Building a global consensus approach to chordoma: a position paper from the medical and patient community

CXCR4 confers stemness and radioresistance in chordoma cells

CXC Chemokine receptor type 4 (CXCR4) is commonly considered a potential marker for cancer stem cells (CSCs). Dedifferentiated-type chordoma (DTC) cells derived from a patient with recurrent chordoma exhibit high CXCR4 expression and demonstrate increased resistance to chemotherapeutic drugs and ionizing radiation (IR) compared to the conventional-type chordoma cell line, U-CH1. However, the precise role of CXCR4 in the stemness and IR resistance of DTC remains unclear. Therefore, this study aims to elucidate the correlation between the expression of CXCR4 and stemness and radioresistance in chordoma. DTC cells expressing CXCR4 (CXCR4+ DTC cells), isolated by magnetic-activated cell sorting, exhibited increased self-renewal activity, tumorigenicity, and IR resistance, accompanied by elevated Sox2 expression. Knockdown of CXCR4 expression using short hairpin RNA, inhibition of CXCR4 signaling with AMD3100, and targeting of STAT3, a downstream effector of CXCR4, with WP1066 in DTC cells significantly diminished their self-renewal ability, tumorigenic potential, IR resistance, and Sox2 expression. Additionally, transfection with a small interfering Sox2 RNA suppressed self-renewal activity, tumorigenicity, and IR resistance in DTC cells, whereas overexpression of CXCR4 reversed these effects in U-CH1 cells. Furthermore, DTC cells infected with shCXCR4 exhibited substantial tumor suppression, and the combination of IR and AMD3100 significantly reduced DTC tumor growth in a mouse xenograft model. These findings underscore the functional significance of CXCR4 as a CSC marker, highlighting its potential as a therapeutic target for malignant chordomas.

Identification of immune subtypes associated with the prognosis in skull base chordoma

Chordoma is a rare malignant bone tumor that is prone to local recurrence. Recent omics studies suggest that chordoma is a heterogenous disease and the tumor immune microenvironment (TIME) may be associated with chordoma recurrence and patient survival. The aim of this study was to explore the prognostic role of TIME in skull base chordoma. We conducted RNA sequencing of fresh frozen tumors from 77 Chinese skull base chordoma patients and performed unsupervised clustering using immune cell scores estimated by single sample gene set enrichment analysis (ssGSEA) to identify potential immune subtypes. Immunohistochemical (IHC) staining, ESTIMATE, CIBERSORT and xCell were used to validate differences in immune composition between the two immune subtypes. An independent cohort of 261 skull base chordoma patients with long follow-up data was further used to investigate the prognostic associations of immune cells. We identified two immune subtypes (A and B) of skull base chordoma. Compared to tumors in cluster A, tumors in cluster B had higher infiltration of most immune cell populations especially macrophages and T cells. The differences were confirmed by IHC staining of CD68, CD163, and CD3 in a subset of patients (n = 51) with fixed tumor blocks available. Moreover, higher proportions of macrophages (CD68 and CD163) were significantly correlated with shorter PFS (CD68: P < 0.001, CD163: P < 0.001) and OS (CD68: P = 0.04, CD163: P = 0.004) in an independent set of 261 patients with long follow-up data. Our study identified immune subtypes of chordoma that were associated with clinical outcomes and highlighted the potential prognostic value of macrophages. These findings may enhance our understanding of TIME and suggest the importance of macrophages in chordomas.

Exploring perspectives on skull base chordoma management: a modified Delphi approach to consensus

OBJECTIVE

Current treatment for skull base chordomas utilizes both surgical resection and adjuvant radiation, but recent studies have demonstrated evidence that has brought the use of adjuvant radiotherapy into question. Chordomas differ greatly in molecular makeup and proliferation. These factors have led to significant variation in management across providers. We used a modified Delphi approach to work towards consensus on standardized operative definitions and evidence-based management of chordomas.

