Wound-Healing Effects of Common Antineoplastic Agents and Perioperative Considerations for the Orthopaedic Surgeon.

In oncologic patients, optimal postoperative wound healing is crucial for the maintenance of systemic therapies and improved survival. Although several risk factors for postoperative wound complications have been identified, the clinical effect of new antineoplastic agents on wound healing remains uncertain. The available literature on the effect of antineoplastic agents in wound healing is complex to analyze because of other confounding risk factors such as radiation therapy and certain patient-specific variables. Available perioperative drug recommendations are based on database opinion and case reports from adverse event alerts. This review highlights the characteristics of old and new antineoplastic agents commonly used in the treatment of sarcoma, carcinoma, and other cancers and their potential effects on the wound-healing process. It also aims to provide perioperative treatment cessation recommendations to guide orthopaedic surgeons and prevent drug-related wound complications to the fullest extent possible.

Wound vacuum-assisted closure temporization after tumor resection of soft tissue sarcomas-A cost analysis in a propensity-score matched population.

BACKGROUND: Vacuum-assisted closure (VAC) temporization is a technique associated with high local control rates used in myxofibrosarcoma. We sought to compare the costs and postoperative outcomes of VAC temporization and single-stage (SS) excision/reconstruction. METHODS: We conducted a retrospective analysis of patients with myxofibrosarcoma surgically treated at our institution between 2000 and 2022. Variables of interest included total, direct, and indirect costs for initial episode of care, 90 days and 1 year after initial admission, and postoperative outcomes. Costs were compared between the VAC temporization and SS groups. RESULTS: After matching, 13 patients in the SS group and 23 in the VAC group were analyzed. We found no difference in median and mean total inpatient costs, between the VAC temporization and SS group. While total 90-day and 1-year costs were higher in the VAC group compared to the SS group, mean costs were similar. There were no differences in postoperative complications between groups. A subanalysis of the entire cohort (n = 139) revealed lower local recurrence and overall death rates in the VAC temporization group. CONCLUSION: VAC temporization had similar inpatient costs and postoperative outcomes to SS excision/reconstruction. While median 90-day and 1-year costs were higher in the VAC group, mean costs did not differ.

Incidence and survival outcomes of patients with high-grade appendicular bone sarcoma and isolated regional lymph node metastasis: A national cohort database study.

BACKGROUND: While distant metastases in primary bone sarcomas have been extensively studied, the impact of isolated regional lymph node (LN) metastasis on survival remains unknown. In patients with primary bone sarcomas, we sought to assess the prevalence of isolated regional LN metastasis and the survival of this population. METHODS: A total of 6651 patients with histologically-confirmed high-grade osteosarcoma, Ewing sarcoma, or chondrosarcoma were retrieved from the SEER database. We defined four subgroups for our analysis: localized disease (N0 M0), isolated regional LN metastasis (N1 M0), isolated distant metastasis (N0 M1), and combined regional LN and distant metastasis (N1 M1). Disease-specific survival (DSS) was assessed using the Kaplan-Meier method. RESULTS: Prevalence of isolated regional LN metastasis (N1 M0) was highest in Ewing sarcoma (27/1097; 3.3 %), followed by chondrosarcoma (18/1702; 1.4 %) and osteosarcoma (26/3740; 0.9 %). In all three histologies, patients with isolated regional LN metastasis had a worse 2-year, 5-year, and 10-year DSS than those with localized disease. Chondrosarcoma patients with isolated regional LN (N1 M0) metastasis had a significantly higher DSS in comparison to those with only distant metastasis (N0 M1) at the 5- and 10-year marks; for osteosarcoma and Ewing sarcoma, only a pattern towards higher survival was seen. Risk factors for presenting isolated regional LN metastasis included tumor location in lower-limb (OR = 2.01) or pelvis (OR = 2.49), diagnosis of Ewing sarcoma (OR = 2.98), and tumor >10 cm (OR = 1.96). CONCLUSIONS: Isolated regional LN metastases in primary bone sarcomas is an infrequent presentation associated with worse survival than localized disease. LEVEL OF EVIDENCE: III.

