Regional anesthesia is associated with improved metastasis free survival after surgical resection of bone sarcomas

There is increasing evidence that perioperative factors, including type of anesthesia, may be an important consideration regarding oncological disease progression. Previous studies have suggested that regional anesthesia can improve oncological outcomes by reducing the surgical stress response that occurs during tumor resection surgery and that may promote metastatic progression. The purpose of this study is to provide the first robust investigation of the impact of adding regional anesthesia to general anesthesia on oncological outcomes following sarcoma resection. One hundred patients with bone sarcoma were retrospectively analyzed in this study. After adjusting for confounding variables such as age and grade of the tumor, patients with bone sarcoma receiving regional anesthesia in addition to general anesthesia during resection had improved metastasis free survival (multivariate hazard ratio of 0.47 and p = 0.034). Future studies are needed to confer the beneficial effect of regional anesthesia, and to further investigate the potential mechanism. Clinical significance: The results from this study provide evidence that regional anesthesia may be advantageous in the setting of bone sarcoma resection surgery, reducing pain while also improving oncological outcomes and should be considered when clinically appropriate.

Surgical Site Infection in Patients Managed with an Endoprosthesis for the Treatment of Cancer: Evaluation of Patient, Disease, and Index Surgical Factors

BACKGROUND

Surgical site infection (SSI) after segmental endoprosthetic reconstruction in patients treated for oncologic conditions remains both a devastating and a common complication. The goal of the present study was to identify variables associated with the success or failure of treatment of early SSI following the treatment of a primary bone tumor with use of a segmental endoprosthesis.

METHODS

The present study used the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) data set to identify patients who had been diagnosed with an SSI after undergoing endoprosthetic reconstruction of a lower extremity primary bone tumor. The primary outcome of interest in the present study was a dichotomous variable: the success or failure of infection treatment. We defined failure as the inability to eradicate the infection, which we considered as an outcome of amputation or limb retention with chronic antibiotic suppression (>90 days or ongoing therapy at the conclusion of the study). Multivariable models were created with covariates of interest for each of the following: surgery characteristics, cancer treatment-related characteristics, and tumor characteristics. Multivariable testing included variables selected on the basis of known associations with infection or results of the univariable tests.

RESULTS

Of the 96 patients who were diagnosed with an SSI, 27 (28%) had successful eradication of the infection and 69 had treatment failure. Baseline and index procedure variables showing significant association with SSI treatment outcome were moderate/large amounts of fascial excision ≥1 cm2) (OR, 10.21 [95% CI, 2.65 to 46.21]; p = 0.001), use of local muscle/skin graft (OR,11.88 [95% CI, 1.83 to 245.83]; p = 0.031), and use of a deep Hemovac (OR, 0.24 [95% CI, 0.05 to 0.85]; p = 0.041). In the final multivariable model, excision of fascia during primary tumor resection was the only variable with a significant association with treatment outcome (OR, 10.21 [95% CI, 2.65 to 46.21]; p = 0.018).

CONCLUSIONS

The results of this secondary analysis of the PARITY trial data provide further insight into the patient-, disease-, and treatment-specific associations with SSI treatment outcomes, which may help to inform decision-making and management of SSI in patients who have undergone segmental bone reconstruction of the femur or tibia for oncologic indications.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Atrx deletion impairs CGAS/STING signaling and increases sarcoma response to radiation and oncolytic herpesvirus

ATRX is one of the most frequently altered genes in solid tumors, and mutation is especially frequent in soft tissue sarcomas. However, the role of ATRX in tumor development and response to cancer therapies remains poorly understood. Here, we developed a primary mouse model of soft tissue sarcoma and showed that Atrx-deleted tumors were more sensitive to radiation therapy and to oncolytic herpesvirus. In the absence of Atrx, irradiated sarcomas had increased persistent DNA damage, telomere dysfunction, and mitotic catastrophe. Our work also showed that Atrx deletion resulted in downregulation of the CGAS/STING signaling pathway at multiple points in the pathway and was not driven by mutations or transcriptional downregulation of the CGAS/STING pathway components. We found that both human and mouse models of Atrx-deleted sarcoma had a reduced adaptive immune response, markedly impaired CGAS/STING signaling, and increased sensitivity to TVEC, an oncolytic herpesvirus that is currently FDA approved for the treatment of aggressive melanomas. Translation of these results to patients with ATRX-mutant cancers could enable genomically guided cancer therapy approaches to improve patient outcomes.

Tumor necrosis is an underappreciated histopathologic factor in the grading of chondrosarcoma

BACKGROUND

Cartilaginous neoplasms can be challenging to grade; there is a need to create an evidence-based rubric for grading. The goal of this study was to identify histopathologic features of chondrosarcoma that were associated with 5-year survival and to compare these to traditional patient, tumor and treatment variables.

METHODS

This was a retrospective review of all patients undergoing surgical resection of a primary chondrosarcoma with at least 2 years of follow up. All specimens were independently reviewed by two pathologists and histopathologic features scored. Univariate and multivariate analyses were performed utilizing Kaplan Meier and proportional hazards methods to identify variables associated with 5-year disease specific survival (DSS) and disease free survival (DFS).

RESULTS

We identified 51 patients with an average follow up of 49 months eligible for inclusion. 30% of tumors were low grade, 45% were intermediate grade, and 25% were high grade. In a univariate analysis considering histopathologic factors, higher tumor mitotic rate (HR 8.9, p < 0.001), tumor dedifferentiation (HR 7.3, p < 0.001), increased tumor cellularity (HR 5.8, p = 0.001), increased tumor atypia (HR 5.8, p = 0.001), LVI (HR 4.7, p = 0.04) and higher tumor necrosis (HR 3.7, p = 0.02) were all associated with worse 5-year DSS. In a multivariate analysis controlling for potentially confounding variables, higher tumor necrosis was significantly associated with disease specific survival survival (HR 3.58, p = 0.035); none of the factors were associated with DFS.

CONCLUSIONS

This study provides an evidence-based means for considering histopathologic markers and their association with prognosis in chondrosarcoma. Our findings suggest that necrosis and LVI warrant further study.

Intraoperative angiography imaging correlates with wound complications following soft tissue sarcoma resection

For soft tissue sarcoma patients receiving preoperative radiation therapy, wound complications are common and potentially devastating. The purpose of this study was to assess the feasibility of intraoperative indocyanine green fluorescent angiography (ICGA) as a predictor of wound complications in these patients. A consecutive series of patients with soft tissue sarcoma of the extremities or pelvis who received neoadjuvant radiation and a subsequent radical resection received intraoperative ICGA with the SPY PHI device (Stryker Inc.) at the time of closure. Retrospective analysis of fluorescence signal along multiple points of the wound length was performed and quantified. The primary endpoint was wound complication, defined as delayed wound healing or wound dehiscence, within 3 months of surgery. Fourteen patients with preoperative irradiated soft tissue sarcoma were consecutively imaged. There were six patients with wound complications classified as "aseptic" in five cases. Using the ICGA, blinded surgeons correctly predicted wound complications in 75% of cases. During the inflow phase, a mean ratio of normal of 0.62 maximized the area under the curve (AUC = 0.90) for predicting wound complications with a sensitivity of 100% and specificity of 77.4%. During the peak phase, a mean ratio of normal of 0.55 maximized the AUC (0.95) for predicting wound complications with a sensitivity of 88.9% and a specificity of 100%. Intraoperative use of ICGA may help to predict wound complications in patients undergoing resection of preoperatively irradiated soft tissue sarcomas of the extremities and pelvis.

Loss of ATRX promotes aggressive features of osteosarcoma with increased NF-κB signaling and integrin binding

Osteosarcoma (OS) is a lethal disease with few known targeted therapies. Here, we show that decreased ATRX expression is associated with more aggressive tumor cell phenotypes, including increased growth, migration, invasion, and metastasis. These phenotypic changes correspond with activation of NF-κB signaling, extracellular matrix remodeling, increased integrin αvβ3 expression, and ETS family transcription factor binding. Here, we characterize these changes in vitro, in vivo, and in a data set of human OS patients. This increased aggression substantially sensitizes ATRX-deficient OS cells to integrin signaling inhibition. Thus, ATRX plays an important tumor-suppression role in OS, and loss of function of this gene may underlie new therapeutic vulnerabilities. The relationship between ATRX expression and integrin binding, NF-κB activation, and ETS family transcription factor binding has not been described in previous studies and may impact the pathophysiology of other diseases with ATRX loss, including other cancers and the ATR-X α thalassemia intellectual disability syndrome.

