Distraction Osteogenesis Reconstruction Following Resection of Bone Sarcomas: Surgical, Functional, and Oncological Outcomes from a Prospective Trial Analysis

BACKGROUND

While sustainable long-term function has been established for biological reconstruction with distraction osteogenesis (DO) following osseous resections, there is a paucity of published data informing surgeons and patients on important milestones in the reconstructive process. The objectives of this study were to determine when to expect complete bone healing and full weight-bearing as well as to quantify the influence of chemotherapy on the osseous regeneration process.

METHODS

Prospectively, pathological and clinical data were collected for 30 consecutive patients who underwent primary or secondary DO-based reconstruction following osseous resection from 2018 to 2021. Serial radiographs indicated the times to cortex formation and full union. An unpaired t test was used to compare the time required for full bone remodeling of segments transported with and without concurrent chemotherapy.

RESULTS

The average resection length was 13.6 cm (range, 4 to 22 cm). Patients underwent an average of 6.1 procedures (range, 1 to 14 procedures). Half (50%) of all procedures were planned, while half were unplanned procedures. All patients achieved full, independent weight-bearing at a median of 12 months (interquartile range [IQR], 9 to 16 months). For the 34 segments transported concurrently with chemotherapy, the mean bone healing index (BHI) was 2.3 ± 0.7, and the mean BHI was 1.2 ± 0.4 for the 25 segments without chemotherapy at any point during their transport (p < 0.0001).

CONCLUSIONS

All 30 patients achieved full bone healing and independent weight-bearing at a median of 1 year postoperatively and continued to show functional improvement afterward. Surgeons and patients can expect bone healing to be nearly twice as fast for segments transported after completion of systemic chemotherapy compared with segments transported concurrently with adjuvant chemotherapy.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

GLUT1 overexpression enhances CAR T cell metabolic fitness and anti-tumor efficacy

The tumor microenvironment presents many obstacles to effective chimeric antigen receptor (CAR) T cell therapy, including glucose competition from tumor and myeloid cells. Using mouse models of acute lymphoblastic leukemia (ALL), renal cell carcinoma (RCC), and glioblastoma (GBM), we show that enforced expression of the glucose transporter GLUT1 enhances anti-tumor efficacy and promotes favorable CAR-T cell phenotypes for two clinically relevant CAR designs, 19-28z and IL13Rα2-BBz. In the NALM6 ALL model, 19-28z-GLUT1 promotes T stem cell-like memory formation and prolongs survival. RNA sequencing of these CAR-T cells reveals that the overexpression of GLUT1, but not GLUT3, enriches for genes involved in glycolysis, mitochondrial respiration, and memory precursor phenotypes. Extending these data, 19-28z-GLUT1 CAR-T cells improve tumor control and response to rechallenge in an RCC patient-derived xenograft model. Furthermore, IL13Rα2-BBz CAR-T cells overexpressing GLUT1 prolong the survival of mice bearing orthotopic GBMs and exhibit decreased exhaustion markers. This novel engineering approach can offer a competitive advantage to CAR-T cells in harsh tumor environments where glucose is limiting.

Tandem Reconstruction of the Femoral Diaphysis Using an Intercalary Prosthesis and a Fibular Free Flap

BACKGROUND

Femoral diaphyseal reconstructions with metal prostheses have mediocre results because of high mechanical forces that result in eventual implant failure. Biological alternatives require prolonged restrictions on weight-bearing and have high rates of infection, nonunion, and fracture. A novel method of utilizing a vascularized fibula in combination with an intercalary prosthesis was developed to complement the immediate stability of the prosthesis with the long-term biological fixation of a vascularized fibular graft.

METHODS

A prospectively maintained database was retrospectively reviewed to identify patients who underwent reconstruction of an oncological intercalary femoral defect using an intercalary prosthesis and an inline fibular free flap (FFF). They were compared with patients who underwent femoral reconstruction using an intercalary allograft and an FFF.

RESULTS

Femoral reconstruction with an intercalary metal prosthesis and an FFF was performed in 8 patients, and reconstruction with an allograft and an FFF was performed in 16 patients. The mean follow-up was 5.3 years and 8.5 years, respectively (p = 0.02). In the bioprosthetic group, radiographic union of the fibula occurred in 7 (88%) of 8 patients, whereas in the allograft group, 13 (81%) of 16 patients had allograft union (p = 1.00) and all 16 patients had fibular union (p = 0.33). The mean time to fibular union in the bioprosthetic group was 9.0 months, whereas in the allograft group, the mean time to allograft union was 15.3 months (p = 0.03) and the mean time to fibular union was 12.5 months (p = 0.42). Unrestricted weight-bearing occurred at a mean of 3.7 months in the prosthesis group and 16.5 months in the allograft group (p < 0.01). Complications were observed in 2 (25%) of 8 patients in the prosthesis group and in 13 (81%) of 16 patients in the allograft group (p = 0.02). Neither chemotherapy nor radiation affected fibular or allograft union rates. Musculoskeletal Tumor Society scores did not differ significantly between the groups (mean, 26 versus 28; p = 0.10).

CONCLUSIONS

Bioprosthetic intercalary femoral reconstruction with a metal prosthesis and an FFF resulted in earlier weight-bearing, a shorter time to union, fewer operations needed for union, and lower complication rates than reconstruction with an allograft and an FFF.