METHODS

Our multidisciplinary panel included participants representing the AANS/CNS Tumor Section and North American Skull Base Society (NASBS) with a track record of publishing on chordoma management. Our approach involved a four-step process: one statement-generation round, two voting rounds to establish consensus and refine statements, and a final external validation round by NASBS members. Anonymous voting was completed via Qualtrics surveys.

RESULTS

The statement-generation process produced 65 statements. Through the Delphi process, 36 statements reached consensus during the first round and an additional 17 were refined for further consensus in the second round. Moderate (67-80%) or strong (> 80%) consensus was achieved for 43 final statements. Forty-one items were externally validated. There was consensus that an endoscopic endonasal approach should be utilized whenever possible. They defined the tumor characteristics (molecular and cytogenic) to consider before offering adjuvant radiotherapy.

CONCLUSIONS

This modified Delphi study generated consensus on 41 statements regarding skull base chordoma management. These statements aim to shed light on the consensus among providers regarding the use of surgery, neoadjuvant radiation, adjuvant radiation, adjuvant systemic therapies, and treatment of recurrence for chordoma.

RAB3B Dictates mTORC1/S6 Signaling in Chordoma and Predicts Response to mTORC1-Targeted Therapy

Chordoma, a rare mesenchymal malignancy, exhibits a high tendency to postoperative recurrence and poor prognosis. To date, its tumorigenic regulatory mechanisms remain elusive, leading to a lack of effective therapeutic targets and drug sensitivity indicators. Here, via transcriptome and proteome analyses, RAB3B is unveiled as a prominent oncogenic regulator in chordoma, with high expression and enhancer-associated transcriptional activity. Notably, RAB3B ablation attenuated the chordoma cell stemness and malignant biological properties in vivo and in vitro. Through determining the RAB3B-mediated program in chordoma, it is identified that it enhanced the phosphorylation of S6 specifically at S235/236 and directly bound to S6. Mechanistically, RAB3B physically interacted with phosphorylase DUSP12, and blocked the DUSP12-mediated dephosphorylation of p-S6 (S235/236). Pharmacological targeting mTORC1 pathway dramatically impeded the RAB3B-induced stemness regulation, protein translation, and chordoma tumorigenicity, while RAB3B knockdown desensitized mTORC1 inhibition. In clinic, the combination of RAB3B and p-S6 suggested a good prognostic value and predicted mTORC1 inhibitors response for chordoma patients. Altogether, this work uncovers RAB3B/DUSP12 as the novel regulators of S6 phosphorylation (S235/236), and suggests the oncogenic and predictive roles of RAB3B/p-S6 in chordoma, indicating therapeutic potentials of mTORC1-targeted therapy for advanced chordoma patients with aberrant RAB3B/p-S6 hyperactivation.

Cucurbitacin B Exhibits Antitumor Effects on Chordoma Cells via Disruption of Brachyury

Chordomas are rare malignant tumors of the bone, originating from remnants of notochordal cells. The transcription factor brachyury, encoded by TBXT, serves as a critical diagnostic marker and is essential for tumor growth. While brachyury's role in regulating the cytoskeleton during embryogenesis and tumorigenesis is well understood, the reverse-whether cytoskeletal alterations can influence brachyury levels-remains unclear. Despite advances in understanding chordoma biology, there are currently no approved targeted therapies, underscoring the need for novel therapeutic approaches. Three chordoma cell lines were treated with cytoskeletal inhibitors, including the actin-targeting compounds Cucurbitacin B (CuB) and Latrunculin B (LatB). Morphological changes, TBXT expression, and cell viability were analyzed. The effects of CuB were examined over time and across concentrations, with cell viability assessed via apoptosis and cytotoxicity assays. Microarray gene expression profiling of ten chordoma cell lines was performed to explore CuB-mediated transcriptional changes. Rescue experiments using a TBXT open reading frame vector and co-treatments with autophagy and proteasome inhibitors were conducted to elucidate the mechanisms of brachyury depletion. Both CuB and LatB induced significant morphological changes, but only CuB caused near-complete depletion of brachyury. This effect was time- and concentration-dependent, correlating with reduced cell viability driven primarily by apoptosis. Microarray analysis revealed that CuB treatment upregulated protein refolding pathways and downregulated protein glycosylation. Notably, TBXT transcription was only slightly suppressed, indicating that brachyury depletion was largely post-transcriptional. Rescue experiments and co-treatments implicated dysregulated protein refolding and endoplasmic reticulum (ER) stress as key mechanisms underlying CuB-mediated brachyury loss. This study demonstrates that actin cytoskeleton disruption by CuB depletes brachyury in chordoma cells, primarily through dysregulated protein refolding and ER stress rather than transcriptional repression. These findings suggest that targeting actin cytoskeleton dynamics or protein unfolding pathways may provide novel therapeutic approaches for chordoma treatment.

