ewing sarcoma are the most common bone sarcomas in children. Their clinical presentation is very variable depending on the age of the patient and tumor location. MRI is the modality of choice to assess these bone sarcomas and has an important function at diagnosis and also for monitoring recurrence or tumor response. Anatomic sequences include T1- and T2-weighted images and provide morphological assessment that is crucial to localize the tumor and describe anatomical boundaries. Multiparametric MRI provides functional information that helps in the assessment of tumor response to therapy by using different imaging sequences and biomarkers. This review manuscript illustrates the role of MRI in osteosarcoma and Ewing sarcoma in the pediatric population, with emphasis on a functional perspective, highlighting the use of diffusion-weighted imaging and dynamic contrast-enhanced MRI at diagnosis, and during and after treatment.

Correlation of histopathology and multi-modal magnetic resonance imaging in childhood osteosarcoma: Predicting tumor response to chemotherapy

Background

Osteosarcoma, which is the most common malignant pediatric bone cancer, remains dependent on an imprecise systemic treatment largely unchanged in 30 years. In this study, we correlated histopathology with magnetic resonance imaging (MRI), used the correlation to extract MRI-specific features representative of tumor necrosis, and subsequently developed a novel classification model for predicting tumor response to neoadjuvant chemotherapy in pediatric patients with osteosarcoma using multi-modal MRI. The model could ultimately serve as a testable biomarker for a high-risk malignancy without successful precision treatments.

Methods

Patients with newly diagnosed high-grade appendicular osteosarcoma were enrolled in a single-center observational study, wherein patients underwent pre-surgical evaluation using both conventional MRI (post-contrast T1-weighted with fat saturation, pre-contrast T1-weighted, and short inversion-time inversion recovery (STIR)) and advanced MRI (diffusion weighted (DW) and dynamic contrast enhanced (DCE)). A classification model was established based on a direct correlation between histopathology and MRI, which was achieved through histologic-MR image co-registration and subsequent extraction of MR image features for identifying histologic tumor necrosis. By operating on the MR image features, tumor necrosis was estimated from different combinations of MR images using a multi-feature fuzzy clustering technique together with a weighted majority ruling. Tumor necrosis calculated from MR images, for either an MRI plane of interest or whole tumor volume, was compared to pathologist-estimated necrosis and necrosis quantified from digitized histologic section images using a previously described deep learning classification method.

Results

15 patients were enrolled, of whom two withdrew, one became ineligible, and two were subjected to inadequate pre-surgical imaging. MRI sequences of n = 10 patients were subsequently used for classification model development. Different MR image features, depending on the modality of MRI, were shown to be significant in distinguishing necrosis from viable tumor. The scales at which MR image features optimally signified tumor necrosis were different as well depending on the MR image type. Conventional MRI was shown capable of differentiating necrosis from viable tumor with an accuracy averaging above 90%. Conventional MRI was equally effective as DWI in distinguishing necrotic from viable tumor regions. The accuracy of tumor necrosis prediction by conventional MRI improved to above 95% when DCE-MRI was added into consideration. Volume-based tumor necrosis estimations tended to be lower than those evaluated on an MRI plane of interest.

Conclusions

The study has shown a proof-of-principle model for interpreting chemotherapeutic response using multi-modal MRI for patients with high-grade osteosarcoma. The model will continue to be evaluated as MR image features indicative of tumor response are now computable for the disease prior to surgery.

Pediatric Osteosarcoma: Pearls and Pitfalls

Osteosarcoma is a malignant bone tumor most commonly presenting in children. It has a bimodal distribution with a peak incidence occurring during the ages of 10-14 years old and in adults greater than age 65. The first peak of osteosarcoma correlates with the increased proliferation of bone during the pubertal growth period. Osteosarcoma most frequently presents with localized bone pain, swelling, and an antalgic gait. The patient may attribute symptoms to trauma or strenuous exercise, causing the patient to be managed conservatively. In these cases, the pain persists and eventually leads to further evaluation. The most common type of osteosarcoma is the conventional high-grade osteosarcoma. For conventional osteosarcoma, the diagnosis is typically made or strongly suggested based upon the initial radiographic appearance. Other types of osteosarcomas include low grade central, telangiectatic, small-cell, surface and intracortical. Consequently, it is important for radiologists to be aware of these subtypes and the imaging features that differentiate them from other etiologies to prevent a delay in treatment.

