Risk factors for survival and local control in chondrosarcoma of bone

Preoperative prediction of histopathological grading in patients with chondrosarcoma using MRI-based radiomics with semantic features

BACKGROUND

Distinguishing high-grade from low-grade chondrosarcoma is extremely vital not only for guiding the development of personalized surgical treatment but also for predicting the prognosis of patients. We aimed to establish and validate a magnetic resonance imaging (MRI)-based nomogram for predicting preoperative grading in patients with chondrosarcoma.

METHODS

Approximately 114 patients (60 and 54 cases with high-grade and low-grade chondrosarcoma, respectively) were recruited for this retrospective study. All patients were treated via surgery and histopathologically proven, and they were randomly divided into training (n = 80) and validation (n = 34) sets at a ratio of 7:3. Next, radiomics features were extracted from two sequences using the least absolute shrinkage and selection operator (LASSO) algorithms. The rad-scores were calculated and then subjected to logistic regression to develop a radiomics model. A nomogram combining independent predictive semantic features with radiomic by using multivariate logistic regression was established. The performance of each model was assessed by the receiver operating characteristic (ROC) curve analysis and the area under the curve, while clinical efficacy was evaluated via decision curve analysis (DCA).

RESULTS

Ultimately, six optimal radiomics signatures were extracted from T1-weighted imaging (T1WI) and T2-weighted imaging with fat suppression (T2WI-FS) sequences to develop the radiomics model. Tumour cartilage abundance, which emerged as an independent predictor, was significantly related to chondrosarcoma grading (p < 0.05). The AUC values of the radiomics model were 0.85 (95% CI, 0.76 to 0.95) in the training sets, and the corresponding AUC values in the validation sets were 0.82 (95% CI, 0.65 to 0.98), which were far superior to the clinical model AUC values of 0.68 (95% CI, 0.58 to 0.79) in the training sets and 0.72 (95% CI, 0.57 to 0.87) in the validation sets. The nomogram demonstrated good performance in the preoperative distinction of chondrosarcoma. The DCA analysis revealed that the nomogram model had a markedly higher clinical usefulness in predicting chondrosarcoma grading preoperatively than either the rad-score or clinical model alone.

CONCLUSION

The nomogram based on MRI radiomics combined with optimal independent factors had better performance for the preoperative differentiation between low-grade and high-grade chondrosarcoma and has potential as a noninvasive preoperative tool for personalizing clinical plans.

Hedgehog pathway in sarcoma: from preclinical mechanism to clinical application

Sarcomas are a diverse group of malignant neoplasms of mesenchymal origin. They develop rarely, but due to poor prognosis, they are a challenging and significant clinical problem. Currently, available therapeutic options have very limited activity. A better understating of sarcomas' pathogenesis may help develop more effective therapies in the future. The Sonic hedgehog (Shh) signaling pathway is involved in both embryonic development and mature tissue repair and carcinogenesis. Shh pathway inhibitors are presently used in the treatment of basal cell carcinoma. Its increased activity has been demonstrated in many sarcomas, including osteosarcoma, Ewing sarcoma, chondrosarcoma, rhabdomyosarcoma, leiomyosarcoma, and malignant rhabdoid tumor. In vitro studies have demonstrated the effectiveness of inhibitors of the Hedgehog pathway in inhibiting proliferation in those sarcomas in which the components of the pathway are overexpressed. These results were confirmed by in vivo studies, which additionally proved the influence of Shh pathway inhibitors on limiting the metastatic potential of sarcoma cells. However, until now, the efficacy of sarcomas treatment with Shh pathway inhibitors has not been established in clinical trials. The reason for that may be the non-canonical activation of the pathway or interactions with other signaling pathways, such as Wnt or Notch. In this review, we present the Shh signaling pathway's role in the pathogenesis of sarcomas, including both canonical and non-canonical signaling. We also propose how this knowledge could be potentially translated into clinics.

Intraosseous conventional central chondrosarcoma does not metastasise irrespective of grade in pelvis, scapula and in long bone locations

Background

Histological grade has been regarded as the most important prognostic factor in conventional central chondrosarcoma. To evaluate whether the presence of an extraosseous tumour component is associated with a decreased metastasis-free survival or disease-specific survival and alternatively to develop a simple prognostic and clinical decision-making tool.

Material and methods

We searched two prospectively maintained international sarcoma centre databases for primary non metastatic central conventional chondrosarcomas of all grades in pelvis, scapula or long bone location, undergoing curative treatment, diagnosed between 2000 and 2020. Pre-treatment MRI scans were reviewed for the presence of an extraosseous mass. The metastasis-free survival (MFS) and disease-specific survival (DSS) were estimated by the Kaplan-Meier method from surgery to event, death or last follow-up.

Results

336 patients were identified between 2000 and 2020, undergoing surgical treatment for conventional central chondrosarcoma. 111 patients (33 %) had grade 1 tumours, 149 patients (44 %) had grade 2, and 76 patient (23 %) had grade 3 chondrosarcomas determined as the highest grade in the final resected specimen. An extraosseous soft tissue component was more frequent in higher grade tumours (p < 0.001) and present in 200 cases (60 %). None of the patients with an intraosseous tumour developed metastases or died of the disease. For patients with extraosseous tumour component, MFS was 92 % (95 % CI, 96-100) at 2-years and 74 % (95 % CI, 67-81) at 10-years and DSS was 91 % (95 % CI, 87-95) at 2-years and 75 % (95 % CI, 68-82) at 10-years. The MFS and DSS was significantly different (p < 0.001) for those patients with or without an extraosseous tumour component, irrespective of grade or anatomical location.

Discussion

The results of this study has shown that the metastatic potential of intraosseous conventional central chondrosarcoma is negligible. The presence of an extraosseous soft tissue component may be used for prognostication and to guide treatment pathways for patients with central cartilage tumours.

The novel dynamic nomogram and risk classification system constructed for predicting post-surgical overall survival and mortality risk in primary chondrosarcoma: a population study based on SEER database

BACKGROUND

Surgery is the predominant method to improve the prognosis of primary chondrosarcoma patients. We aimed to construct the first reliable nomogram to predict the post-surgical overall survival (OS) of primary chondrosarcoma patients.

METHODS

We downloaded all primary chondrosarcoma patients treated with surgery between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database, and randomized them into training set (60%) and validation set (40%). Cox proportional regression analysis was applied to the training set to identify independent prognostic variables, and then constructed a nomogram for predicting 3-, 5-, and 8-year OS. The Harrell's concordance index (C-index), receiver operating characteristic curve (ROC), the area under curve (AUC), calibration curve and decision curve analysis (DCA) was used to assess the predictive efficacy and clinical applicability of the nomogram. The nomogram was also compared with The American Joint Committee on Cancer (AJCC) staging system.

RESULTS

A total of 1005 post-surgical primary chondrosarcoma patients were included in this study. We finally identified five independent prognostic variables to construct the nomogram, being age, grade, tumor size, disease stage and histological type. The C-index results showed that the prediction performance of the nomogram was significantly better than the AJCC staging system. In the training set, (C-index: 0.805, 95% CI 0.879-0.730 vs 0.686, 95% CI 0.606-0.766); in the validation set, (C-index: 0.811, 95% CI 0.895-0.727 vs 0.697, 95% CI 0.647-0.799). Additionally, the AUC values generated by the ROC were all greater than 0.8, which also indicated the excellent predictive performance of the nomogram. The calibration curves showed that the predicted survival rate was highly similar to the actual. Time-dependent ROC and DCA showed that the nomogram has better predictive performance and net clinical benefits than the AJCC staging system. Finally, a risk stratification system based on nomogram was constructed.

CONCLUSION

We successfully constructed and validated the first nomogram that could reliably predict 3-, 5-, and 8-year post-surgical OS in primary chondrosarcoma patients. Furthermore, the web-based dynamic nomogram could be more conveniently applied to clinic, providing assistance to surgeons and patients.

Prognostic Factors for Survival in Patients With High-grade Chondrosarcoma

BACKGROUND/AIM

Chondrosarcoma (CS) is a rare primary malignant bone tumor, which is the second most common tumor after osteosarcoma. Since chemotherapy and radiotherapy have poor efficacy for CS, amputation or surgical wide resection is the main strategy for localized high-grade CS, making CS therapy difficult. As studies on high-grade CS are limited owing to its rare nature, there are many unknown prognostic factors for survival.

PATIENTS AND METHODS

This retrospective cohort study included 44 patients with high-grade CS who underwent surgery at a single institution. Overall survival (OS), distant failure-free survival (DFFS), and local failure-free survival (LFFS) were evaluated using the Kaplan-Meier method. Furthermore, we evaluated prognostic factors for survival in patients with high-grade CS using univariate and multivariate analyses.

RESULTS

The 5-year OS, LFFS, and DFFS rates of high-grade CS were 75.9%, 90.8%, and 66.5%, respectively. Univariate analysis revealed that tumor size, tumor grade, and surgical margin were significant prognostic factors for OS and DFFS, and distant metastasis was significantly associated with OS. Furthermore, the multivariate analysis indicated that the presence of local recurrence and distant metastasis was significantly associated with OS.

CONCLUSION

Local recurrence and distant metastasis were significant prognostic factors for high-grade CS.

