Postmetastasis survival in high-grade extremity osteosarcoma: A retrospective analysis of prognostic factors in 126 patients

Preoperative prediction of high-grade osteosarcoma response to neoadjuvant therapy based on a plain CT radiomics model: A dual-center study

Objective

To develop a model combining clinical and radiomics features from CT scans for a preoperative noninvasive evaluation of Huvos grading of neoadjuvant chemotherapy in patients with HOS.

Methods

183 patients from center A and 42 from center B were categorized into training and validation sets. Features derived from radiomics were obtained from unenhanced CT scans.Following dimensionality reduction, the most optimal features were selected and utilized in creating a radiomics model through logistic regression analysis. Integrating clinical features, a composite clinical radiomics model was developed, and a nomogram was constructed. Predictive performance of the model was evaluated using ROC curves and calibration curves. Additionally, decision curve analysis was conducted to assess practical utility of nomogram in clinical settings.

Results

LASSO LR analysis was performed, and finally, three selected image omics features were obtained.Radiomics model yielded AUC values with a good diagnostic effect for both patient sets (AUCs: 0.69 and 0.68, respectively). Clinical models (including sex, age, pre-chemotherapy ALP and LDH levels, new lung metastases within 1 year after surgery, and incidence) performed well in terms of Huvos grade prediction, with an AUC of 0.74 for training set. The AUC for independent validation set stood at 0.70. Notably, the amalgamation of radiomics and clinical features exhibited commendable predictive prowess in training set, registering an AUC of 0.78. This robust performance was subsequently validated in the independent validation set, where the AUC remained high at 0.75. Calibration curves of nomogram showed that the predictions were in good agreement with actual observations.

Conclusion

Combined model can be used for Huvos grading in patients with HOS after preoperative chemotherapy, which is helpful for adjuvant treatment decisions.

Japanese orthopaedic association (JOA) clinical practice guidelines on the management of malignant bone tumors - Secondary publication

BACKGROUND

In Japan, there are currently no general guidelines for the treatment of primary malignant bone tumors. Therefore, the Japanese Orthopaedic Association established a committee to develop guidelines for the appropriate diagnosis and treatment of primary malignant bone tumors for medical professionals in clinical practice.

METHODS

The guidelines were developed in accordance with "Minds Clinical Practice Guideline Development Handbook 2014″ and "Minds Clinical Practice Guideline Development Manual 2017". The Japanese Orthopaedic Association's Bone and Soft Tissue Tumor Committee established guideline development and systematic review committees, drawing members from orthopedic specialists leading the diagnosis and treatment of bone and soft tissue tumors. Pediatricians, radiologists, and diagnostic pathologists were added to both committees because of the importance of multidisciplinary treatment. Based on the diagnosis and treatment algorithm for primary malignant bone tumors, important decision-making points were selected, and clinical questions (CQ) were determined. The strength of recommendation was rated on two levels and the strength of evidence was rated on four levels. The recommendations published were selected based on agreement by 70% or more of the voters.

RESULTS

The guideline development committee examined the important clinical issues in the clinical algorithm and selected 22 CQs. The systematic review committee reviewed the evidence concerning each CQ and a clinical value judgment was added by experts. Eventually, 25 questions were published and the text of each recommendation was determined.

CONCLUSION

Since primary malignant bone tumors are rare, there is a dearth of strong evidence based on randomized controlled trials, and recommendations cannot be applied to all the patients. In clinical practice, appropriate treatment of patients with primary malignant bone tumors should be based on the histopathological diagnosis and degree of progression of each case, using these guidelines as a reference.

Prognostic Impact of Pulmonary Metastasectomy in Bone Sarcoma Patients: A Retrospective, Single-Centre Study