Pediatric skeletal diffusion-weighted magnetic resonance imaging, part 2: current and emerging applications

Diffusion-weighted imaging (DWI) complements the more established T1, fluid-sensitive and gadolinium-enhanced magnetic resonance pulse sequences used to assess several pediatric skeletal pathologies. There is optimism that the technique might not just be complementary but could serve as an alternative to gadolinium and radiopharmaceuticals for several indications. As a non-contrast, free-breathing and noninvasive technique, DWI is especially valuable in children and is readily incorporated into existing MRI protocols. The indications for skeletal DWI in children include distinguishing between benign and malignant skeletal processes, initial assessment and treatment response assessment for osseous sarcomas, and assessment of inflammatory arthropathies and femoral head ischemia, among others. A notable challenge of diffusion MRI is the dynamic nature of the growing pediatric skeleton. It is important to consider the child's age when placing DWI findings in context with potential marrow pathology. This review article summarizes the current and evolving applications of DWI for assessing the pediatric skeleton, rounding off the discussion with evolving directions for further research in this realm.

Semi-Automatic Volumetric and Standard Three-Dimensional Measurements for Primary Tumor Evaluation and Response to Treatment Assessment in Pediatric Rhabdomyosarcoma

Current prognostic classification of rhabdomyosarcoma in children requires precise measurements of the tumor. The purpose of the study was to compare the standard three-dimensional (3D) measurements with semi-automatic tumor volume measurement method concerning assessment of the primary tumor size and the degree of response to treatment for rhabdomyosarcoma in children. Magnetic Resonance Imaging data on 31 children with treated rhabdomyosarcoma based on the Cooperative Weichteilsarkom Studiengruppe (CWS) guidance was evaluated. Tumor sizes were measured by two methods: 3D standard measurements and semi-automatic tumor volume measurement (VOI) at diagnosis, and after 9 and 17/18 weeks of the induction chemotherapy. Response to treatment and prediction values were assessed. The tumor volume medians calculated using VOI were significantly higher in comparison with those calculated using the 3D method both during the diagnosis as well as after 9 weeks of the chemotherapy and during the 17-18th week of the treatment. The volume measurements based on the generalized estimating equations on the VOI method were significantly better than the 3D method (p = 0.037). The volumetric measurements alone can hardly be considered an unequivocal marker used to make decisions on modification of the therapy in patients with rhabdomyosarcoma.

[18F]FDG PET/CT quantitative parameters for the prediction of histological response to induction chemotherapy and clinical outcome in patients with localised bone and soft-tissue Ewing sarcoma

OBJECTIVE

The application of [¹⁸F]FDG PET/CT in predicting histologic response to induction chemotherapy in patients with Ewing sarcoma (EWS) has been proposed using the values of pre-post treatment SUV_max as a referral parameter, although with heterogeneous results. The aim of this retrospective study was to evaluate the diagnostic accuracy of [¹⁸F]FDG PET/CT volumetric parameters (metabolic tumour volume (MTV) and total lesion glycolysis (TLG)) as compared to SUV_max to predict response to chemotherapy and clinical outcome in patients with localised EWS of bone and soft-tissue.

METHODS

Twenty-eight patients with non-metastatic EWS of bone (n = 20) and soft tissues (n = 8) who underwent a [¹⁸F]FDG PET/CT scan before (PET₁) and after induction chemotherapy (PET₂) were enclosed in the analysis. Values of PET metrics (SUV_max, MTV, TLG) at diagnosis and after neoadjuvant chemotherapy as well as the percentage change between PET₁ and PET₂ (ΔSUV, ΔMTV and ΔTLG) were correlated to histological response and to progression-free survival (PFS).

RESULTS

ΔTLG (cut-off: -60%) is the best predictor for histologic response with 100% sensitivity and 77.8% specificity. MTV₁ > 33.4 cm³ and TLG₁ > 112 were also associated with a favourable histologic response (sensitivity 80% and specificity 77.8% for both). On multivariate analysis, SUV₂ (> 3.3) and ΔTLG (< -18%) were independent predictors of worse PFS.