Postoperative Outcomes of Total Humerus Replacement for Oncologic Reconstruction of the Upper Limb: A Systematic Review of the Literature.

BACKGROUND: Total humerus replacement (THR) is a reconstruction procedure performed after resection of massive humeral tumors. However, there is limited literature on the rates of failure and functional outcomes of this implant. Our study aimed to determine the main failure modes, implant survival, and postoperative functional outcomes of THR. METHODS: A comprehensive search of the PubMed and Embase databases was conducted. We registered our study on PROSPERO (448684) and used the Strengthening the Reporting of Observational Studies in Epidemiology checklist for quality assessment. The Henderson classification was used to assess endoprosthesis failure and the Musculoskeletal Tumor Society (MSTS) score for functional outcomes. Weighted means and standard deviations were calculated. RESULTS: Ten studies comprising 171 patients undergoing THR were finally included. The overall failure rate was 32.2%. Tumor progression (12.6%) and prosthetic infections (9.4%) were the most common failure modes, followed by soft-tissue failures (5.9%), aseptic loosening (3.5%), and structural failure (1.8%). Two-year, 5-year, and 10-year implant survival rates for the entire cohort were 86%, 81%, and 69.3%. Ten-year implant survival for primary THRs was 78.3%, compared with 38.6% for revision THRs (p = 0.049). The mean MSTS score at the last follow-up was 77%. Patients whose implants did not fail had a higher MSTS score (79.3%) than those with failed implants (71.4%) (p = 0.02). CONCLUSION: One-third of THR will fail, mostly due to tumor progression and prosthetic infection. Overall functional scores were acceptable, with MSTS scores displaying great hand and elbow function but limited shoulder function. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

Neoplastic pathologic hip fractures are associated with a higher risk of post-operative bleeding and thromboembolic events.

INTRODUCTION: Surgical treatment of hip fractures leads to significant post-operative complications. Although pathologic fractures (PF) are associated with worse outcomes, most studies do not differentiate between etiology (neoplastic and non-neoplastic PF). We seek to compare 30-day complication rates between 1) native hip fractures and neoplastic PF, and 2) neoplastic and non-neoplastic PF. MATERIALS AND METHODS: A total of 127,819 patients with hip fractures and 5104 with PF diagnosed from 2005 to 2021 were retrieved from the NSQIP database. We included 1843 patients with neoplastic PF and 3261 with non-neoplastic PF. Demographics, pre-operative labs and co-morbidities, and post-operative outcomes were analyzed. Propensity-score matching was conducted to control for confounders. RESULTS: Patients with a neoplastic PF had a significantly higher rate of deep venous thrombosis (DVT) (4 % vs 1.2 %, p = 0.001) and pulmonary embolism (PE) (2.4 % vs 0.7 %, p < 0.001), than native hip fractures. Rates of post-operative bleeding were significantly higher in the neoplastic PF group (29.3 % vs 23.9 %, p < 0.001) than non-neoplastic PF. No differences in soft tissue complications were found. When comparing neoplastic and non-neoplastic PF, the former had a higher rate of PE (2.5 % vs 1.0 %, p = 0.015) and post-operative bleeding (27.6 % vs 22.0 %, p = 0.009). Unplanned readmission rates and 30-day mortality rate were also higher in the neoplastic PF group. CONCLUSION: Neoplastic PF of the hip are associated with higher risk of thromboembolic event rates and post-operative bleeding than both native hip fractures and non-neoplastic PF. No differences in rates of soft tissue complications were found between groups.

Complications and Functional Outcomes after Reconstruction of the Proximal Humerus with Allograft-Prosthetic Composite - A Systematic Review of the Literature.

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.

Phosphaturic mesenchymal tumor: management and outcomes of ten patients treated at a single institution.