The Epidemiology of Chondrosarcoma in Iran Based on Iran National Cancer Registry

Background: Chondrosarcoma is regarded as the second most common primary bone malignancy following osteosarcoma. Objectives: The present study aimed at determining the epidemiology, incidence, and survival rate of chondrosarcoma in the Iranian population, according to the Iran National Cancer Registry (INCR). Methods: In an epidemiological study, patients with limb chondrosarcoma were evaluated based on INCR data between 2008 and 2015. Data included patients’ demographic characteristics, date of diagnosis, location of the tumor, patient’s survival, and type of tumor based on the International Classification of Diseases for Oncology (ICD-O-3; first revision, third edition) were collected and analyzed. Results: Out of 732 enrolled patients, 425 patients (58.06%) were male and 307 (41.94%) were female with a mean age of 44.08 (SD = 19.31) and 45.06 (SD = 18.72), respectively. Age-standardized incidence rates (ASIR) were 1.73 and 1.27 per 1 million person-years for males and females, respectively. Conventional chondrosarcoma was the most common subtype with ASIR 1.28 and constituted 84.7% of patients with chondrosarcoma. About 71.03% of all Chondrosarcoma patients (70.35% of males and 71.99% of females) were between 20 to 59 years old. The 1-, 3-, 5-, and 7-year survival rates of patients were 0.87, 0.73, 0.57, and 0.47, respectively. Also, the mean survival time was 6.12 years (95% CI: 5.85 - 7.39). Conclusions: The incidence of chondrosarcoma in Iran is not as high as in other countries, but as patients are younger in Iran, the survival rate is worse compared to other countries. Therefore, better case findings and better care are needed to improve the patients' outcomes in Iran.

Chondrosarcoma of the toe: A case report and literature review

BACKGROUND

Chondrosarcoma of the foot is a rare malignant bone tumour, and it is even rarer when it originates in a toe bone. Surgical excision is the only effective treatment. The osteolytic destruction of the tumour severely affects limb function and carries the risk of distant metastasis. Most such tumours are removed surgically to minimize local recurrence and distant metastases, maximize limb function, and prolong the patient's tumour-free survival time. The main objective of this article is to present the case of a chondrosarcoma that invaded the first phalanx of the left foot and formed a large phalangeal mass with osteolytic destruction of the distal bone.

CASE SUMMARY

A 74-year-old man suffered from swelling of his left toe for six months, with pain and swelling for two months. Computed tomography and magnetic resonance imaging showed that the tumour on the first phalanx of the left foot was approximately 54.9 mm × 44.6 mm, surrounded by a significant soft tissue signal mass, with osteolytic destruction of the distal phalanx and a speckled bone-like high-density shadow within it.

CONCLUSION

Chondrosarcoma occurring in a toe bone is extremely rare. In this case, extensive surgical resection of the large low-grade chondrosarcoma, which showed osteolytic destruction and invaded the distal metatarsal bone, was safe and effective.

A Web-Based Prediction Model for Overall Survival of Elderly Patients With Malignant Bone Tumors: A Population-Based Study

Background: Malignant bone tumors (MBT) are one of the causes of death in elderly patients. The purpose of our study is to establish a nomogram to predict the overall survival (OS) of elderly patients with MBT.

Methods: The clinicopathological data of all elderly patients with MBT from 2004 to 2018 were downloaded from the SEER database. They were randomly assigned to the training set (70%) and validation set (30%). Univariate and multivariate Cox regression analysis was used to identify independent risk factors for elderly patients with MBT. A nomogram was built based on these risk factors to predict the 1-, 3-, and 5-year OS of elderly patients with MBT. Then, used the consistency index (C-index), calibration curve, and the area under the receiver operating curve (AUC) to evaluate the accuracy and discrimination of the prediction model was. Decision curve analysis (DCA) was used to assess the clinical potential application value of the nomogram. Based on the scores on the nomogram, patients were divided into high- and low-risk groups. The Kaplan-Meier (K-M) curve was used to test the difference in survival between the two patients.

Results: A total of 1,641 patients were included, and they were randomly assigned to the training set (N = 1,156) and the validation set (N = 485). The univariate and multivariate analysis of the training set suggested that age, sex, race, primary site, histologic type, grade, stage, M stage, surgery, and tumor size were independent risk factors for elderly patients with MBT. The C-index of the training set and the validation set were 0.779 [0.759–0.799] and 0.801 [0.772–0.830], respectively. The AUC of the training and validation sets also showed similar results. The calibration curves of the training and validation sets indicated that the observed and predicted values were highly consistent. DCA suggested that the nomogram had potential clinical value compared with traditional TNM staging.

Conclusion: We had established a new nomogram to predict the 1-, 3-, 5-year OS of elderly patients with MBT. This predictive model can help doctors and patients develop treatment plans and follow-up strategies.

Complex Bone Tumors of the Trunk-The Role of 3D Printing and Navigation in Tumor Orthopedics: A Case Series and Review of the Literature

The combination of 3D printing and navigation promises improvements in surgical procedures and outcomes for complex bone tumor resection of the trunk, but its features have rarely been described in the literature. Five patients with trunk tumors were surgically treated in our institution using a combination of 3D printing and navigation. The main process includes segmentation, virtual modeling and build preparation, as well as quality assessment. Tumor resection was performed with navigated instruments. Preoperative planning supported clear margin multiplanar resections with intraoperatively adaptable real-time visualization of navigated instruments. The follow-up ranged from 2–15 months with a good functional result. The present results and the review of the current literature reflect the trend and the diverse applications of 3D printing in the medical field. 3D printing at hospital sites is often not standardized, but regulatory aspects may serve as disincentives. However, 3D printing has an increasing impact on precision medicine, and we are convinced that our process represents a valuable contribution in the context of patient-centered individual care.

Prognostic importance of IDH mutations in chondrosarcoma: An individual patient data meta-analysis

Introduction

IDH1/2 mutations are prevalent in cartilaginous tumors including chondrosarcoma. This meta‐analysis using individual patient data (IPD) aimed to investigate the clinical and prognostic association of these mutations in chondrosarcoma patients.

Methods

Two electronic databases including PubMed and Web of Science were searched for relevant data. We included studies providing IPD of chondrosarcoma with available IDH1/2 mutational status for meta‐analysis. Chi‐square and t‐test were performed to compare the groups with and without IDH1/2 mutations. For survival analysis, log‐rank test, and Cox proportional hazards model were used to investigate the association of IDH mutations with patient outcomes.

Results

Fourteen studies with 488 patients were analyzed. IDH1 and IDH2 mutations were detected in 38.7% and 12.1% of cases, respectively. IDH1/2 mutations were significantly associated with an older age (p = 0.003), tumor origins (p < 0.001), tumor grades (p < 0.001), larger diameter (p = 0.003), relapse (p = 0.014), and patient mortality (p = 0.04). Multivariate Cox regression analysis adjusted for age, gender, tumor grade, and tumor sites confirmed the negative impact of IDH1/2 mutations on patient overall survival (HR = 1.90; 95% CI = 1.06–3.42; p = 0.03).

Conclusion

Our meta‐analysis demonstrated the distinct characteristics of IDH1/2‐mutated chondrosarcomas in comparison to those without mutations. These mutations could serve as an independent prognostic biomarker to better prognosticate patient outcomes and design appropriate treatment plans.

Chondrosarcoma-from Molecular Pathology to Novel Therapies

Chondrosarcoma (CHS) is the second most common primary malignant bone sarcoma. Overall survival and prognosis of this tumor are various and often extreme, depending on histological grade and tumor subtype. CHS treatment is difficult, and surgery remains still the gold standard due to the resistance of this tumor to other therapeutic options. Considering the role of differentiation of CHS subtypes and the need to develop new treatment strategies, in this review, we introduced a multidisciplinary characterization of CHS from its pathology to therapies. We described the morphology of each subtype with the role of immunohistochemical markers in diagnostics of CHS. We also summarized the most frequently mutated genes and genome regions with altered pathways involved in the pathology of this tumor. Subsequently, we discussed imaging methods and the role of currently used therapies, including surgery and the limitations of chemo and radiotherapy. Finally, in this review, we presented novel targeted therapies, including those at ongoing clinical trials, which can be a potential future target in designing new therapeutics for patients with CHS.

Innovative chest wall reconstruction with a locking plate and cement spacer after radical resection of chondrosarcoma in the sternum: A case report

BACKGROUND

Chondrosarcoma, a cartilage matrix producing tumor, is the second most commonly observed primary bone tumor after osteosarcoma, accounting for 15% of all chest wall malignancies. We herein report the case of a patient with chondrosarcoma of the sternum and our management of the chest wall defects that presented following radical tumor resection.

CASE SUMMARY

A 31-year-old patient presented to our hospital with dull pain and a protruding mass overlying the chest for 3 mo. The presence of nocturnal pain and mass size progression was reported, as were overhead arm elevation-related limitations. Computed tomography showed a focal osteoblastic mass in the sternum with bony exostosis and adjacent soft tissue calcification. Positron emission tomography-computed tomography revealed hypermetabolic activity with a mass located over the upper sternum. Magnetic resonance imaging showed a focal ill-defined bony mass of the sternum with cortical destruction and periosteal reaction. Preoperative biopsy showed a consistent result with chondrosarcoma with immunohistochemical positivity for S100 and focal positivity for IDH-1. The grade II chondrosarcoma diagnosis was confirmed by postoperative pathology. The patient underwent radical tumor resection and chest wall reconstruction with a locking plate and cement spacer. The patient was discharged 1 wk after surgery without any complications. At the 1-year follow-up, there was no local recurrence on imaging. The functional scores, including Constant Score, Nottingham Clavicle Score, and Oxford Shoulder Score, showed the absence of pain in the performance of daily activities or substantial functional disabilities.