Abstract 1061: Exportin 1 (XPO1) inhibition alone or in combination as a novel therapeutic strategy in osteosarcoma

Background: Osteosarcoma is an aggressive bone cancer in which therapeutic advancements have been limited over the last 30 years, in part due to genomic heterogeneity. The combination of high-throughput drug screening platforms that efficiently pinpoint drug sensitivities with patient-derived cross-species models is an innovative approach to address the critical need to identify novel treatment strategies for osteosarcoma patients.

Methods: We performed high-throughput drug screens on patient-derived osteosarcoma cell lines D418 (canine) and 17-3x (human), followed by validation of the top compounds, to identify drug sensitivities and novel therapeutic combinations.

Results: High-throughput drug screens using 2100 bioactive compounds show that osteosarcoma cell lines D418 and 17-3x exhibited sensitivity to standard-of-care chemotherapy drugs, inhibitors of XPO1 nuclear export, and proteasome inhibitors. The XPO1 inhibitor, verdinexor (VER), and the proteasome inhibitor, bortezomib (BORT), induced dose-dependent cytotoxicity in multiple osteosarcoma cell lines (D418, IC50VER: 3187 nM, IC50BORT: 2.8 nM; 17-3x IC50VER: 679 nM, IC50BORT: 10.9 nM). In addition, dual XPO1 and proteasome inhibition synergistically reduced cell proliferation in D418 (synergy score=12.89) and 17-3x (synergy score=17.87) cell lines (p &lt;0.05). Selinexor (SEL), an FDA approved XPO1 inhibitor used in combination with bortezomib to treat multiple myeloma, also demonstrated dose-dependent single-agent activity in patient-derived osteosarcoma cell lines (D418, IC50SEL: 370 nM; 17-3x IC50SEL: 101 nM). With drug screening of 119 oncology compounds in combination with selinexor in 17-3x cells, XPO1 inhibition again shows synergistic activity with proteasome inhibition in osteosarcoma.

Conclusions: Inhibition of XPO1-mediated nuclear export is a promising therapeutic strategy in osteosarcoma. These effects may be further potentiated when used in combination with other agents, such as proteasome inhibitors. Additional drug screening and validation assays are underway to identify novel synergistic agents for use in combination with XPO1 inhibitors in osteosarcoma.

Citation Format: Laurie Graves, Gabrielle Rupprecht, Erdem Altunel, Etienne M. Flamant, Sneha Rao, Dharshan Sivara, Alexander L. Lazarides, Sarah M. Hoskinson, Maya U. Sheth, Serene Cheng, So Young Kim, Kathryn E. Ware, Anika Agarwal, Mark M. Cullen, Casey Syal, Laura E. Selmic, Jeffrey I. Everitt, Shannon J. McCall, Cindy Eward, Trinayan Kashyap, Marie Maloof, Christopher J. Walker, Yosef Landesman, Lars Wagner, William C. Eward, David S. Hsu, Jason A. Somarelli. Exportin 1 (XPO1) inhibition alone or in combination as a novel therapeutic strategy in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1061.

Exome sequencing of hepatocellular carcinoma in lemurs identifies potential cancer drivers: A pilot study

Background and objectives

Hepatocellular carcinoma occurs frequently in prosimians, but the cause of these liver cancers in this group is unknown. Characterizing the genetic changes associated with hepatocellular carcinoma in prosimians may point to possible causes, treatments and methods of prevention, aiding conservation efforts that are particularly crucial to the survival of endangered lemurs. Although genomic studies of cancer in non-human primates have been hampered by a lack of tools, recent studies have demonstrated the efficacy of using human exome capture reagents across primates.

Methodology

In this proof-of-principle study, we applied human exome capture reagents to tumor-normal pairs from five lemurs with hepatocellular carcinoma to characterize the mutational landscape of this disease in lemurs.

Results

Several genes implicated in human hepatocellular carcinoma, including ARID1A, TP53 and CTNNB1, were mutated in multiple lemurs, and analysis of cancer driver genes mutated in these samples identified enrichment of genes involved with TP53 degradation and regulation. In addition to these similarities with human hepatocellular carcinoma, we also noted unique features, including six genes that contain mutations in all five lemurs. Interestingly, these genes are infrequently mutated in human hepatocellular carcinoma, suggesting potential differences in the etiology and/or progression of this cancer in lemurs and humans.

Conclusions and implications

Collectively, this pilot study suggests that human exome capture reagents are a promising tool for genomic studies of cancer in lemurs and other non-human primates.

Lay Summary

Hepatocellular carcinoma occurs frequently in prosimians, but the cause of these liver cancers is unknown. In this proof-of-principle study, we applied human DNA sequencing tools to tumor-normal pairs from five lemurs with hepatocellular carcinoma and compared the lemur mutation profiles to those of human hepatocellular carcinomas.

Investigating readmission rates for patients undergoing oncologic resection and endoprosthetic reconstruction for primary sarcomas and tumors involving bone

BACKGROUND

Little is known about the drivers of readmission in patients undergoing Orthopaedic oncologic resection. The goal of this study was to identify factors independently associated with 90-day readmission for patients undergoing oncologic resection and subsequent prosthetic reconstruction for primary tumors involving bone.

METHODS

This was a retrospective comparative cohort study of patients treated from 2008 to 2019 who underwent endoprosthetic reconstruction for a primary bone tumor or soft tissue tumor involving bone, as well as those who underwent a revision endoprosthetic reconstruction if the primary endoprosthetic reconstruction was performed for an oncologic resection. The primary outcome measure was unplanned 90-day readmission.

RESULTS

A total of 149 patients were identified who underwent 191 surgeries were for a primary bone or soft tissue tumor. The 90-day readmission rate was 28.3%. Female gender, depression, higher tumor grade, vascular reconstruction, longer procedure duration, longer length of stay (LOS), multiple surgeries during an admission and disposition to a Skilled Nursing Facility were associated with readmission (p < 0.05). In a multivariate analysis, female sex, higher tumor grade and longer procedure duration were independently associated with risk of readmission (p < 0.05).

CONCLUSIONS

Readmission rates are high following endoprosthetic reconstruction for Orthopaedic oncologic resections. Further work is necessary to help minimize unplanned readmissions.

Why Do Patients Undergoing Extremity Prosthetic Reconstruction for Metastatic Disease Get Readmitted?

BACKGROUND

Orthopedic oncology patients are particularly susceptible to increased readmission rates and poor surgical outcomes, yet little is known about readmission rates. The goal of this study is to identify factors independently associated with 90-day readmission for patients undergoing oncologic resection and subsequent prosthetic reconstruction for metastatic disease of the hip and knee.

METHODS

This is a retrospective comparative cohort study of all patients treated from 2013 to 2019 at a single tertiary care referral institution who underwent endoprosthetic reconstruction by an orthopedic oncologist for metastatic disease of the extremities. The primary outcome measure was unplanned 90-day readmission.

RESULTS

We identified 112 patients undergoing 127 endoprosthetic reconstruction surgeries. Metastatic disease was most commonly from renal (26.8%), lung (23.6%), and breast (13.4%) cancer. The most common type of skeletal reconstruction performed was simple arthroplasty (54%). There were 43 readmissions overall (33.9%). When controlling for confounding factors, body mass index >40, insurance status, peripheral vascular disease, and longer hospital length of stay were independently associated with risk of readmission (P ≤ .05).

CONCLUSION

Readmission rates for endoprosthetic reconstructions for metastatic disease are high. Although predicting readmission remains challenging, risk stratification presents a viable option for helping minimize unplanned readmissions.

LEVEL OF EVIDENCE

III.

Extent of tumor fibrosis/hyalinization and infarction following neoadjuvant radiation therapy is associated with improved survival in patients with soft-tissue sarcoma

Introduction

Current standard of care for most intermediate and high‐grade soft‐tissue sarcomas (STS) includes limb‐preserving surgical resection with either neoadjuvant radiation therapy (NRT) or adjuvant radiation therapy. To date, there have been a few studies that attempt to correlate histopathologic response to NRT with oncologic outcomes in patients with STS.