BACKGROUND: Phosphaturic mesenchymal tumor (PMT) is a rare tumor that causes tumor-induced osteomalacia. Patients present with non-specific symptoms secondary to renal phosphate wasting and decreased bone mineralization. We sought to assess: (1) What are the common presenting features, laboratory and imaging findings, histologic findings of phosphaturic mesenchymal tumors? (2) What are the available treatment strategies for phosphaturic mesenchymal tumors and their long-term outcomes in terms of local recurrence and symptom control after treatment? METHODS: We retrospectively identified patients with a histologic diagnosis of PMT located in the axial or appendicular skeleton, or surrounding soft tissues. A total of 10 patients were finally included in our study. RESULTS: Median tumor size was 1.9 cm (range, 1.1 to 6.1) and median time from symptom onset to diagnosis was 3 years (range, 0.5 to 15 years). All patients but one presented with hypophosphatemia (median 1.9 mg/dL, range 1.2 to 3.2). Pre-operative FGF-23 was elevated in all cases (median 423.5 RU/mL, range 235 to 8950). Six patients underwent surgical resection, three were treated percutaneously (radiofrequency ablation or cryoablation), and one refused treatment. Only one patient developed local recurrence and no patients developed metastatic disease. At last follow-up, nine patients showed no evidence of disease and one was alive with disease. CONCLUSION: Phosphaturic mesenchymal tumor is a rare tumor presenting with non-specific symptoms. Surgery is the standard treatment when negative margins can be achieved without significant morbidity. In patients with small tumors in surgically-inaccessible areas, radiofrequency ablation or cryoablation can be performed successfully.

Reconstruction of the elbow with distal humerus endoprosthetic replacement after tumor resection: a systematic review of the literature and institutional case series.

BACKGROUND: Distal humerus replacement (DHR) is a modular endoprosthesis mainly used for bone reconstruction after resection of primary or metastatic bone lesions. Studies on DHR failure rates and postoperative functional outcomes are scarce. We sought to assess implant survival, modes of failure, and functional outcomes in patients undergoing DHR for oncologic indications. METHODS: A systematic review of the PubMed and Embase databases was performed. PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (457,260). Quality appraisal of included studies was conducted using the STROBE checklist. Prosthetic failure was assessed using the Henderson classification for megaprosthetic failures. We additionally performed a retrospective review of patients treated with a DHR for oncologic indications at a large tertiary care academic center. Weighted means were calculated to pool data. RESULTS: Eleven studies with a total of 162 patients met the inclusion criteria. Mean follow-up was 3.7 years (range, 1.66-8 years). Henderson type 2 failures (aseptic loosening) were the most common mode of failure, occurring in 12% of cases (range, 0%-33%). Five-year implant survival was 72% (range, 49%-93.7%). Mean postoperative Musculoskeletal Tumor Society (MSTS) score was 81.1 (range, 74-84.3). In our institutional case series, 2 out of 5 patients had DHR revision for periprosthetic fracture and aseptic loosening at 16 and 27 months after surgery, respectively. CONCLUSIONS: Distal humerus replacement is a successful reconstruction strategy for tumors of the distal humerus, with high implant survival and good to excellent functional outcomes.

Is Unplanned Excision of Soft Tissue Sarcomas Associated with Worse Oncological Outcomes?-A Systematic Review and Meta-Analysis.