CONCLUSION

The diagnosis of chondrosarcoma must be considered when chest wall tumors are encountered. The surgical reconstructive materials, with a locking plate and cement spacer, used in our study are cost-effective and readily-available for the sternum defect.

Chondrosarcoma local recurrence in the Cancer Registry of Norway cohort (1990-2013): Patterns and impact

BACKGROUND

There appears to be an association between local recurrence (LR) and risk of metastasis and death in central conventional chondrosarcoma (CCCS) of bone, but this has not been quantified in modern cohorts at a subtype level.

METHODS

We identified nonmetastatic cases of CCCS (N = 180) from the Cancer Registry of Norway. We present prognostic analysis of LR accounting for immortal time bias by descriptive statistics and multivariable Cox models.

RESULTS

Of 40 LR, one case demonstrated upgrading while two dedifferentiation. LR was associated with increased risk of metastasis (hazard ratio [HR] = 4.1 [confidence interval, 1.5-10.7]) and death (HR = 9.3 [5.0-17.5]) overall. LR was associated with significant increased risk of metastasis for those with a soft tissue component, axial location, malignancy grade 2, but not atypical cartilaginous tumor's, appropriately treated curettage patients, intramedullary tumors, grade 1 histology, extremity location or "Oslo low risk" group status. We found an increased risk of death for all groups except for those treated by appropriate curettage or belonging to the "Oslo low risk" group. About 50% of LR CCCS were asymptomatic and revealed by routine follow-up.

CONCLUSIONS

Upgrading of LR for CCCS was a seldom event. LR was associated with significant increased risk of metastasis and death overall, but not for appropriately treated curettage patients or "Oslo low risk" status.

Differences in clinical characteristics and tumor prognosis between primary and secondary conventional pelvic chondrosarcoma

BACKGROUND

Chondrosarcoma (CS) most commonly involves the pelvis. This study aimed to analyze differences in clinical characteristics and prognostic factors between primary and secondary conventional pelvic CS, and provide reference for clinical diagnosis and treatment.

METHODS

Eighty patients (54 primary cases and 26 secondary cases) with pelvic CS were included in this retrospective study. The tumor site, Enneking stage, soft tissue mass, margin, initial tumor grade, incidence of local recurrence and distant metastasis were evaluated. Kaplan-Meier method was used to calculate the overall survival rate. X2 test and log-rank test were used for univariate analysis, and Cox test was used in multivariate analysis.

RESULTS

The average age of patients with secondary CS was significantly younger than that of patients with primary CS (P < 0.001). The soft tissue mass of patients with secondary CS was significantly larger than that of patients with primary CS (P = 0.002). There was a significant difference in initial tumor pathologic grade between the two groups (P = 0.002). No statistically significant difference was observed in the local recurrence rate between the two groups. The median recurrence time of patients with primary CS after the first treatment was significantly shorter than that of patients with secondary CS (P < 0.001). The overall survival rate of patients with secondary CS was much higher than that of patients with primary CS (P = 0.003). Cox regression analysis showed that the initial tumor grade was an independent factor in the overall survival rate of patients with CS.

CONCLUSION

There were significant differences in age, soft tissue mass, initial tumor grade, and overall survival rate between the two groups. The overall survival rate of pelvic CS was related to the initial tumor grade of CS.

Magnetic Resonance Imaging Role in the Differentiation Between Atypical Cartilaginous Tumors and High-Grade Chondrosarcoma: An Updated Systematic Review

Chondrosarcoma (CS) is a malignant tumor affecting the bones while atypical cartilaginous tumors (ACTs) are chondral tumors with moderate cellularity, mild atypia, and with myxoid changes and mild metastatic ability. Both can have one of the worst prognoses if not identified early enough. Magnetic resonance imaging (MRI) has been one of the modalities to detect such tumors and we aim to determine the common characteristic and features to be seen while screening for CS or ACTs. We conducted a systematic review of the previously published reports that investigated the diagnostic ability of MRI and the reported characteristics that can differentiate between ACTs and high-grade chondrosarcomas (HGCS). A comprehensive relevant database search was performed to include all the relevant studies. Among these studies, seven studies investigated the overall accuracy in the classification of the different chondroma types. Additionally, many studies reported the characteristic findings of each tumor according to the MRI results. These characteristics mainly included trapped fat, bone marrow edema, cortical damage, and soft-tissue expansion. Therefore, further attention should be given to these criteria for better assessment, differentiation, and favorable outcomes. MRI can efficiently identify some of the characteristics of both ACTs and HGCS. However, combining it with other radiological modalities may lead to a better differentiation. The detection of ACTs and HGCS lesions with MRI solely has been doubted before in the literature.

Chondrosarcoma of bone in children and adolescents

PURPOSE

Chondrosarcomas typically present in adults during the fifth to seventh decades and are rare in young patients. The biological behaviour and oncological outcomes may be different in children and adolescents.

METHODS

We retrospectively evaluated the outcomes of all patients with chondrosarcoma of bone who were younger than 18 years of age at the time of diagnosis and were treated at our centre between 1995 and 2018.

RESULTS

The 15 consecutive patients studied included nine male and six female cases, with a mean age at diagnosis of 13 years (7 to 17). The median follow-up was 117 months (30 to 277). The tumours were primary and secondary in ten and five patients, respectively. The tumours were central in 13 and surface in two patients. The tumour locations were the humerus in five, digits in five, femur in three, radius in one and pelvis in one patient. The histological grades were grade I in seven, grade II in seven and grade III in one patient. The surgical treatments were limb salvage in ten patients and ray amputation in five patients. The surgical margins were wide in eight, marginal in two and intralesional in five patients. All the patients were alive and continuously free of disease at the time of the last follow-up. No patient developed metastases or local recurrence.

CONCLUSION

Chondrosarcoma of bone in children and adolescent patients has a very good prognosis and is less aggressive compared with published outcomes in older patients.

LEVEL OF EVIDENCE

IV.

Non-Conventional Treatments for Conventional Chondrosarcoma

Chondrosarcomas are the most common malignant tumors of the cartilage, are seen predominantly in adults, and have varied clinical behavior. The majority of them affect the medullary canal of long bones and pelvic bones. The prognosis of chondrosarcoma is closely related to histological grading; however, the grading is subject to interobserver variability. Conventional chondrosarcomas are overall considered to be chemotherapy- and radiation-resistant, resulting in limited treatment options. The majority of advanced conventional chondrosarcomas are treated with chemotherapy without any survival benefit. Recent studies have evaluated molecular genetic findings which have improved the understanding of chondrosarcoma biology. Newer therapeutic targets are desperately needed. In this review article, we explore ongoing clinical trials evaluating novel ways of treating advanced conventional chondrosarcoma.

Follow-Up in Bone Sarcoma Care: A Cross-Sectional European Study

Background

Follow-up of high-grade bone sarcoma patients with repeated radiological imaging aims at early detection of recurrent disease or distant metastasis. Repeated radiological imaging does expose (mostly young) patients to ionising radiation. At this point, it is not known whether frequent follow-up increases overall survival. Additionally, frequent follow-up subjects patients and families to psychological stress. This study aims to assess follow-up procedures in terms of frequency and type of imaging modalities in bone tumour centres across Europe for comparison and improvement of knowledge as a first step towards a more uniform approach towards bone sarcoma follow-up.

Methods

Data were obtained through analysis of several follow-up protocols and a digital questionnaire returned by EMSOS members of bone tumour centres all across Europe.

Results

All participating bone tumour centres attained a minimum follow-up period of ten years. National guidelines revealed variations in follow-up intervals and use of repeated imaging with ionising radiation. A local and a chest X-ray were obtained at 47.6% of the responding clinics at every follow-up patient visit.

Conclusions

Variations were seen among European bone sarcoma centres with regards to follow-up intervals and use of repeated imaging. The majority of these expert centres follow existing international guidelines and find them sufficient as basis for a follow-up surveillance programme despite lack of evidence. Future research should aim towards evidence-based follow-up with focus on the effects of follow-up strategies on health outcomes, cost-effectiveness, and individualised follow-up algorithms.

Treatment method and prognostic factors of chondrosarcoma: based on Surveillance, Epidemiology, and End Results (SEER) database

BACKGROUND

Chondrosarcoma is a malignant tumor originating from cartilage tissue. It is the second most malignant bone tumor, accounting for about 10% to 15% of all primary bone tumors. So far, there have been no reports of large-scale clinical statistics on the relationship between non-surgical treatment and prognosis in patients with chondrosarcoma.

METHODS

Through the search of the Surveillance, Epidemiology, and End Results (SEER) database, chondrosarcoma patients registered between January 1, 2004 and December 31, 2016 were selected as research goals. Univariate analysis of overall survival (OS) and chondrosarcoma-specific survival (CSSS) by Kaplan-Meier survival analysis and log-rank test. Mapping Kaplan-Meier curves for prognostic factors that are significant for OS and CSSS in patients with chondrosarcoma. After univariate analysis, the prognostic factors that have a significant effect on the prognosis were included in the multivariate Cox regression analysis, and the independent factors that affected the prognosis were screened.

RESULTS

A total of 1,128 patients with chondrosarcoma were included in the study. Univariate analysis showed that prognostic factors such as age, gender, primary site, histological type, grade, tumor size, metastasis, surgery, radiotherapy, chemotherapy and treatment method had significant effects on all-cause mortality (ACM) and chondrosarcoma-specific mortality (CSSM). These factors were included in the multivariate Cox regression analysis. The results showed age, primary site, histological type, grade, tumor size, metastasis, and treatment method were independent factors affecting ACM and CSSM.