This retrospective study aimed at analyzing the impact of metastasectomy on post-metastasis survival (PMS) in bone sarcoma patients with lung metastases. Altogether, 47 bone sarcoma patients (24 males, median age at diagnosis of lung metastases: 21.8 (IQR: 15.6–47.3) years) with primary (n = 8) or secondary (n = 39) lung metastases treated at a single university hospital were retrospectively included. Based on a propensity score, inverse probability of treatment weight (IPTW) was calculated to account for selection bias whether patients had undergone metastasectomy or not. The most common underlying histology was osteosarcoma (n = 37; 78.7%). Metastasectomy was performed in 39 patients (83.0%). Younger patients (p = 0.025) with singular (p = 0.043) and unilateral lesions (p = 0.024), as well as those with an interval ≥ 9 months from primary diagnosis to development of lung metastases (p = 0.024) were more likely to undergo metastasectomy. Weighted 1- and 3-year PMS after metastasectomy was 80.8% and 58.3%, compared to 88.5% and 9.1% for patients who did not undergo metastasectomy. Naive Cox-regression analysis demonstrated a significantly prolonged PMS for patients with metastasectomy (HR: 0.142; 95%CI: 0.045–0.450; p = 0.001), which was confirmed after IPTW-weighting (HR: 0.279; 95%CI: 0.118–0.662; p = 0.004), irrespective of age, time to metastasis, and the number of lesions. In conclusion, metastasectomy should be considered in bone sarcoma patients with lung metastases, after carefully considering the individual risks, to possibly improve PMS.

DPY30 promotes the growth and survival of osteosarcoma cell by regulating the PI3K/AKT signal pathway

Osteosarcoma (OS) is characterized by aggressive features including invasiveness and high incidence of metastasis. OS patients with metastases are difficult to treat and suffer from a poor prognosis. DPY30 (protein dpy-30 homolog) is a key component of SET1/MLL family of H3K4 methyltransferases, which is implicated in the progression of multiple cancers. However, the potential functional engagement of DPY30 in OS remains to be unveiled. The objective of this study is to investigate the potential roles of DPY30 in the regulation of malignant phenotypes of OS cells. We examined DPY30 expression from a published dataset (GSE28424) as well as in OS tissues and adjacent normal tissues from OS patients. The association of DPY30 expression level and clinicopathologic parameters was assessed by Chi-square test. The role of DPY30 in regulating the malignant phenotype of OS cells and tumorigenesis was examined by in vitro functional assays and xenograft mouse model. We reported an upregulation of DPY30 in OS tumor tissues in both published dataset and clinical samples. A high level of DPY30 expression was associated with larger tumor size and more metastasis in OS patients, as well as poor overall survival. DPY30 knockdown in OS cells significantly impairs proliferation, migration and invasion, but induced cellular apoptosis. We further demonstrated that the agonist of PI3K/AKT pathway can rescue the inhibitory effects of DPY30 knockdown in OS cells. Together, our data indicate that DPY30 functions as an oncogene to promote the malignancy of OS cells possibly through PI3K/AKT pathway. The dependency of OS cells on DPY30 overexpression is a targetable vulnerability in OS cells.

Analysis of Clinical Manifestations and Prognostic Factors Affecting Osteosarcoma

Objective

This study is aimed at exploring the clinical manifestations and prognostic factors of osteosarcoma.

Methods

The clinical data of patients with osteosarcoma who were treated in our hospital from January 2018 to March 2020 were selected for retrospective analysis. The general information of the patients, including age, gender, tumor diameter, tumor location, tumor type, surgical method, and Enneking stage, distant disease metastasis, KPS score, and the number of postoperative adjuvant chemotherapy, were grouped by prognosis for statistical analysis. The clinical characteristics, morbidity and mortality, and prognostic factors of patients were statistically analyzed.

Results

Among the 83 patients in this group, there were 52 males and 31 females, 59 tumors > 10 cm in diameter and 24 tumors < 10 cm in diameter, 16 tumors in the upper limbs and 67 tumors in the lower limbs, 25 tumors in osteoblastoma, 16 tumors in chondroblastoma, 42 tumors in fibroblastoma, 62 tumors in stage II, and 21 tumors in stage III of Enneking stage, 10 tumors in distant metastasis, and 10 tumors in distant metastasis. The death rate of this group was 19.28% (16/83). Multifactor regression analysis confirmed that the Enneking stage III, distant metastasis, KPS score < 70, and the number of postoperative adjuvant chemotherapy < 6 were important factors influencing the death of osteosarcoma (P < 0.05).

Conclusion

Enneking stage III, distant metastasis, KPS score < 70, and the number of postoperative adjuvant chemotherapy < 6 are important influencing factors of osteosarcoma death. Clinical practice can take corresponding preventive and control measures according to the existence of these factors to ensure a good prognosis.