Methods

Using our institutional database, we identified 58 patients who received NRT followed by surgical resection for primary intermediate or high‐grade STS and 34 patients who received surgical resection without NRT but did receive adjuvant radiation therapy or did not receive any radiation therapy. We analyzed four histologic parameters of response to therapy: residual viable tumor, fibrosis/hyalinization, necrosis, and infarction (each ratiometrically determined). Data were stratified into two binary groups. Unadjusted, 5‐ and 10‐year overall survival, and relapsed‐free survival (RFS) were calculated using the Kaplan–Meier method.

Results

Analysis of pathologic characteristics showed that patients treated with NRT demonstrate significantly higher tumor infarction, higher tumor fibrosis/hyalinization, and a lower percent viable tumor compared with patients not treated with NRT (p < 0.0001). Based on Kaplan–Meier curve analysis and multivariate cox proportional hazard model for OS and RFS, patients treated with NRT and showing >12.5% tumor fibrosis/hyalinization have significantly higher overall survival and recurrence‐free survival at 5 and 10 years.

Discussion and Conclusion

We have identified three histopathologic characteristics—fibrosis, hyalinization, and infarction—that may serve as predictive biomarkers of response to NRT for STS patients. Future prospective studies will be needed to confirm this association.

Reverse total shoulder arthroplasty for oncologic reconstruction of the proximal humerus: a systematic review

BACKGROUND

In recent years, there has been growing interest in the use of reverse total shoulder arthroplasty (rTSA) for reconstruction of the proximal humerus after oncologic resection. However, the indications and outcomes of oncologic rTSA remain unclear.

METHODS

We conducted a systematic review to identify studies that reported outcomes of patients who underwent rTSA for oncologic reconstruction of the proximal humerus. Extracted data included demographic characteristics, indications, operative techniques, outcomes, and complications. Weighted means were calculated according to sample size.

RESULTS

Twelve studies were included, containing 194 patients who underwent rTSA for oncologic reconstruction of the proximal humerus. The mean patient age was 48 years, and 52% of patients were male. Primary malignancies were present in 55% of patients; metastatic disease, 30%; and benign tumors, 9%. The mean humeral resection length was 12 cm. The mean postoperative Musculoskeletal Tumor Society score was 78%; Constant score, 60; and Toronto Extremity Salvage Score, 77%. The mean complication rate was 28%, with shoulder instability accounting for 63% of complications. Revisions were performed in 16% of patients, and the mean implant survival rate was 89% at a mean follow-up across studies of 53 months.

CONCLUSIONS

Although the existing literature is of poor study quality, with a high level of heterogeneity and risk of bias, rTSA appears to be a suitable option in appropriately selected patients undergoing oncologic resection and reconstruction of the proximal humerus. The most common complication is instability. Higher-quality evidence is needed to help guide decision making on appropriate implant utilization for patients undergoing oncologic resection of the proximal humerus.

A Zebrafish Model of Metastatic Colonization Pinpoints Cellular Mechanisms of Circulating Tumor Cell Extravasation

Metastasis is a multistep process in which cells must detach, migrate/invade local structures, intravasate, circulate, extravasate, and colonize. A full understanding of the complexity of this process has been limited by the lack of ability to study these steps in isolation with detailed molecular analyses. Leveraging a comparative oncology approach, we injected canine osteosarcoma cells into the circulation of transgenic zebrafish with fluorescent blood vessels in a biologically dynamic metastasis extravasation model. Circulating tumor cell clusters that successfully extravasated the vasculature as multicellular units were isolated under intravital imaging (n = 6). These extravasation-positive tumor cell clusters sublines were then molecularly profiled by RNA-Seq. Using a systems-level analysis, we pinpointed the downregulation of KRAS signaling, immune pathways, and extracellular matrix (ECM) organization as enriched in extravasated cells (p < 0.05). Within the extracellular matrix remodeling pathway, we identified versican (VCAN) as consistently upregulated and central to the ECM gene regulatory network (p < 0.05). Versican expression is prognostic for a poorer metastasis-free and overall survival in patients with osteosarcoma. Together, our results provide a novel experimental framework to study discrete steps in the metastatic process. Using this system, we identify the versican/ECM network dysregulation as a potential contributor to osteosarcoma circulating tumor cell metastasis.

Identifying Modifiable and Non-modifiable Risk Factors of Readmission and Short-Term Mortality in Chondrosarcoma: A National Cancer Database Study

BACKGROUND

Limited data are available to inform the risk of readmission and short-term mortality in musculoskeletal oncology. The goal of this study was to identify factors independently associated with 30-day readmission and 90-day mortality following surgical resection of chondrosarcoma.

METHODS

We retrospectively reviewed 6653 patients following surgical resection of primary chondrosarcoma in the National Cancer Database (2004-2017). Both demographic and clinicopathologic variables were assessed for correlation with readmission and short-term mortality utilizing univariate and multivariate logistic regression modeling.

RESULTS

Of 220 readmissions (3.26%), risk factors independently associated with an increased risk of unplanned 30-day readmission included Charlson-Deyo Comorbidity Index (CDCC) (odds ratio [OR] 1.31; p = 0.027), increasing American Joint Committee on Cancer (AJCC) stage (OR 1.31; p = 0.004), undergoing major amputation (OR 2.38; p = 0.001), and axial skeletal location (OR 1.51; p = 0.028). A total of 137 patients died within 90 days of surgery (2.25%). Risk factors associated with increased mortality included the CDCC (OR 1.60; p = 0.001), increasing age (OR 1.06; p < 0.001), having Medicaid insurance status (OR 3.453; p = 0.005), living in a zip code with a higher educational attainment (OR 1.59; p = 0.003), increasing AJCC stage (OR 2.32; p < 0.001), longer postoperative length of stay (OR 1.015; p = 0.033), and positive surgical margins (OR 2.75; p = 0.001). Although a majority of the cohort did not receive radiation therapy (88.8%), receiving radiotherapy (OR 0.132; p = 0.010) was associated with a decreased risk of short-term mortality.

CONCLUSIONS

Several tumor, treatment, and patient factors can help inform the risk of readmission and short-term mortality in patients with surgically treated chondrosarcoma.

Identifying Modifiable and Non-modifiable Risk Factors of Readmission and Short-Term Mortality in Osteosarcoma: A National Cancer Database Study

BACKGROUND

There are limited data to inform risk of readmission and short-term mortality in musculoskeletal oncology. The goal of this study was to identify factors independently associated with 30-day readmission and 90-day mortality following surgical resection of osteosarcoma.

METHODS

We retrospectively reviewed patients (n = 5293) following surgical resection of primary osteosarcoma in the National Cancer Database (2004-2015). Univariate and multivariate methods were used to correlate variables with readmission and short-term mortality.

RESULTS

Of 210 readmissions (3.97%), risk factors independently associated with unplanned 30-day readmission included comorbidity burden (odds ratio [OR] 2.4, p = 0.042), Medicare insurance (OR 1.9, p = 0.021), and axial skeleton location (OR 1.5, p = 0.029). A total of 91 patients died within 90 days of their surgery (1.84%). Risk factors independently associated with mortality included age (hazard ratio 1.1, p < 0.001), increasing comorbidity burden (OR 6.6, p = 0.001), higher grade (OR 1.7, p = 0.007), increasing tumor size (OR 2.2, p = 0.03), metastatic disease at presentation (OR 8.5, p < 0.001), and amputation (OR 2.0, p = 0.04). Chemotherapy was associated with a decreased risk of short-term mortality (p < 0.001).

CONCLUSIONS

Several trends were clear: insurance status, tumor location and comorbidity burden were independently associated with readmission rates, while age, amputation, grade, tumor size, metastatic disease, and comorbidity burden were independently associated with short-term mortality.

Treatment of Chondroblastoma with Denosumab: A Case Report with a Correlative Analysis of Effect on the RANK Signaling Pathway

CASE

A 15-year-old boy with chondroblastoma of the right hemipelvis presented with significant periacetabular bone destruction. Neoadjuvant denosumab treatment facilitated initial joint preserving surgery. Unfortunately, he experienced 2 local recurrences and underwent wide surgical resection 2 years after his initial diagnosis.

CONCLUSION

Inhibition of the receptor activator of NF-κB (RANK)/RANK ligand (RANK-L) pathway with denosumab has been used neoadjuvantly for the treatment of giant cell tumor of bone, but its role in the treatment of chondroblastoma is less understood. This patient's clinical response and effect on cellular RANK/RANK-L activity support the consideration of denosumab in the treatment algorithm for other osteolytic bone tumors such as chondroblastoma.