A novel perspective on bone tumors: advances in organoid research

Bone tumor organoids are three-dimensional cell culture models derived from patient tissues or cells, capable of highly replicating the growth patterns and cell interactions of bone tumors in vitro. Current treatments for bone tumors are hindered by challenges such as drug resistance, recurrence, and metastasis. Organoids enhance the physiological relevance of bone tumor models, thereby improving treatment precision and overcoming the limitations of current therapeutic approaches. Organoid technology has made preliminary applications in bone tumor research, including primary bone tumors, metastatic bone tumors, and bone marrow-derived bone tumors. This review will explore the establishment of bone tumor organoids, summarize their applications and prospects in various bone tumor diseases, and discuss their integration with emerging technologies. Additionally, the limitations and future directions of bone tumor organoid research will be discussed. In the future, bone tumor organoids are expected to promote the further development of precision medicine.

Combinatorial therapies for epigenetic, immunotherapeutic, and genetic targeting of chordoma

PURPOSE

Chordoma, a rare malignancy of the axial skeleton and skull base, presents significant therapeutic challenges due to the high rates of tumor recurrence and resistance. While surgical resection and radiation therapy remain the gold standard of treatment, the lack of additional treatment options necessitates the exploration of novel therapies. Combinatorial therapies hold significant potential in shaping patient prognosis. By targeting the immunotherapeutic, epigenetic, and genetic landscapes of chordoma, these methods enable the more effective and personalized management of the diverse molecular mechanisms driving chordoma growth and resistance.

METHODS

To elucidate such potential, we conducted a literature review of all published articles on the usage of immunotherapeutic, epigenetic, and genetic approaches for chordoma treatment from 2014 to 2024.

RESULTS

Eighty-one papers were excluded based on our inclusion criteria. From the remaining thirty-nine publications, we found evidence supporting the efficacy of immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR) T-cell therapies, and monoclonal antibodies; the roles of DNA methylation patterns, histone modification pathways, and miRNA regulation; and the contribution of cancer stem-like cells (CSCs) to chordoma progression.

CONCLUSION

Our findings underscore the importance of a multidirectional approach in chordoma treatment throughout the disease progression to reduce morbidity and improve patient outcomes despite the heterogeneity of chordoma.

The Association of Gender in the Management and Prognosis of Vertebral and Sacral Chordoma: A SEER Analysis

Background/Objectives: Chordomas are rare primary osseous tumors of the spine and skull base that may portend significant morbidity and mortality. Gender disparities in the management and outcomes of spinal and pelvic chordomas have been sparsely studied. This study aimed to examine the effect of gender on the treatment utilization and outcomes in patients with vertebral column and sacrum/pelvis chordomas. Methods: A retrospective cohort study was performed using the 2000 to 2020 Surveillance, Epidemiology, and End Results (SEER) Registry, a U.S. population-based cancer registry database. Patients with histologically confirmed chordoma of the vertebral column or the sacrum/pelvis were identified using ICD-O-3 codes. The study population was divided into gender-based cohorts: male and female. The patient demographics, tumor characteristics, treatment variables, and mortality were assessed. Results: A total of 791 patients were identified and stratified by gender: 485 (61.3%) male and 306 (38.7%) female. The mean tumor size was similar between the cohorts (p = 0.377), as was the tumor location, with most arising from the pelvic bones/sacrum/coccyx (p = 0.953). While the treatment characteristics did not significantly vary, among patients who received both radiotherapy and surgery, neo-adjuvant radiotherapy was utilized at higher frequencies in the male patients (p = 0.011). For vertebral column chordomas, the median (p = 0.230) and five-year survival (p = 0.220) was similar between cohorts, and gender was not a predictor of survival (p = 0.239). Similarly, for pelvic chordomas, the median (p = 0.820) and five-year survival (p = 0.820) was similar between cohorts, and gender was not associated with survival (p = 0.816). Conclusions: Our study suggests that gender may influence treatment utilization but not mortality in patients with chordomas of the spine and sacrum.

