Aims:Surgical management of intermediate and malignant tumours in the pelvis is complex. Complications are frequent and either related to the surgery itself or to post-surgical failure of the reconstruction technique. This systematic review and meta-analysis aims at analyzing all reported complications following PI to PIII pelvic resections for intermediate and malignant tumours. Methods:Based on a systematic literature search on PubMed adhering to the PRISMA guidelines, 1,683 study records were identified, of which we included 90 original studies published until 22 July 2025. Overall complication rates were assessed with random-effects meta-analysis. Differences in complication rates between reconstruction types (i.e. megaprosthetic, mostly biological, none) were evaluated with meta regression analysis. Results:Data on 2,199 patients (1,250 males (57%)) with mainly PI to PIII pelvic resections were analyzed. The most common reconstruction types were custom-made implants (21%; n = 451) and ice-cream cone prostheses (14%; n = 312). Pooled rates of infections, wound healing problems, nerve injuries, and deep vein thrombosis (DVT) amounted to 15% (95% CI 12% to 18%), 13% (95% CI 10% to 15%), 7% (95% CI 5% to 9%), and 4% (95% CI 2% to 6%), respectively. Further, pooled implant revision/removal and secondary external hemipelvectomy rates were 14% (95% CI 11% to 17%) and 4% (95% CI 3% to 5%). Mostly biological reconstructions were associated with higher rates of nerve injuries (p < 0.001), construct failures (p = 0.010), and secondary implant revision/removal (p = 0.003) compared to megaprosthetic reconstruction. Further, biological reconstructions were associated with increased secondary external hemipelvectomy rates compared to megaprosthetic reconstructions (p = 0.005) or no reconstructions (p = 0.001). Conclusion:Treatment of pelvic malignancies is challenging, with technically demanding resections and complex reconstructions. Across all reconstruction techniques following sacrum-sparing pelvic resections, infections and wound healing problems are the most common complications, yet there is also a considerable proportion of patients with neurovascular complications and DVTs.

Background:Survival prediction in metastatic long-bone disease is essential for surgical decision-making, yet the performance of legacy prognostic models has declined in the era of immunotherapy and molecularly targeted agents. As these systemic therapies become routine, treatment patterns themselves may influence survival in ways not captured by earlier models. We, therefore, quantified preoperative systemic therapy use over the last decade and evaluated its association with postoperative overall survival in patients undergoing surgery for long-bone metastases. Methods:We conducted a retrospective cohort study of 975 consecutive adults who underwent surgery for long-bone metastases at two affiliated tertiary centers between January 2010 and June 2022. Preoperative systemic therapy was categorized into four groups: chemotherapy only, targeted therapy only, combined chemotherapy and targeted therapy, or neither. Postoperative was defined as time from surgery to death from any cause. We described temporal uptake of therapies by calendar year and assessed associations with postoperative survival using multivariable Cox regression adjusting for demographics, ECOG performance status, Katagiri primary tumor grouping, visceral/brain metastases, and laboratory variables. Adjusted survival over calendar time was summarized via marginal standardization at fixed horizons (1, 3, 12, and 24 months). Results:Use of targeted agents including checkpoint inhibitors rose markedly, from 2% in 2015 to 43% in 2022. In multivariable Cox models, preoperative chemotherapy alone was associated with worse survival versus no preoperative systemic therapy (HR 1.41, 95% CI 1.21-1.65; p < 0.01), as was combined chemotherapy plus targeted therapy (HR 1.24, 95% CI 1.05-1.47; p = 0.01). In contrast, targeted therapy alone before surgery was associated with better survival (HR 0.76, 95% CI 0.58-0.99; p = 0.04). Adjusted survival appeared to increase modestly across calendar years, but the pre-specified joint Wald test for the calendar year spline terms was not significant (p = 0.17), indicating a non-significant trend over time. Conclusion:This study found that preoperative systemic therapy patterns are strongly associated with post-operative survival in metastatic long-bone disease: targeted therapy alone correlates with improved survival whereas preoperative use of chemotherapy-alone or combined with targeted agents-was associated with worse survival. These findings support incorporating contemporary treatment exposure into prognostic models and suggest that model recalibration to the immunotherapy era may be warranted.