LEVEL OF EVIDENCE

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

Breast Cancer Macrophage Heterogeneity and Self-renewal are Determined by Spatial Localization

Tumor-infiltrating macrophages support critical steps in tumor progression, and their accumulation in the tumor microenvironment (TME) is associated with adverse outcomes and therapeutic resistance across human cancers. In the TME, macrophages adopt diverse phenotypic alterations, giving rise to heterogeneous immune activation states and induction of cell cycle. While the transcriptional profiles of these activation states are well-annotated across human cancers, the underlying signals that regulate macrophage heterogeneity and accumulation remain incompletely understood. Here, we leveraged a novel ex vivo organotypic TME (oTME) model of breast cancer, in vivo murine models, and human samples to map the determinants of functional heterogeneity of TME macrophages. We identified a subset of F4/80highSca-1+ self-renewing macrophages maintained by type-I interferon (IFN) signaling and requiring physical contact with cancer-associated fibroblasts. We discovered that the contact-dependent self-renewal of TME macrophages is mediated via Notch4, and its inhibition abrogated tumor growth of breast and ovarian carcinomas in vivo, as well as lung dissemination in a PDX model of triple-negative breast cancer (TNBC). Through spatial multi-omic profiling of protein markers and transcriptomes, we found that the localization of macrophages further dictates functionally distinct but reversible phenotypes, regardless of their ontogeny. Whereas immune-stimulatory macrophages (CD11C+CD86+) populated the tumor epithelial nests, the stroma-associated macrophages (SAMs) were proliferative, immunosuppressive (Sca-1+CD206+PD-L1+), resistant to CSF-1R depletion, and associated with worse patient outcomes. Notably, following cessation of CSF-1R depletion, macrophages rebounded primarily to the SAM phenotype, which was associated with accelerated growth of mammary tumors. Our work reveals the spatial determinants of macrophage heterogeneity in breast cancer and highlights the disruption of macrophage self-renewal as a potential new therapeutic strategy.

Long-Term Outcomes in Patients With Localized Ewing Sarcoma Treated With Interval-Compressed Chemotherapy on Children's Oncology Group Study AEWS0031

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Long-term outcomes from Children's Oncology Group study AEWS0031 were assessed to determine whether the survival advantage of interval-compressed chemotherapy (ICC) was maintained over 10 years in patients with localized Ewing sarcoma (ES). AEWS0031 enrolled 568 eligible patients. Patients were randomly assigned to receive vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide alternating once every 3 weeks (standard timing chemotherapy [STC]) versus once every 2 weeks (ICC). For this updated report, one patient was excluded because of uncertainty of original diagnosis. The 10-year event-free survival (EFS) was 70% with ICC compared with 61% with STC (P = .03), and 10-year overall survival (OS) was 76% with ICC compared with 69% with STC (P = .04). There was no difference in the 10-year cumulative incidence of second malignant neoplasms (SMNs; PC [see Data Supplement, online only] = .5). A test for interaction demonstrated that ICC provided greater risk reduction for patients with tumor volume ≥200 mL than for patients with tumors <200 mL, but no evidence for a significant interaction in other subgroups defined by age, primary site, and histologic response. With longer-term follow-up, ICC for localized ES is associated with superior EFS and OS without an increased risk for SMN compared with STC. ICC is associated with improved outcomes even in adverse-risk patient groups.

Giant-cell-poor giant cell tumor of bone: report of two cases and literature review

Giant cell tumor of bone (GCTB) is a locally aggressive tumor that shows predilection for the metaphysis/epiphysis of long bones, with an incidence of 4-5% of primary bone tumors. GCTB shows two main populations of cells: mononuclear cells and non-neoplastic multi-nucleated giant cells, with or without fibrous background. On the other hand, giant-cell-poor GCTB are rare with only few reports in the literature. These cases offer a diagnostic challenge, given the absence of giant cells and such cases have consistently been shown to harbor the H3F3A gene mutation by sequencing. The H3.3 G34W mutation-specific monoclonal antibody has shown high specificity in the diagnosis of GCTB. Two cases of giant-cell-poor GCTB are presented in this study, in which giant cells were absent or sparse and the diagnosis of GCTB was confirmed by the expression of H3.3 G34W monoclonal antibody in the mononuclear cells by immunohistochemistry. Whether this represents a histologic variant of GCTB or partial involution of GCTB is not yet fully understood; however, an immune response, infectious/inflammatory reaction, and/or anti-tumor cytokine production have been purported to be factors inciting disease regression in GCTB.

Operative Treatment and Outcomes of Pediatric Patients with an Extremity Bone Tumor: A Secondary Analysis of the PARITY Trial Data

BACKGROUND

Osteosarcoma and Ewing sarcoma are the 2 most common primary bone sarcomas, occurring predominantly in pediatric patients, with the incidence of osteosarcoma correlating with periods of peak bone-growth velocity. Although survival outcomes have plateaued over the past several decades, ongoing treatment advances have improved function, decreased infection rates, and improved other clinical outcomes in patients with bone tumors. Recently, the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial addressed the serious problem of surgical site infection (SSI) and the lack of consensus regarding the appropriate prophylactic postoperative antibiotic regimen. The objective of the present secondary analysis of the PARITY trial was to characterize the modern treatment and surgical and oncologic outcomes of pediatric patients with bone tumors at 1 year postoperatively.

METHODS

The PARITY trial included patients ≥12 years old with a bone tumor or soft-tissue sarcoma that was invading the femur or tibia, necessitating osseous resection and endoprosthetic reconstruction. This pediatric subanalysis of the PARITY trial data included all PARITY patients ≤18 years old. As in the main PARITY study, patients were randomized to either a 5-day or 1-day course of postoperative antibiotic prophylaxis. The primary outcome measure was the development of an SSI within 1 year, and secondary outcomes included antibiotic-related adverse events, unplanned additional operations, local recurrence, metastasis, and death.

RESULTS

A total of 151 patients were included. An adjudicated SSI occurred in 27 patients (17.9%). There was no difference in the rate of any SSI between the 5-day and 1-day antibiotic groups (hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.4 to 1.9; p = 0.82). Antibiotic-related complications occurred in 13 patients (8.6%), with no difference noted between groups (HR, 0.46; 95% CI, 0.2 to 1.4; p = 0.18). A total of 45 patients (29.8%) required a return to the operating room within the first postoperative year, which corresponded with a 68.8% reoperation-free rate of survival at 1 year when accounting for competing risks. The most common reason for reoperation was infection (29 of 45; 64.4%). A total of 7 patients (4.6%) required subsequent amputation of the operative extremity, and an additional 6 patients (4.0%) required implant revision within 12 months. A total of 36 patients (23.8%) developed metastases, and 6 patients (4.0%) developed a local recurrence during the first postoperative year. A total of 11 patients (7.3%) died during the study period. There were no significant differences in oncologic outcomes between the 5-day and 1-day antibiotic groups (HR, 0.97; 95% CI, 0.5-1.8; p = 0.92).