BACKGROUND: Soft tissue sarcomas are a group of rare neoplasms which can be mistaken for benign masses and be excised in a non-oncologic fashion (unplanned excision). Whether unplanned excision (UE) is associated with worse outcomes is highly debated due to conflicting evidence. METHODS: We performed a systematic review and meta-analysis following PRISMA guidelines. Main outcomes analyzed were five-year overall survival (OS), five-year local recurrence-free survival (LRFS), amputation rate and plastic reconstruction surgery rate. Risk ratios were used to compare outcomes between patients treated with planned and unplanned excision. RESULTS: We included 16,946 patients with STS, 6017 (35.5%) with UE. UE was associated with worse five-year LRFS (RR 1.35, p = 0.019). Residual tumor on the tumor bed was associated with lower five-year LRFS (RR = 2.59, p < 0.001). Local recurrence was associated with worse five-year OS (RR = 1.82, p < 0.001). UE was not associated with a worse five-year OS (RR = 0.90, p = 0.16), higher amputation rate (RR = 0.77, p = 0.134), or a worse plastic reconstruction surgery rate (RR = 1.25, p = 0.244). CONCLUSIONS: Unplanned excision of Soft Tissue Sarcomas and the presence of disease in tumor bed after one were associated with worse five-year LRFS. Tumor bed excision should remain the standard approach, with special consideration to the presence of residual disease.

A Bibliometric Analysis of the 500 Most Cited Papers in Orthopaedic Oncology.

BACKGROUND: Despite notable progress over time, broad insight into the scientific landscape of orthopaedic oncology is lacking. We conducted a bibliometric analysis of the 500 most cited papers in the field. METHODS: We searched the Science Citation Index Expanded database of the Web of Science Core Collection to find the 500 most cited articles in the field. RESULTS: Citation count ranged from 81 to 1,808. Articles were published from 1965 to 2018. Over half of all articles were published in the United States (53.6%). The 2000s was the most productive decade with 170 (34%) articles. All articles were written in English and were published across 29 journals. Female participation as first authors significantly increased from the 1960s to the 2010s (0% vs 14.6%, P = 0.0434). Similarly, female involvement as senior authors grew from the 1960s to the 2010s (0% vs 12.2%, P = 0.0607). Primary bone sarcomas were the most cited topic among articles from the 1970s to the 1980s. From studies produced in the 1990s up until the 2010s, reconstruction procedures were the most cited topic. CONCLUSION: Trends over the years have resulted in an emphasis on a surgical technique. Notable progress has been made regarding gender diversity, yet disparities still exist.

What is the diagnostic accuracy of fluorescence-guided surgery for margin assessment in appendicular bone and soft tissue tumors? - A systematic review of clinical studies.

BACKGROUND: Fluorescence-guided surgery (FGS) is a novel technique to successfully assess surgical margins intraoperatively. Investigation and adoption of this technique in orthopaedic oncology remains limited. METHODS: The PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (380520). Studies describing the use of FGS for resection of bone and soft tissue sarcomas (STS) on humans were included. Diagnostic performance metrics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and accuracy) and margin positivity rate were the outcomes assessed. RESULTS: Critical appraisal using the Joanna Brigs Institute checklists showed significant concerns for study quality. Sensitivity of FGS ranged from 22.2 % to 100 % in three of the four studies assessing his metrics; one study in appendicular tumors in the pediatric population reported 0 % sensitivity in the three cases included. Specificity ranged from 9.38 % to 100 %. PPV ranged from 14.6 % to 70 % while NPV was between 53.3 % and 100 %. The diagnostic accuracy ranged from 21.62 % to 92.31 %. Margin positivity rate ranged from 2 % to 50 %, with six of the seven studies reporting values between 20 % and 50 %. CONCLUSIONS: FSG is a feasible technique to assess tumor margins in bone and STS. Reported performance metrics and margin positivity rates vary widely between studies due to low study quality and high heterogeneity in dying protocols. LEVEL OF EVIDENCE: Level III, diagnostic study.

Does Wound VAC Temporization Offer Patient-Reported Outcomes Similar to Single-Stage Excision Reconstruction After Myxofibrosarcoma Resection?