Aims:The aim of this study was to achieve consensus on important topics related to tenosynovial giant cell tumour (TGCT) and giant cell tumour of bone (GCTB), and to identify areas for future research. Methods:In January 2026, a consensus meeting, The Birmingham Orthopaedic Oncology Meeting (BOOM), held in Cape Town, South Africa, gathered 314 delegates from 59 countries to debate 21 consensus statements on tenosynovial giant cell tumour (TGCT) and giant cell tumour of bone (GCTB) through a modified Delphi process. Results:Of the 21 statements, two achieved unanimous consensus, 18 strong consensus, and one moderate consensus. Unanimous consensus was reached for prioritizing joint-preserving intralesional curettage in GCTB when feasible, and for supporting non-surgical approaches in anatomically challenging cases, particularly sacral lesions. The statement addressing the role of denosumab in GCTB achieved only moderate consensus. The use of adjuvants in GCTB, as well as the management of recurrent and systemic GCTB, including long-term use of denosumab, reached strong consensus. Strong consensus was achieved in the surgical and non-surgical management for both primary and recurrent TGCT. Surveillance strategies for both TGCT and GCTB generated substantial discussion despite strong consensus, reflecting ongoing uncertainty and lack in evidence. Conclusion:This international consensus provides practical guidance for the management of TGCT and GCTB while identifying important gaps in evidence. Joint-preserving surgery remains central to the treatment of GCTB, with selective integration of systemic therapies and individualized surveillance. The consensus framework highlights priorities for future collaborative research in orthopaedic oncology.

BACKGROUND:Primary pelvic bone sarcomas in children are rare and associated with poor outcomes, but large-volume, multicenter data are lacking. QUESTIONS/PURPOSES:We asked: What is the overall survival of pediatric patients with primary pelvic bone sarcomas following surgical treatment? What are the rates of local recurrence and postoperative complications? Which factors are associated with these outcomes? METHODS:We retrospectively reviewed 119 patients younger than 16 years treated surgically for primary pelvic sarcoma at five referral centers between 1990 and 2023. Survival was estimated with Kaplan-Meier methods, and recurrence and complications with competing risk models. Prognostic factors were analyzed with Cox regression. RESULTS:Estimated survival was 59% at 5-years and 55% at 10-years. Local recurrence occurred in 19% of patients, most within 2 years. Positive margins and poor response to chemotherapy were associated with worse survival and recurrence (p < 0.01), while radiotherapy showed a non-significant trend toward reduced recurrence (p = 0.054). Complications developed in 47% of patients at 5-years, most often wound dehiscence and deep infections. Reconstruction was not significantly associated with complications (p = 0.379). CONCLUSION:Pediatric pelvic sarcomas remain challenging, with poor long-term survival, high recurrence, and frequent complications. Negative margins and good chemotherapy response are the most important prognostic factors. Radiotherapy, particularly in the preoperative setting, may have an expanding role when clear wide margins are not achievable. Multicenter collaboration is essential to optimize treatment strategies and improve outcomes in rare diseases like pelvic bone sarcomas in the pediatric population. LEVEL OF EVIDENCE:Type 3 multicentric study.

Aims:The aim of this study was to achieve consensus for important topics related to periprosthetic infection (PJI) in orthopaedic oncology, and to identify areas for future research. Methods:In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) held in Birmingham, UK, gathered 309 delegates from 53 countries to debate 20 consensus statements on PJI in orthopaedic oncology using a modified Delphi process. Results:Of 20 questions and statements on PJI in orthopaedic oncology, none achieved unanimous consensus, 18 achieved strong consensus, one achieved moderate consensus, and one achieved weak consensus. The statements that reached consensus with notable agreement were on the prophylaxis of infection, management of leaking wounds, and surgical strategies for the treatment of PJI. Short-duration antibiotic prophylaxis was deemed as effective as longer courses for lower-risk reconstructions, and aggressive management was recommended for wounds draining beyond five to seven days to prevent deep infection. Furthermore, single-stage, two-stage, and 1.5-stage revision were recognized as valid strategies, with two-stage revision remaining the most reliable. The statements that did not achieve consensus were on the role of debridement, antibiotics, and implant retention and prolonged antibiotic use post-revision. Conclusion:The BOOM meeting achieved consensus for important topics on periprosthetic infection in orthopaedic oncology, but highlighted the low quality of the underlying evidence. This study has provided recommendations for the treatment of leaky wounds, duration of postoperative antibiotic prophylaxis, and choice of revision strategy.