CONCLUSIONS

There were no significant differences in surgical or oncologic outcomes between pediatric patients who underwent a 1-day versus 5-day antibiotic regimen following endoprosthetic reconstruction in the PARITY trial. Surgeons should be aware of and counsel patients and caregivers regarding the 30% rate of reoperation and the risks of infection (17.9%), death (7.3%), amputation (4.6%), and implant revision (4%) within the first postoperative year.

LEVEL OF EVIDENCE

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

Tenosynovial Giant Cell Tumor Observational Platform Project (TOPP) Registry: A 2-Year Analysis of Patient-Reported Outcomes and Treatment Strategies

BACKGROUND

The Tenosynovial giant cell tumor Observational Platform Project (TOPP) registry is an international prospective study that -previously described the impact of diffuse-type tenosynovial giant cell tumour (D-TGCT) on patient-reported outcomes (PROs) from a baseline snapshot. This analysis describes the impact of D-TGCT at 2-year follow-up based on treatment strategies.

MATERIAL AND METHODS

TOPP was conducted at 12 sites (EU: 10; US: 2). Captured PRO measurements assessed at baseline, 1-year, and 2-year follow-ups were Brief Pain Inventory (BPI), Pain Interference, BPI Pain Severity, Worst Pain, EQ-5D-5L, Worst Stiffness, and -Patient-Reported Outcomes Measurement Information System. Treatment interventions were no current/planned treatment (Off-Treatment) and systemic treatment/surgery (On-Treatment).

RESULTS

A total of 176 patients (mean age: 43.5 years) were included in the full analysis set. For patients without active treatment strategy -(Off-Treatment) at baseline (n = 79), BPI Pain Interference (1.00 vs. 2.86) and BPI Pain Severity scores (1.50 vs. 3.00) were numerically favorable in patients remaining Off-Treatment compared with those who switched to an active treatment strategy at year 1. From 1-year to 2-year -follow-ups, patients who remained Off-Treatment had better BPI Pain Interference (0.57 vs. 2.57) and Worst Pain (2.0 vs. 4.5) scores compared with patients who switched to an alternative treatment strategy. In addition, EQ-5D VAS scores (80.0 vs. 65.0) were higher in patients who remained -Off-Treatment between 1-year and 2-year follow-ups compared with patients who changed treatment strategy. For patients receiving systemic treatment at baseline, numerically favorable scores were seen in patients remaining on systemic therapy at 1-year follow-up: BPI Pain Interference (2.79 vs. 5.93), BPI Pain Severity (3.63 vs. 6.38), Worst Pain (4.5 vs. 7.5), and Worst Stiffness (4.0 vs. 7.5). From 1-year to 2-year follow-up, EQ-5D VAS scores (77.5 vs. 65.0) were higher in patients who changed from systemic treatment to a different treatment strategy.

CONCLUSION

These findings highlight the impact D-TGCT has on patient quality of life, and how treatment strategies may be influenced by these outcome measures. (ClinicalTrials.gov number: NCT02948088).

Tumour extracellular vesicles and particles induce liver metabolic dysfunction

Cancer alters the function of multiple organs beyond those targeted by metastasis1,2. Here we show that inflammation, fatty liver and dysregulated metabolism are hallmarks of systemically affected livers in mouse models and in patients with extrahepatic metastasis. We identified tumour-derived extracellular vesicles and particles (EVPs) as crucial mediators of cancer-induced hepatic reprogramming, which could be reversed by reducing tumour EVP secretion via depletion of Rab27a. All EVP subpopulations, exosomes and principally exomeres, could dysregulate hepatic function. The fatty acid cargo of tumour EVPs-particularly palmitic acid-induced secretion of tumour necrosis factor (TNF) by Kupffer cells, generating a pro-inflammatory microenvironment, suppressing fatty acid metabolism and oxidative phosphorylation, and promoting fatty liver formation. Notably, Kupffer cell ablation or TNF blockade markedly decreased tumour-induced fatty liver generation. Tumour implantation or pre-treatment with tumour EVPs diminished cytochrome P450 gene expression and attenuated drug metabolism in a TNF-dependent manner. We also observed fatty liver and decreased cytochrome P450 expression at diagnosis in tumour-free livers of patients with pancreatic cancer who later developed extrahepatic metastasis, highlighting the clinical relevance of our findings. Notably, tumour EVP education enhanced side effects of chemotherapy, including bone marrow suppression and cardiotoxicity, suggesting that metabolic reprogramming of the liver by tumour-derived EVPs may limit chemotherapy tolerance in patients with cancer. Our results reveal how tumour-derived EVPs dysregulate hepatic function and their targetable potential, alongside TNF inhibition, for preventing fatty liver formation and enhancing the efficacy of chemotherapy.

Cathepsin protease expression in infiltrative soft tissue sarcomas: cathepsin-K correlates with infiltrative tumor growth and clinical outcomes

Cathepsin proteases, activated in the lysosomes, are upregulated in many cancers. Intraoperative detection systems of microscopic residual tumor using cathepsin-mediated release of fluorescent nanoparticles may guide surgical excisions to improve local control. We sought to define the genetic and proteomic expression of cathepsins and their clinicopathological correlates in myxofibrosarcoma and undifferentiated pleomorphic sarcoma (UPS)-soft tissue sarcomas with high rates of positive resection margins and local recurrence-and to establish a cellular justification for cathepsin-dependent systems to identify residual cancer in the resection bed. Real-time quantitative polymerase chain reaction analysis of 58 fresh-frozen tumor specimens revealed that 56 (97%) had elevated mRNA expression of ≥1 cathepsin, including cathepsin-B (79%), cathepsin-K (59%), cathepsin-L (71%), and -S (71%). Immunohistochemical analysis of these fresh-frozen specimens revealed that 98% of tumors were positive for one or more of cathepsin-B (85%), cathepsin-K (50%), cathepsin-L (63%), and -S (10%). Strong cathepsin-K expression was associated with greater risks of local recurrence (hazard ratio, 3.78; p = 0.044) and disease-specific mortality (hazard ratio, 3.70; p = 0.025). Immunohistochemical analysis of 33 formalin-fixed paraffin-embedded block samples revealed that 97% were positive for cathepsin-B (88%), cathepsin-K (76%), cathepsin-L (52%), or -S (52%) at the tumor periphery; cathepsin-K positivity correlated with a radiographic tail-like sign (p = 0.004) and microscopic infiltrative growth (p = 0.020). We conclude that cathepsins are broadly overexpressed in myxofibrosarcoma and UPS, and cathepsin-K may be an immunohistochemical marker of local infiltration and poorer prognosis that could be used to guide precision surgery.