CONCLUSIONS

[¹⁸F]FDG PET/CT could accurately predict histologic response to neoadjuvant chemotherapy in patients with EWS, also showing a possible prognostic value for future disease relapse.

KEY POINTS

• The variation of the PET parameter tumour lesion glycolysis (TLG) can predict the histologic response to induction chemotherapy (sensitivity 100%, specificity 77.8%), in patients with Ewing sarcoma. • The percentage variation of TLG and the value of the SUVmax at PET scan after chemotherapy show a prognostic role for future disease relapse. The combination of both the parameters identifies three prognostic classes of patients with low, intermediate and high risk of disease relapse.

Effect of Cisplatin Arterial Infusion (CAI) on Primary Nonmetastatic Pelvic Osteosarcoma: A Preliminary Study

Purpose

The critical role of arterial infusion chemotherapy in the multimodal treatment of extremity bone cancer has been investigated extensively, but few studies have focused on pelvic osteosarcoma. Therefore, we attempted to evaluate the clinical significance of arterial infusion chemotherapy in the treatment of pelvic osteosarcoma.

Patients and Methods

We combined a cisplatin arterial infusion regimen with multidrug systematic chemotherapy as a neoadjuvant protocol for the treatment of pelvic osteosarcoma. The course number and dosage of cisplatin arterial infusion were adjusted to achieve a maximal tumor response evaluated by contrast-enhanced MRI per RECIST 1.1. Good responders received the same systematic combination for postoperative chemotherapy, and poor responders received second-line therapy. Twelve patients with nonmetastatic high-grade pelvic osteosarcoma were included. Survival, chemotherapy response and adverse events data were analyzed.

Results

The mean follow-up period was 56.1 months. Four patients died of refractory tumor progression, and 1 patient with local recurrence had no evidence of disease for 27 months after receiving secondary amputation and resection. Kaplan-Meier survival analysis demonstrated a 57.8% overall survival and 52.5% event-free survival rate at 5 years. Eight of 12 patients had a >90% tumor necrosis rate according to histopathologic examinations. The rates of local adverse events were lower than those reported for extremity osteosarcoma.

Conclusion

Our study initially indicated that the cisplatin arterial infusion regimen was a potential therapy with good tolerance in the treatment of pelvic osteosarcoma.

Multiparametric MRI with diffusion-weighted imaging in predicting response to chemotherapy in cases of osteosarcoma and Ewing's sarcoma

OBJECTIVE

To evaluate the multiparametric MRI in predicting chemotherapy response in pathologically proven cases of osteosarcoma and Ewing's sarcoma. Correlation between the tumor size changes and internal breakdown using RECIST 1.1, modified RECIST, quantitative apparent diffusion coefficient (ADC) and tumor volume as well as dynamic contrast-enhanced MRI (DCE-MRI).

METHODS

The study included 104 patients pathologically proved osteosarcoma (53) and Ewing`s sarcoma (51) underwent MRI examinations; before and after chemotherapy. All patients were assessed using the RECIST 1.1 criteria, m-RECIST, quantitative ADC, and tumor volume evaluation. 21 patients underwent DCE-MRI curve type with quantitative parameters. Correlation between the different evaluations was carried out. Results were correlated with the post-operative pathology in 42 patients who underwent surgery and for statistical evaluation, Those patients were classified into responders (≥90% necrosis) and non-responders (<90% necrosis).

RESULTS

The initial mean ADC of 104 patients of osteosarcoma and Ewing's sarcoma (0.90 ± 0.29) and (0.71 ± 0.16) respectively, differed significantly from that after treatment (1.62 ± 0.46) and (1.6 ± 0.39) respectively with (p<0.001).ADC variations (ADC%) in the non-progressive group were higher than those of the progressive group (128.3 ± 63.49 vs 36.34 ± 78.7) % with (p<0.001).ADC values and ADC variations were inversely correlated with morphologic changes, regardless of the effectiveness of chemotherapy expressed as changes in tumor size based on (RECIST 1.1, RECIST, and 3D volume). Linear regression analysis revealed a Pearson correlation coefficient of r=-0.427, -0.498 and -0.408, respectively with (p<0.001).An increase in the ADC value was not always associated with a reduction in tumor volume. The disease control rate (defined as the percentage of CR+PR+SD patients) was 89.4% and 93.9% according to RECIST 1.1 and m-RECIST respectively.42 out of the 104 patients had postsurgical histological evaluation as regards the chemotherapeutic response divided into two groups. ADC values showed a statistically significant difference between Group A and Group B being more evident with minimum ADC% (p<0.001).