BACKGROUND CONTEXT:Osteosarcoma of the mobile spine is a rare and complex condition, with limited case series informing treatment decisions. Recent advancements in treatment paradigms, particularly in en bloc resection and novel radiation techniques, may incite new treatment guidelines and improve patient outcomes. The clinical outcomes of patients treated for osteosarcoma of the mobile spine at our institution were reported over a decade ago, and this study provides an updated assessment of management strategies and patient outcomes since the initial publication. PURPOSE:To provide an updated analysis of clinical results for the treatment of mobile spine osteosarcoma. STUDY DESIGN/SETTING:Retrospective cohort study. PATIENT SAMPLE:A total of 32 patients treated at a single center for osteosarcoma of the spine over 22 years. OUTCOME MEASURES:Estimation of overall patient survival, local recurrence, and the presence of metastatic disease. METHODS:Inclusion criteria were adult patients treated for osteosarcoma originating in the vertebral column with the exclusion of the sacrum at Massachusetts General Hospital between 2001 and 2023. The overall survival was evaluated using the Kaplan-Meier method, grouped by type of resection (en bloc versus intralesional) and histological subtype (osteoblastic, chondroblastic, other/unknown). Prognostic factors were assessed using Cox proportional hazards modeling. RESULTS:A total of 22 of the 32 patients were given en bloc resection, while 10 received piecemeal resection. We found higher overall survival with en bloc resection compared to intralesional resection (median survival 81.54 months versus 12.42 months, p=.006) using Kaplan-Meier analysis techniques. However, in multivariable regression, neither en bloc resection nor histological subtype were predictive of better outcomes. Resection of greater than one level and younger age were associated with poor survival (p<.05). CONCLUSIONS:This study highlights the continued challenges for patients with spinal osteosarcoma despite advances in surgical techniques and radiation modalities. If feasible, en bloc resection yields improved overall survival compared to intralesional resection, but the 5-year mortality rate remains high. Histological subtype did not significantly predict outcomes, while tumors involving multiple vertebral levels and younger age were associated with worse survival.

Aims:Following resection of a primary bone tumour, reconstruction is commonly performed using either a megaprosthesis or biological reconstruction. Periprosthetic joint infection (PJI) remains one of the most frequent complications. Various treatment strategies exist for PJI, including debridement, antibiotics, and implant retention (DAIR), and single- and two-stage revision, although consensus on optimal management remains elusive. This study aimed to investigate the global practices regarding DAIR in tumour cases through an electronic survey among orthopaedic oncology surgeons. Methods:A global cross-sectional observational survey study was distributed to 272 orthopaedic oncology surgeons who attended the BOOM Consensus Meeting in January 2024. The survey contained 19 multiple choice questions focusing on DAIR practices. Responses were collected anonymously and analyzed using descriptive statistics. Results:The survey was completed by 173/272 surgeons (64%) from 44 countries. While 62% (169/272) routinely performed radical soft-tissue debridement in DAIR, only 39% exchanged all modular components, indicating variability in surgical approaches. DAIR was more commonly performed in acute rather than chronic infections, with 55% finding it very useful in acute cases. The use of local antibiotic delivery was supported by 56%, although only 49% found antibiotic cement coatings beneficial. Systemic antibiotic duration post-DAIR varied, with 39% favouring six weeks and 35% preferring three months. Conclusion:The study highlights global inconsistencies in DAIR practices for PJI in orthopaedic oncology, with financial disparities impacting modular component exchange. Standardized definitions are lacking, and we propose that if only polyethylene is changed, then the procedure is referred to as 'poly exchange'; we recommend defining the procedure as DAIR when extensive debridement, lavage, and removal, wash, and reimplanting of all modular components is done while retaining stable stems, followed by suppressive antibiotic therapy; and finally, we recommend that if all the modular components are changed for new ones, the procedure is referred to as 'DAIR plus'.