Malignant undifferentiated epithelioid neoplasms with MAML2 rearrangements: A clinicopathologic study of seven cases demonstrating a heterogenous entity

Among mesenchymal tumors, MAML2 gene rearrangements have been described in a subset of composite hemangioendothelioma and myxoinflammatory fibroblastic sarcoma (MIFS). However, we have recently encountered MAML2-related fusions in a group of seven undifferentiated malignant epithelioid neoplasms that do not fit well to any established pathologic entities. The patients included five males and two female, aged 41-71 years old (median 65 years). The tumors involved the deep soft tissue of extremities (hip, knee, arm, hand), abdominal wall, and the retroperitoneum. Microscopically, the tumors consisted of solid sheets of atypical epithelioid to histiocytoid cells with abundant cytoplasm. Prominent mitotic activity and necrosis were present in 4 cases. In 3 cases, the cells displayed hyperchromatic nuclei or conspicuous macronucleoli, and were admixed with background histiocytoid cells and a lymphoplasmacytic infiltrate. By immunohistochemistry (IHC), the neoplastic cells had a nonspecific phenotype. On targeted RNA sequencing, MAML2 was the 3' partner and fused to YAP1 (4 cases), ARHGAP42 (2 cases), and ENDOD1 (1 case). Two cases with YAP1::MAML2 harbored concurrent RAF kinase fusions (RBMS3::RAF1 and AGK::BRAF, respectively). In 2 cases with targeted DNA sequencing, mutations in TP53, RB1 and PTEN were detected in 1 case, and PDGFRB mutations, CCNE1 amplifications and CDKN2A/2B deletion were detected in another case, which showed strong and diffuse PDGFRB expression by IHC. Of the 4 cases with detailed clinical history (median follow-up period 8 months), three developed distant metastatic disease (one of which died of disease); one case remained free of disease 3 years following surgical excision. In conclusion, we describe a heterogeneous series of MAML2-rearranged undifferentiated malignant epithelioid neoplasms, a subset of which may overlap with a recently described MIFS variant with YAP1::MAML2 fusions, further expanding the clinicopathologic spectrum of mesenchymal neoplasms with recurrent MAML2 gene rearrangements.

Operative management of metastatic disease of the acetabulum: review of the literature and prevailing concepts

Metastatic disease of the periacetabular region is a common problem in orthopaedic oncology, associated with severe pain, decreased mobility, and substantial decline of the quality of life. Conservative management includes optimisation of pain management, activity modification, and radiation therapy. However, patients with destructive lesions affecting the weight-bearing portion of the acetabulum often require reconstructive surgery to decrease pain and restore mobility. The goal of surgery is to provide an immediately stable and durable construct, allowing immediate postoperative weight-bearing and maintaining functional independence for the remaining lifetime of the patient. A variety of surgical techniques have been reported, most of which are based upon cemented total hip arthroplasty, but also include porous tantalum implants and percutaneous cementoplasty. This review discusses the various reconstructive concepts and options, including their respective indications and outcome. A reconstructive algorithm incorporating different techniques and strategies based upon location and quality of remaining bone is also presented.

Deep Learning-Based Objective and Reproducible Osteosarcoma Chemotherapy Response Assessment and Outcome Prediction

Osteosarcoma is the most common primary bone cancer, whose standard treatment includes pre-operative chemotherapy followed by resection. Chemotherapy response is used for prognosis and management of patients. Necrosis is routinely assessed after chemotherapy from histology slides on resection specimens, where necrosis ratio is defined as the ratio of necrotic tumor/overall tumor. Patients with necrosis ratio ≥90% are known to have a better outcome. Manual microscopic review of necrosis ratio from multiple glass slides is semiquantitative and can have intraobserver and interobserver variability. In this study, an objective and reproducible deep learning-based approach was proposed to estimate necrosis ratio with outcome prediction from scanned hematoxylin and eosin whole slide images (WSIs). To conduct the study, 103 osteosarcoma cases with 3134 WSIs were collected. Deep Multi-Magnification Network was trained to segment multiple tissue subtypes, including viable tumor and necrotic tumor at a pixel level and to calculate case-level necrosis ratio from multiple WSIs. Necrosis ratio estimated by the segmentation model highly correlates with necrosis ratio from pathology reports manually assessed by experts. Furthermore, patients were successfully stratified to predict overall survival with P = 2.4 × 10-6 and progression-free survival with P = 0.016. This study indicates that deep learning can support pathologists as an objective tool to analyze osteosarcoma from histology for assessing treatment response and predicting patient outcome.

Distinct IDH1/2-associated Methylation Profile and Enrichment of TP53 and TERT Mutations Distinguish Dedifferentiated Chondrosarcoma from Conventional Chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a rare high-grade chondrosarcoma characterized by a well-differentiated chondrosarcoma (WDCS) component that abruptly transitions to a high-grade, noncartilaginous sarcomatous component. To date, the molecular pathogenesis of DDCS and its distinction from conventional chondrosarcoma remain poorly understood. By targeted sequencing, we examined the mutational and copy-number profiles of 18 DDCS, including macrodissected WDCS components, compared with 55 clinically sequenced conventional chondrosarcomas. In conjunction with publicly available external data, we analyzed the methylation and expression profiles of 34 DDCS and 94 conventional chondrosarcomas. Isocitrate dehydrogenase 1/isocitrate dehydrogenase 2 (IDH1/IDH2) mutations were present in 36% conventional chondrosarcomas and 71% DDCS. Compared with conventional chondrosarcomas, DDCS had higher frequencies of TP53 and TERT promoter mutations and CDKN2A/B copy-number losses. Paired analysis of macrodissected WDCS and the high-grade components revealed TERT promoter mutations as early events. Despite phenotypic similarities, the percentage of genome with copy-number alterations in DDCS was significantly lower than that in other high-grade sarcomas. Differential methylation analysis revealed reduction of IDH1/IDH2-associated global hypermethylation characteristically seen in conventional chondrosarcoma and a distinct methylation profile in DDCS. The WDCS and high-grade components in DDCS showed similar methylation profiles. These CpG sites were associated with upregulated expression of genes involved in G2-M checkpoints and E2F targets. Genomic profiling revealed enrichment of TP53, TERT promoter, and CDKN2A/B alterations in DDCS. Integrated methylation and gene expression analysis revealed distinct IDH1/IDH2-associated methylation and transcriptional profiles as early events in DDCS, which may underlie the pathogenesis of dedifferentiation in chondrosarcomas.