CONCLUSION

Quantitative diffusion-weighted imaging with ADC mapping and ADC % after chemotherapy allows a detailed analysis of the treatment response in osteosarcoma and Ewing's sarcoma. The therapeutic response can be underestimated using RECIST 1.1, so the modified RECIST should be also considered.

ADVANCES IN KNOWLEDGE

Quantitative ADC especially ADC% provided an accurate non-invasive tool in the assessment of post-therapeutic cases of osteosarcoma and Ewing's sarcoma.

A nomogram for predicting cancer-specific survival in patients with osteosarcoma as secondary malignancy

The prognostic factors for survival among patients with secondary osteosarcoma remain unclear. The aim of this study was to develop a practical nomogram for predicting cancer-specific survival (CSS) in patients with osteosarcoma as a secondary malignancy. The surveillance, epidemiology, and end results database was used for the identification of osteosarcoma cases. The total sample comprised 5860 cases of primary osteosarcoma and 268 cases of secondary osteosarcoma during the period from 1973 to 2015. The CSS and overall survival (OS) of primary and secondary osteosarcomas were analyzed. The predictors of CSS for secondary osteosarcoma were identified and integrated to build a nomogram. Validation of the nomogram was performed using concordance index (C-index) and calibration plots. The results indicated that patients with secondary osteosarcoma had poorer CSS and OS than patients with primary osteosarcoma. The nomogram model exhibited high discriminative accuracy in the training cohort (C-index = 0.826), which was confirmed in the internal validation cohort (C-index = 0.791). In addition, the calibration plots confirmed good concordance for prediction of CSS at 3, 5, and 10 years. In conclusion, we developed a practical nomogram that provided individual predictions of CSS for patients with secondary osteosarcoma. This nomogram may help clinicians with prognostic evaluations and with the development of individualized therapies for this aggressive disease.

Monitoring Response to Neoadjuvant Chemotherapy of Primary Osteosarcoma Using Diffusion Kurtosis Magnetic Resonance Imaging: Initial Findings

Objective

To determine whether diffusion kurtosis imaging (DKI) is effective in monitoring tumor response to neoadjuvant chemotherapy in patients with osteosarcoma.

Materials and Methods

Twenty-nine osteosarcoma patients (20 men and 9 women; mean age, 17.6 ± 7.8 years) who had undergone magnetic resonance imaging (MRI) and DKI before and after neoadjuvant chemotherapy were included. Tumor volume, apparent diffusion coefficient (ADC), mean diffusivity (MD), mean kurtosis (MK), and change ratio (ΔX) between pre- and post-treatment were calculated. Based on histologic response, the patients were divided into those with good response (≥ 90% necrosis, n = 12) and those with poor response (< 90% necrosis, n = 17). Several MRI parameters between the groups were compared using Student's t test. The correlation between image indexes and tumor necrosis was determined using Pearson's correlation, and diagnostic performance was compared using receiver operating characteristic curves.

Results

In good responders, MD_post, ADC_post, and MK_post values were significantly higher than in poor responders (p < 0.001, p < 0.001, and p = 0.042, respectively). The ΔMD and ΔADC were also significantly higher in good responders than in poor responders (p < 0.001 and p = 0.01, respectively). However, no significant difference was observed in ΔMK (p = 0.092). MD_post and ΔMD showed high correlations with tumor necrosis rate (r = 0.669 and r = 0.622, respectively), and MD_post had higher diagnostic performance than ADC_post (p = 0.037) and MK_post (p = 0.011). Similarly, ΔMD also showed higher diagnostic performance than ΔADC (p = 0.033) and ΔMK (p = 0.037).

Conclusion

MD is a promising biomarker for monitoring tumor response to preoperative chemotherapy in patients with osteosarcoma.

Current review of surgical management options for extremity bone sarcomas

Modern surgical management of extremity bone sarcomas is governed by limb-sparing surgery combined with adjuvant and neoadjuvant chemotherapy.