An integrated comparative physiology and molecular approach pinpoints mediators of breath-hold capacity in dolphins

Background and objectives

Ischemic events, such as ischemic heart disease and stroke, are the number one cause of death globally. Ischemia prevents blood, carrying essential nutrients and oxygen, from reaching tissues, leading to cell and tissue death, and eventual organ failure. While humans are relatively intolerant to ischemic events, other species, such as marine mammals, have evolved a unique tolerance to chronic ischemia/reperfusion during apneic diving. To identify possible molecular features of an increased tolerance for apnea, we examined changes in gene expression in breath-holding dolphins.

Methodology

Here, we capitalized on the adaptations possesed by bottlenose dolphins (Tursiops truncatus) for diving as a comparative model of ischemic stress and hypoxia tolerance to identify molecular features associated with breath holding. Given that signals in the blood may influence physiological changes during diving, we used RNA-Seq and enzyme assays to examine time-dependent changes in gene expression in the blood of breath-holding dolphins.

Results

We observed time-dependent upregulation of the arachidonate 5-lipoxygenase (ALOX5) gene and increased lipoxygenase activity during breath holding. ALOX5 has been shown to be activated during hypoxia in rodent models, and its metabolites, leukotrienes, induce vasoconstriction.

Conclusions and implications

The upregulation of ALOX5 mRNA occurred within the calculated aerobic dive limit of the species, suggesting that ALOX5 may play a role in the dolphin’s physiological response to diving, particularly in a pro-inflammatory response to ischemia and in promoting vasoconstriction. These observations pinpoint a potential molecular mechanism by which dolphins, and perhaps other marine mammals, respond to the prolonged breath holds associated with diving.

A Comparative Oncology Drug Discovery Pipeline to Identify and Validate New Treatments for Osteosarcoma

Simple Summary

Osteosarcoma is a rare bone cancer that occurs primarily in children. The discovery of new treatments for osteosarcoma and other rare cancer types has been severely limited by access to patient samples to study these often-complex diseases. Here we capitalize on naturally-occurring cancers in pet dogs to study the biology of these rare cancers. Using living cells from canine and human patients to test thousands of drugs simultaneously, we identify a unique combination of drugs that disrupts protein degradation and protein trafficking in cancer cells. This drug combination represents a promising new treatment to treat both dogs and people with osteosarcoma.

Abstract

Background: Osteosarcoma is a rare but aggressive bone cancer that occurs primarily in children. Like other rare cancers, treatment advances for osteosarcoma have stagnated, with little improvement in survival for the past several decades. Developing new treatments has been hampered by extensive genomic heterogeneity and limited access to patient samples to study the biology of this complex disease. Methods: To overcome these barriers, we combined the power of comparative oncology with patient-derived models of cancer and high-throughput chemical screens in a cross-species drug discovery pipeline. Results: Coupling in vitro high-throughput drug screens on low-passage and established cell lines with in vivo validation in patient-derived xenografts we identify the proteasome and CRM1 nuclear export pathways as therapeutic sensitivities in osteosarcoma, with dual inhibition of these pathways inducing synergistic cytotoxicity. Conclusions: These collective efforts provide an experimental framework and set of new tools for osteosarcoma and other rare cancers to identify and study new therapeutic vulnerabilities.

Limb salvage versus amputation in patients with osteosarcoma of the extremities: an update in the modern era using the National Cancer Database

BACKGROUND

Historically, amputation was the primary surgical treatment for osteosarcoma of the extremities; however, with advancements in surgical techniques and chemotherapies limb salvage has replaced amputation as the dominant treatment paradigm. This study assessed the type of surgical resection chosen for osteosarcoma patients in the twenty-first century.

METHODS

Utilizing the largest registry of primary osteosarcoma, the National Cancer Database (NCDB), we retrospectively analyzed patients with high grade osteosarcoma of the extremities from 2004 through 2015. Differences between patients undergoing amputation and patients undergoing limb salvage are described. Unadjusted five-year overall survival between patients who received limb salvage and amputation was assessed utilizing Kaplan Meier curves. A multivariate Cox proportional hazard model and propensity matched analysis was used to determine the variables independently correlated with survival.

RESULTS

From a total of 2442 patients, 1855 underwent limb salvage and 587 underwent amputation. Patients undergoing amputation were more likely to be older, male, uninsured, and live in zip codes associated with lower income. Patients undergoing amputation were also more likely to have larger tumors, more comorbid conditions, and metastatic disease at presentation. After controlling for confounders, limb salvage was associated with a significant survival benefit over amputation (HR: 0.70; p < 0.001). Although this may well reflect underlying biases impacting choice of treatment, this survival benefit remained significant after propensity matched analysis of all significantly different independent variables (HR: 0.71; p < 0.01).

CONCLUSION

Among patients in the NCDB, amputation for osteosarcoma is associated with advanced age, advanced stage, larger tumors, greater comorbidities, and lower income. Limb salvage is associated with a significant survival benefit, even when controlling for significant confounding variables and differences between cohorts.

Tumor Subtype Determines Therapeutic Response to Chimeric Polypeptide Nanoparticle-based Chemotherapy in Pten-deleted Mouse Models of Sarcoma

PURPOSE

Nanoparticle-encapsulated drug formulations can improve responses to conventional chemotherapy by increasing drug retention within the tumor and by promoting a more effective antitumor immune response than free drug. New drug delivery modalities are needed in sarcomas because they are often chemoresistant cancers, but the rarity of sarcomas and the complexity of diverse subtypes makes it challenging to investigate novel drug formulations.

EXPERIMENTAL DESIGN

New drug formulations can be tested in animal models of sarcomas where the therapeutic response of different formulations can be compared using mice with identical tumor-initiating mutations. Here, using Cre/loxP and CRISPR/Cas9 techniques, we generated two distinct mouse models of Pten-deleted soft-tissue sarcoma: malignant peripheral nerve sheath tumor (MPNST) and undifferentiated pleomorphic sarcoma (UPS). We used these models to test the efficacy of chimeric polypeptide doxorubicin (CP-Dox), a nanoscale micelle formulation, in comparison with free doxorubicin.

RESULTS

The CP-Dox formulation was superior to free doxorubicin in MPNST models. However, in UPS tumors, CP-Dox did not improve survival in comparison with free doxorubicin. While CP-Dox treatment resulted in elevated intratumoral doxorubicin concentrations in MPNSTs, this increase was absent in UPS tumors. In addition, elevation of CD8+ T cells was observed exclusively in CP-Dox-treated MPNSTs, although these cells were not required for full efficacy of the CP nanoparticle-based chemotherapy.

CONCLUSIONS

These results have important implications for treating sarcomas with nanoparticle-encapsulated chemotherapy by highlighting the tumor subtype-dependent nature of therapeutic response.

Defining a textbook surgical outcome for patients undergoing surgical resection of intermediate and high-grade soft tissue sarcomas of the extremities

BACKGROUND

Quality measures for the surgical management soft tissue sarcoma of the extremity are limited. The purpose of this study was to define a textbook surgical outcome (TO) for soft tissue sarcoma of the extremities (STS-E) and to examine its associations with hospital volume and overall survival.

METHODS

All patients in the National Cancer Database undergoing resection of primary STS-E between 2004 and 2015 were identified. The primary outcome was a TO, defined as: hospital length of stay (LOS) <75th percentile, survival >90 days from the date of surgery, no readmission within 30 days of discharge, and negative surgical margins (R0 resection).

RESULTS

Overall, 7658 patients met criteria for inclusion; a TO was achieved in 4291 (56%) patients. Of patients who did not achieve TOs, 51.9% (n = 1748) had an extended LOS, and 47.3% (n = 1591) did not have negative margins. Older age, more medical comorbidities, and non-white or black race were independently associated with not receiving a TO (P = .034). With respect to tumor and treatment characteristics, larger tumor size, lower extremity location and higher grade were independently associated with not receiving a TO (P < .001). Hospital volume was not associated with a TO. TOs conferred a significant survival benefit (hazrds ratio = 0.71 [0.65-0.78], P < .001). A TO was associated with a 27.5% longer survival time (P < .001).

CONCLUSIONS

This study defined a TO in intermediate and high-grade STS-E and demonstrated that this outcome measure is associated with overall survival. Facility volume was not associated with a TO.