Imaging of the skull base and orbital tumors

The skull base and orbit have complicated anatomical structures where various tumors can occur. The tumor may present with neurological symptoms; however, its diagnosis is clinically difficult owing to accessibility issues. Therefore, diagnostic imaging is crucial in assessing tumors in the skull base and orbit and guiding subsequent management. Notably, some tumors have a predilection for a specific site of origin, and identifying the site of origin on imaging can help narrow the differential diagnosis. At the skull base, chordomas typically occur in the clivus, chondrosarcomas in the paramedian areas, paragangliomas in the jugular foramen, neurogenic tumors, and perineural spread in the neural foramen. Among orbital tumors, cavernous hemangiomas usually occur in the intraconal space, and pleomorphic adenomas and adenoid cystic carcinomas occur in the lacrimal glands. Some skull base and orbital tumors exhibit distinctive imaging features. Chordomas and chondrosarcomas of the skull base show high signal intensities on T2-weighted images, with chondrosarcomas often displaying cartilaginous calcifications. Paragangliomas are characterized by their hypervascular nature. In the orbit, cavernous hemangiomas and pleomorphic adenomas present unique dynamic patterns. Immunoglobulin G4-related disease forms lesions along the nerves. Identifying the tumor origin and its imaging characteristics can help narrow the differential diagnosis of skull base and orbital tumors.

The efficacy and safety of tyrosine kinase inhibitors in the treatment of advanced or metastatic chordoma: a single-arm meta-analysis

Chordoma is a rare malignant tumor with a higher incidence in males than in females. There is an increasing number of clinical studies related to tyrosine kinase inhibitors (TKIs), yet the efficacy and safety of different drugs vary. In this single-arm meta-analysis evaluating the efficacy and safety of TKIs for chordoma treatment, 12 studies involving 365 patients were analyzed. The findings suggest that TKIs can improve outcomes, with an objective response rate of 1.7% and 29% based on RECIST and Choi criteria, a median progression-free survival (mPFS) of 8.41 months and a median overall survival (mOS) of 36.6 months. Imatinib, in particular, showed a longer mOS of 39.3 months compared to 25.0 months for other TKIs. However, high toxicity was noted, with a 95% overall incidence of adverse events (AEs), including hypertension, nausea and vomiting, and edema. Serious AEs occurred at a rate of 55%. In subgroup analysis, Imatinib showed a lower incidence of AEs compared to other TKIs. Combination therapy reduced the risk of severe adverse events compared to monotherapy. The study underscores the potential of TKIs to extend survival in chordoma patients but also highlights the need for careful management of treatment-related toxicity. Combining TKIs, especially imatinib, with other treatments may avoid serious adverse events. Further high-quality clinical trials are needed to confirm these findings and optimize treatment protocols.

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines (2016) and provides a reference standard for the clinical care of UK patients with primary malignant bone tumours (PMBT) and giant cell tumours (GCTB) of bone. The guidelines recommend treatments that are effective and should be available in the UK, and support decisions about management and service delivery. The document represents a consensus amongst British Sarcoma Group members in 2024. Key recommendations are that bone pain, or a palpable mass should always lead to further investigation and that patients with clinical or radiological findings suggestive of a primary bone tumour at any anatomic site should be referred to a specialist centre and managed by an accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow-up schedules are suggested.