All the resection and reconstruction techniques have to achieve oncologic excision margins, with survival rates and functional results superior to amputation.

The main reconstruction techniques of bone defects resulted after resection are: modular endoprosthetic reconstruction; bone graft reconstruction; bone transport; resection arthrodesis; and rotationplasty.

Oncologic resection and modular endoprosthetic reconstruction are the generally approved surgical options adopted for the majority of cases in major specialized bone sarcoma centres.

Good basic principles, efficient multidisciplinary approach and sustained research in the field can provide a better future for the challenge posed by extremity bone sarcoma treatment.

Cite this article: EFORT Open Rev 2019;4:174-182. DOI: 10.1302/2058-5241.4.180048

The current status of MRI in the pre-operative assessment of intramedullary conventional appendicular osteosarcoma

Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majority of cases being conventional intra-medullary high-grade tumours affecting the appendicular skeleton. Treatment is typically with a combination of neo-adjuvant chemotherapy, tumour resection with limb reconstruction and post-operative chemotherapy. The current article reviews the role of magnetic resonance imaging (MRI) in the pre-operative assessment of high-grade central conventional osteosarcoma.

Conventional 99mTc-(hydroxy) methylene diphosphate remains useful to predict osteosarcoma response to neoadjuvant chemotherapy: Individual patient data and aggregate data meta-analyses

BACKGROUND

The current standard of chemotherapy response evaluation holds the most important prognostic factor to be the histological assessment of the tumor necrosis of the excised lesion, but the major challenge is to find an early prognostic factor that will allow the adjuvant treatment regimen to be adjusted. The objective of this systematic review is to provide an up-to-date and unprecedented summary of the value of Technetium-methylene diphosphate or -hydroxymethylene diphosphate (Tc-MDP/HMDP) scintigraphy for the preoperative evaluation of osteosarcoma response to chemotherapy.

METHODS

Studies evaluating the alteration ratio (percentage change of the Tc-99m -MDP/HMDP uptake between before and after neoadjuvant chemotherapy) to predict the histological response of osteosarcoma to chemotherapy were searched for in MEDLINE, EMBASE, and Web of Science. A meta-analysis of individual patient data (IPD) was performed to determine the optimal cut-off point from the receiver operating characteristic (ROC) curve. Additionally, aggregate data (AD) meta-analysis was performed to compare the value of Tc-MDP/HMDP scintigraphy with that of other quantitative modalities, such as dynamic magnetic resonance imaging (MRI), Tl scintigraphy, and F-FDG PET-CT.

RESULTS

Seven studies with 154 patients were included for the IPD meta-analysis. The optimal cut-off point of the alteration ratio was 31.0%. Five studies with 123 patients were considered for the AD meta-analysis. The pooled sensitivity and specificity were 0.76 (95% CI, 0.63-0.86) and 0.89 (95% CI, 0.79-0.95), respectively. There was a significant difference between the good and poor responders in terms of the diagnostic odds ratio. The summary ROC curve demonstrated that the area under curve (AUC) was 0.892, indicating excellent diagnostic accuracy.

CONCLUSION

Our findings have suggested that conventional Tc-MDP/HMDP scintigraphy remains as useful as recent quantitative modalities to predict the histological response of osteosarcoma to neoadjuvant chemotherapy.

A correlation analysis between tumor imaging changes and p-AKT and HSP70 expression in tumor cells after osteosarcoma chemotherapy