BACKGROUND: Vacuum-assisted closure (VAC) temporization is a promising technique to achieve local control in aggressive soft tissue sarcomas. Despite its previously reported efficacy, adoption of VAC temporization remains limited, primarily due to the scarce literature on patient-reported outcomes (PROs) supporting its efficacy. This study compared the postoperative PROs after VAC temporization or single-stage (SS) excision and reconstruction for patients undergoing surgical resection for myxofibrosarcoma management. METHODS: A retrospective analysis of myxofibrosarcoma patients who underwent surgical resections at our institution from 2016 to 2022 was performed. Postoperative PROs collected prospectively for those treated with VAC temporization or SS excision/reconstruction were compared using a visual analog scale (VAS) for pain and three Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaires: Global Health Short-Form Mental (SF Mental), Global Health Short-Form Physical (SF Physical), and Physical Function Short-Form 10a (SF 10a). Absolute and differential (postoperative minus preoperative) scores at the 1-month, 3-month, 6-month, 1-year, and 2-year time points were compared. RESULTS: The analysis included 79 patients (47 treated with VAC temporization and 32 treated with SS excision/reconstruction). All outcomes were similar between the groups except for physical function 1 year after surgery, in which the differential PROMIS SF 10a scores were higher in the SS group (p = 0.001). All the remaining absolute and differential PROMIS and VAS pain scores were similar between the groups at all time points. Postoperative complications did not differ between the groups. CONCLUSION: The PROs for physical and mental health, physical function, and pain were similar between the myxofibrosarcoma patients who had VAC temporization and those who had SS excision/reconstruction after surgical resection.

LT and SOX9 expression are associated with gene sets that distinguish Merkel cell polyomavirus (MCPyV)-positive and MCPyV-negative Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive malignant neuroendocrine tumour. There are two subsets of MCC, one related to Merkel cell polyomavirus (MCPyV) and the other to ultraviolet radiation (UVR). MCPyV-positive and MCPyV-negative MCCs have been considered to be different tumours, as the former harbour few DNA mutations and are not related to UVR, and the latter usually arise in sun-exposed areas and may be found in conjunction with other keratinocytic tumours, mostly squamous cell carcinomas. Two viral oncoproteins, large T antigen (LT; coded by MCPyV_gp3) and small T antigen (sT; coded by MCPyV_gp4), promote different carcinogenic pathways. OBJECTIVES: To determine which genes are differentially expressed in MCPyV-positive and MCPyV-negative MCC; to describe the mutational burden and the most frequently mutated genes in both MCC subtypes; and to identify the clinical and molecular factors that may be related to patient survival. METHODS: Ninety-two patients with a diagnosis of MCC were identified from the medical databases of participating centres. To study gene expression, a customized panel of 172 genes was developed. Gene expression profiling was performed with nCounter technology. For mutational studies, a customized panel of 26 genes was designed. Somatic single nucleotide variants (SNVs) were identified following the GATK Best Practices workflow for somatic mutations. RESULTS: The expression of LT enabled the series to be divided into two groups (LT positive, n = 55; LT negative, n = 37). Genes differentially expressed in LT-negative patients were related to epithelial differentiation, especially SOX9, or proliferation and the cell cycle (MYC, CDK6), among others. Congruently, LT displayed lower expression in SOX9-positive patients, and differentially expressed genes in SOX9-positive patients were related to epithelial/squamous differentiation. In LT-positive patients, the mean SNV frequency was 4.3; in LT-negative patients it was 10 (P = 0.03). On multivariate survival analysis, the expression of SNAI1 [hazard ratio (HR) 1.046, 95% confidence interval (CI) 1.007-1.086; P = 0.02] and CDK6 (HR 1.049, 95% CI 1.020-1.080; P = 0.001) were identified as risk factors. CONCLUSIONS: Tumours with weak LT expression tend to co-express genes related to squamous differentiation and the cell cycle, and to have a higher mutational burden. These findings are congruent with those of earlier studies.

