The sensitivity, specificity, and diagnostic accuracy of whole-bone MRI for identifying skip metastases in appendicular osteosarcoma and Ewing sarcoma

Comparative Analysis of Skip Metastasis in Pediatric Osteosarcoma: Clinical Features and Outcomes

BACKGROUND

Skip metastasis (SM) is a synchronous regional bone metastasis. Using new imaging modalities, the detection of SM is easier and possibly more common. We reviewed patients with SM and compared their characteristics and outcomes to other patients with osteosarcoma treated at our center.

METHODS

We reviewed retrospectively children (<18 years) with newly diagnosed osteosarcoma who presented from June 2006 to March 2022. Patients' characteristics, treatment modalities, and outcomes were analyzed. All cases were discussed in a multidisciplinary clinic that included 2 experienced radiologists.

RESULTS

We identified 155 patients with osteosarcoma, among which 13 (8.3%) patients had SM detected by MRI. Patients with SM had a median age at diagnosis of 11.2 years (range 7 to 17). Three patients had lung metastasis at diagnosis. Bone scan was positive for the SM in 8 patients (62%). All patients underwent primary tumor resection after neoadjuvant chemotherapy (amputation in 5, limb salvage surgery in 8). Five had postchemotherapy necrosis ≥90% in primary tumor. Seven patients relapsed/progressed (1 local and 6 in the lung), all relapsed patients died of disease. Compared to the rest of the patients, those with SM had similar clinical features to patients without SM; outcomes were similar with no significant differences in event-free survival and overall survival ( P =0.7 and 0.3, respectively).

CONCLUSION

In this study, we observed a percentage of patients with SM comparable to previous reports. Patients with SM exhibited clinical features akin to the rest of our patients. Thorough evaluation of imaging studies and multidisciplinary care, coupled with meticulous surgical planning, are crucial for achieving a cure, which remained unjeopardized in our patients with SM.

Skip metastases in appendicular Ewing sarcoma: relationship to distant metastases at diagnosis, chemotherapy response and overall survival

OBJECTIVE

To identify in appendicular Ewing sarcoma (ES), if skip metastases (SM) are associated with distant metastases at presentation, response to neoadjuvant chemotherapy and overall outcome.

MATERIALS AND METHOD

Patients with appendicular ES from 2007 to 2021 who had whole-bone MRI to identify SM were included in the study. Patient demographics included age/gender, bone involved, the presence of SM, longitudinal tumour length, presence of extra-osseous disease and its axial depth if present from whole-bone MRI and lung metastases and distant bone metastases from staging studies. Response to neoadjuvant chemotherapy from resection specimens and overall survival were noted. Comparison of these factors between patients with and without SM was undertaken.

RESULTS

Ninety-five patients (66 males; 29 females: mean age 15.8 years; range 5-48 years) were included. On whole-bone MRI, 80 (84.2%) patients had no SM and 15 (15.8%) patients had one or more SM. Of patients without a SM, lung metastases were present in 16 (21%), distant bone metastases in 7 (11%), while 51 (75%) had a good response to chemotherapy compared with 7 (50%), 3 (27%), and 10 (77%), respectively, in patients with a SM. SM were significantly associated with lung metastases (p = 0.02), but not with distant skeletal metastases (p = 0.13), chemotherapy response (p = 0.88), tumour length (p = 0.47), presence of (p = 0.15) or axial depth of extra-osseous disease (p = 0.4). SM were associated with a significantly poorer survival (p = 0.007) and three times greater risk of death during follow-up.

CONCLUSIONS

In appendicular ES, the identification of a SM is associated with the presence of lung metastases at presentation and poorer survival.