Does facility volume influence survival in patients with primary malignant bone tumors of the vertebral column? A comparative cohort study

BACKGROUND CONTEXT

Facility volume has been correlated with survival in many cancers. This relationship has not been established in primary malignant bone tumors of the vertebral column (BTVC).

PURPOSE

To investigate whether facility patient volume is associated with overall survival in patients with primary malignant BTVCs.

STUDY DESIGN

Retrospective comparative cohort.

PATIENT SAMPLE

Adult patients with chordomas, chondrosarcomas, or osteosarcomas of the mobile spine.

OUTCOME MEASURES

Five-year survival.

METHODS

We retrospectively analyzed 733 patients with primary malignant BTVCs in the national cancer database from 2004 through 2015. Univariate and multivariate analyses were used to correlate specific outcome measures with facility volume. Volume was stratified based on cumulative martingale residuals to determine the inflection point of negative to positive impact on survival based on the patient cohort. Long-term survival was compared between patients treated at high and low volume using the Kaplan-Meier method. Only patients with malignant primary tumors were considered eligible for inclusion; patients with incomplete treatment data or benign tumors were excluded.

RESULTS

Patients treated at high-volume centers (HVCs) were younger (p=.0003) and more likely to be insured (p<.0001). There were no significant differences in tumor characteristics. Patients treated at high-volume facilities had improved 5-year survival of 71% versus 58% at low-volume centers (p<.0001). Patients treated at HVCs were more likely to receive surgical treatment (91% vs. 80%, p<.0001); if surgery was performed, they were more likely to undergo an en bloc resection (48% vs. 30%, p<.0001). However, there were no differences in margin status or utilization of radiotherapy or chemotherapy between HVCs and low-volume centers. In a multivariate analysis, facility volume was independently associated with improved survival overall (HR 0.75 [0.58-0.97], p=.03).

CONCLUSIONS

Primary malignant BTVCs are rare, even for HVCs. Despite this, patient survival was significantly improved when treatment was performed at HVCs.

Extirpative Cultures Reveal Infectious Pubic Bone Osteomyelitis in Prostate Cancer Survivors With Urinary-Pubic Symphysis Fistulae (UPF)

OBJECTIVE

To examine the infectious features of patients with urinary pubic symphysis fistula (UPF) and their association with osteomyelitis.

METHODS

We conducted a review of our quality improvement database for 36 patients with UPF undergoing bone resection and extirpative surgery from October 2012 to January 2019. An assessment of bone and urine cultures was carried out along with surgical, radiologic, and demographic data. We analyzed descriptive statistics and used Fisher Exact Tests and unpaired Welch t tests to assess for associations with positive bone cultures.

RESULTS

In our cohort, 33 patients (91.7%) had positive bone cultures with the 3 most common organisms being candida (22.0%), enterococcus (18.0%), and pseudomonas (10.0%). There was a correlation between positive preoperative urine culture and positive bone culture (P <.01), with 63.0% of those with positive urine cultures growing the same organism on bone culture.

CONCLUSION

In this series, 91.7% of patients undergoing extirpative surgery for UPF at our institution have positive bone cultures at time of pubic bone debridement. Additionally, we demonstrate a statistically significant correlation between positive urine cultures and positive bone cultures in these patients. This supports the need for a multidisciplinary approach including infectious disease, orthopedic surgery and reconstructive urology in order to address this complex clinical condition.

Preclinical Testing of a Novel Niclosamide Stearate Prodrug Therapeutic (NSPT) Shows Efficacy Against Osteosarcoma

Therapeutic advances for osteosarcoma have stagnated over the past several decades, leading to an unmet clinical need for patients. The purpose of this study was to develop a novel therapy for osteosarcoma by reformulating and validating niclosamide, an established anthelminthic agent, as a niclosamide stearate prodrug therapeutic (NSPT). We sought to improve the low and inefficient clinical bioavailability of oral dosing, especially for the relatively hydrophobic classes of anticancer drugs. Nanoparticles were fabricated by rapid solvent shifting and verified using dynamic light scattering and UV-vis spectrophotometry. NSPT efficacy was then studied in vitro for cell viability, cell proliferation, and intracellular signaling by Western blot analysis; ex vivo pulmonary metastatic assay model; and in vivo pharmacokinetic and lung mouse metastatic model of osteosarcoma. NSPT formulation stabilizes niclosamide stearate against hydrolysis and delays enzymolysis; increases circulation in vivo with t _1/2 approximately 5 hours; reduces cell viability and cell proliferation in human and canine osteosarcoma cells in vitro at 0.2-2 μmol/L IC₅₀; inhibits recognized growth pathways and induces apoptosis at 20 μmol/L; eliminates metastatic lesions in the ex vivo lung metastatic model; and when injected intravenously at 50 mg/kg weekly, it prevents metastatic spread in the lungs in a mouse model of osteosarcoma over 30 days. In conclusion, niclosamide was optimized for preclinical drug delivery as a unique prodrug nanoparticle injected intravenously at 50 mg/kg (1.9 mmol/L). This increased bioavailability of niclosamide in the blood stream prevented metastatic disease in the mouse. This chemotherapeutic strategy is now ready for canine trials, and if successful, will be targeted for human trials in patients with osteosarcoma.

From the Clinic to the Bench and Back Again in One Dog Year: How a Cross-Species Pipeline to Identify New Treatments for Sarcoma Illuminates the Path Forward in Precision Medicine

Cancer drug discovery is an inefficient process, with more than 90% of newly-discovered therapies failing to gain regulatory approval. Patient-derived models of cancer offer a promising new approach to identify new treatments; however, for rare cancers, such as sarcomas, access to patient samples is limited, which precludes development of patient-derived models. To address the limited access to patient samples, we have turned to pet dogs with naturally-occurring sarcomas. Although sarcomas make up <1% of all human cancers, sarcomas represent 15% of cancers in dogs. Because dogs have similar immune systems, an accelerated pace of cancer progression, and a shared environment with humans, studying pet dogs with cancer is ideal for bridging gaps between mouse models and human cancers. Here, we present our cross-species personalized medicine pipeline to identify new therapies for sarcomas. We explore this process through the focused study of a pet dog, Teddy, who presented with six synchronous leiomyosarcomas. Using our pipeline we identified proteasome inhibitors as a potential therapy for Teddy. Teddy was treated with bortezomib and showed a varied response across tumors. Whole exome sequencing revealed substantial genetic heterogeneity across Teddy's recurrent tumors and metastases, suggesting that intra-patient heterogeneity and tumoral adaptation were responsible for the heterogeneous clinical response. Ubiquitin proteomics coupled with exome sequencing revealed multiple candidate driver mutations in proteins related to the proteasome pathway. Together, our results demonstrate how the comparative study of canine sarcomas offers important insights into the development of personalized medicine approaches that can lead to new treatments for sarcomas in both humans and canines.

Improving Cancer Drug Discovery by Studying Cancer across the Tree of Life

Despite a considerable expenditure of time and resources and significant advances in experimental models of disease, cancer research continues to suffer from extremely low success rates in translating preclinical discoveries into clinical practice. The continued failure of cancer drug development, particularly late in the course of human testing, not only impacts patient outcomes, but also drives up the cost for those therapies that do succeed. It is clear that a paradigm shift is necessary if improvements in this process are to occur. One promising direction for increasing translational success is comparative oncology-the study of cancer across species, often involving veterinary patients that develop naturally-occurring cancers. Comparative oncology leverages the power of cross-species analyses to understand the fundamental drivers of cancer protective mechanisms, as well as factors contributing to cancer initiation and progression. Clinical trials in veterinary patients with cancer provide an opportunity to evaluate novel therapeutics in a setting that recapitulates many of the key features of human cancers, including genomic aberrations that underly tumor development, response and resistance to treatment, and the presence of comorbidities that can affect outcomes. With a concerted effort from basic scientists, human physicians and veterinarians, comparative oncology has the potential to enhance the cost-effectiveness and efficiency of pipelines for cancer drug discovery and other cancer treatments.