Significance

DDCS is a rare, high-grade chondrosarcoma with a dismal prognosis. About 50%-80% of DDCS harbor IDH1/IDH2 mutations. We uncover a significant alteration of IDH-associated methylation profile in DDCS, which we propose is key to the progression to dedifferentiation. In this context, the potential effect of the use of IDH inhibitors is unclear but important to address, as clinical trials of selective IDH1 inhibitors showed worse outcome in DDCS.

Pexidartinib Provides Modest Pain Relief in Patients With Tenosynovial Giant Cell Tumor: Results From ENLIVEN

BACKGROUND

The double-blind, randomized, placebo-controlled phase 3 study of orally administered PLX3397 in patients with pigmented villonodular synovitis or giant cell tumor of the tendon sheath (ENLIVEN) showed that pexidartinib provides a robust objective tumor response in adults with tenosynovial giant cell tumors (TGCT) not amenable to improvement with surgery. Based on these results, in 2019, pexidartinib received accelerated approval in the United States in this population as a breakthrough therapy under an orphan drug designation. However, the ability of pexidartinib to relieve pain in ENLIVEN was not fully detailed, and the relationship between pain relief and objective tumor response was not described.

QUESTIONS/PURPOSES

(1) What level of pain relief was achieved by pexidartinib treatment in ENLIVEN? (2) How was pain relief related to objective tumor responses? (3) How durable was pain relief?

METHODS

The current study included planned primary and exploratory assessments of patient-assessed worst pain at the site of the tumor in the ENLIVEN trial. ENLIVEN was a phase 3 randomized, placebo-controlled clinical trial in which adults with TGCT not amenable to improvement with surgery received pexidartinib or placebo for 24 weeks, after which eligible patients could receive open-label pexidartinib. Of 174 patients assessed for eligibility, 121 were randomized (50% [60] to placebo, 50% [61] to pexidartinib), and 120 were given either placebo or pexidartinib (59 received placebo and 61 received pexidartinib) and were included in an intent-to-treat analysis. Fifty-nine percent (71 of 120) of the overall treated population was female, and 88% (106 of 120) were White. Mean age was 45 ± 13 years. Tumors were mostly in the lower extremities (92% [110 of 120]), most commonly in the knee (61% [73 of 120]) and ankle (18% [21 of 120]). As a secondary outcome, patients scored worst pain at the site of the tumor in the past 24 hours on an 11-point numeric rating scale (NRS). The primary definition of a pain response was a decrease of at least 30% in the weekly mean worst-pain NRS score and increase of less than 30% in narcotic analgesic use between baseline and week 25. Planned exploratory assessments of pain included the frequency of a pain response using alternative thresholds, including a decrease in worst-pain NRS score of 50% or more and a decrease of at least 2 points (minimum clinically important difference [MCID]), the magnitude of pain reduction between baseline and week 25, correlation between worst-pain NRS score and tumor shrinkage by RECIST 1.1 criteria, and the durability of the pain response during the open-label extension. Pain responses during the randomized portion of the trial were compared according to intention-to-treat analysis, with a one-sided threshold of p < 0.025 to reduce the risk of false-positive results. Pain assessment was complete for 59% (35 of 59) of patients in the placebo group and 54% (33 of 61) of patients in the pexidartinib group. Demographic and disease characteristics did not differ between the two treatment groups.

RESULTS

A difference in the primary assessment of a pain response was not detected between pexidartinib and placebo (response percentage 31% [19 of 61] [95% CI 21% to 44%] versus 15% [9 of 59] [95% CI 8% to 27%]; one-sided p = 0.03). In the exploratory analyses, pexidartinib provided a modest improvement in pain (response percentage 26% [16 of 61] [95% CI 17% to 38%] versus 10% [6 of 59] [95% CI 5% to 20%]; one-sided p = 0.02 using the 50% threshold and 31% [19 of 61] [95% CI 21% to 44%] versus 14% [8 of 59] [95% CI 7% to 25%]; one-sided p = 0.02 using the MCID threshold). The least-squares mean change in the weekly mean worst-pain NRS score between baseline and week 25 was larger in patients treated with pexidartinib than placebo (-2.5 [95% CI -3.0 to -1.9] versus -0.3 [95% CI -0.9 to 0.3]; p < 0.001), although the mean difference between the two groups (-2.2 [95% CI -3.0 to -1.4]) was just over the MCID. Improvement in the weekly mean worst-pain NRS score correlated with the reduction in tumor size (r = 0.44; p < 0.001) and tumor volume score (r = 0.61; p < 0.001). For patients in the open-label extension, the change in the worst-pain NRS score from baseline was similar to the change at the end of the randomized portion and just above the MCID (mean -2.7 ± 2.2 after 25 weeks and -3.3 ± 1.7 after 50 weeks of receiving pexidartinib).