Cranial and vertebral osteosarcoma commonly has T2 signal heterogeneity, contrast enhancement, and osteolysis on MRI: A case series of 35 dogs

Magnetic resonance imaging (MRI) is commonly used to evaluate the central nervous system (CNS) in dogs; however, published studies describing the MRI appearance of cranial and vertebral osteosarcoma are scarce. In this multicenter, retrospective, case series study, MRI studies of 35 dogs with cranial or vertebral osteosarcoma were prospectively scored by consensus of two veterinary radiologists. Recorded characteristics were location, signal intensity (compared to gray matter), homogeneity, contrast enhancement, margin delineation, local invasion, osteolysis, osteosclerosis, zone of transition, periosteal proliferation, pathological fracture, meningeal/CNS involvement, and presence of metastatic disease. Locations included the parietal bone (n = 1), occipital bone (n = 2), or cervical (n = 5), thoracic (n = 17), lumbar (n = 7), or sacral vertebrae (n = 3). Common features included signal heterogeneity in T2-weighted (T2W) images (n = 35), contrast enhancement (in all 34 dogs with postcontrast MRI), osteolysis (n = 34), compression of the CNS or cauda equina (n = 33), an associated soft tissue mass (n = 33), a long zone of transition (n = 30), osteosclerosis (n = 28), signal isointensity to normal-appearing gray matter in T1-weighted images (T1W, n = 26), and T2W hyperintensity of adjacent brain or spinal cord (n = 23). Other findings included periosteal proliferation (n = 18), meningeal contrast enhancement (n = 17), T1W and T2W hypointense foci in the soft tissue mass (n = 14), invasion into adjacent bones (n = 10), pathological vertebral fractures (n = 7), regional lymphadenopathy (n = 6), skip metastases (n = 2), lung nodule (n = 1), diaphragmatic nodule (n = 1), and brain invasion (n = 1). Contrast enhancement was typically strong and heterogeneous. Magnetic resonance imaging features of cranial and vertebral osteosarcoma were analogous to those previously reported for other imaging modalities. Osteosarcoma should be a differential diagnosis for compressive, contrast-enhancing, osteolytic lesions of the cranium or vertebrae.

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

Osteosarcoma MRI Image-Assisted Segmentation System Base on Guided Aggregated Bilateral Network

Osteosarcoma is a primary malignant tumor. It is difficult to cure and expensive to treat. Generally, diagnosis is made by analyzing MRI images of patients. In the process of clinical diagnosis, the mainstream method is the still time-consuming and laborious manual screening. Modern computer image segmentation technology can realize the automatic processing of the original image of osteosarcoma and assist doctors in diagnosis. However, to achieve a better effect of segmentation, the complexity of the model is relatively high, and the hardware conditions in developing countries are limited, so it is difficult to use it directly. Based on this situation, we propose an osteosarcoma aided segmentation method based on a guided aggregated bilateral network (OSGABN), which improves the segmentation accuracy of the model and greatly reduces the parameter scale, effectively alleviating the above problems. The fast bilateral segmentation network (FaBiNet) is used to segment images. It is a high-precision model with a detail branch that captures low-level information and a lightweight semantic branch that captures high-level semantic context. We used more than 80,000 osteosarcoma MRI images from three hospitals in China for detection, and the results showed that our model can achieve an accuracy of around 0.95 and a params of 2.33 M.

Risk and Prognostic Factors for Different Organ Metastasis in Primary Osteosarcoma: A Large Population-Based Analysis

OBJECTIVE

Based on a large public cohort, we aimed to investigate the prevalence of distant metastases in patients with osteosarcoma, to evaluate the survival of patients with different metastases and to reveal the related risk and prognostic factors for distant metastases.

METHODS

The information of osteosarcoma patients with or without distant metastases was retrospectively extracted from the Surveillance, Epidemiology, and End Result database from January 2010 to December 2015. Patients were excluded if they were diagnosed at autopsy or via death certification. The Kaplan-Meier method was used to calculate the overall survival in the entire cohort and across patients with metastases to different organs. The related prognostic factors were investigated by univariate and multivariate Cox proportional hazard regression analysis. The logistic regression method was used to reveal the risk factors for the development of different metastases. The effects of different variables on the survival and prevalence of distant metastases were compared using subgroup analysis. Variables with P < 0.05 in the univariate regression analysis were further examined using multivariate regression analysis.