Surgery Has Positive Effects on Spinal Osteosarcoma Prognosis: A Population-Based Database Study

OBJECTIVE

The treatment of osteosarcoma of the spine remains controversial. Our aim was to explore the treatment of patients with spinal osteosarcoma.

METHODS

We analyzed the data from 727 spinal osteosarcoma patients from the Surveillance, Epidemiology, and End Results database from 1973 to 2015. X-tile software was used to find the optimal cutoff values for age and economic income. The Kaplan-Meier estimator method was used to analyze overall survival and cancer-specific survival. Univariate and multivariate Cox analyses were used to identify the independent prognostic factors. Propensity score matching was used to reduce the possibility of selection bias. A logistic regression model was used to clarify the relevant factors affecting a patient's decision to undergo surgery.

RESULTS

Among 727 eligible spinal osteosarcoma patients, 370 (50.9%) had undergone surgery and 357 (49.1%) had not undergone surgery. Significant differences were found in the effects of patient age at diagnosis, Surveillance, Epidemiology, and End Results historical stage, and tumor grade on the patients' decision to undergo surgery (P < 0.05). Surgery was an independent prognostic factor for overall survival and cancer-specific survival of patients with spinal osteosarcoma. The same results were found after 1:1 propensity score matching. The surgery group had more favorable survival compared with the nonsurgery group.

CONCLUSIONS

Surgery can provide survival benefits for patients with osteosarcoma of the spine. The patients with spinal osteosarcoma who had undergone surgery experienced favorable survival benefits. Thus, surgery can be a suitable treatment for patients with spinal osteosarcoma.

Synchronous lung and multiple soft tissue metastases developed from osteosarcoma of tibia: a rare case report and genetic profile analysis

Background

Osteosarcoma is the most common primary malignant bone tumor with a highly metastatic propensity in children and young adolescents. The majority of metastases develope in the lung, while metastases to the extrapulmonary locations have rarely been discussed, especially in skeletal muscle.

Case presentation

We reported a young patient with pathologically diagnosed osteosarcoma of the right tibia who was initially treated with standard chemotherapy and complete surgical resection. However, pulmonary metastases and multiple soft tissue masses in skeletal muscle developed four years after the index surgical resection. Subsequently, a targeted next-generation sequencing assay based on an 806 oncogenes and tumor suppressor genes panel was performed to analyze genetic alterations in this patient with rare metastatic pattern. The genetic analysis revealed canonical somatic mutations of RB1 and germline variants of ALK (c.862 T > C), BLM (c.1021C > T), PTCH1 (c.152_154del), MSH2 (c.14C > A), RAD51C (c.635G > A). Using silico prediction programs, the germline variants of the MSH2 and RAD51C were predicted as “Possibly Damaging” by Polymorphism Phenotyping v2 (PolyPhen-2) and “Tolerated” by Sorting Intolerant from Tolerant (SIFT); BLM was classified as “Tolerated”, while the germline variant of ALK was predicted to be pathogenic by both PolyPhen-2 and SIFT.

Conclusions

Osteosarcoma with extrapulmonary metastases is rare, especially located in the skeletal muscle, which predicts a worse clinical outcome compared with lung-only metastases. The several novel variants of ALK, BLM, PTCH1 in this patient might expand the mutational spectrums of the osteosarcoma. All the results may contribute to a better understanding of the clinical course and genetic characteristics of osteosarcoma patients with metastasis.

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.

Treatment of 120 adult osteosarcoma patients with metachronous and synchronous metastases: A retrospective series of the French Sarcoma Group