CONCLUSION

Based on the current study, a modest reduction in pain, just larger than the MCID, may be an added benefit of pexidartinib in these patients, although the findings are insufficient to justify the routine use of pexidartinib for pain relief.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Complementary Effects of Surgery and Pexidartinib in the Management of Patients with Complex Diffuse-Tenosynovial Giant Cell Tumor

Tenosynovial giant cell tumor (TGCT) is a rare neoplasm of the joint synovium that has a wide clinical spectrum including pain and stiffness in the affected joint, joint swelling, periarticular erosions, and cartilage loss, which can severely impact quality of life. The mainstay treatment for TGCT has been surgery involving partial or total synovectomy using arthroscopic or open techniques. However, surgical resection alone is associated with high recurrence rates, particularly in diffuse-TGCT (D-TGCT) cases. The 3 cases presented here summarize a combination approach (surgery+pexidartinib [tyrosine kinase inhibitor]) in patients with previously unresectable or inoperable D-TGCT. Case 1-Hip. A 29-year-old male was treated with pexidartinib prior to surgery, resulting in tumor reduction. A left total hip arthroplasty (THA) was then performed with a lack of recurrence in 12 months postoperative, and the patient currently on pexidartinib treatment. Case 2-Foot. A 35-year-old female, nearly a decade following a left foot mass resection, was treated with pexidartinib following disease recurrence. A decrease in soft tissue lesions at the midfoot and decreased marrow enhancement at the first metatarsal head were seen within 4-5 months of pexidartinib treatment; the patient is currently on pexidartinib (400 mg/day) with improved symptom control. Case 3-Knee. A 55-year-old male patient received pexidartinib pre- and postoperatively. A reduction in swelling and the size of the popliteal cyst was significant and maintained, with the synovial disease growing when pexidartinib was discontinued. Surgery and adjuvant therapy eliminated the disease as of the last follow-up visit (11 months postoperative). These cases provide a unique perspective based on tumor location, type/timing of treatment strategy, and patient outcomes. Optimal treatment strategies for this debilitating disease may entail utilizing a combination approach (surgery+systemic treatment) to reduce surgical morbidity and the risk of postoperative disease recurrence.

A prospective real-world study of the diffuse-type tenosynovial giant cell tumor patient journey: A 2-year observational analysis

BACKGROUND AND OBJECTIVES

Diffuse-tenosynovial giant cell tumor (D-TGCT) is a rare, locally aggressive, typically benign neoplasm affecting mainly large joints, representing a wide clinical spectrum. We provide a picture of the treatment journey of D-TGCT patients as a 2-year observational follow-up.

METHODS

The TGCT Observational Platform Project registry was a multinational, multicenter, prospective observational study at tertiary sarcoma centers spanning seven European countries and two US sites. Histologically confirmed D-TGCT patients were categorized as either those who remained on initial treatment strategy (determined at baseline visit) or those who changed treatment strategy with specific changes documented (e.g., systemic treatment to surgery) at the 1-year and/or 2-year follow-up visits.

RESULTS

A total of 176 patients were assessed, mean diagnosis age was 38.4 (SD ± 14.6) years; most patients had a knee tumor (120/176, 68.2%). For the 2-year observation period, most patients (75.5%) remained on the baseline treatment strategy throughout, 54/79 patients (68.4%) remained no treatment, 30/45 patients (66.7%) remained systemic treatment, 39/39 patients (100%) remained surgery. Those who changed treatment strategy utilized multimodal treatment options.

CONCLUSIONS

This is the first prospectively collected analysis to describe D-TGCT patient treatments over an extended follow-up and demonstrates the need for multidisciplinary teams to determine an optimal treatment strategy.

What Proportion of Patients With Musculoskeletal Sarcomas Demostrate Symptoms of Depression or Anxiety?

BACKGROUND

It is estimated that the 12-month prevalence of depression in the United States is 8.6%, and for anxiety it is 2.9%. Although prior studies have evaluated depression and anxiety in patients with carcinoma, few have specifically evaluated patients with sarcoma, who often have unique treatment considerations such as mobility changes after surgery.

QUESTIONS/PURPOSES

We evaluated patients with sarcoma seen in our orthopaedic oncology clinic to determine (1) the proportion of patients with depression symptoms, symptom severity, how many patients triggered a referral to mental health professionals based upon our prespecified cutoff scores on the nine-item Patient Health Questionnaire (PHQ-9), and if their symptoms varied by disease state; (2) the proportion of patients with anxiety symptoms, symptom severity, how many patients triggered a referral to mental health professionals based upon our prespecified cutoff scores on the seven-item Generalized Anxiety Disorder Scale (GAD-7), and if they symptoms varied by disease state; (3) whether other factors were associated with the proportion and severity of symptoms of anxiety or depression, such as tumor location in the body (axial skeleton, upper extremity, or lower extremity), general type of tumor (bone or soft tissue), specific diagnosis, use of chemotherapy, length of follow-up (less than 1 year or greater than 1 year), and gender; and (4) what proportion of patients accepted referrals to mental health professionals, when offered.

METHODS

This study was a cross-sectional survey study performed at a single urban National Cancer Institute-designated Comprehensive Cancer Center from April 2021 until July 2021. All patients seen in the orthopaedic clinic 18 years of age and older with a diagnosis/presumed diagnosis of sarcoma were provided the PHQ-9 as well as the GAD-7 in our clinic. We did not track those who elected not to complete the surveys. Surveys were scored per survey protocol (each question was scored from 0 to 3 and summed). Specifically, PHQ-9 scores the symptoms of depression as 5 to 9 (mild), 10 to 14 (moderate), 15 to 19 (moderately severe), and 20 to 27 (severe). The GAD-7 scores symptoms of anxiety as 5 to 9 (mild), 10 to 14 (moderate), and 15 to 21 (severe). Patients with PHQ-9 or GAD-7 scores of 10 to 14 were referred to social work and those with scores 15 or higher were referred to psychiatry. Patients with thoughts of self-harm were referred regardless of score. Patients were divided based on disease state: patients during their initial management; patients with active, locally recurrent disease; patients with active metastatic disease; patients with prior recurrence or metastatic lesions who were subsequently treated and now have no evidence of disease (considered to be patients with discontinuous no evidence of disease); patients with no evidence of disease; and patients with an active, noncancerous complication but otherwise no evidence of disease. We additionally looked at the association of gender, chemotherapy administration, and tumor location on survey responses. Data are summarized using descriptive statistics. Differences across categories of disease state were tested for statistical significance using Kruskal-Wallis tests for continuous variables and Fisher exact tests for categorical variables as well as pairwise Wilcoxon rank sum tests.