RESULTS

In total, 1470 osteosarcoma patients (mean age 30 ± 22 years) were included, among which 278 patients (18.9%) were initially diagnosed with distant metastasis. The median follow-up duration was 33.0 (30.2-35.8) months. The lung was the most common metastatic site (83.8%), followed by the bone (21.9%), liver (2.9%), and brain (2.2%). A total of 232 patients (83.5%) presented only one distant metastatic site, while the other 46 patients showed two or more metastatic sites. A lower proportion of metastasis was observed in patients aged from 25 to 59 years [odds ratio (OR) = 0.59; 95% confidence interval (CI): 0.37-0.95]. More metastases were noted in patients with T2/T1 (OR = 1.91; 95% CI: 1.28-2.84), T3/T1 (OR = 4.48; 95% CI: 1.78-11.30) and N1/N0 stages (OR = 6.66; 95% CI: 2.68-16.56). The 1-, 3-, and 5-year overall survival rates for metastatic patients were 57.3% (95% CI: 50.8%-63.8%), 25.3% (95% CI: 18.8%-31.9%), and 18.1% (95% CI: 10.2%-26.0%), respectively. Metastatic patients older than 25 years were prone to have poor survival and a relatively better prognosis (hazard ratio = 0.41; 95% CI: 0.25-0.69) was noticed among those who underwent surgery on the primary site. Different metastatic organs have homogeneous and heterogeneous risk and prognostic factors.

CONCLUSION

The high incidence of initial distant metastasis in osteosarcoma and the inconsistent predictive factors should be given more attention in the clinical management of patients with osteosarcoma.

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.

Current approaches to management of bone sarcoma in adolescent and young adult patients

Bone tumors are a group of histologically diverse diseases that occur across all ages. Two of the commonest, osteosarcoma (OS) and Ewing sarcoma (ES), are regarded as characteristic adolescent and young adult (AYA) cancers with an incidence peak in AYAs. They are curable for some but associated with unacceptably high rates of treatment failure and morbidity. The introduction of effective new therapeutics for bone sarcomas is slow, and to date, complex biology has been insufficiently characterized to allow more rapid therapeutic exploitation. This review focuses on current standards of care, recent advances that have or may soon change that standard of care and challenges to the expert clinical research community that we suggest must be met.

Metastatic Progression of Osteosarcomas: A Review of Current Knowledge of Environmental versus Oncogenic Drivers

Simple Summary

Osteosarcomas are heterogeneous bone tumors with complex genetic and chromosomic alterations. The numerous patients with metastatic osteosarcoma have a very poor prognosis, and only those who can have full surgical resection of the primary tumor and of all the macro metastasis can survive. Despite the recent improvements in prediction and early detection of metastasis, big efforts are still required to understand the specific mechanisms of osteosarcoma metastatic progression, in order to reveal novel therapeutic targets.

Abstract

Metastases of osteosarcomas are heterogeneous. They may grow simultaneously with the primary tumor, during treatment or shortly after, or a long time after the end of the treatment. They occur mainly in lungs but also in bone and various soft tissues. They can have the same histology as the primary tumor or show a shift towards a different differentiation path. However, the metastatic capacities of osteosarcoma cells can be predicted by gene and microRNA signatures. Despite the identification of numerous metastasis-promoting/predicting factors, there is no efficient therapeutic strategy to reduce the number of patients developing a metastatic disease or to cure these metastatic patients, except surgery. Indeed, these patients are generally resistant to the classical chemo- and to immuno-therapy. Hence, the knowledge of specific mechanisms should be extended to reveal novel therapeutic approaches. Recent studies that used DNA and RNA sequencing technologies highlighted complex relations between primary and secondary tumors. The reported results also supported a hierarchical organization of the tumor cell clones, suggesting that cancer stem cells are involved. Because of their chemoresistance, their plasticity, and their ability to modulate the immune environment, the osteosarcoma stem cells could be important players in the metastatic process.