Therapeutic strategies for mobile spine chordoma: en bloc Versus intralesional surgery with adjuvant charged-particle therapy

PURPOSE

The aim of this retrospective study is to analyze the impact of en bloc resection with negative margins versus intralesional resection plus adjuvant hadron-therapy (HT) on local control (LC) and overall survival (OS) in patients with mobile spine chordomas. Mechanical complications incidence as well as risk factors, and outcome differences are investigated as secondary endpoints.

METHODS

33 patients in a period from January 2013 to December 2021 were enrolled for the final analysis. The inclusion criteria were: lesions located in the mobile spine (C1-L5), age ≥ 15 years, minimum follow-up of 2 years, en bloc or intralesional surgical resection, virgin or recurrent chordomas, with only one previous surgical treatment.

RESULTS

No difference was found in terms of LC between the two groups. The presence of pathologic fracture at pre-operative imaging and the presence of macroscopic residual tumor after surgery, independently from its entity, seemed to be associated with an increased risk of LR. No difference was found between planned en bloc and planned intralesional surgery in terms of mechanical complications occurrence. Eight patients (24.24%) had mechanical complications during the follow up period: male sex, presence of pathologic fracture at baseline, a combined surgical approach, the use of carbon fiber-only hardware appeared to be associated with an increased risk of mechanical complications after the primary surgery.

CONCLUSIONS

En bloc resection, whenever possible, is always to be preferred for its widely recognized potential in LC and OS improvement. However, technology advances in high-dose conformal charged-particle therapy have allowed improvement of local control rates as an adjuvant therapy of intralesional surgery for mobile spine chordoma, with acceptable acute and chronic toxicity.

Latest Developments in Targeted Biological Therapies in the Management of Chordoma and Chondrosarcoma

STUDY DESIGN

Systematic review.

OBJECTIVES

The objective of this review paper was to summarize targeted molecular therapy options for spinal chordoma and chondrosarcoma, and to provide an update on the relevant clinical trials open for recruitment.

METHODS

A systematic review of the current literature was performed, according to PRISMA guidelines, to summarize the latest developments in non-surgical molecular treatment options for low grade malignant primary spinal tumours. We also summarize those actively recruiting clinical trials based on clinicaltrials.gov.

RESULTS

A total of 73 studies and completed clinical trials were reviewed. Twenty actively recruiting clinical trials (eight for chordoma and twelve for chondrosarcoma) were identified.

CONCLUSIONS

There is a strong need to find new therapeutic options to complement surgical resection and radiation therapy, which remain the cornerstone of management. Targeted therapies against molecular pathways show promise as compared to conventional chemotherapy.

Repeated chest wall reconstruction after resection of a sternal chondroid chordoma with long-term postoperative infection of the reconstructive material

We present the case of a 23-year-old man with a chondroid chordoma of the sternum. The patient underwent chest wall resection, followed by stabilization using a sandwich graft of Prolene mesh and methylmethacrylate, covered with bilateral pedicled musculus pectoralis flaps. After adjuvant radiotherapy and 2 years of follow-up, the patient developed a graft-associated infection. We removed the allogeneic material and the encapsulated abscess, and the wound was conditioned through negative wound pressure therapy. This time, wound closure and chest wall stabilization were achieved with a Prolene mesh covered by a free anterolateral thigh flap. This case demonstrates the importance of carefully considering the material for chest wall stabilization and establishing multidisciplinary cooperation.