Common genetic variation and risk of osteosarcoma in a multi-ethnic pediatric and adolescent population

Osteosarcoma, a malignant primary bone tumor most commonly diagnosed in children and adolescents, has a poorly understood genetic etiology. Genome-wide association studies (GWAS) and candidate-gene analyses have identified putative risk variants in subjects of European ancestry. However, despite higher incidence among African-American and Hispanic children, little is known regarding common heritable variation that contributes to osteosarcoma incidence and clinical presentation across racial/ethnic groups. In a multi-ethnic sample of non-Hispanic white, Hispanic, African-American and Asian/Pacific Islander children (537 cases, 2165 controls), we performed association analyses assessing previously-reported loci for osteosarcoma risk and metastasis, including meta-analysis across racial/ethnic groups. We also assessed a previously described association between genetic predisposition to longer leukocyte telomere length (LTL) and osteosarcoma risk in this independent multi-ethnic dataset. In our sample, we were unable to replicate previously-reported loci for osteosarcoma risk or metastasis detected in GWAS of European-ancestry individuals in either ethnicity-stratified analyses or meta-analysis across ethnic groups. Our analyses did confirm that genetic predisposition to longer LTL is a risk factor for osteosarcoma (ORmeta: 1.22; 95% CI: 1.09-1.36; P = 3.8 × 10-4), and the strongest effect was seen in Hispanic subjects (OR: 1.32; 95% CI: 1.12-1.54, P = 6.2 × 10-4). Our findings shed light on the replicability of osteosarcoma risk loci across ethnicities and motivate further characterization of these genetic factors in diverse clinical cohorts.

Epidemiologic and survival trends in adult primary bone tumors of the spine

BACKGROUND CONTEXT

Malignant primary spinal tumors are rare making it difficult to perform large studies comparing epidemiologic, survival, and treatment trends. We investigated the largest registry of primary bone tumors, the National Cancer Database (NCDB), to compare epidemiologic and survival trends among these tumors.

PURPOSE

To use the NCDB to describe current epidemiologic trends, treatment modalities, and overall survival rates in patients with chordomas, osteosarcomas, chondrosarcomas, and Ewing sarcomas of the mobile spine. The secondary objective was to determine prognostic factors that impact overall survival rates.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

A total of 1,011 patients with primary bone tumors of the spine (377 chordomas, 223 chondrosarcomas, 278 Ewing sarcomas, and 133 osteosarcomas).

OUTCOME MEASURES

Five-year survival.

METHODS

We reviewed the records of 1,011 patients in the NCDB from 2004 through 2015 with histologically confirmed primary osteosarcoma, chondrosarcoma, Ewing sarcoma, or chordoma of the spine. Demographic, clinical, and outcomes data were compiled and compared using chi-squared tests and ANOVA. Long-term survival was compared using the Kaplan-Meier method with statistical comparisons based on the log-rank test. Multivariate analysis was performed to determine survival determinants.

RESULTS

Surgical resection was the primary mode of treatment for chondrosarcoma (90%), chordoma (84%), and osteosarcoma (80%). The treatment for Ewing sarcoma was multimodal involving chemotherapy, radiation therapy, and surgical resection. Five-year survival rates varied significantly with chordomas and chondrosarcomas having the greatest survival (70% and 69%), osteosarcomas having the worse survival (38%), and Ewing having intermediate 5-year survival at 62% (overall log-rank p<.0001). Multivariate analysis demonstrated significantly improved 5-year survival rates with younger age at diagnosis, private insurance status, lower comorbidity score, lower tumor grade, smaller tumor size, surgical resection, and negative surgical margin. Radiation therapy only improved survival for Ewing sarcoma.

CONCLUSIONS

This study provides the most comprehensive description of the epidemiologic, treatment, and survival trends of primary bone tumors of the mobile spine. Second, patient and tumor characteristics associated with improved 5-year survival were identified using a multivariate model.

Recurrent Extradural Myxopapillary Ependymoma With Oligometastatic Spread

Myxopapillary ependymomas are a slow-growing, grade I type glial tumor in the lumbosacral region. More rarely, they can present as extradural, subcutaneous sacrococcygeal, or perisacral masses, and it is under these circumstances that they are more likely to spread. Here, we report the presentation of a sacrococcygeal mass in patient that was initially resected confirming extradural myxopapillary ependymoma. At initial resection, multiple small pulmonary nodules were detected. This mass recurred 2 years later at the resection site with an interval increase in the previously imaged pulmonary nodules. Resection of both the post-sacral mass and largest lung metastasis confirmed recurrent myxopapillary ependymoma with oligometastatic spread. Because these tumors are rare, with extradural presentation being even more infrequent, to this date there are no definitive therapeutic guidelines for initial treatment and continued surveillance. For myxopapillary ependymoma, current standard of care is first-line maximal surgical resection with or without postoperative radiotherapy depending on the extent of disease and extent of resection. However, there remains insufficient evidence on the role of radiotherapy to oligometastatic foci in providing any further survival benefit or extending time to recurrence. Thus, prospective studies assessing the role of upfront treatment of oligometastases with local resection and adjuvant radiotherapy are needed for improved understanding of extradural myxopapillary ependymoma.

Immune dysregulation and osteosarcoma: Staphylococcus aureus downregulates TGF-β and heightens the inflammatory signature in human and canine macrophages suppressed by osteosarcoma

Since William Coley utilized bacterial immunotherapy to treat sarcomas in the late 19th century, an association between infection and improved survival has been reported for human and canine osteosarcoma patients. One of the reasons for this improved survival is likely a reactivation of the host immune system towards an inflammatory anti-tumour response, and one of the key players is the macrophage. Yet, despite their importance, the response of macrophages to infectious agents in the context of osteosarcoma has not been thoroughly evaluated. The aim of this study was to evaluate how in vitro exposure to a bacterial agent (Staphylococcus aureus) influenced canine and human macrophage differentiation in the presence of osteosarcoma. Our hypothesis was that S. aureus would, in the presence of osteosarcoma, induce a macrophage phenotype with significantly increased inflammatory signatures. Consistent with our hypothesis, human macrophages co-cultured with osteosarcoma and S. aureus exhibited increased IFN-γ, TNF-α and IL-12p70 cytokine secretion, decreased TGF-β cytokine secretion and increased mRNA expression of TNF-α when compared with macrophages co-cultured with osteosarcoma and to macrophages cultured alone. Canine macrophages similarly exhibited increased IFN-γ and TNF-α cytokine secretion, decreased TGF-β cytokine secretion, increased mRNA expression of TNF-α and increased surface receptor expression of CD80 when co-cultured with osteosarcoma and S. aureus. Collectively, the findings of this study suggest that infection upregulates the inflammatory immune response to counteract osteosarcoma-induced immune suppression. This work informs a potential therapeutic strategy to optimize inflammatory stimuli for triggering an anti-osteosarcoma macrophage response.

E-Cadherin Represses Anchorage-Independent Growth in Sarcomas through Both Signaling and Mechanical Mechanisms

CDH1 (also known as E-cadherin), an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining adherens junctions, regulating migration and invasion, and mediating intracellular signaling. Downregulation of E-cadherin is a hallmark of epithelial-to-mesenchymal transition (EMT) and correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly understood. Here, by combining mathematical models with wet-bench experiments, we identify the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional consequences. Unlike carcinomas, E-cadherin overexpression in sarcomas does not induce a mesenchymal-to-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts to downregulate phosphorylated CREB1 (p-CREB) and the transcription factor, TBX2, to inhibit anchorage-independent growth. RNAi-mediated knockdown of TBX2 phenocopies the effect of E-cadherin on CREB levels and restores sensitivity to anchorage-independent growth in sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by preventing anchorage-independent growth. IMPLICATIONS: We highlight how E-cadherin can restrict aggressive behavior in sarcomas through both biochemical signaling and biomechanical effects.

An Integrative Systems Biology and Experimental Approach Identifies Convergence of Epithelial Plasticity, Metabolism, and Autophagy to Promote Chemoresistance

The evolution of therapeutic resistance is a major cause of death for cancer patients. The development of therapy resistance is shaped by the ecological dynamics within the tumor microenvironment and the selective pressure of the host immune system. These selective forces often lead to evolutionary convergence on pathways or hallmarks that drive progression. Thus, a deeper understanding of the evolutionary convergences that occur could reveal vulnerabilities to treat therapy-resistant cancer. To this end, we combined phylogenetic clustering, systems biology analyses, and molecular experimentation to identify convergences in gene expression data onto common signaling pathways. We applied these methods to derive new insights about the networks at play during transforming growth factor-β (TGF-β)-mediated epithelial–mesenchymal transition in lung cancer. Phylogenetic analyses of gene expression data from TGF-β-treated cells revealed convergence of cells toward amine metabolic pathways and autophagy during TGF-β treatment. Knockdown of the autophagy regulatory, ATG16L1, re-sensitized lung cancer cells to cancer therapies following TGF-β-induced resistance, implicating autophagy as a TGF-β-mediated chemoresistance mechanism. In addition, high ATG16L expression was found to be a poor prognostic marker in multiple cancer types. These analyses reveal the usefulness of combining evolutionary and systems biology methods with experimental validation to illuminate new therapeutic vulnerabilities for cancer.