The Role of FDG-PET and Whole-Body MRI in High Grade Bone Sarcomas With Particular Focus on Osteosarcoma

Sarcoma represents less than 2% of adult malignancies and about 15% to 20% of malignancies in children and adolescents/young adults. This neoplasm accounts for more than 80 different clinico-pathological entities with different clinical behavior; osteosarcoma and ewing sarcoma are the most frequent primary bone tumors. Because of the general poor prognosis, it is important to find out as many prognostic factors as possible to choose the best therapeutical approach and to correctly schedule the follow-up examinations. Third level imaging such as MRI and PET/CT are of utmost importance in the evaluation of sarcoma patients. The spine and bones in general are optimal sites to be evaluated with FDG PET/CT since the physiological background is low. The standardized uptake value (SUV max, a semiquantitave parameter) is used as a surrogate for proliferative cell rate, and the spatial heterogeneity of FDG distribution within the primary mass as a surrogate for malignancy. In several studies SUVmax was a predictive value for overall survival and progression-free survival. Whole-body MRI is a well-established technique for systemic, radiation-free evaluation, which is mostly applied in the oncological field. WB-MRI provides a combination of anatomical and functional sequences and is useful specifically in the evaluation of disease in organs with relatively high background activity such as the brain, liver, kidney, and spinal canal. These technologies provide accurate staging (also useful to drive the biopsy towards the most active foci in large heterogeneous masses), therapy assessment, relapse detection of local recurrence and distance metastasis but also prognostic indexes, in the context of whole body diagnostic procedures. This paper will provide an overview of the role and added value of PET/CT and WB-MRI in bone sarcomas particular focus on osteosarcoma. We also analyzed the role of the PET/CT and MRI for target delineation of radiation therapy and we and we will do an analysis of future prospects as new tracer non FDG.

Skip metastases in high-grade intramedullary appendicular osteosarcoma: an indicator of more aggressive disease?

OBJECTIVE

To determine whether skip metastases (SM) in high-grade appendicular osteosarcoma (HG-OS) are an indicator of more aggressive disease.

MATERIALS AND METHOD

Retrospective review of patients with histologically confirmed diagnosis HG-OS of the long bones from 2007 to 2020, who had whole-bone MRI to identify SM. Data collected included patient age/gender, bone involved, the presence of SM, the presence of lung metastases from chest CT, the presence of distant bone metastases from whole-body bone scintigraphy or whole-body MRI, and chemotherapy response from resection specimen histology. The presence of lung or bone metastases and chemotherapy response were compared between patients without and with SM.

RESULTS

The study included 241 patients (146 males; 95 females: mean age 18.2 years; range 4-73 years). Based on whole-bone MRI, 202 (83.8%) patients had no SM and 39 (16.2%) patients had a SM. Of patients without a SM, lung metastases were identified in 44 (22%) and distant bone metastases in 6 (3%) cases, while 80 (43%) had a good chemotherapy response and 105 (57%) had a poor chemotherapy response. Of patients with a SM, lung metastases were identified in 22 (58%) and distant bone metastases in 8 (21%) cases, while 11 (32%) had a good chemotherapy response and 23 (68%) had a poor chemotherapy response. The presence of SM was significantly associated with both lung metastases (p < 0.001) and skeletal metastases (p < 0.001), but not with chemotherapy response (p = 0.24). Patients with SM also had poorer survival (p < 0.001).

CONCLUSIONS

The presence of SM in appendicular HG-OS suggests more aggressive disease.

[Treatment strategies for tumor-related pathological fractures of the extremities]

Pathological fractures of the extremities frequently lead to uncertainty with respect to the treatment strategy and timing. The origin of metastases is typically breast, bronchial, renal and prostate cancer and myelomas. Primary bone tumors play a subordinate role. The majority affect the femur, humerus and occasionally the tibia. Surgery is typically the first line treatment as healing under conservative treatment is unlikely. The most important goal is to relieve pain and the preservation or restoration of function. For correct assessment of indications, analysis of the fracture pattern and oncological aspects including dignity, entity, prognosis, metastatic status and the general condition of the patient need to be taken into consideration. Based on all these aspects the surgical approach can be chosen. Treatment options range from osteosynthetic stabilization and augmentation osteosynthesis up to endoprosthesis replacement. The treatment is carried out in an interdisciplinary procedure as additional measures need to be addressed in addition to the surgical treatment.