RESULTS

Overall, symptoms of depression were seen in 35% (67 of 190) of patients, at varying levels of severity: 19% (37 of 190) had mild symptoms, 9% (17 of 190) had moderate symptoms, 6% (12 of 190) had moderately severe symptoms, and 1% (1 of 190) had severe symptoms. Depresssion symptoms severe enough to trigger a referral were seen in 17% (32 of 190) of patients overall. Patients scored higher on the PHQ-9 during their initial treatment or when they had recurrent or metastatic disease, and they were more likely to trigger a referral during those timepoints as well. The mean PHQ-9 was 5.7 ± 5.8 during initial treatment, 6.1 ± 4.9 with metastatic disease, and 7.4 ± 5.2 with recurrent disease as compared with 3.2 ± 4.2 if there was no evidence of disease (p = 0.001). Anxiety symptoms were seen in 33% (61 of 185) of patients: 17% (32 of 185) had mild symptoms, 8% (14 of 185) had moderate symptoms, and 8% (15 of 185) had severe symptoms. Anxiety symptoms severe enough to trigger a referral were seen in 16% (29 of 185) of patients overall. Patients scored higher on the GAD-7 during initial treatment and when they had recurrent disease or an active noncancerous complication. The mean GAD-7 was 6.3 ± 3.2 in patients with active noncancerous complications, 6.8 ± 5.8 in patients during initial treatment, and 8.4 ± 8.3 in patients with recurrent disease as compared with 3.1 ± 4.2 in patients with no evidence of disease (p = 0.002). Patients were more likely to trigger a referral during initial treatment (32% [9 of 28]) and with recurrent disease (43% [6 of 14]) compared with those with no evidence of disease (9% [9 of 97]) and those with discontinuous no evidence of disease (6% [1 of 16]; p = 0.004). There was an increase in both PHQ-9 and GAD-7 scores among patients who had chemotherapy. Other factors that were associated with higher PHQ-9 scores were location of tumor (upper extremity versus lower extremity or axial skeleton) and gender. Another factor that was associated with higher GAD-7 scores included general category of diagnosis (bone versus soft tissue sarcoma). Specific diagnosis and length of follow-up had no association with symptoms of depression or anxiety. Overall, 22% (41 of 190) of patients were offered referrals to mental health professionals; 73% (30 of 41) accepted the referral.

CONCLUSION

When treating patients with sarcoma, consideration should be given to potential concomitant psychiatric symptoms. Screening, especially at the highest-risk timepoints such as at the initial diagnosis and the time of recurrence, should be considered. Further work should be done to determine the effect of early psychiatric referral on patient-related outcomes and healthcare costs.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Abstract B023: Prospective clinical genomic profiling of ewing sarcoma: ERF and FGFR1 mutations as recurrent secondary alterations of potential biological and therapeutic relevance

Background: Ewing Sarcoma (ES) is a primitive sarcoma defined by EWSR1–ETS fusions as the primary driver alteration. To expand our understanding of the genetic and molecular characterization of ES, we conducted a comprehensive analysis of clinical genomic profiling data on tumors from 113 patients using the MSK-IMPACT platform (Integrated Mutation Profiling of Actionable Cancer Targets). Methods: The dataset consisted of ES patients prospectively tested with the FDA-cleared MSK-IMPACT large panel, hybrid capture-based NGS assay. To assess the functional significance of ERF loss, we generated ES cell lines with increased expression of ERF as well as lines with knockdown of ERF. We assessed cell viability, clonogenic growth, and motility and performed transcriptomic and epigenetic analyses. Finally, we validated our findings in vivo using cell line xenografts. Results: Unlike previous ES genomic cohorts, ours included more adult patients (&gt;18 years of age) and more patients with advanced stage at presentation. TP53, STAG2, and CDKN2A were the most common alterations and were associated with worse overall survival at 5-years. Notably, 3% had activating FGFR1 alterations (1 amplification and 2 hotspot activating kinase domain mutations). Mining data generated using a targeted RNAseq assay that includes FGFR1 based on the Archer Anchored Multiplex PCR technology, FGFR1 was highly expressed in the ES cohort (N=42). The 2 patients with activating FGFR1 mutations had relatively high expression of FGFR1. The second novel subset of patients in our cohort were defined by recurrent secondary alterations in ERF, which encodes an ETS domain transcriptional repressor, in 7% of patients (5 truncating mutations, 1 deep deletion, 2 missense mutations). ERF alterations were non-overlapping with STAG2 alterations, suggesting a potentially important biologic role in ES. As the functional significance of FGFR1 mutation in ES has been previously studied, we focused our functional studies on the role of ERF status in ES. In vitro, increased expression of ERF decreased tumor cell growth, colony formation, and motility in two ES cell lines, while ERF loss induced cellular proliferation and clonogenic growth. Transcriptomic analysis of cell lines with ERF loss revealed increased expression of genes and pathways associated with aggressive tumor biology, and epigenetic, chromatin-based studies revealed that ERF competes with EWSR1-FLI1 at ETS binding sites. Conclusion: Our study reveals a previously unexplored role of ERF loss-of-function in ES. Older age in our cohort, and a higher proportion of patients with advanced disease at presentation, could potentially explain the finding of ERF alterations which were associated with aggressive tumor biology in our preclinical studies. Our functional analyses of how ERF modulates EWSR1-FLI1 oncogenicity may open a new window into the pathobiology of ES. Moreover, our data suggest that 3% of ES patients harbor activating FGFR1 mutations, the first targetable kinase alteration in this sarcoma.

Citation Format: Arielle Elkrief, Koichi Ogura, Anita S. Bowman, Richard P. Koche, Ryma Benayed, Audrey Mauguen, Marissa S. Mattar, Inna Khodos, Elisa de Stanchina, Paul A. Meyers, John H. Healey, William D. Tap, Neerav Shukla, Meera Hameed, Ahmet Zehir, Charles Sawyers, Rohit Bose, Emily Slotkin, Marc Ladanyi. Prospective clinical genomic profiling of ewing sarcoma: ERF and FGFR1 mutations as recurrent secondary alterations of potential biological and therapeutic relevance [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr B023.

Geographic Access to High-Volume Care Providers and Survival in Patients with Bone Sarcomas: Nationwide Patterns in the United States

BACKGROUND

Clinical practice guidelines recommend centralized care for patients with bone sarcoma. However, the relationship between the distance that patients travel to obtain care, institutional treatment volume, and survival is unknown.