CONCLUSIONS

This study found that although non-surgical treatment of chondrosarcoma has made great progress, at present, it is still not considered that non-surgical treatment can significantly improve the prognosis. There are many factors affecting the prognosis of chondrosarcoma, including age, primary site, histological type, grade, tumor size, distant metastasis and treatment method. In the future, more samples and more detailed data will be needed to study the treatment of chondrosarcoma and to analyze the important factors affecting prognosis through big data analysis.

Cold Atmospheric Plasma Treatment of Chondrosarcoma Cells Affects Proliferation and Cell Membrane Permeability

Chondrosarcoma is the second most common malign bone tumor in adults. Surgical resection of the tumor is recommended because of its resistance to clinical treatment such as chemotherapy and radiation therapy. Thus, the prognosis for patients mainly depends on sufficient surgical resection. Due to this, research on alternative therapies is needed. Cold atmospheric plasma (CAP) is an ionized gas that contains various reactive species. Previous studies have shown an anti-oncogenic potential of CAP on different cancer cell types. The current study examined the effects of treatment with CAP on two chondrosarcoma cell lines (CAL-78, SW1353). Through proliferation assay, the cell growth after CAP-treatment was determined. A strong antiproliferative effect for both cell lines was detected. By fluorescein diacetate (FDA) assay and ATP release assay, alterations in the cell membrane and associated translocation of low molecular weight particles through the cytoplasmic membrane were observed. In supernatant, the non-membrane-permeable FDA and endogenously synthesized ATP detected suggest an increased membrane permeability after CAP treatment. Similar results were shown by the dextran-uptake assay. Furthermore, fluorescence microscopic G-/F-actin assay was performed. G- and F-actin were selectively dyed, and the ratio was measured. The presented results indicate CAP-induced changes in cell membrane function and possible alterations in actin-cytoskeleton, which may contribute to the antiproliferative effects of CAP.

Risk stratification for central conventional chondrosarcoma of bone: A novel system predicting risk of metastasis and death in the Cancer Registry of Norway cohort

BACKGROUND AND OBJECTIVES

Interobserver variability in histological grading of central conventional chondrosarcoma (CCCS) limits the quality of patient information and research progression. We aim to quantify known and new prognostic variables and propose a risk stratification model.

METHOD

We selected 149 cases from the Cancer Registry of Norway. Cox proportional hazard models were estimated. Based on these results a dichotomous risk classification was proposed and presented by Kaplan-Meier estimates for rates of local recurrence, metastasis, and disease-specific survival.

RESULTS

The influence of axial skeletal location (Hazard ratio [HR] = 19.06), a soft tissue component ≥1 cm (HR = 13.45), and histological grade 3 (HR = 16.46) are all significant in predicting the rate of metastasis. The creation of a variable combining axial skeletal location and a soft tissue component ≥1 cm strongly predicts the risk of metastasis (HR = 14.02; P < .001) and death (HR = 2.74; P = .030) at multivariate analysis, making the histological grade insignificant. Together with metastasis at diagnosis (HR = 285.65; P < .001), this forms the basis of our proposed risk stratification, producing a small high-risk group (39 cases with 33% risk of metastasis) and a large low-risk group (103 cases with 2% risk of metastasis) without a histological grade.

CONCLUSION

Axial skeletal location and a soft tissue component ≥1 cm combined divides a CCCS cohort into low- and high-risk groups without a histological grade.

Chondrosarcomas in children and adolescents

Chondrosarcomas in children and adolescents are uncommon and constitute < 5% of all chondrosarcomas. There are very few studies discussing extremity chondrosarcomas in young patients.

The pelvis is the most common site, followed by the proximal femur.

As cartilaginous tumours can be quite challenging to diagnose, it is best for these lesions to be discussed in a multidisciplinary meeting which includes a radiologist and a pathologist specializing in bone tumours.

Treatment principles are similar to those in adults, with adequate surgical excision respecting oncologic principles being the mainstay of treatment. Select extremity Grade I chondrosarcomas may be managed with extended intralesional curettage without increasing the risk for local recurrence or metastatic disease, but case selection is critical and should be based on clinical, imaging and histological characteristics.

Chondrosarcomas are resistant to chemotherapy and relatively radioresistant. For mesenchymal chondrosarcomas, there may be a role for chemotherapy, though data on this is limited.

Prognosis and rate of recurrence correlate directly to the adequacy of the surgical resection.

Chondrosarcomas in younger patients behave in a similar fashion to those in adults, and outcomes in the young are no different from those in adults.

Cite this article: EFORT Open Rev 2020;5:90-95. DOI: 10.1302/2058-5241.5.190052

[Late complications following neo-/adjuvant radiotherapy and surgery for sarcomas of the extremities or pelvis/retroperitoneum : Preventative measures]

Radiotherapy is one of the pillars in the multimodal therapy of sarcomas of the extremities or pelvis/retroperitoneum. It can be delivered prior to or following surgery. Novel radiation techniques, such as intensity-modulated radiotherapy using high-energy photons or protons, contribute to the reduction of acute and late toxicities. This review article summarizes these concepts.

Survival and Prognosis of Chondrosarcoma Subtypes: SEER Database Analysis

Chondrosarcomas are rare tumors and, historically, investigation of these tumors has been limited to small series and single-institution studies. There have been no studies that evaluated the identification or comparison of differences in prognostic factors between the five known non-conventional chondrosarcoma subtypes (myxoid, juxtacortical, clear-cell, mesenchymal, and dedifferentiated). The purpose of this paper was to determine the demographic, clinical, incidence, and tumor characteristics of all five known non-conventional chondrosarcoma subtypes, determine the 1-, 5-year, and median survival differences between these subtypes, and to determine the demographic and clinical variables that are significant prognostic indicators for each chondrosarcoma subtypes. We retrospectively reviewed the SEER database for all patients with non-conventional chondrosarcoma. χ² testing was used for correlations between clinical variables. Kaplan-Meier and Cox proportional hazard analysis were used to compare survival of the subtypes, and to assess the prognostic value of age group, race, sex, grade, anatomic location, and metastatic involvement. Several demographic characteristics including gender, race, age, and grade varied between chondrosarcoma subtypes. The tumor characteristics showed marked differences in presence of metastasis on presentation between the subtypes with increasing order of rate of metastasis with juxtacortical (2.1%), clear cell (5.7%), myxoid (7.6%), mesenchymal (10.6%), and the highest in dedifferentiated (19.8%). One-, 5-year, and median survival differed significantly between chondrosarcomas subtypes. The highest median survival was found in the juxtacortical subtype (97 months), followed by clear cell (79 months), myxoid (60 months), mesenchymal (33.5 months), and lowest in dedifferentiated (11 months). The only prognostic variable that was shown to significantly impact the survival of each non-conventional chondrosarcoma subtype was a metastatic disease at diagnosis (p = 0.03 to p < 0.001). Subtyping classification of chondrosarcoma should be made whenever possible, given differences in survival and prognostic factors between chondrosarcoma subtypes. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:311-319, 2020.

Risk Factors for Incidence and Prognosis in Chondrosarcoma Patients with Pulmonary Metastasis at Initial Diagnosis

Background

The incidence and prognostic factors of chondrosarcoma patients have been reported in early studies. However, the association between risk factors and the incidence or prognosis of chondrosarcoma patients with pulmonary metastasis remains unclear. Therefore, we assessed these risk factors among chondrosarcoma patients with pulmonary metastasis.

Material/Methods

From 1365 chondrosarcoma patients in the Surveillance, Epidemiology, and End Results (SEER) database, we collected the information of 69 patients with pulmonary metastasis at the initial diagnosis of chondrosarcoma from 2010 to 2016. We investigated the incidence, risk factors, and prognostic factors for pulmonary metastasis patients by using multivariate logistic regression and multivariate Cox regression analyses.

Results

Data from a total of 69 (6.8%) chondrosarcoma patients with pulmonary metastasis at initial diagnosis were extracted. Patients with the following characteristics were positively associated with higher risk of pulmonary metastasis: dedifferentiated subtype, high grade of malignancy, extracompartmental tumor (Enneking B), presence of regional lymph nodes, local recurrence, large tumor size (larger than 15 cm), and being married. Older patients (older than 67 years), and patients with clear cell chondrosarcoma or large tumor size (larger than 15 cm) exhibited the worse prognosis and survival (overall and cancer-specific). Resection of the primary tumor tended to be correlated with a better prognosis.

Conclusions

The incidence of pulmonary metastasis in chondrosarcoma was approximately 6.8%, with poor prognosis. Identifying risk factors and their associations with the incidence and prognosis in chondrosarcoma patients with pulmonary metastasis could provide a reference for clinical surveillance and guide the design of personalized treatment plans.

Total Sacrectomy for the Treatment of Advanced Pelvic Chondrosarcoma

Primary tumors of sacrum are rare. The most common malignant tumors are metastasis, and only 6% of all malignant tumors arise from the sacrum. Chondrosarcoma is the third most common primary bone malignancy following myeloma and osteosarcoma. Surgery is usually the most important therapeutic modality; the wide en bloc excision remains the treatment of choice. These technically demanding procedures require a multidisciplinary expert team (neurosurgery, surgical and orthopedic oncology, colorectal surgery, and plastic surgery) involvement. We present in this article a case of a 52-year-old man who presented less infrequent symptoms, and the diagnosis was made in a very advanced stage. The wide surgical excision of the mass was performed by two different anterior and posterior approaches in one stage. The free surgical margins were difficult to achieve because it presented a voluminous tumor with invasion of the rectum, bone, and sacral plexus, but the age, low histological grade, and extensive experience in extreme pelvic surgery of our multidisciplinary team allowed approaching the patient with debulking surgery en bloc, successfully. Total hospital stay was 20 days. The patient was discharged without any complications. At the 6-months' follow-up, the patient showed no local recurrence.