Comparison of T1-weighted turbo spin echo and out-of-phase T1-weighted gradient echo Dixon MRI for the assessment of intra-medullary length of appendicular bone tumours

OBJECTIVE

Intra-medullary tumour length is accurately assessed on T1-weighted turbo spin echo (T1W TSE) MRI which can be relatively time consuming, whilst the gradient echo Dixon (T1W GrE Dixon) technique is a rapid sequence (imaging time ~ 30 s). The aim of this study was to determine if the out-of-phase Dixon (OP T1W GrE Dixon) sequence can produce equivalent measurements of intra-medullary tumour length compared to the T1W TSE sequence.

MATERIALS AND METHOD

Tumour length was assessed in 90 patients undergoing MRI for staging of primary bone tumours with both T1W TSE and OP T1W GrE Dixon MRI sequences at 3 T (n = 42) and 1.5 T (n = 48). Tumour length was measured independently by different observers allowing assessment of inter-observer correlation, and the correlation between measurements on T1W TSE and OP T1W GrE Dixon sequences was also determined.

RESULTS

There were 53 males and 37 females (mean age 36.4 years; range 2-77 years). Inter-observer correlation for tumour length on both the T1W TSE and T1W OP GrE Dixon sequences was very good (ICC = 0.94-0.98), and measurement of tumour length comparing T1W TSE and T1W GrE Dixon was also very good (ICC = 0.91-0.99). In 4 cases, tumour length was significantly overestimated on T1W TSE images due to extensive reactive marrow oedema, but more accurately determined on the OP sequence when compared to resection specimens.

CONCLUSIONS

The OP T1W GrE Dixon sequence is comparable to T1W TSE for assessment of the intra-medullary length of appendicular bone tumours, and more accurate in the presence of extensive reactive marrow oedema.

Rare Primary Malignant Bone Sarcomas

Simple Summary

Primary malignant bone tumors are infrequent cancers. More than 90% of these neoplasms are classified as osteosarcomas, Ewing sarcomas or chondrosarcomas, and their clinical presentation, diagnosis, and treatment principles are well-established. The entities described in this article, are ultra-rare varieties of bone sarcomas, and there clinical and histological characteristics are not well known. Therefore, they are very difficult to be diagnosed and there is a lot of uncertainty on their treatment. Because of their rarity, it is also extremely difficult to perform clinical research on these cancers. This article creates more awareness of these very rare bone tumors. It explains how to recognize and diagnose each entity and it summarizes the medical scientific literature that is available on these cancers. Increasing awareness and clinical research for these cancers are key elements to improve the prognosis for patients with these diseases in the long term.

Abstract

Rare primary malignant bone sarcomas (RPMBS), other than osteosarcoma, chondrosarcoma, chordoma, and Ewing sarcoma, account for about 5–10% of primary bone tumors and represent a major diagnostic challenge. These tumors include spindle cell and round cell sarcoma entities, hemangiopericytoma-like and vascular tumors. Additionally, several histotypes, traditionally described in the soft tissues, such as myxofibrosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor of bone, have been reported in patients with primary bone tumors. While wide surgical resection is the mainstay of local treatment, systemic therapy of these rare entities is controversial. Patients with undifferentiated spindle cell or pleomorphic high-grade tumors of bone, are usually treated with osteosarcoma-like chemotherapy, while patients with round cell and undifferentiated round cell tumors (URCTs), may respond to sarcoma treatment regimens for Ewing sarcoma patients. Studies on analogies and differences among these ultra-rare tumors have seldom been reported. This review describes relevance, clinical aspects, diagnostic procedures, staging, treatment recommendations, and current research in this composite tumor group.