This study sought to investigate osteosarcoma property changes after neoadjuvant chemotherapy and to analyze any correlation between changes with phospho-AKT (p-AKT) and heat shock protein 70 (HSP70) expression in osteosarcoma cells. Thirty patients with osteosarcoma treated at Liaocheng People's Hospital between January and October, 2016 were given an imaging examination before and after neoadjuvant chemotherapy to examine osteosarcoma tumor properties, with images scored. Immunohistochemistry was used to determine p-AKT and HSP70 expression levels, as well as tumor cell necrosis rate (TCNR), in specimens obtained before and after chemotherapy. The correlation between the imaging changes of osteosarcoma after chemotherapy and the expressions of p-AKT and HSP70 in tumor cells. Compared with pre-chemotherapy, the imaging scores of the 30 patients significantly increased after chemotherapy (P<0.05). The radiographic score of the TCNR ≥90% group was 11.3±0.5, which was significantly higher than that of the TCNR <90% group (8.7±0.3, P<0.05). p-AKT expression in osteosarcoma cells was found in 13.3% of samples (4/30 cases) after chemotherapy, which was significantly lower than prior to chemotherapy (73.3%, 22/30 cases, P<0.05). After chemotherapy, HSP70 expression in osteosarcoma cells was found in 6.7% of samples (2/30 cases), which was significantly lower than prior to chemotherapy (83.3%, 25/30 cases, P<0.05). p-AKT and HSP70 expression levels were found to be correlated with TCNR after chemotherapy (P<0.05). After chemotherapy, p-AKT and HSP70 expression levels demonstrated a positive correlation with TCNR. Tumor property changes, as uncovered by imaging, were significantly inversely correlated with tumor cell p-AKT and HSP70 expression after chemotherapy. Therefore, osteosarcoma properties, as determined through X-ray imaging, were closely related to p-AKT and HSP70 expression in osteosarcoma cells after neoadjuvant chemotherapy. The effect of chemotherapy can be evaluated by observing the above examination results.

Value of diffusion-weighted imaging for evaluating chemotherapy response in osteosarcoma: A meta-analysis

The histological examination of the tumor necrosis upon surgery remains the most reliable prognostic factor for osteosarcoma. However, the detection of more early prognostic factors is desirable in order to increase the survival rates and decrease the risk rates for iatrogenic toxicity. The purpose of the current systematic review and meta-analysis was to provide an up-to-date summary of the role of diffusion-weighted imaging (DWI) for the preoperative assessment of the chemotherapy response in osteosarcoma. Articles evaluating DWI for the preoperative assessment of the chemotherapy response of osteosarcoma were systematically searched for in four electronic literature databases. The mean difference in apparent diffusion coefficient (ADC) following neoadjuvant chemotherapy between good and poor histological responders was assessed in 5 studies. The mean difference in the ADC ratio (the percentage change in ADC between post-neoadjuvant and pre-neoadjuvant chemotherapy) reported in 3 studies was also assessed. Five articles with 106 patients fulfilled all of the inclusion criteria for the meta-analysis. Significant mean differences were found between good and poor responders in the ADC in the 5 studies (P=0.03) and the ADC ratio in the 3 studies (P<0.00001). The good responders demonstrated a higher ADC and a higher ADC ratio than the poor responders. DWI performed with ADC values was useful for predicting the chemotherapeutic response of osteosarcoma. This method may have promising potential as a preoperative non-invasive modality.

Surgical Innovation in Sarcoma Surgery

The field of orthopaedic oncology relies on innovative techniques to resect and reconstruct a bone or soft tissue tumour. This article reviews some of the most recent and important innovations in the field, including biological and implant reconstructions, together with computer-assisted surgery. It also looks at innovations in other fields of oncology to assess the impact and change that has been required by surgeons; topics including surgical margins, preoperative radiotherapy and future advances are discussed.

Bufalin Inhibits Proliferation and Induces Apoptosis in Osteosarcoma Cells by Downregulating MicroRNA-221

Bufalin, a major component of the Chinese medicine ChanSu, which is prepared from the skin and parotid venom glands of toads, has shown cytotoxicity in several malignant tumors. Here, we reported that bufalin inhibited proliferation and induced mitochondria-dependent apoptosis in U-2OS and Saos-2 osteosarcoma cells with intracellular reactive oxygen species (ROS) production. By microRNA (miR) array analysis and quantitative reverse transcription polymerase chain reaction, we found that miR-221 was downregulated after treatment with bufalin. In accordance with TargetScan prediction and luciferase reporter assay, Bcl2 binding component 3 (BBC3) was the direct target of miR-221. Furthermore, upregulating miR-221 by its MIMIC and suppressing BBC3 by small interfering RNA (siRNA) reversed the effects of bufalin on osteosarcoma cells. Collectively, our data indicate that bufalin inhibits cell proliferation and induces mitochondria-dependent apoptosis in osteosarcoma cells through downregulating miR-221 and triggering BBC3 expression.

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.