Microsurgery in musculoskeletal oncology

Sarcomas are rare mesenchymal bone and soft tissue tumors of the musculoskeletal system. In the past, the primary treatment modality was amputation of the involved limb and the 5-year survival was very low for high-grade tumors. During the last three decades, limb salvage has become the rule rather than the exception and the use of neoadjuvant and adjuvant therapies (radiation and chemotherapy) has dramatically increased disease-free survival. Reconstruction of large bone and soft tissue defects, though, still remains a significant challenge in sarcoma patients. In particular, vascularized tissue transfer has proved extremely helpful in dealing with complex bone and soft tissue or functional defects that are frequently encountered as a result of the tumor or as a complication of surgery and adjuvant therapies. The principles, indications and results of microsurgical reconstruction differ from trauma patients and are directly related not only to the underlying disease process, but also to the local and systemic therapeutic modalities applied to the individual patient. Although plastic reconstruction in the oncological patients is not free of complications, usually these complications are manageable and do not jeopardize oncological outcome. The overall treatment strategy should be tailored to the patient's and sarcoma profile.

Genetic determinants of childhood and adult height associated with osteosarcoma risk

BACKGROUND

Although increased height has been associated with osteosarcoma risk in previous epidemiologic studies, to the authors' knowledge the relative contribution of stature during different developmental timepoints remains unclear. Furthermore, the question of how genetic determinants of height impact osteosarcoma etiology remains unexplored. Genetic variants associated with stature in previous genome-wide association studies may be biomarkers of osteosarcoma risk.

METHODS

The authors tested the associations between osteosarcoma risk and polygenic scores for adult height (416 variants), childhood height (6 variants), and birth length (5 variants) in 864 osteosarcoma cases and 1879 controls of European ancestry.

RESULTS

Each standard deviation increase in the polygenic score for adult height, corresponding to a 1.7-cm increase in stature, was found to be associated with a 1.10-fold increase in the risk of osteosarcoma (95% confidence interval [95% CI], 1.01-1.19; P =.027). Each standard deviation increase in the polygenic score for childhood height, corresponding to a 0.5-cm increase in stature, was associated with a 1.10-fold increase in the risk of osteosarcoma (95% CI, 1.01-1.20; P =.023). The polygenic score for birth length was not found to be associated with osteosarcoma risk (P =.11). When adult and childhood height scores were modeled together, they were found to be independently associated with osteosarcoma risk (P =.037 and P = .043, respectively). An expression quantitative trait locus for cartilage intermediate layer protein 2 (CILP2), rs8103992, was significantly associated with osteosarcoma risk after adjustment for multiple comparisons (odds ratio, 1.35; 95% CI, 1.16-1.56 [P = 7.93×10-5 and Padjusted =.034]).

CONCLUSIONS

A genetic propensity for taller adult and childhood height attainments contributed independently to osteosarcoma risk in the current study data. These results suggest that the biological pathways affecting normal bone growth may be involved in osteosarcoma etiology.

Synovial Chondromatosis

Synovial chondromatosis is a rare, benign condition of unknown etiology in which the synovium undergoes metaplasia leading to cartilaginous nodules that ultimately break free, mineralize, and even ossify. The most commonly involved joint is the knee. Patients may be asymptomatic or may present with pain, swelling, and limited range of motion. Plain radiographs can be diagnostic and mineralized nodules are pathognomonic. Recommended treatment involves arthroscopic or open removal of loose bodies with or without a synovectomy to prevent further articular and periarticular destruction and to relieve symptoms.

Race is an independent predictor of survival in patients with soft tissue sarcoma of the extremities

BACKGROUND

In the United States, race and socioeconomic status are well known predictors of adverse outcomes in several different cancers. Existing evidence suggests that race and socioeconomic status may impact survival in soft tissue sarcoma (STS). We investigated the National Cancer Database (NCDB), which contains several socioeconomic and medical variables and contains the largest sarcoma patient registry to date. Our goal was to determine the impact of race, ethnicity and socioeconomic status on patient survival in patients with soft tissue sarcoma of the extremities (STS-E).

METHODS

We retrospectively analyzed 14,067 STS-E patients in the NCDB from 1998 through 2012. Patients were stratified based on race, ethnicity and socioeconomic status. Univariate and multivariate analyses were used to correlate specific outcomes and survival measures with these factors. Then, long-term survival between groups was evaluated using the Kaplan-Meier (KM) method with comparisons based on the log-rank test. Multiple variables were analyzed between two groups.

RESULTS

Of the 14,067 patients analyzed, 84.9% were white, 11% were black and 4.1% were Asian. Black patients were significantly more likely (7.18% vs 5.65% vs 4.47%) than white or Asian patients to receive amputation (p = 0.027). Black patients were also less likely to have either an above-median education level or an above-median income level (p < 0.001). In addition, black patients were more likely to be uninsured (p < 0.001) and more likely to have a higher Charleson Comorbidity Score than white or Asian patients. Tumors were larger in size upon presentation in black patients than in white or Asian patients (p < 0.001). Black patients had significantly poorer overall survival than did white or Asian patients (p < 0.001) with a KM 5-year survival of 61.4% vs 66.9% and 69.9% respectively, and a 24% higher independent likelihood of dying in a multivariate analysis.

CONCLUSION

This large database review reveals concerning trends in black patients with STS-E. These include larger tumors, poorer resources, a greater likelihood of amputation, and poorer survival than white and Asian patients. Future studies are warranted to help ensure adequate access to effective treatment for all patients.

Abstract A17: Generation and comparison of CRISPR/Cas9 and Cre-mediated genetically engineered mouse models of sarcoma

Genetically engineered mouse models (GEMMs) that employ site-specific recombinase (SSR) technology are important tools for cancer research, and recently the CRISPR/Cas9 system has been increasingly utilized to model cancer in mice. Here, we used CRISPR/Cas9 to generate two primary mouse models of sarcoma, undifferentiated pleomorphic sarcoma (UPS) in a GEMM, and malignant peripheral nerve sheath tumor (MPNST) in wild-type mice, to demonstrate the versatility of the system to generate multiple soft-tissue sarcoma subtypes. Because CRISPR technology is becoming more prevalent in cancer modeling, it is critical to thoroughly evaluate if these models are indeed comparable as tools to study cancer biology compared to conventional GEMMs initiated by recombinase technology. We used two Kras-driven sarcoma models of UPS generated with either Cre recombinase technology or CRISPR/Cas9 technology and compared the mutational profiles, histology, and growth kinetics of these models. KrasLSL-G12D/+; Rosa26LSL-Cas9-EGFP/+ (KC) mice received intramuscular delivery of an adenovirus expressing Cre recombinase and a single guide RNA (sgRNA) targeting Trp53. Cre-mediated expression of oncogenic Kras and Cas9, in combination with CRISPR/Cas9-mediated knockout of Trp53, was sufficient to generate primary soft-tissue sarcomas. Compared to the Cre/loxP model, we determined that sarcomas generated with CRISPR/Cas9 had similar growth kinetics, histology, copy number variation, and mutational load as assessed by whole-exome sequencing. We also demonstrated that off-target mutations in the sarcomas initiated by the Cas9 endonuclease were rare in tumors. Finally, we analyzed the Cas9-mediated indels present in tumors as genetic barcodes, which will enable future studies of tumor heterogeneity and clonality. These results show that sarcomas generated with CRISPR/Cas9 technology are similar to sarcomas generated with conventional modeling techniques. Ultimately this work corroborates CRISPR/Cas9-generated mouse models with traditional GEMMs phenotypically and genotypically, and expands the range of sarcoma mouse models available for research.