Merkel cell carcinoma (MCC) is an aggressive form of skin tumour. There are two subtypes of MCC: one of them is related to a virus called Merkel cell polyomavirus (MCPyV); the other one is related to persistent exposure to sunlight. The aim of this research was to find differences between these subtypes in their molecular behaviour (the genes that are expressed and the mutations that may be found). To do this, we carried out two studies, one to investigate gene expression (the process cells use to convert the instructions in our DNA into a functional product such as a protein) and one to look at gene mutations (changes in the DNA sequence). We found that the tumours that were not related to MCPyV expressed genes related to epithelial differentiation (the process by which unspecialized cells gain features characteristics of epithelial cells, which, among other things, make up the outer surface of the body), which means that the origin of both MCC subtypes may be different. We also found that MCPyV-related tumours had fewer mutations. Our findings are important because they help us to understand the biology of the MCC subtypes and could help with the development of new treatments for people diagnosed with skin tumours.

Treatment and Outcomes of 4,973 Unicameral Bone Cysts: A Systematic Review and Meta-Analysis.

¼ Unicameral bone cysts (UBCs) can increase the risk of pathologic fractures of both long and short bones. Although multiple treatments exist, data are conflicting regarding optimal management.¼ We sought to analyze treatment strategies for UBCs and their rates of successful treatment.¼ Success rates were analyzed according to treatment modality, with emphasis on filling techniques and/or decompression associated with curettage, and injection compounds.¼ Curettage with bone substitute and cyst decompression was identified as a highly successful technique for UBC treatment.¼ Decompressing the cyst wall after injection, regardless of the specific compound used, had a greater potential to enhance healing rates.¼ The management decision should be individually guided within the patient's context.

Debridement, Antibiotics, and Implant Retention (DAIR) Plus Offers Similar Periprosthetic Joint Infection Treatment Success Rates to Two-Stage Revision in Oncologic Megaprosthesis.

BACKGROUND: Prosthetic joint infections (PJIs) after megaprosthesis implantation are associated with high rates of treatment failure and amputation. Our study analyzed PJI treatment success rates by surgical strategy and assessed risks of reinfection and amputation. METHODS: We retrospectively analyzed the outcomes of patients diagnosed with PJI after undergoing megaprosthesis implantation for oncologic indications. The 2011 Musculoskeletal Infection Society criteria were used to define PJI. Reinfection, reoperation, and amputation for PJI recurrence were assessed. A total of 67 patients with megaprosthesis PJIs were included. There were fourteen patients who were treated with debridement, antibiotics, and implant retention (DAIR), 31 with DAIR plus (DAIR with modular component exchange and stem retention), and 21 with two-stage revisions. Kaplan-Meier estimates were used for survival analyses and Cox proportional hazards for risk factor analyses. RESULTS: The two-year reinfection-free survival was 25% for DAIR and 60% for DAIR plus or two-stage revision (P = .049). The five-year amputation-free survival was 84% for DAIR plus or two-stage revision, and 48% for DAIR (P = .13). Reinfection-free, reoperation-free, and amputation-free survival were similar between DAIR plus and two-stage revision at the 2- and 5-year marks. Body mass index ≥30 (hazard ratio [HR] = 2.65) and chronic kidney disease (HR = 11.53) were risk factors for reinfection. Treatment with DAIR plus or two-stage revision (HR = 0.44) was a protective factor against reinfection. CONCLUSIONS: A DAIR was associated with high rates of treatment failure and higher amputation rates than DAIR plus or 2-stage surgery. A DAIR plus was not inferior to 2-stage revision clearing a PJI and might be performed in patients who cannot withstand two-stage revision surgery.

Risk factors for local recurrence of upper extremity desmoid tumors.