Treatment options for metastatic osteosarcomas are scarce. Following failure of standard first line therapy, patients who relapse present a challenging treatment dilemma, and have a poor prognosis. Surgical removal of all metastases is essential. A retrospective analysis of patients with metastatic osteosarcomas was conducted in 15 French Sarcoma Group centers. From January 2009 to December 2018, we identified 120 adult patients; 36 with synchronous and 84 with metachronous metastases with 74 males and 46 females. Mean age was 30 years (18-53). Metastatic sites were lung, bone and other in 91, 11 and 24 patients, respectively. Mean time to first metachronous metastases was 22 months (4-97). All patients except 13 (10.8%) with metachronous metastases received a first line systemic treatment for relapse, and 39 patients (32.5%) were included in a clinical trial. Eighty-one patients (67.5%) had local treatment of distant metastases. Median progression free survival (PFS) and overall survival (OS) were 5.5 (95% CI 4.6-6.4) and 20.5 months (95% CI 13.2-27.7) respectively for the overall group. In multivariate analysis, more than five metastases, time to first metastases <24 months, were statistically significant negative prognostic factors for OS and PFS (P = .002, ≤.001 and P = .006, ≤.001, respectively). Surgery of metastases was associated with better prognosis on OS and PFS (P = .001 and .037, respectively). The presence of bone metastases was a negative prognostic factor on OS but not on PFS (P = .021). In reference sarcoma centers, relapsed osteosarcoma patients with more than one metastasis commonly receive more than one line of systemic therapy, and are included in clinical trial if available.

Prognostic factors of chondroblastic osteosarcoma and nomogram development for prediction: A population-based, STROBE-compliant study

The present study aimed to develop nomograms to predict survival in patients with chondroblastic osteosarcoma (COS).An analysis was conducted of 320 cases of COS collected from the surveillance, epidemiology, and end results (SEER) database between 2004 and 2015. Independent prognostic factors were screened using univariate and multivariate Cox analyses. Subsequently, nomograms were established to predict the patients' cancer-specific survival (CSS) and overall survival (OS) rates. The prediction accuracy and discriminative ability of the nomograms were examined using calibration curves and the concordance index (C-index).As revealed in the univariate and multivariate Cox regression analysis, age, tumor size, the primary site, the presence of metastasis, a history of having undergone surgery, and a history of having received radiotherapy were found to be independent prognostic factors associated with survival in patients with COS (all P < .05). Furthermore, age >39 years, the presence of distant metastasis, no history of having undergone any surgery, and tumor size >103 mm were found to be associated with poor prognosis in patients, while the primary site of the mandible and no history of having undergone radiotherapy showed associations with a more favorable prognosis in patients. Next, nomograms were constructed to predict the OS and CSS in patients with COS.We constructed nomograms that can provide accurate survival predictions in patients with chondroblastic osteosarcoma. These nomograms can help surgeons customize the treatment strategies for patients with chondroblastic osteosarcoma.

Predictive model for the 5-year survival status of osteosarcoma patients based on the SEER database and XGBoost algorithm

Osteosarcoma is the most common bone malignancy, with the highest incidence in children and adolescents. Survival rate prediction is important for improving prognosis and planning therapy. However, there is still no prediction model with a high accuracy rate for osteosarcoma. Therefore, we aimed to construct an artificial intelligence (AI) model for predicting the 5-year survival of osteosarcoma patients by using extreme gradient boosting (XGBoost), a large-scale machine-learning algorithm. We identified cases of osteosarcoma in the Surveillance, Epidemiology, and End Results (SEER) Research Database and excluded substandard samples. The study population was 835 and was divided into the training set (n = 668) and validation set (n = 167). Characteristics selected via survival analyses were used to construct the model. Receiver operating characteristic (ROC) curve and decision curve analyses were performed to evaluate the prediction. The accuracy of the prediction model was excellent both in the training set (area under the ROC curve [AUC] = 0.977) and the validation set (AUC = 0.911). Decision curve analyses proved the model could be used to support clinical decisions. XGBoost is an effective algorithm for predicting 5-year survival of osteosarcoma patients. Our prediction model had excellent accuracy and is therefore useful in clinical settings.

Direct conversion of osteosarcoma to adipocytes by targeting TNIK

Osteosarcoma (OS) is an aggressive mesenchymal tumor for which no molecularly targeted therapies are available. We have previously identified TRAF2- and NCK-interacting protein kinase (TNIK) as an essential factor for the transactivation of Wnt signal target genes and shown that its inhibition leads to eradication of colorectal cancer stem cells. The involvement of Wnt signaling in the pathogenesis of OS has been implicated. The aim of the present study was to examine the potential of TNIK as a therapeutic target in OS. RNA interference or pharmacological inhibition of TNIK suppressed the proliferation of OS cells. Transcriptome analysis suggested that a small-molecule inhibitor of TNIK upregulated the expression of genes involved in OS cell metabolism and downregulated transcription factors essential for maintaining the stem cell phenotype. Metabolome analysis revealed that this TNIK inhibitor redirected the metabolic network from carbon flux toward lipid accumulation in OS cells. Using in vitro and in vivo OS models, we confirmed that TNIK inhibition abrogated the OS stem cell phenotype, simultaneously driving conversion of OS cells to adipocyte-like cells through induction of PPARγ. In relation to potential therapeutic targeting in clinical practice, TNIK was confirmed to be in an active state in OS cell lines and clinical specimens. From these findings, we conclude that TNIK is applicable as a potential target for treatment of OS, affecting cell fate determination.