OBJECTIVE:To determine the utility of a triangular margin as an imaging diagnostic feature for fibrous dysplasia. MATERIALS AND METHODS:We retrospectively reviewed all surgically biopsied or managed benign and malignant bone tumors by a single orthopedic oncologist over 19 years (2003 to 2022). A musculoskeletal radiologist and an orthopedic oncologist, both with >10 years of experience, retrospectively evaluated all imaging in consensus. Groups were compared using the χ 2 test. RESULTS:There were a total of 152 subjects [mean age 49±21 (range 7.8 to 91) years]; 80 (53%) females and 72 (47%) males. There were 52 subjects with fibrous dysplasia, 31 subjects with other benign bone tumors, and 69 subjects with malignant bone tumors. The sensitivity and specificity of a triangular margin for distinguishing fibrous dysplasia from other benign or malignant bone tumors were 74% and 96% on radiographs, 73% and 100% on CT, and 78% and 91% on MRI, respectively. The triangular margin was more prevalent in fibrous dysplasia (85%) versus benign (16%) and malignant (1.6%) primary bone tumors in all 3 modalities ( P <0.001). Multivariate analysis of the aggregated imaging data suggests that if a lesion has a triangular margin, it is 14 times more likely to be a fibrous dysplasia than another benign bone tumor ( P =0.012). CONCLUSIONS:The presence of a triangular margin could increase a radiologist's confidence that a bone tumor is fibrous dysplasia.

Watch this full-length, narrated surgical video demonstrating the use of photodynamic nails for bone reinforcement in combination with complex total hip arthroplasty in the setting of radiation osteitis.

Dermatofibroma/fibrous histiocytoma is a common tumor of the dermis, composed of myofibroblasts, dendrocytes, and macrophages with characteristic entrapment of dermal collagen fibers at the periphery of the tumor. Various subtypes of dermatofibroma, including cellular, aneurysmal, and atypical dermatofibroma, are associated with an increased risk of recurrence, especially with incomplete excision. Two cases of benign fibrous histiocytoma with recurrence and metastasis are described. Patient 1 had a cellular fibrous histiocytoma with KIRREL1::PRKCD fusion presenting as a superficial and deep soft tissue mass involving the scapula and lateral clavicle. Patient 1 subsequently developed metastasis to the chest wall and thigh. Patient 2 had a recurrent aneurysmal fibrous histiocytoma with LAMTOR1::PRKCD fusion presenting as a large shoulder mass with invasion of the clavicle and lymph node metastasis. Patient 2 developed rapid local recurrence and PET-avid pulmonary nodules, radiologically consistent with metastasis. Fibrous histiocytoma is typically a morphologically benign neoplasm that only rarely exhibits clinically aggressive behavior with multiple recurrences and metastases. Although uncommon, recognition of this entity is important so that pathologists and sarcoma oncologists can ensure accurate diagnosis, multidisciplinary management, and appropriate clinical surveillance. In addition, complex chromosomal abnormalities may serve as useful indicators of fibrous histiocytoma with the risk of aggressive clinical behavior.

Giant cell tumors of bone are locally aggressive, frequently harbor H3F3A p.G34W mutations, and rarely undergo malignant transformation. The pathogenesis of malignant transformation remains incompletely characterized. Herein, we present 28 malignant giant cell tumors of bone from 14 males and 14 females, aged 16 to 65 (median 39) years. Primary sites included long bones (n=20), pelvis (n=3), vertebrae (n=2), and rarely rib, phalanx, and cuneiform (n=1 each). Sixteen (62%) of 26 tumors with available history represented malignant transformation or recurrence of conventional giant cell tumors of bone, at intervals of 1.3 to 35 (median 7.3) years before malignant transformation. Eight of 15 patients with available treatment history received denosumab before a diagnosis of malignancy. Ten (38%) of 26 tumors with available history likely arose de novo, including 7 with conventional areas and 3 H3F3A -mutant sarcomas lacking conventional giant cell tumor of bone. Of 28 malignant giant cell tumors of bone, 18 (64%) and 10 (36%) harbored osteoblastic and chondroblastic elements, respectively. Among 23 tumors with available genetic testing or surrogate immunohistochemistry, 17 (74%) were p.G34W-mutant, whereas other tumors carried H3F3A p.G34L (n=2), p.G34V (n=2), and p.G34R (n=1) alterations; 1 tumor harbored H3F3B p.K116E and p.R117S in cis. Seven (70%) of 10 malignant giant cell tumors of bone showed complex copy number alterations by single nucleotide polymorphism (SNP) array, DNA next-generation sequencing (NGS), and/or karyotype analysis. In contrast, complex chromosomal alterations were lacking in 32 conventional giant cell tumors of bone tested (24 by karyotype, 7 by SNP array, 1 by DNA NGS), 3 atypical giant cell tumors of bone with isolated marked nuclear atypia (2 by karyotype, 1 by SNP array) and 3 metastasizing conventional giant cell tumors of bone (2 by DNA NGS, 1 by karyotype). Clinical follow-up was available for 20 patients (71%), and one additional patient had metastases at presentation. Overall, 14 of 21 patients (67%) developed metastases, and 10 of 20 patients with follow-up (50%) died of disease at 2 months to 9.6 years (median 7 mo). Most patients were treated with chemotherapy; 1 patient (PD-L1 TPS >95%) was treated with pembrolizumab, with complete clinical response of metastatic disease at 2.5 years. In conclusion, malignant giant cell tumors of bone typically arise from long bones, harbor osteosarcomatous and/or chondrosarcomatous differentiation, and show significant risk for distant metastasis and demise. Our data suggest that copy number analysis may be useful in distinguishing malignant giant cell tumors of bone from their conventional, atypical, and metastasizing conventional counterparts.