Prognostic Factors and Treatment Options for Patients with High-Grade Chondrosarcoma

Background

The goal of this study was to determine the prognostic factors exclusive for high-grade chondrosarcoma and whether adjuvant radiotherapy could achieve better overall survival (OS) or cancer-specific survival (CSS) for patients with high-grade chondrosarcoma.

Material/Methods

Surveillance, Epidemiology, and End Results (SEER) cancer registry database was utilized to extract the chondrosarcoma cases diagnosed between 1973 and 2014. Among these cases, the histological grades of poorly differentiated (grade 3) and undifferentiated (grade 4) were categorized as high-grade and included in this study. Chondrosarcoma OS and CSS were the primary outcomes in the present study. The log-rank test was performed for univariate analysis, and the Cox regression model was conducted for multivariate analysis.

Results

A total of 743 patients with high-grade chondrosarcoma were identified in this study (430 cases were poorly differentiated tumors, and 313 cases were undifferentiated tumors). Age at diagnosis, pathological grade, histo-type, SEER stage, tumor size and surgical resection were identified as independent predictors in both OS and CSS analysis of high-grade chondrosarcoma. When stratified by histological grade, surgical resection remained the effective treatment. Strikingly, radiotherapy was determined as an independent protective factor in both OS and CSS analysis of undifferentiated (grade 4) dedifferentiated chondrosarcoma, and adjuvant radiotherapy combined surgical resection could improve both the OS and CSS of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma compared with other treatment regimens.

Conclusions

Our study first demonstrated that adjuvant radiotherapy combined surgery could improve the survival of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma. These results encourage the application of adjuvant radiotherapy for patients with high-grade chondrosarcoma and maximize the patients’ outcome.

Regional Lymph Node Involvement Is Associated With Poorer Survivorship in Patients With Chondrosarcoma: A SEER Analysis

BACKGROUND

Regional lymph node involvement is thought to be rare in patients with chondrosarcoma, but its actual prevalence is unclear. Additionally, it is often not considered when prognostic factors are analyzed in patients with chondrosarcoma. However, it has been well established that lymph node involvement is a poor prognostic marker in patients with many types of bone and soft tissue sarcoma, including rhabdomyosarcoma, osteosarcoma, and Ewing's sarcoma. Although lymph node metastases are rare among all sarcoma types, it is important to consider whether lymph node metastases should be assessed in patients with chondrosarcoma because these metastases may impact survival.

QUESTIONS/PURPOSES

(1) What is the reported prevalence of regional lymph node involvement in patients with chondrosarcoma? (2) Do patients who have chondrosarcomas with regional lymph node involvement have different clinicopathologic presentations and survival than patients without regional lymph node involvement? (3) Is regional lymph node involvement independently associated with prognosis in patients with chondrosarcoma?

METHODS

The data of patients with chondrosarcoma registered in the Surveillance Epidemiology and End Results database (SEER) (1988-2015) were analyzed for the reported prevalence of regional lymph node involvement and its relationship with clinicopathologic features and the 5-year overall survival rate. From 1988 to 2015, 5528 patients with chondrosarcoma were registered in the SEER database. After screening by the inclusion criterion-chondrosarcoma as the first primary tumor, diagnosis with histology confirmation, patients with active followup and available information about regional node status-3374 patients met the inclusion criteria and were analyzed. Demographics and clinicopathologic data were compared using chi-square or Fisher's exact tests. Logistic regression analysis was used to assess the adjusted odds ratio. The overall survival rate was estimated with Kaplan-Meier curves and log-rank tests. Univariate and multivariate analyses of overall survival were performed with Cox proportional hazard models. In addition, a series of sensitivity analyses were performed to assess the robustness of the final Cox proportional hazard model.

RESULTS

Forty-four patients (1.3%) were recorded in the database as having regional lymph node involvement at the time of the primary diagnosis. Lymph node metastases were more likely to be reported in an extraskeletal primary site (3% [13 of 426] versus 1% [31 of 2948], adjusted odds ratio [OR] = 2.9, 95% CI, 1.5-5.8; p = 0.003) for bone primary sites and tumors with maximum diameter ≥ 8 cm (2% [26 of 1045] versus 1% [10 of 1075], adjusted OR = 2.9, 95% CI, 1.3-6.3; p = 0.008) and poorer differentiation (4% [24 of 608] versus 1% [14 of 2308], adjusted OR = 4.0, 95% CI, 2.0-8.2; p < 0.001), and in those with distant metastases (7% [14 of 203] versus 1% [30 of 3148], adjusted OR = 3.5, 95% CI, 1.7-7.1, p = 0.001). The 5-year overall survival rates of patients with and without regional lymph node involvement were 28% (95% CI, 15-42%) and 77% (95% CI, 75-78%), respectively (p < 0.001). After controlling for age, sex, race, grade, metastatic status, size, and histologic subtype, the presence of regional lymph node involvement was associated with poorer survival (hazard ratio, 2.20; 95% CI, 1.50-3.24; p < 0.001); this finding was confirmed in several sensitivity analyses.

CONCLUSION

The prevalence of regional lymph node involvement in patients with chondrosarcoma was 1.3% in the SEER database. Although chondrosarcomas are rare, patients with chondrosarcomas who have regional node metastases have a poorer prognosis than those who have not reported to have them. This may underrepresent the true proportion of patients with lymph node metastases given the inaccuracies of reporting in this database, but we believe these findings indicate that clinicians should examine patients more carefully for chondrosarcoma with lymph node metastases. Future studies are needed to assess potential treatment strategies to improve the prognosis of these patients.

LEVEL OF EVIDENCE

Level III, prognostic study.

Does the SORG Algorithm Predict 5-year Survival in Patients with Chondrosarcoma? An External Validation

BACKGROUND

We developed a machine learning algorithm to predict the survival of patients with chondrosarcoma. The algorithm demonstrated excellent discrimination and calibration on internal validation in a derivation cohort based on data from the Surveillance, Epidemiology, and End Results (SEER) registry. However, the algorithm has not been validated in an independent external dataset.

QUESTIONS/PURPOSES

Does the Skeletal Oncology Research Group (SORG) algorithm accurately predict 5-year survival in an independent patient population surgically treated for chondrosarcoma?

METHODS

The SORG algorithm was developed using the SEER registry, which contains demographic data, tumor characteristics, treatment, and outcome values; and includes approximately 30% of the cancer patients in the United States. The SEER registry was ideal for creating the derivation cohort, and consequently the SORG algorithm, because of the high number of eligible patients and the availability of most (explanatory) variables of interest. Between 1992 to 2013, 326 patients were treated surgically for extracranial chondrosarcoma of the bone at two tertiary care referral centers. Of those, 179 were accounted for at a minimum of 5 years after diagnosis in a clinical note at one of the two institutions, unless they died earlier, and were included in the validation cohort. In all, 147 (45%) did not meet the minimum 5 years of followup at the institution and were not included in the validation of the SORG algorithm. The outcome (survival at 5 years) was checked for all 326 patients in the Social Security death index and were included in the supplemental validation cohort, to also ascertain validity for patients with less than 5 years of institutional followup. Variables used in the SORG algorithm to predict 5-year survival including sex, age, histologic subtype, tumor grade, tumor size, tumor extension, and tumor location were collected manually from medical records. The tumor characteristics were collected from the postoperative musculoskeletal pathology report. Predicted probabilities of 5-year survival were calculated for each patient in the validation cohort using the SORG algorithm, followed by an assessment of performance using the same metrics as used for internal validation, namely: discrimination, calibration, and overall performance. Discrimination was calculated using the concordance statistic (or the area under the Receiver Operating Characteristic (ROC) curve) to determine how well the algorithm discriminates between the outcome, which ranges from 0.5 (no better than a coin-toss) to 1.0 (perfect discrimination). Calibration was assessed using the calibration slope and intercept from a calibration plot to measure the agreement between predicted and observed outcomes. A perfect calibration plot should show a 45° upwards line. Overall performance was determined using the Brier score, ranging from 0 (excellent prediction) to 1 (worst prediction). The Brier score was compared with the null-model Brier score, which showed the performance of a model that ignored all the covariates. A Brier score lower than the null model Brier score indicated greater performance of the algorithm. For the external validation an F1-score was added to measure the overall accuracy of the algorithm, which ranges between 0 (total failure of an algorithm) and 1 (perfect algorithm).The 5-year survival was lower in the validation cohort than it was in the derivation cohort from SEER (61.5% [110 of 179] versus 76% [1131 of 1544] ; p < 0.001). This difference was driven by higher proportion of dedifferentiated chondrosarcoma in the institutional population than in the derivation cohort (27% [49 of 179] versus 9% [131 of 1544]; p < 0.001). Patients in the validation cohort also had larger tumor sizes, higher grades, and nonextremity tumor locations than did those in the derivation cohort. These differences between the study groups emphasize that the external validation is performed not only in a different patient cohort, but also in terms of disease characteristics. Five-year survival was not different for both patient groups between subpopulations of patients with conventional chondrosarcomas and those with dedifferentiated chondrosarcomas.