INTRODUCTION: Upper extremity (UE) desmoid tumors are locally aggressive neoplasms with high recurrence rates. Our study sought to analyze the demographics and treatment strategies of UE desmoid tumors and identify risk factors for recurrence. MATERIALS AND METHODS: A retrospective review of 52 patients with histologically confirmed UE desmoid tumors treated at our institution between 1990 and 2015 was conducted. Survival was assessed using the Kaplan-Meier method and the Cox proportional hazards model was used for risk factor analysis. RESULTS: For the entire cohort, median age was 40 (29-47) years, 75% were female, and 48% had local recurrence. The median tumor size was 45 (15-111) cm3 on imaging. Twenty-two patients had a previous resection. The most common treatments were surgery alone (50%) and surgery with adjuvant radiotherapy (21%). Tumor size ≥5 cm and tumor volume ≥40 cm3 on imaging were associated with increased recurrence (p = 0.006 and p = 0.005, respectively). Age and sex were not associated with local recurrence. Patients with a tumor size ≥5 cm were 2.6 times more likely to present with recurrence. At the 10-year mark, a lower local recurrence-free survival was seen in patients with tumors ≥5 cm (72.2% vs. 36.3%, p = 0.042) or ≥40 cm3 (67.2% vs. 32.7%, p = 0.034). CONCLUSION: In our study, only tumor dimensions appeared to modify recurrence risk.

Dual Mobility for Oncological Hip Reconstruction: Significantly Reduced Dislocation Rates at 5 years.

BACKGROUND: Although dual mobility total hip arthroplasty has become increasingly common in recent years, limited remains known on dual mobility in surgical oncology. This university-based investigation compared dislocation and revision rates of DMs, conventional total hip arthroplasty (THA), and hemiarthroplasties (HAs) for oncological hip reconstruction. METHODS: An institutional tumor registry was used to identify 221 patients undergoing 45 DMs, 67 conventional THAs, and 109 HAs, performed for 17 primary hip tumors and 204 hip metastases between 2010 and 2020. The median age at surgery was 65 years, and 52% were female. The mean follow-up was 2.5 years. Kaplan-Meier survivorship curves and log-rank tests were done to compare dislocation and revision rates among all 221 patients, after a one-to-one propensity match, based on age, sex, tumor type (metastasis, primary tumor), and tumor localization (femur, acetabulum). RESULTS: The 5-year survivorship free of dislocation was 98% in DMs, 66% in conventional THAs ( P = 0.03; all P values compared with DMs), and 97% among HAs ( P = 0.48). The 5-year survivorship free of revision was 69% in DMs, 62% in conventional THAs ( P = 0.68), and 92% in HAs ( P = 0.06). After propensity matching, the 5-year survivorship free of dislocation was 42% in 45 conventional THAs ( P = 0.027; compared with all 45 DMs) and 89% in 16 matched HAs ( P = 0.19; compared with 16 DMs with femoral involvement only). The 5-year survivorship free of revision was 40% in matched conventional THAs ( P = 0.91) and 100% in matched HAs ( P = 0.19). CONCLUSIONS: DMs showed markedly lower rates of dislocation than conventional THAs, with overall revision rates remaining comparable among different designs. DMs should be considered the option of choice for oncological hip reconstruction if compared with conventional THAs. HAs are a feasible alternative when encountering femoral disease involvement only. LEVEL OF EVIDENCE: III.

Prediction of 5-year survival in soft tissue leiomyosarcoma using a machine learning model algorithm.

BACKGROUND AND OBJECTIVES: Leiomyosarcoma (LMS) is associated with one of the poorest overall survivals among soft tissue sarcomas. We sought to develop and externally validate a model for 5-year survival prediction in patients with appendicular or truncal LMS using machine learning algorithms. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used for development and internal validation of the models; external validation was assessed using our institutional database. Five machine learning algorithms were developed and then tested on our institutional database. Area under the receiver operating characteristic curve (AUC) and Brier score were used to assess model performance. RESULTS: A total of 2209 patients from the SEER database and 81 patients from our tertiary institution were included. All models had excellent calibration with AUC 0.84-0.85 and Brier score 0.15-0.16. After assessing the performance indicators according to the TRIPOD model, we found that the Elastic-Net Penalized Logistic Regression outperformed other models. The AUCs of the institutional data were 0.83 (imputed) and 0.85 (complete-case analysis) with a Brier score of 0.16. CONCLUSION: Our study successfully developed five machine learning algorithms to assess 5-year survival in patients with LMS. The Elastic-Net Penalized Logistic Regression retained performance upon external validation with an AUC of 0.85 and Brier score of 0.15.