BACKGROUND CONTEXT Osteosarcoma of the mobile spine is a rare and complex condition, with limited case series informing treatment decisions. Advancements in treatment paradigms, particularly in en bloc resection and novel radiation techniques, may incite new treatment guidelines and improve patient outcomes. The clinical outcomes of patients treated for osteosarcoma of the mobile spine at our institution were reported over a decade ago, and this study provides an updated assessment of management strategies and patient outcomes since the initial publication. PURPOSE To provide an updated analysis of clinical results for the treatment of mobile spine osteosarcoma. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Thirty-two patients treated at a single center for osteosarcoma of the spine over 22 years. OUTCOME MEASURES Estimation of overall patient survival, local recurrence, and the presence of metastatic disease. METHODS Inclusion criteria were adult patients treated for osteosarcoma originating in the vertebral column with the exclusion of the sacrum at Massachusetts General Hospital between 2001 and 2023. Overall survival was evaluated using the Kaplan-Meier method, grouped by type of resection (en bloc versus intralesional) and histological subtype (osteoblastic, chondroblastic, other/unknown). Prognostic factors were assessed using Cox proportional hazards modeling. Univariate analysis was conducted to determine potential covariates. Factors that showed a trend toward significance (p <0.1) or were clinically significant were included as covariates in multivariate analysis. We considered the following covariates: age at surgery (years), margin status (positive or negative margins), number of spinal levels resected (one level, or two or more levels), region of the spine (cervical, thoracic, lumbar), and tumor size (cm). RESULTS Twenty-two of the 32 patients were given en bloc resection, while ten received piecemeal resection. Adjusting for tumor size, en bloc resection was associated with significantly improved overall survival compared to intralesional resection (HR=4.97, 95% CI: 1.27-19.47, p=0.02). However, in multivariable regression, neither en bloc resection (p=0.21) nor histological subtype (osteoblastic, p=0.43, other or unknown, p=0.07) were predictive of better outcomes. Resection of greater than one level and younger age were associated with poor survival (p<0.05). CONCLUSIONS This study highlights the continued challenges for patients with spinal osteosarcoma despite advances in surgical techniques and radiation modalities. If feasible, en bloc resection yields improved overall survival compared to intralesional resection, but the five-year mortality rate remains high. Histological subtype did not significantly predict outcomes, while tumors involving multiple vertebral levels and younger age were associated with worse survival. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Abstract In the United States, ~15000 cases of bone and soft-tissue sarcomas are diagnosed annually, representing roughly 1% of all incident cancers. While several studies have analyzed independent predictors of outcomes for these sarcomas, small samples and confounding bias have limited their ability to establish reliable conclusions. The present analysis provides a comprehensive epidemiological description of patients with any of 16 distinct bone and soft-tissue sarcomas by querying the Surveillance, Epidemiology, and End Results database between 2000 and 2020. Incidence, prevalence, incidence-based mortality, survival rates, and case-fatality ratios were computed. Using patient age, sex, race, and ethnicity, as well as tumor size, grade, and stage as covariates, multivariable survival Cox proportional hazards regression analyses were performed to model hazard ratios (HRs) and identify independent predictors of worse prognosis. Only patients with myosarcoma and fibrous histiocytoma witnessed a decrease in the prevalence of their disease over time (both, p<0.05). The incidence of chondrosarcoma and synovial sarcoma increased in White and Asian patients but decreased in Black individuals (both, p<0.001), while their case-fatality rates remained constant and increased, respectively, regardless of race and ethnicity (all, p<0.05). Case-fatality rates only declined significantly for White and Non-Hispanic patients with solitary fibrous tumor (both, p<0.05). Aside from alveolar soft-part sarcoma and clear cell sarcoma, a 10-year increase in age of patients with bone and soft-tissue sarcomas resulted in 18% to 61% higher likelihood of death (all, p<0.05). For most malignancies, having a tumor size greater than 5 cm yielded a 37% to 189% higher likelihood of death. While incidence trends suggest improvements in diagnostic techniques and early tumor detection, survival and case-fatality trends indicate potential for advancement in treatment for most bone and soft-tissue sarcomas. Citation Format: Marc El Beaino, Rachel Baum, Katherine M. Connors, Karim Masrouha, Santiago A. Lozano-Calderon, Patrick P. Lin. Epidemiology of bone and soft-tissue sarcomas: A two-decade analysis of the surveillance, epidemiology, and end results program [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4844.