Citation Format: Jianguo Huang, Mark Chen, Melodi Javid Whitley, Hsuan-Cheng Kuo, Eric S. Xu, Andrea Walens, Yvonne M. Mowery, David Van Mater, William C. Eward, Diana M. Cardona, Lixia Luo, Yan Ma, Omar M. Lopez, Christopher E. Nelson, Jacqueline N. Robinson-Hamm, Anupama Reddy, Sandeep S. Dave, Charles A. Gersbach, Rebecca D. Dodd, David G. Kirsch. Generation and comparison of CRISPR/Cas9 and Cre-mediated genetically engineered mouse models of sarcoma [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr A17.

Beyond Mirels: Factors Influencing Surgical Outcome of Metastasis to the Extremities in the Modern Era

Mirels scoring system for determining prophylactic stabilization need of skeletal metastases includes a limited number of variables and does not differentiate between procedure types. This study sought to identify additional variables associated with surgical failure, radiographic disease progression, and patient survival. A retrospective review was performed of patients from January 2004 to 2014 who underwent surgical treatment of skeletal metastases of the extremities, were >18 years of age, and had adequate radiographic surveillance. Eighty-nine metastatic bone lesions in 77 patients were included. Mirels score >8 (p = .015) and tumor origin (p = .008) were associated with surgical failure, which was 16.8%. Male gender (p < .001) and use of bone cement (p = .019) were associated with radiographic progression, 43.8% overall. Antiresorptive medications usage (p = .02) was associated with survival. The study concluded that tumor origin may be highly important when considering surgical treatment for metastatic bone disease and antiresorptive medications should be used postoperatively, given an association with survival. (Journal of Surgical Orthopaedic Advances 27(3):178-186, 2018).

NF1+/- Hematopoietic Cells Accelerate Malignant Peripheral Nerve Sheath Tumor Development without Altering Chemotherapy Response

Haploinsufficiency in the tumor suppressor NF1 contributes to the pathobiology of neurofibromatosis type 1, but a related role has not been established in malignant peripheral nerve sheath tumors (MPNST) where NF1 mutations also occur. Patients with NF1-associated MPNST appear to have worse outcomes than patients with sporadic MPNST, but the mechanism underlying this correlation is not understood. To define the impact of stromal genetics on the biology of this malignancy, we developed unique mouse models that reflect the genetics of patient-associated MPNST. Specifically, we used adenovirus-Cre injections to generate MPNST in Nf1Flox/Flox; Ink4a/ArfFlox/Flox and Nf1Flox/-; Ink4a/ArfFlox/Flox paired littermate mice to model tumors from NF1-wild-type and NF1-associated patients, respectively. In these models, Nf1 haploinsufficiency in hematopoietic cells accelerated tumor onset and increased levels of tumor-infiltrating immune cells comprised of CD11b+ cells, monocytes, and mast cells. We observed that mast cells were also enriched in human NF1-associated MPNST. In a coclinical trial to examine how the tumor microenvironment influences the response to multiagent chemotherapy, we found that stromal Nf1 status had no effect. Taken together, our results clarify the role of the NF1-haploinsufficient tumor microenvironment in MPNST. Cancer Res; 77(16); 4486-97. ©2017 AACR.

Generation and comparison of CRISPR-Cas9 and Cre-mediated genetically engineered mouse models of sarcoma

Genetically engineered mouse models that employ site-specific recombinase technology are important tools for cancer research but can be costly and time-consuming. The CRISPR-Cas9 system has been adapted to generate autochthonous tumours in mice, but how these tumours compare to tumours generated by conventional recombinase technology remains to be fully explored. Here we use CRISPR-Cas9 to generate multiple subtypes of primary sarcomas efficiently in wild type and genetically engineered mice. These data demonstrate that CRISPR-Cas9 can be used to generate multiple subtypes of soft tissue sarcomas in mice. Primary sarcomas generated with CRISPR-Cas9 and Cre recombinase technology had similar histology, growth kinetics, copy number variation and mutational load as assessed by whole exome sequencing. These results show that sarcomas generated with CRISPR-Cas9 technology are similar to sarcomas generated with conventional modelling techniques and suggest that CRISPR-Cas9 can be used to more rapidly generate genotypically and phenotypically similar cancers.

The stability of the hip after the use of a proximal femoral endoprosthesis for oncological indications: analysis of variables relating to the patient and the surgical technique

AIMS

Instability of the hip is the most common mode of failure after reconstruction with a proximal femoral arthroplasty (PFA) using an endoprosthesis after excision of a tumour. Small studies report improved stability with capsular repair of the hip and other techniques, but these have not been investigated in a large series of patients. The aim of this study was to evaluate variables associated with the patient and the operation that affect post-operative stability. We hypothesised an association between capsular repair and stability.

PATIENTS AND METHODS

In a retrospective cohort study, we identified 527 adult patients who were treated with a PFA for tumours. Our data included demographics, the pathological diagnosis, the amount of resection of the abductor muscles, the techniques of reconstruction and the characteristics of the implant. We used regression analysis to compare patients with and without post-operative instability.

RESULTS

A total of 20 patients out of 527 (4%) had instability which presented at a mean of 35 days (3 to 131) post-operatively. Capsular repair was not associated with a reduced rate of instability. Bivariate analysis showed that a posterolateral surgical approach (odds ratio (OR) 0.11, 95% confidence interval (CI) 0.02 to 0.86) and the type of implant (p = 0.046) had a significant association with reduced instability; age > 60 years predicted instability (OR 3.17, 95% CI 1.00 to 9.98). Multivariate analysis showed age > 60 years (OR 5.09, 95% CI 1.23 to 21.07), female gender (OR 1.73, 95% CI 1.04 to 2.89), a malignant primary bone tumour (OR 2.04, 95% CI 1.06 to 3.95), and benign condition (OR 5.56, 95% CI 1.35 to 22.90), but not metastatic disease or soft-tissue tumours, predicted instability, while a posterolateral approach (OR 0.09, 95% CI 0.01 to 0.53) was protective against instability. No instability occurred when a synthetic graft was used in 70 patients.

CONCLUSION

Stability of the hip after PFA is influenced by variables associated with the patient, the pathology, the surgical technique and the implant. We did not find an association between capsular repair and improved stability. Extension of the tumour often dictates surgical technique; however, our results indicate that PFA using a posterolateral approach with a hemiarthroplasty and synthetic augment for soft-tissue repair confers the lowest risk of instability. Patients who are elderly, female, or with a primary benign or malignant bone tumour should be counselled about an increased risk of instability. Cite this article: Bone Joint J 2017;99-B:531-7.

A Novel Imaging System Distinguishes Neoplastic from Normal Tissue During Resection of Soft Tissue Sarcomas and Mast Cell Tumors in Dogs

OBJECTIVE

To assess the ability of a novel imaging system designed for intraoperative detection of residual cancer in tumor beds to distinguish neoplastic from normal tissue in dogs undergoing resection of soft tissue sarcoma (STS) and mast cell tumor (MCT).

STUDY DESIGN

Non-randomized prospective clinical trial.

ANIMALS

12 dogs with STS and 7 dogs with MCT.

METHODS

A fluorescent imaging agent that is activated by proteases in vivo was administered to the dogs 4-6 or 24-26 hours before tumor resection. During surgery, a handheld imaging device was used to measure fluorescence intensity within the cancerous portion of the resected specimen and determine an intensity threshold for subsequent identification of cancer. Selected areas within the resected specimen and tumor bed were then imaged, and biopsies (n=101) were obtained from areas that did or did not have a fluorescence intensity exceeding the threshold. Results of intraoperative fluorescence and histology were compared.

RESULTS

The imaging system correctly distinguished cancer from normal tissue in 93/101 biopsies (92%). Using histology as the reference, the sensitivity and specificity of the imaging system for identification of cancer in biopsies were 92% and 92%, respectively. There were 10/19 (53%) dogs which exhibited transient facial erythema soon after injection of the imaging agent which responded to but was not consistently prevented by intravenous diphenhydramine.

CONCLUSION

A fluorescence-based imaging system designed for intraoperative use can distinguish canine soft tissue sarcoma (STS) and mast cell tumor (MCT) tissue from normal tissue with a high degree of accuracy. The system has potential to assist surgeons in assessing the adequacy of tumor resections during surgery, potentially reducing the risk of local tumor recurrence. Although responsive to antihistamines, the risk of hypersensitivity needs to be considered in light of the potential benefits of this imaging system in dogs.

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.