RESULTS

The concordance statistic for the validation cohort was 0.87 (95% CI, 0.80-0.91). Evaluation of the algorithm's calibration in the institutional population resulted in a calibration slope of 0.97 (95% CI, 0.68-1.3) and calibration intercept of -0.58 (95% CI, -0.20 to -0.97). Finally, on overall performance, the algorithm had a Brier score of 0.152 compared with a null-model Brier score of 0.237 for a high level of overall performance. The F1-score was 0.836. For the supplementary validation in the total of 326 patients, the SORG algorithm had a validation of 0.89 (95% CI, 0.85-0.93). The calibration slope was 1.13 (95% CI, 0.87-1.39) and the calibration intercept was -0.26 (95% CI, -0.57 to 0.06). The Brier score was 0.11, with a null-model Brier score of 0.19. The F1-score was 0.901.

CONCLUSIONS

On external validation, the SORG algorithm retained good discriminative ability and overall performance but overestimated 5-year survival in patients surgically treated for chondrosarcoma. This internet-based tool can help guide patient counseling and shared decision making.

LEVEL OF EVIDENCE

Level III, prognostic study.

Chondrosarcoma: the impact of comorbidity - 30 years of experience from a population-based database including 199 consecutive chondrosarcoma patients

Background

Adjustment for comorbidity when investigating potential prognostic factors, especially in elderly cancer patients, is imperative. Patients diagnosed with chondrosarcoma are elderly and more comorbidity is expected for these patients. Demographic changes are awaited in the future resulting in more and more elderly patients with comorbidity. The aims of this study were to characterize patients with chondrosarcoma treated at a single institute and to evaluate various prognostic factors for survival adjusted for comorbidity.

Material and methods

Between 1979 and 2008, 199 patients were treated at the Sarcoma Centre of Aarhus University Hospital, for chondrosarcoma. The incidence was calculated as a WHO age-standardized incidence rate (IR) per million per year. The endpoints were overall mortality and disease-specific mortality. Possible prognostic factors were analyzed for patients with intermediate/high-grade localized tumors by the uni- and multivariate Cox-proportional hazard method.

Results

The WHO age-standardized IR in western Denmark in the period 1979–2008 was 2.4/million inhabitants/year (95% CI: 2.2;2.6). The 5-year overall and disease-specific mortality for the 199 patients were 29% (95% CI: 23;36) and 22% (95% CI: 16;27), respectively. The 5-year disease-specific mortality for patients with metastatic disease was significantly higher than for patients with localized disease. The median time to relapse was 2.0 years. Patients who relapse within 1 year after the primary diagnosis have a significantly higher 5-year overall mortality compared to patients who relapse after 1 year. The presence of comorbidity and high-grade tumors were independent prognostic factors for both the overall mortality and the disease-specific mortality of chondrosarcoma patients.

Conclusion

Patients with comorbidity had a significantly increased overall mortality and disease-specific mortality. We found that adjusting for comorbidity is important when investigating a cohort of elderly patients.

Results of a prospective phase 2 study of pazopanib in patients with surgically unresectable or metastatic chondrosarcoma

BACKGROUND

This single-arm, multicenter, phase 2 study evaluated the safety and antitumor activity of pazopanib in patients with unresectable or metastatic conventional chondrosarcoma.

METHODS

Eligible patients had conventional chondrosarcoma of any grade with measurable tumors that were unresectable or metastatic. Patients with mesenchymal, dedifferentiated, and extraskeletal myxoid chondrosarcoma subtypes and patients who received prior tyrosine kinase inhibitor therapy were excluded. Pazopanib at 800 mg once daily was administered for 28-day cycles. Tumor responses were evaluated by local radiology assessments every 2 cycles. The primary endpoint was the disease control rate (DCR) at week 16 (4 cycles).

RESULTS

Forty-seven patients were enrolled. The DCR at 16 weeks was 43% (95% confidence interval [CI], 28%-58%), which was superior to the null hypothesis rate of 30%, but the 2-sided P value (exact test) was .09 (1-sided P = .045). One patient had a partial response. The median overall survival was 17.6 months (95% CI, 11.3-35.0 months), and the median progression-free survival was 7.9 months (95% CI, 3.7-12.6 months). Grade 3 or higher adverse events were infrequent; hypertension (26%) and elevated alanine aminotransferase (9%) were most common.

CONCLUSIONS

This study provides evidence of positive drug activity for pazopanib in conventional chondrosarcoma.

Survival and prognostic factors in conventional G1 chondrosarcoma

Background

Chondrosarcoma is the second most frequent malignant bone tumor. Grade I chondrosarcoma (syn.: atypical cartilaginous tumor) is classified as an intermediately and locally aggressive neoplasm and typically is treated less aggressively (i.e., by intralesional curettage). Does the data regarding local recurrence (LR) and metastatic disease justify this?

Methods

From 1982 to 2014, 37 consecutive patients with G1 chondrosarcoma had been resected or curetted. The margin was defined as R0 (wide resection) or R1 (marginal resection). All patients were followed for evidence of local recurrence or metastatic disease. Overall and recurrence-free survival were calculated, and various potentially prognostic factors were evaluated.

Results

In 23 patients (62%), the tumor was widely (R0) resected, whereas in 14 patients, (38%) the resection was marginal (R1). Overall survival was 97% after 5 years, 92% after 10 years, and 67% after 20 years. Five-year local recurrence-free survival was 96%. Ten-year local recurrence-free survival was 83%. Local recurrence-free survival showed a significant correlation to margin status but no correlation to location or age. None of the patients with local recurrence died during the follow-up. One patient had metastatic disease at initial presentation, and a further five patients developed metastatic disease during follow-up. Metastatic disease proofed to be a highly significant factor for survival but was not correlated to local recurrence.

Conclusions

There was no significant correlation between the outcome and the primary tumor location. Marginal resection was a risk factor for LR, but there was no significant difference in the overall survival in patients with or without LR. Metastatic disease (16%) was more common than expected from the literature and a significant predictor for poor overall survival.

Successfully Treated Lung and Renal Metastases from Primary Chondrosarcoma of the Scapula with Radiofrequency Ablation and Surgical Resection

Since chondrosarcoma is a relatively rare type of malignant bone tumors characterized by its ability to produce a cartilage matrix and aggressive behavior, a consensus clinical management strategy has not been established. We report a 55-year-old woman who presented with renal metastasis arising from chondrosarcoma of the scapula. Chondrosarcoma of the left scapula was diagnosed 15 years earlier. After surgical resection of a local recurrence in the left scapula, she received focal radiofrequency ablation (RFA). She underwent focal RFA and surgical resection for a total of 21 times for lung metastases. Because invasion of the renal pelvis was suspected from urine cytology, she underwent laparoscopic nephroureterectomy. The histopathological findings showed metastatic chondrosarcoma involving the right renal parenchyma. The patient has remained clinically stable without recurrence for 18 months. To the best of our knowledge, this is the first report of metastatic chondrosarcoma of the lung and renal parenchyma with involvement of the renal pelvis in which remission was achieved with multimodal treatment including RFA and surgical resection.

Overexpression of ClC-3 Chloride Channel in Chondrosarcoma: An In Vivo Immunohistochemical Study with Tissue Microarray

Background

Recently, ClC-3 chloride channel expression has been noted to be high in some tumors. In chondrosarcoma, which is a malignant tumor with a high incidence in the bone, there has been no previous literature regarding ClC-3 chloride channel expression. Here we evaluated the expression of ClC-3 chloride channel in chondrosarcoma and explored its clinical significance.

Material/Methods

In this study, 75 chondrosarcoma and 5 normal cartilage tissues were collected. Thereafter, tissue microarray was performed. Immunohistochemistry was also used to observe the level of ClC-3 chloride channel expression between normal and chondrosarcoma tissues.

Results

Results showed that the expression of ClC-3 chloride channel in the normal chondrocyte was thinner, since it showed distinct differentiation among chondrosarcoma specimens. Interestingly, we noticed that the moderately-differentiated chondrosarcoma (MDC) and the poorly-differentiated chondrosarcoma (PDC) exhibited 94.44% of ClC-3 chloride channel. Besides, the subcellular localization of ClC-3 chloride channel was changed in association with malignant degree changes. The subcellular localization of ClC-3 chloride channel in the MDC and PDC tissue was localized in the cytoplasm and both nucleus and cytoplasm: 83.33% (5 out of 6 cases) and 91.66% (11 out of 12 cases) respectively. On the other hand, we noticed that patient age and gender could have a relation with ClC-3 chloride channel expression; 30- to 60-year-old males showed more expression.

Conclusions

These results demonstrated a high frequency of ClC-3 chloride channel overexpression and subcellular localization differences in MDC and PDC tissue, suggesting a specific role of ClC-3 chloride channel in the pathogenesis of chondrosarcoma.

Can clinical radiomics nomogram based on 3D multiparametric MRI features and clinical characteristics estimate early recurrence of pelvic chondrosarcoma?

BACKGROUND

Chondrosarcoma (CS) is the second most common primary malignant bone tumor, with a relatively high recurrence rate. However, an effective method that estimates whether pelvic CS will recur after surgery, which influences the formulation of a clinical treatment plan, remains lacking.

PURPOSE

To develop and validate a clinical radiomics nomograms based on 3D multiparametric magnetic resonance imaging (mpMRI) features and clinical characteristics that could estimate early recurrence (ER) (≤1 year) of pelvic CS.

STUDY TYPE

Retrospective.

