Radiological Assessment and Outcome of Local Disease Progression after Neoadjuvant Chemotherapy in Children and Adolescents with Localized Osteosarcoma

Prognostic factors in high-grade pediatric osteosarcoma among children and young adults: Greek Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST) data along with a systematic review and meta-analysis

The 5-year overall survival of children and adolescents with osteosarcoma has been in plateau during the last 30 years. The present systematic review (1976-2023) and meta-analysis aimed to explore factors implicated in the prognosis of children and young adults with high-grade osteosarcoma. Original studies including patients ≤30 years and the Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST) data (2010-2021) referred to children ≤14 years were analysed. Individual participant data (IPD) and summary estimates were used to assess the n-year survival rates, as well as the association of risk factors with overall survival (OS) and event-free survival (EFS). IPD and the n-year survival rates were pooled using Kaplan-Meier and Cox regression models, and random effects models, respectively. Data from 8412 patients, including 46 publications, NARECHEM-ST data, and 277 IPD from 10 studies were analysed. The summary 5-year OS rate was 64% [95% confidence interval (95%CI): 62%-66%, 37 studies, 6661 patients] and the EFS was 52% (95%CI: 49%-56%, 30 studies, 5010 patients). The survival rates generally differed in the pre-specified subgroups. Limb-salvage surgery showed a higher 5-year OS rate (69%) versus amputation (47%). Good responders had higher OS rates at 3 years (94%) and 5 years (81%), compared to poor responders at 3 years (66%), and 5 years (56%). Patients with metastatic disease had a higher risk of death [Hazard Ratio (HR): 3.60, 95%CI: 2.52, 5.15, 11 studies]. Sex did not have an impact on EFS (HR females/males: 0.90, 95%CI: 0.54, 1.48, 3 studies), whereas age>18 years seems to adversely affect EFS (HR 18+/<10 years: 1.36, 95%CI: 1.09, 1.86, 3 studies). Our results summarize the collective experience on prognostic factors of high-grade osteosarcoma among children and young adults. Poor response to neoadjuvant chemotherapy and metastatic disease at diagnosis were confirmed as primary risk factors of poor outcome. International collaboration of osteosarcoma study groups is essential to improve survival.

Progression before local control in osteosarcoma: Outcome and prognosis-predictive factors

BACKGROUND

The prognosis and impact of early disease progression in patients with osteosarcoma prior to local control (LC), and the potential therapeutic benefits of ifosfamide/etoposide (IE) remain underexplored in the medical literature.

METHODS

A retrospective study was conducted on pediatric patients (≤18 years) with osteosarcoma who presented to King Hussein Cancer Center between June 2006 and March 2022. We studied patients with disease progression before LC.

RESULTS

Among 195 patients, 31 (17males) exhibited disease progression before LC. The median age at diagnosis was 14.1 years, and patients were followed for a median of 23.1 months (range: 5.8-94.7). The majority of tumors were located in the extremities (n = 28). Ten patients (48%) had lung-only metastasis. Twenty-five patients showed progression at the local site only, and six showed progression both at local/metastatic sites. For the 25 patients with local-site-only progression, the decision for 24 was immediate LC via LSS (n = 9), amputation (n = 10), hemimandibulectomy (n = 1), and radiation therapy (n = 1). Three families refused amputation. Among the six patients with combined local/metastatic site progression, the decision was for two to intensify chemotherapy by adding IE, while the other four were recommended immediate LC. However, two of them refused surgery. In total, five patients received IE as intensification for progression, all of whom subsequently progressed. The 5-year event-free survival and overall survival were 27.2% and 31.3%, respectively.

CONCLUSION

Our findings suggest that early disease progression before LC in patients with osteosarcoma is associated with poor prognosis. However, patients initially diagnosed with localized disease and who later exhibited local-disease-only progression appeared to have better outcomes. The potential role of IE in the treatment of patients exhibiting early progression merits further investigation in a larger study cohort.

Rotationplasty with Tibial Nerve Coaptation: A Case Report

CASE

We present the case of a 14-year-old adolescent boy with a distal femoral osteosarcoma partially encasing the tibial nerve. He underwent rotationplasty with resection and coaptation (end-to-end repair) of the tibial nerve. By 1 year postoperatively, he had recovered sensation on the plantar aspect of his foot and Medical Research Council scale 4+/5 gastro-soleus contraction that powered extension of the new knee.

CONCLUSION

Tibial nerve resection is not an absolute contraindication for rotationplasty, even in an adolescent. Nerve coaptation allows for well-functioning rotationplasty as an alternative to endoprosthetic reconstruction or above-knee amputation.

Machine Learning-Based Radiomics Nomogram With Dynamic Contrast-Enhanced MRI of the Osteosarcoma for Evaluation of Efficacy of Neoadjuvant Chemotherapy

Objectives

This study aims to evaluate the value of machine learning-based dynamic contrast-enhanced MRI (DCE-MRI) radiomics nomogram in prediction treatment response of neoadjuvant chemotherapy (NAC) in patients with osteosarcoma.

Methods

A total of 102 patients with osteosarcoma and who underwent NAC were enrolled in this study. All patients received a DCE-MRI scan before NAC. The Response Evaluation Criteria in Solid Tumors was used as the standard to evaluate the NAC response with complete remission and partial remission in the effective group, stable disease, and progressive disease in the ineffective group. The following semi-quantitative parameters of DCE-MRI were calculated: early dynamic enhancement wash-in slope (Slope), time to peak (TTP), and enhancement rate (R). The acquired data is randomly divided into 70% for training and 30% for testing. Variance threshold, univariate feature selection, and least absolute shrinkage and selection operator were used to select the optimal features. Three classifiers (K-nearest neighbor, KNN; support vector machine, SVM; and logistic regression, LR) were implemented for model establishment. The performance of different classifiers and conventional semi-quantitative parameters was evaluated by confusion matrix and receiver operating characteristic curves. Furthermore, clinically relevant risk factors including age, tumor size and site, pathological fracture, and surgical staging were collected to evaluate their predictive values for the efficacy of NAC. The selected clinical features and imaging features were combined to establish the model and the nomogram, and then the predictive efficacy was evaluated.

Results

The clinical relevance risk factor analysis demonstrates that only surgical stage was an independent predictor of NAC. A total of seven radiomic features were selected, and three machine learning models (KNN, SVM, and LR) were established based on such features. The prediction accuracy (ACC) of these three models was 0.89, 0.84, and 0.84, respectively. The area under the subject curve (AUC) of these three models was 0.86, 0.92, and 0.93, respectively. As for Slope, TTP, and R parameters, the prediction ACC was 0.91, 0.89, and 0.81, respectively, while the AUC was 0.87, 0.85, and 0.83, respectively. In both the training and testing sets, the ACC and AUC of the combined model were higher than those of the radiomics models (ACC = 0.91 and AUC = 0.95), which indicate an outstanding performance of our proposed model.

Conclusions

The radiomics nomogram demonstrates satisfactory predictive results for the treatment response of patients with osteosarcoma before NAC. This finding may provide a new decision basis to improve the treatment plan.