Introduction Allograft prosthetic composite (APC) reconstruction is performed after resection of proximal humerus tumors or failure of arthroplasty implants. There is limited literature on the postoperative outcomes of this technique. We sought to assess implant survival, failure rates, and postoperative functional outcomes after APC reconstruction of the proximal humerus. Methods A systematic review of the PubMed and Embase databases was conducted. The study was registered on PROSPERO (ID: 448663). The STROBE checklist was used for quality assessment. Implant failure was determined using the Henderson classification for biological reconstruction. Functional outcome was primarily assessed using the Musculoskeletal Tumor Society (MSTS) score at last follow-up. Results Twenty-five studies with a total of 488 patients were included. Mean follow-up in reporting studies ranged from 2.5 to 10 years. Five-year revision-free survival for implants ranged from 41 to 92%. Overall implant failure rate ranged from 9 to 54%, and reoperation rate ranged from 0 to 55%. Graft-host non-union (type 2) was the most common mode of failure, with rates ranging from 0 to 75%. The mean MSTS scores at last follow-up ranged from 57 to 90% across studies. A trend towards better functional outcomes was seen in patients having an APC with a reverse total shoulder arthroplasty (rTSA) compared with those with hemiarthroplasty (HA). Conclusions APCs show promise in proximal shoulder reconstruction, with heterogenous functional outcomes that are non-inferior to other reconstruction techniques. Graft host non-union is a common mode of failure and remains a concern in this type of prosthesis. Future studies should compare rTSA-APCs and rTSA endoprostheses while controlling for potential confounders.