POPULATION

In all, 103 patients (ER = 41, non-ER = 62) with histologically proven CS were retrospectively analyzed and divided into a training set (n = 72) and a validation set (n = 31).

FIELD STRENGTH/SEQUENCE

3.0T axial T₁ -weighted (T₁ -w), T₂ -weighted (T₂ -w), diffusion weighted imaging (DWI), contrast-enhanced T₁ -weighted (CET₁ -w).

ASSESSMENT

Risk factors (sex, age, type, grade, resection margins, etc.) associated with ER were evaluated. Five individual models based on T₁ -w, T₂ -w, DWI, CET₁ -w, and clinical data were built. Then we compared the performance of models based on T₁ -w, T₂ -w, CET₁ -w and their combination. Lastly, two nomograms based on the best model + clinical data and DWI + clinical data were built.

STATISTICAL TESTS

The area under the receiver operating characteristic curve (AUC) and accuracy (ACC) were used to evaluate different models.

RESULTS

Grade was the most important univariate clinical predictor of ER of pelvic CS patients (odds ratio [OR]1 = 4.616, OR2 = 8.939, P < 0.05). T₁ -w + T₂ -w + CET₁ -w had a significantly higher performance than CET₁ -w in the training set (P = 0.01). Radiomics features are more important than clinical characteristics in clinical radiomics nomograms, especially for multisequence combined features (OR = 3.208, P < 0.01). Clinical radiomics nomogram based on combined features (T₁ -w + T₂ -w + CET₁ -w) + clinical data achieved an AUC of 0.891 and ACC of 0.857, followed by DWI + clinical data (AUC = 0.882, ACC = 0.760) in the validation set.

DATA CONCLUSION

The clinical radiomics nomogram had good performance in estimating ER of pelvic CS patients, which would be helpful in clinical decision-making.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:435-445.

Predictors of the survival of patients with chondrosarcoma of bone and metastatic disease at diagnosis

Purpose: Chondrosarcoma with metastatic disease has a very poor prognosis. However, the prognosis and potential prognostic factors of patients with primary chondrosarcoma of bone and metastasis at presentation have not been documented because of its rarity. Therefore, we examined the prognosis of this special cohort and identify possible prognostic factors.

Methods: The Surveillance, Epidemiology, and End Results (SEER) program database was used to identify patients with primary chondrosarcoma of bone and metastatic disease at diagnosis from 2000 to 2013. The prognostic analysis was performed using the Kaplan-Meier method and a Cox proportional hazards regression model.

Results: The SEER database contained 264 cases. The overall survival (OS) and cancer-survival specific (CSS) rates of the entire group at 5 years were 28.4% and 31.2%, respectively. The median OS and CSS were 14.0 ± 2.5 and 17.0 ± 2.6 months, respectively. Multivariate analysis revealed that low tumor grade, surgical treatment, tumor size < 10 cm, and first primary tumor were associated with improved OS. Tumor grade, tumor size, and surgery were independent predictors of CSS. Radiation therapy had no effect on either OS or CSS.

Conclusion: Among patients with primary chondrosarcoma of bone and metastasis at presentation, low tumor grade, surgical treatment, tumor size < 10 cm, and first primary tumor predict prolonged survival.

Proximal humerus chondrosarcoma.Long-term clinical and oncological outcomes

INTRODUCTION

The proximal humerus is a common site for primary bone sarcomas, of which chondrosarcoma represents 15%. There are few reports about this select group of tumours. We set out to analyse a group of patients with proximal humerus chondrosarcoma treated with surgery and to assess their long term surgical and oncological outcomes.

MATERIAL AND METHODS

A retrospective review was performed and all patients with a proximal humerus chondrosarcoma treated with surgery were included in the study. Overall survival and local recurrence rates were analyzed. Post-operative complications were recorded and limb salvage surgery failures classified according to the Henderson classification.

RESULTS

37 patients were included in the study. The median age was 46 years (SD: 15.6, range: 17-24), 24 (65%) were female and the mean follow-up was 8.5 years (SD: 6.4, range: 2 -26). Eighteen patients were classified as grade 1 (49%), 15 as grade 2 (40%), 2 as grade 3 (5%) and 2 dedifferentiated chondrosarcomas (5%). The 10-year overall survival was 94.5% and the 10-year event-free survival was 84.5%. Five patients developed local recurrences (13%) and none of them was grade 1. The reconstruction failure rate was 27% at 5 years and 34% at 10 years. There were no complications or local recurrence in patients treated with curettage.

CONCLUSION

Proximal humerus chondrosarcoma presented high survival rates. Curettage and bone grafting is a safe procedure, with low risk of complications and local recurrence for grade 1 chondrosarcomas and should be the first indication for the proximal humerus. Reconstruction of the proximal humerus after a wide resection has a 5-year failure rate of 27% and 10-year failure rate of 34%.

Intralesional treatment versus wide resection for central low-grade chondrosarcoma of the long bones

BACKGROUND

Grade I or low-grade chondrosarcoma (LGCS) is a primary bone tumour with low malignant potential. Historically, it was treated by wide resection, since accurate pre-operative exclusion of more aggressive cancers can be challenging and under-treatment of a more aggressive cancer could negatively influence oncological outcomes. Intralesional surgery for LGCS has been advocated more often in the literature over the past few years. The potential advantages of less aggressive treatment are better functional outcome and lower complication rates although these need to be weighed against the potential for compromising survival outcomes.

OBJECTIVES

To assess the benefits and harms of intralesional treatment by curettage compared to wide resection for central low-grade chondrosarcoma (LGCS) of the long bones.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 4), MEDLINE and Embase up to April 2018. We extended the search to include trials registries, reference lists of relevant articles and review articles. We also searched 'related articles' of included studies suggested by PubMed.

SELECTION CRITERIA

In the absence of prospective randomised controlled trials (RCTs), we included retrospective comparative studies and case series that evaluated outcome of treatment of central LGCS of the long bones. The primary outcome was recurrence-free survival after a minimal follow-up of 24 months. Secondary outcomes were upgrading of tumour; functional outcome, as assessed by the Musculoskeletal Tumor Society (MSTS) score; and occurrence of complications.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recognised by Cochrane. We conducted a systematic literature search using several databases and contacted corresponding authors, appraised the evidence using the ROBINS-I risk of bias tool and GRADE, and performed a meta-analysis. If data extraction was not possible, we included studies in a narrative summary.

MAIN RESULTS

We included 18 studies, although we were only able to extract participant data from 14 studies that included a total of 511 participants; 419 participants were managed by intralesional treatment and 92 underwent a wide resection. We were not able to extract participant data from four studies, including 270 participants, and so we included them as a narrative summary only. The evidence was at high risk of performance, detection and reporting bias.Meta-analysis of data from 238 participants across seven studies demonstrated little or no difference in recurrence-free survival after intralesional treatment versus wide resection for central LGCS in the long bones (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.92 to 1.04; very low-certainty evidence). MSTS scores were probably better after intralesional surgery (mean score 93%) versus resection (mean score 78%) with a mean difference of 12.69 (95% CI 2.82 to 22.55; P value < 0.001; 3 studies; 72 participants; low-certainty evidence). Major complications across six studies (203 participants) were lower in cases treated by intralesional treatment (5/125 cases) compared to those treated by wide resection (18/78 cases), with RR 0.23 (95% CI 0.10 to 0.55; low-certainty evidence). In four people (0.5% of total participants) a high-grade (grade 2 or dedifferentiated) tumour was found after a local recurrence. Two participants were treated with second surgery with no evidence of disease at their final follow-up and two participants (0.26% of total participants) died due to disease. Kaplan-Meier analysis of data from 115 individual participants across four studies demonstrated 96% recurrence-free survival after a maximum follow-up of 300 months after resection versus 94% recurrence-free survival after a maximum follow-up of 251 months after intralesional treatment (P value = 0.58; very low-certainty evidence). Local recurrence or metastases were not reported after 41 months in either treatment group.

AUTHORS' CONCLUSIONS

Only evidence of low- and very low-certainty was available for this review according to the GRADE system. Included studies were all retrospective in nature and at high risk of selection and attrition bias. Therefore, we could not determine whether wide resection is superior to intralesional treatment in terms of event-free survival and recurrence rates. However, functional outcome and complication rates are probably better after intralesional surgery compared to wide resection, although this is low-certainty evidence, considering the large effect size. Nevertheless, recurrence-free survival was excellent in both groups and a prospective RCT comparing intralesional treatment versus wide resection may be challenging for both practical and ethical reasons. Future research could instead focus on less invasive treatment strategies for these tumours by identifying predictors that help to stratify participants for surgical intervention or close observation.

Proton therapy for skull base tumors: A review of clinical outcomes for chordomas and chondrosarcomas

BACKGROUND

Skull base chordomas and chondrosarcomas are rare tumors traditionally treated by surgical resection and adjuvant radiation therapy (RT). We will discuss data evaluating clinical outcomes of proton therapy in the treatment of skull base chordomas and chondrosarcomas.

METHODS

A literature review was performed using a MEDLINE search from January 1990 to January 2017.

RESULTS

The published data suggest that the dose intensification allowed by proton therapy has resulted in good clinical outcomes and a tolerable toxicity profile.

CONCLUSION

Proton therapy is a modern RT technique that has demonstrated improved preliminary clinical outcomes in the treatment of skull base chordomas and chondrosarcomas compared to conventional radiotherapy, and comparable to other advanced photon-based RT techniques.

Can Machine-learning Techniques Be Used for 5-year Survival Prediction of Patients With Chondrosarcoma?