Incidence and prognosis of distant metastasis in malignant peripheral nerve sheath tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are a type of soft tissue sarcomas (STS) with recurrence and metastatic potential. We aimed to investigate the risk factors for developing distant metastases (DM) and to identify the prognostic factors in patients with DM.

METHODS

Based on the Surveillance, Epidemiology, and End Result (SEER) database, MPNST patients diagnosed between 2010 and 2016 were extracted in our study. The logistic regression model was performed for predicting DM development while the Cox proportional hazard regression model was conducted for revealing the prognostic factors.

RESULTS

Eventually, 764 patients diagnosed with MPNSTs were included with 109 cases presenting with metastases at initial diagnosis. Larger tumor size and lymph node metastases were independent risk factors for developing DM. The median overall survival (OS) for patients with metastases was 8.0 (95% CI: 6.1-9.9) months. Multiple metastatic sites and no surgical treatment were prognostic factors for worse survival. Tumors located in non-head and neck region were related with better survival.

CONCLUSIONS

The incidence of DM was 14.3% with a dismal median OS of 8.0 months for metastatic MPNSTs. More evaluation should be applied for patients with large tumor size and lymph metastases. Tumors located in head and neck region and the presence of multiple metastases predicted worse survival outcome. Surgical treatment can significantly improve the survival of MPNST patients with distant metastasis.

Homogenous and Heterogenous Prognostic Factors for Patients with Bone Sarcoma

Objective

The aim of this study was to examine the survival rate of patients with different bone sarcomas and to investigate homogenous and heterogenous prognostic factors for different types of bone sarcomas.

Methods

This is a retrospective analysis of records from the Surveillance, Epidemiology, and End Result (SEER) database. Clear information on the distant metastasis of cancer is provided in the SEER database for patients diagnosed between January 2010 and December 2016. Data for the four types of malignant bone sarcomas were extracted, including osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma. Patients with bone sarcomas originated from other sites, diagnosed at autopsy, or indicated in death certification were excluded. The overall survival was calculated for the entire cohort and across different bone sarcomas using the Kaplan–Meier method. A subgroup analysis of the different survival rates of four types of bone sarcomas in various levels of each variable was conducted and the differences were tested with the log‐rank test. Cox proportional hazard regression analysis was performed to determine the prognostic factors. Variables with P < 0.05 in the univariate Cox regression analysis were further analyzed using a multivariate Cox regression analysis. The prognostic factors in four groups of bone sarcomas were compared to determine the homogenous and heterogenous factors.

Results

A total of 4732 patients were included with a follow up of 25 (0–83) months. The mean age of patients was 39.7 ± 24.1 years. The 1‐year, 3‐year, and 5‐year overall survival rate for the entire cohort was 86.2% (95% confidence interval [CI]: 85.2%–87.2%), 70.5% (95% CI: 68.9%–72.1%), and 63.0% (95% CI: 61.2%–64.8%), respectively. Factors including age older than 40 years, higher grade, regional and distant stage, tumor in the extremities, T2 stage, bone and lung metastases, and non‐surgery were significantly associated with the poor survival of the entire cohort. The mean overall survival duration of patients with chordoma, chondrosarcoma, Ewing sarcoma, and osteosarcoma was 66.86 (95% CI: 64.06–69.66), 63.53 (95% CI: 61.81–65.25), 58.06 (95% CI: 55.49–60.62) and 54.91 (95% CI: 53.14–56.69) months, respectively. Compared with chordoma, the hazard ratio (HR) and 95% CI for patients with chondrosarcoma, Ewing sarcoma, and osteosarcoma were 1.30 (95% CI: 1.04–1.62; P = 0.023), 1.69 (95% CI: 1.33–2.14; P < 0.001), and 2.00 (95% CI: 1.61–2.48; P <0.001), respectively. Different bone sarcomas showed homogenous and heterogenous prognostic factors.