Abstract Background The ability to predict survival accurately in patients with osseous metastatic disease of the extremities is vital for patient counseling and guiding surgical intervention. We, the Skeletal Oncology Research Group (SORG), previously developed a machine-learning algorithm (MLA) based on data from 1999 to 2016 to predict 90-day and 1-year survival of surgically treated patients with extremity bone metastasis. As treatment regimens for oncology patients continue to evolve, this SORG MLA-driven probability calculator requires temporal reassessment of its accuracy. Question/purpose Does the SORG-MLA accurately predict 90-day and 1-year survival in patients who receive surgical treatment for a metastatic long-bone lesion in a more recent cohort of patients treated between 2016 and 2020? Methods Between 2017 and 2021, we identified 674 patients 18 years and older through the ICD codes for secondary malignant neoplasm of bone and bone marrow and CPT codes for completed pathologic fractures or prophylactic treatment of an impending fracture. We excluded 40% (268 of 674) of patients, including 18% (118) who did not receive surgery; 11% (72) who had metastases in places other than the long bones of the extremities; 3% (23) who received treatment other than intramedullary nailing, endoprosthetic reconstruction, or dynamic hip screw; 3% (23) who underwent revision surgery, 3% (17) in whom there was no tumor, and 2% (15) who were lost to follow-up within 1 year. Temporal validation was performed using data on 406 patients treated surgically for bony metastatic disease of the extremities from 2016 to 2020 at the same two institutions where the MLA was developed. Variables used to predict survival in the SORG algorithm included perioperative laboratory values, tumor characteristics, and general demographics. To assess the models’ discrimination, we computed the c-statistic, commonly referred to as the area under the receiver operating characteristic (AUC) curve for binary classification. This value ranged from 0.5 (representing chance-level performance) to 1.0 (indicating excellent discrimination) Generally, an AUC of 0.75 is considered high enough for use in clinical practice. To evaluate the agreement between predicted and observed outcomes, a calibration plot was used, and the calibration slope and intercept were calculated. Perfect calibration would result in a slope of 1 and intercept of 0. For overall performance, the Brier score and null-model Brier score were determined. The Brier score can range from 0 (representing perfect prediction) to 1 (indicating the poorest prediction). Proper interpretation of the Brier score necessitates a comparison with the null-model Brier score, which represents the score for an algorithm that predicts a probability equal to the population prevalence of the outcome for each patient. Finally, a decision curve analysis was conducted to compare the potential net benefit of the algorithm with other decision-support methods, such as treating all or none of the patients. Overall, 90-day and 1-year mortality were lower in the temporal validation cohort than in the development cohort (90 day: 23% versus 28%; p < 0.001, and 1 year: 51% versus 59%; p<0.001). Results Overall survival of the patients in the validation cohort improved from 28% mortality at the 90-day timepoint in the cohort on which the model was trained to 23%, and 59% mortality at the 1-year timepoint to 51%. The AUC was 0.78 (95% CI 0.72 to 0.82) for 90-day survival and 0.75 (95% CI 0.70 to 0.79) for 1-year survival, indicating the model could distinguish the two outcomes reasonably. For the 90-day model, the calibration slope was 0.71 (95% CI 0.53 to 0.89), and the intercept was -0.66 (95% CI -0.94 to -0.39), suggesting the predicted risks were overly extreme, and that in general, the risk of the observed outcome was overestimated. For the 1-year model, the calibration slope was 0.73 (95% CI 0.56 to 0.91) and the intercept was -0.67 (95% CI -0.90 to -0.43). With respect to overall performance, the model’s Brier scores for the 90-day and 1-year models were 0.16 and 0.22. These scores were higher than the Brier scores of internal validation of the development study (0.13 and 0.14) models, indicating the models’ performance has declined over time. Conclusion The SORG MLA to predict survival after surgical treatment of extremity metastatic disease showed decreased performance on temporal validation. Moreover, in patients undergoing innovative immunotherapy, the possibility of mortality risk was overestimated in varying severity. Clinicians should be aware of this overestimation and discount the prediction of the SORG MLA according to their own experience with this patient population. Generally, these results show that temporal reassessment of these MLA-driven probability calculators is of paramount importance because the predictive performance may decline over time as treatment regimens evolve. The SORG-MLA is available as a freely accessible internet application at https://sorg-apps.shinyapps.io/extremitymetssurvival/. Level of Evidence Level III, prognostic study.

To evaluate clinical and radiological features of extraskeletal myxoid chondrosarcomas (EMC). Our pathology database was queried for cases of EMCs. Tumor location, size, imaging appearance, presence of metastases, disease recurrence, and clinical outcome were documented. Imaging studies were evaluated in consensus by a musculoskeletal radiologist and an orthopedic oncologist. Thirty subjects met the inclusion criteria (mean age 52.7 ± 16.2 years; 19 male, 11 female), 17 (56.7

OBJECTIVES:Metastatic bone disease is estimated to develop in up to 17% of patients with melanoma, compromising skeleton integrity resulting in skeletal-related events (SREs), which impair quality of life and reduce survival. The objective of the study was to investigate (1) the proportion of melanoma patients developing SREs following diagnosis of bone metastasis and (2) the predictors for SREs in this patient cohort. METHODS:Four hundred and eighty-one patients with bone metastatic melanoma from two tertiary centers in the United States from 2008 to 2018 were included. The primary outcome was 90-day and 1-year occurrence of a SRE, including pathological fractures of bones, cord compression, hypercalcemia, radiotherapy, and surgery. Fine-Gray regression analysis was performed for overall SREs and pathological fracture, with death as a competing risk. RESULTS:By 1-year, 52% (258/481) of patients experienced SREs, and 28% (137/481) had a pathological fracture. At 90-day, lytic lesions, bone pain, elevated calcium and absolute lymphocyte, and decreased albumin and hemoglobin were associated with higher SRE risk. The same factors, except for decreased hemoglobin, were shown to predict development of SREs at 1-year. CONCLUSION:The high incidence of SREs and pathological fractures warrants vigilance using the identified factors in this study and preventative measures during clinical oncological care.