BACKGROUND

Several studies have identified prognostic factors for patients with chondrosarcoma, but there are few studies investigating the accuracy of computationally intensive methods such as machine learning. Machine learning is a type of artificial intelligence that enables computers to learn from data. Studies using machine learning are potentially appealing, because of its possibility to explore complex patterns in data and to improve its models over time.

QUESTIONS/PURPOSES

The purposes of this study were (1) to develop machine-learning algorithms for the prediction of 5-year survival in patients with chondrosarcoma; and (2) to deploy the best algorithm as an accessible web-based app for clinical use.

METHODS

All patients with a microscopically confirmed diagnosis of conventional or dedifferentiated chondrosarcoma were extracted from the Surveillance, Epidemiology, and End Results (SEER) Registry from 2000 to 2010. SEER covers approximately 30% of the US population and consists of demographic, tumor characteristic, treatment, and outcome data. In total, 1554 patients met the inclusion criteria. Mean age at diagnosis was 52 years (SD 17), ranging from 7 to 102 years; 813 of the 1554 patients were men (55%); and mean tumor size was 8 cm (SD 6), ranging from 0.1 cm to 50 cm. Exact size was missing in 340 of 1544 patients (22%), grade in 88 of 1544 (6%), tumor extension in 41 of 1544 (3%), and race in 16 of 1544 (1%). Data for 1-, 3-, 5-, and 10-year overall survival were available for 1533 (99%), 1512 (98%), 1487 (96%), and 977 (63%) patients, respectively. One-year survival was 92%, 3-year survival was 82%, 5-year survival was 76%, and 10-year survival was 54%. Missing data were imputed using the nonparametric missForest method. Boosted decision tree, support vector machine, Bayes point machine, and neural network models were developed for 5-year survival. These models were chosen as a result of their capability of predicting two outcomes based on prior work on machine-learning models for binary classification. The models were assessed by discrimination, calibration, and overall performance. The c-statistic is a measure of discrimination. It ranges from 0.5 to 1.0 with 1.0 being perfect discrimination and 0.5 that the model is no better than chance at making a prediction. The Brier score measures the squared difference between the predicted probability and the actual outcome. A Brier score of 0 indicates perfect prediction, whereas a Brier score of 1 indicates the poorest prediction. The Brier scores of the models are compared with the null model, which is calculated by assigning each patient a probability equal to the prevalence of the outcome.

RESULTS

Four models for 5-year survival were developed with c-statistics ranging from 0.846 to 0.868 and Brier scores ranging from 0.117 to 0.135 with a null model Brier score of 0.182. The Bayes point machine was incorporated into a freely available web-based application. This application can be accessed through https://sorg-apps.shinyapps.io/chondrosarcoma/.

CONCLUSIONS

Although caution is warranted, because the prediction model has not been validated yet, healthcare providers could use the online prediction tool in daily practice when survival prediction of patients with chondrosarcoma is desired. Future studies should seek to validate the developed prediction model.

LEVEL OF EVIDENCE

Level III, prognostic study.

The impact of biopsy sampling errors and the quality of surgical margins on local recurrence and survival in chondrosarcoma

Purpose

To examine the frequency of computed tomography (CT)-guided biopsy sampling errors in chondrosarcomas, as well as the impact of these errors and the achieved surgical margins on local recurrence-free survival (LRFS) and disease-specific survival (DSS).

Material and methods

A total of 68 consecutive patients treated for chondrosarcoma from 2000–2015 were retrospectively reviewed with a minimum follow-up duration of 2 years.

Results

The primary location was at the extremities in 46 patients (67.6%) and at the axial skeleton in 22 patients (32.4%). Seven patients underwent planned intralesional curettage. Surgical margins were assessed in the remaining 53 patients and included 21 wide (39.6%), 25 marginal (47.1%), and seven intralesional (13.2%) resections. Biopsy sampling errors occurred in ten patients (14.7%). LRFS was 82.2±7.8% at 5 years and 76.9±7.8% at 10 years. An intact anatomical barrier was associated with the most preferable LRFS of 89±10.5% after 10 years. DSS was 79.2±8.5% at 5 years and 75.5±6.4% at 10 years. The metric distance of the surgical margin and the presence of a biopsy sampling error did not affect either LRFS or DSS.

Conclusion

Even though histological grading in chondrosarcoma is difficult, sampling errors in preoperative biopsies are relatively rare and do not adversely affect outcomes. The presence of an anatomical barrier has a greater impact on LRFS than the metric distance of the surgical margins.

Prognostic factors for patients with chondrosarcoma: A survival analysis based on the Surveillance, Epidemiology, and End Results (SEER) database (1973-2012)

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First, it is a population-based study which can provide big sample size.

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Second, similar articles about chondrosarcoma using big data are lacking.

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Third, the relationship between treatment type and survival outcomes was analyzed in detail.

Current reports on prognostic factors for chondrosarcoma mainly involve patients in treatment centers. Few are based on multicenter or multi-eras. We analyzed existing data from the Surveillance, Epidemiology, and End Results (SEER) database to investigate the risk factors for survival outcomes. All patients with chondrosarcoma from 1973 to 2012 were identified. 3737 patients were eligible and included. In survival analysis, patient had good survival outcome if the patient was female, young, with localized stage, well grade, small tumor size, treated with surgery, while patient was male, old, with distant stage, undifferentiated grade, tumor size <50 mm, located in vertebral or pelvic bones, underwent radiation had bad survival outcome. Surgery types from having best survival outcomes to worst were local excision, radical excision, amputation, no surgery. ‘Well’ and ‘moderately’ grade seems to be suitable for local excision, but ‘poorly’ and ‘undifferentiated’ grade suitable for wide local excision. Multivariate COX regression analysis showed year of diagnosis, sex, age of diagnosis, stage, grade, tumor site, surgery, radiation were independent risk factors. Year of diagnosis, sex, age of diagnosis, stage, grade, tumor site, surgery, radiation were independent risk factors. Excision is a better treatment than amputation. Doctors can use wide local excision to treat chondrosarcoma, especially when encountering high grade chondrosarcoma or pelvic chondrosarcoma.

Chondrosarcoma: An overview of clinical behavior, molecular mechanisms mediated drug resistance and potential therapeutic targets

Sarcomas are known as a heterogeneous class of cancers arisen in the connective tissues and demonstrated various histological subtypes including both soft tissue and bone origin. Chondrosarcoma is one of the main types of bone sarcoma that shows a considerable deficiency in response to chemotherapy and radiotherapy. While conventional treatment based on surgery, chemo-and radiotherapy are used in this tumor, high rate of death especially among children and adolescents are reported. Due to high resistance to current conventional therapies in chondrosarcoma, there is an urgent requirement to recognize factors causing resistance and discover new strategies for optimal treatment. In the past decade, dysregulation of genes associated with tumor development and therapy resistance has been studied to find potential therapeutic targets to overcome resistance. In this review, clinical aspects of chondrosarcoma are summarized. Moreover, it gives a summary of gene dysregulation, mutation, histone modifications and non-coding RNAs associated with tumor development and therapeutic response modulation. Finally, the probable role of tumor microenvironment in chondrosarcoma drug resistance and targeted therapies as a promising molecular therapeutic approach are summarized.

Survival and prognostic factors in conventional central chondrosarcoma

BACKGROUND

Chondrosarcoma is the second most frequent primary malignant bone tumor. Treatment is mainly based on surgery. In general, wide resection is advocated at least in G2 and G3 tumors. But which margins should be achieved? Does localization as for example in the pelvis have a higher impact on survival than surgical margins themselves?

METHODS

From 1982 to 2014, 87 consecutive patients were treated by resection. The margin was defined as R0 (wide resection), R1 (marginal resection) or, R2 if the tumor was left intentionally. All patients were followed for evidence of local recurrence or distant metastasis. Overall and recurrence-free survival were calculated, significance analysis was performed.

RESULTS

In 54 (62%) cases a R0 resection, in 31 (36%) a R1 and in 2 (2%) patients a R2-resection was achieved. Histology proved to be G1 in 37 patients (43%), G2 in 41 (47%) and G3 in 9 cases (10%). 5-year local recurrence-free survival (LRFS) was 75%. Local recurrence-free survival showed a significant association with the margin status and the localization of the tumor with pelvic lesions doing worst. Metastatic disease was initially seen in 4 patients (4.6%), 19 others developed metastatic disease during follow-up. Overall survival of the entire group at 5 and 10 years were 79 and 75%, respectively. The quality of surgical margins and the presence of local recurrence did not influence overall survival in a multivariate analysis. Pelvic lesions had a worse prognosis as did higher grades of the tumor, metastatic disease and age.

CONCLUSIONS

The mainstay of therapy in Chondrosarcoma remains surgery. Risk factors as grading, metastatic disease, age and location significantly influence overall survival. Margin status (R0 vs. R1) did influence local recurrence-free survival but not overall survival. Chondrosarcomas of the pelvis have a higher risk of local recurrence and should be treated more aggressively.

Staging of Bone and Soft-tissue Sarcomas

The purpose of staging in orthopaedic oncology is to provide a framework for classifying tumors based on their risk of local recurrence and distant metastasis to guide treatment decisions. Two separate systems are commonly used to categorize bone and soft-tissue sarcomas. The Musculoskeletal Tumor Society system for bone sarcomas and the Enneking system for soft-tissue sarcomas are the original staging systems developed by orthopaedic surgeons. The American Joint Committee on Cancer staging systems for bone and soft-tissue sarcomas are periodically updated based on new data, and they are currently on their eighth edition.