METHODS

We used the National Cancer Database to examine associations between travel distance and survival among 8,432 patients with bone sarcoma diagnosed from 2004 to 2015. Associations were identified using multivariable Cox regression analyses that controlled for sociodemographic, clinical, and hospital-level factors; subgroup analyses stratified patients by histological diagnosis, tumor stage, and pediatric or adult status.

RESULTS

Mortality risk was lower among patients who traveled ≥50 miles (≥80.5 km) than among patients who traveled ≤10 miles (≤16.1 km) (hazard ratio [HR], 0.69 [95% confidence interval (CI), 0.63 to 0.76]). Among hospital-level factors, facility volume independently affected survival: mortality risk was lower among patients at high-volume facilities (≥20 cases per year) than at low-volume facilities (≤5 cases per year), with an HR of 0.72 (95% CI, 0.66 to 0.80). The proportion of patients who received care at high-volume facilities varied by distance traveled (p < 0.001); it was highest among patients who traveled ≥50 miles (53%) and lower among those who traveled 11 to 49 miles (17.7 to 78.9 km) (32%) or ≤10 miles (18%). Patients who traveled ≥50 miles to a high-volume facility had a lower risk of mortality (HR, 0.65 [95% CI, 0.56 to 0.77]) than those who traveled ≤10 miles to a low-volume facility. In subgroup analyses, this association was evident among patients with all 3 major histological subtypes; those with stage-I, II, and IV tumors; and adults.

CONCLUSIONS

This national study showed that greater travel burden was associated with higher survival rates in adults, a finding attributable to patients traveling to receive care at high-volume facilities. Despite the burdens associated with travel, modification of referral pathways to specialized centers may improve survival for patients with bone sarcoma.

LEVEL OF EVIDENCE

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

Neoplastic synovial lining cells that coexpress podoplanin and CD90 overproduce CSF-1, driving tenosynovial giant cell tumor

Tenosynovial giant cell tumor (TCGT) is a rare neoplasm affecting the synovium of joints, bursae, and tendon sheaths. The overproduction of colony-stimulating factor-1 (CSF-1) by a minority of the tumor population works in a paracrine fashion to drive tumor growth. Pathology of the reactive, monocytic component has been well elucidated, whereas the populations of neoplastic cells and all the sources of CSF-1 overproduction are incompletely characterized. Podoplanin (PDPN), or gp38, is a cell surface glycoprotein that is expressed on fibroblast-like synovial cells and upregulated in rheumatoid arthritis and many cancers; it governs cell mobility, epithelial-mesenchymal transition, and other functions and is associated with lymphangiogenesis and poor prognosis in many solid tumors, which underscores its local and possible systemic effects. We found higher PDPN expression in TGCT than in internal controls of patients' healthy synovium. Flow cytometry partitioned PDPN^high cells into PDPN^high CD90⁺ and PDPN^high CD14⁺ populations. Quantitative real-time polymerase chain reaction analysis of the PDPN^high CD90⁺ cells revealed that CSF-1 expression was 10-fold higher than in PDPN^high CD14⁺ cells. Therefore, we conclude that the lining fibroblast-like synovial cells, which express PDPN^high CD90⁺ , are responsible for the overproduction of CSF-1 and for driving tumor growth.

Prospective Clinical Genomic Profiling of Ewing Sarcoma: ERF and FGFR1 Mutations as Recurrent Secondary Alterations of Potential Biologic and Therapeutic Relevance

Ewing sarcoma (ES) is a primitive sarcoma defined by EWSR1-ETS fusions as the primary driver alteration. To better define the landscape of cooperating secondary genetic alterations in ES, we analyzed clinical genomic profiling data of 113 patients with ES, a cohort including more adult patients (> 18 years) and more patients with advanced stage at presentation than previous genomic cohorts.

Clinical sequencing of soft tissue and bone sarcomas delineates diverse genomic landscapes and potential therapeutic targets

The genetic, biologic, and clinical heterogeneity of sarcomas poses a challenge for the identification of therapeutic targets, clinical research, and advancing patient care. Because there are > 100 sarcoma subtypes, in-depth genetic studies have focused on one or a few subtypes. Herein, we report a comparative genetic analysis of 2,138 sarcomas representing 45 pathological entities. This cohort is prospectively analyzed using targeted sequencing to characterize subtype-specific somatic alterations in targetable pathways, rates of whole genome doubling, mutational signatures, and subtype-agnostic genomic clusters. The most common alterations are in cell cycle control and TP53, receptor tyrosine kinases/PI3K/RAS, and epigenetic regulators. Subtype-specific associations include TERT amplification in intimal sarcoma and SWI/SNF alterations in uterine adenosarcoma. Tumor mutational burden, while low compared to other cancers, varies between and within subtypes. This resource will improve sarcoma models, motivate studies of subtype-specific alterations, and inform investigations of genetic factors and their correlations with treatment response.

Clinical genomic profiling in the management of patients with soft tissue and bone sarcoma

There are more than 70 distinct sarcomas, and this diversity complicates the development of precision-based therapeutics for these cancers. Prospective comprehensive genomic profiling could overcome this challenge by providing insight into sarcomas' molecular drivers. Through targeted panel sequencing of 7494 sarcomas representing 44 histologies, we identify highly recurrent and type-specific alterations that aid in diagnosis and treatment decisions. Sequencing could lead to refinement or reassignment of 10.5% of diagnoses. Nearly one-third of patients (31.7%) harbor potentially actionable alterations, including a significant proportion (2.6%) with kinase gene rearrangements; 3.9% have a tumor mutational burden ≥10 mut/Mb. We describe low frequencies of microsatellite instability (<0.3%) and a high degree of genome-wide loss of heterozygosity (15%) across sarcomas, which are not readily explained by homologous recombination deficiency (observed in 2.5% of cases). In a clinically annotated subset of 118 patients, we validate actionable genetic events as therapeutic targets. Collectively, our findings reveal the genetic landscape of human sarcomas, which may inform future development of therapeutics and improve clinical outcomes for patients with these rare cancers.