Conclusion

Different clinicopathological characteristics and prognoses were revealed in patients with osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma. The risk factors can potentially guide prognostic prediction and sarcoma‐specific treatment.

Nomograms for predicting overall survival and cancer-specific survival of chondroblastic osteosarcoma patients

BACKGROUND

The establishment of precise and personalized prediction systems for chondroblastic osteosarcoma patients is important for guiding the treatment.

METHODS

The univariate logrank test and multivariate Cox regression analysis were performed to identify independent prognostic factors for overall survival (OS) and cancer-specific survival (CSS). Nomograms were constructed to estimate the OS and CSS based on these factors. Internal and external validation was performed. The predictive power of the nomograms was determined by C-index and calibration plots.

RESULTS

A total of 401 chondroblastic osteosarcoma cases were identified. Univariate and multivariate analysis revealed that age at diagnosis, histological grade, tumor size, Surveillance, Epidemiology, and End Results stage, and surgical resection were independent prognostic factors for OS and CSS. The five factors were incorporated to construct the nomograms for estimating the 3- and 5-year OS and CSS. The C-index values for the internal validation of the OS and CSS nomogram were 0.732 and 0.746, respectively, and for the external validation were 0.780 and 0.808, respectively. The calibration curves revealed that the predicted OS and CSS could well match the actual survival rate.

CONCLUSIONS

The nomograms for predicting 3- and 5-year OS and CSS were constructed and were proved to be accurate and reliable by the internal and external validation.

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.

Evaluating and Predicting the Probability of Death in Patients with Non-Metastatic Osteosarcoma: A Population-Based Study

BACKGROUND Osteosarcoma is one of the most common bone tumors, with strong local aggressiveness and early metastasis. The aim of this study was to describe the epidemiological data and evaluate the prognostic factors for overall survival (OS) and cause-specific survival (CSS) in patients with non-metastatic osteosarcoma. MATERIAL AND METHODS Patients histologically diagnosed with non-metastatic osteosarcoma between 2005 and 2014 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Survival analysis, machine learning, and Lasso regression were used to identify the prognostic factors for OS and CSS, and the accuracy of the nomograms was tested and compared with the American Joint Committee on Cancer (AJCC) staging systems. RESULTS The entire cohort comprised 1000 patients with non-metastatic osteosarcoma. The multivariable analysis suggested that age, tumor size, grade, and American Joint Committee on Cancer (AJCC) T staging were independent prognostic factors for OS and CSS. Additionally, the nomograms based on these results could better predict probability of OS (Internal validation C-index, 0.7095) and CSS (0.7100) compared with the sixth (OS: 0.613; CSS: 0.628) and seventh edition AJCC staging systems (0.602, 0.613). CONCLUSIONS Relatively young age and low histopathological grade were favorable factors for both OS and CSS. Nomograms based on multivariable models worked well in predicting the probability of death for patients with non-metastatic osteosarcoma.

12b80 - Hydroxybisphosphonate Linked Doxorubicin: Bone Targeted Strategy for Treatment of Osteosarcoma

To reply to as yet unmet medical needs to treat osteosarcoma, a form of primary bone cancer, we conceived the 12b80 compound by covalently conjugating antineoplastic compound doxorubicin to a bone targeting hydroxybisphosphonate vector and turned it into a prodrug through a custom linker designed to specifically trigger doxorubicin release in acidic bone tumor microenvironment. Synthesis of 12b80 was thoroughly optimized to be produced at gram scale. 12b80 was evaluated in vitro for high bone support affinity, specific release of doxorubicin in acidic condition, lower cytotoxicity, and cellular uptake of the prodrug. In vivo in rodents, 12b80 displayed rapid and sustained targeting of bone tissue and tumor-associated heterotopic bone and permitted a higher doxorubicin payload in tumor bone environment compared to nonvectorized doxorubicin. Consequently, 12b80 showed much lower toxicity compared to doxorubicin, promoted strong antitumor effects on rodent orthotopic osteosarcoma, displayed a dose-response therapeutic effect, and was more potent than doxorubicin/zoledronate combination.