Proton beam and carbon ion radiotherapy in skull base chordoma: a systematic review, meta-analysis and meta-regression with trial sequential analysis

Chordomas are rare, locally aggressive tumors that have a high rate of recurrence, especially at the skull base. This systematic review and meta-analysis aimed to analyze the efficacy and safety of proton beam therapy (PBT) and carbon ion radiotherapy (CIRT) for skull base chordoma. We conducted a systematic search of MEDLINE, EMBASE, CENTRAL, Web of Science, and Ovid up to November 26, 2023, following the PRISMA statement. Studies involving more than 10 patients with skull base chordoma treated with PBT or CIRT were included. The outcomes analyzed were local control, overall survival, progression-free survival, and toxicities. Meta-analysis was performed using the Mantel-Haenszel method and the inverse variance method. Fourteen studies met the inclusion criteria, encompassing 1,145 patients (671 treated with PBT and 474 with CIRT). No significant difference was found between PBT and CIRT for 5-year local control (LC) and overall survival (OS). The only timepoint with a difference in local control was at 3 years, when PBT showed an advantage in local control (90% vs. 83% for CIRT; p = 0.05) and progression-free survival was similar (94% for PBT vs. 83% for CIRT; p = 0.09). Sensitivity analysis and meta-regression revealed no significant influence of predefined parameters on outcomes. Publication bias was suggested by asymmetrical funnel plots. Both PBT and CIRT are effective treatments for skull base chordoma, with comparable long-term efficacy. This meta-analysis underscores the need for individualized treatment approaches and further research to refine these therapies in clinical practice.

Extracellular Vesicles from a Novel Chordoma Cell Line, ARF-8, Promote Tumorigenic Microenvironmental Changes When Incubated with the Parental Cells and with Human Osteoblasts

Chordomas are rare, generally slow-growing spinal tumors that nonetheless exhibit progressive characteristics over time, leading to malignant phenotypes and high recurrence rates, despite maximal therapeutic interventions. The tumors are notoriously resistant to therapies and are often located in regions that complicate achieving gross total resections. Cell lines from these tumors are rare as well. We cultured a new chordoma cell line (ARF-8) derived from an extensive clival chordoma that extended back to the cervical spine. We characterized the ARF-8 cellular and extracellular vesicle (EV) proteomes, as well as the impacts of ARF-8 EVs on the proteomes and secretomes of recipient cells (both ARF-8 and human osteoblasts) in autocrine and paracrine settings. Our proteomic analyses suggested roles for transforming growth factor beta (TGFB/TGFβ), cell-matrix interactions involving the epithelial-to-mesenchymal transition (EMT), and cell-extracellular matrix interactions in cell migration, consistent with a migratory/metastatic tumor phenotype. We demonstrated that ARF-8 tumor cell migration was dependent on general (arginine-glycine-aspartic acid [RGD]-based) integrin activity and that ARF-8 EVs could promote such migration. ARF-8 EVs also prompted proteomic/secretomic changes in human osteoblast cells, again with indications that cell-cell and cell-extracellular matrix interactions would be activated. All the characteristics typically associated with chordomas as cancers-migration and invasion, therapeutic resistance, metastatic potential-can be driven by tumor EVs. Overall, ARF-8 EVs promoted predicted tumorigenic phenotypes in recipient cells and suggested novel therapeutic targets for chordomas.

The novel developed and validated multiparametric MRI-based fusion radiomic and clinicoradiomic models predict the postoperative progression of primary skull base chordoma

Local progression of primary skull base chordoma (PSBC) is a sign of treatment failure. Predicting the postoperative progression of PSBC can aid in the development of individualized treatment plans to improve patients' progression-free survival (PFS) after surgery. This study aimed to develop a multiparametric MRI-based fusion radiomic model (FRM) and clinicoradiomic model (CRM) via radiomic and clinical analysis and to explore their validity in predicting postoperative progression in PSBC patients before surgery. In this retrospective study, a total of 129 patients with PSBC from our institution, including 57 patients with progression, were enrolled and randomized to the training set (TS) or the validation set (VS) at a 2:1 ratio. Radiomic features were extracted and dimensionally reduced from 3.0 T/axial T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and contrast-enhanced T1-weighted imaging (CE-T1WI) sequences for each patient, and the features were used for radiomic analysis. Univariate and multivariate Cox regression analyses were used to screen for key clinical factors. We constructed models on the basis of multivariate logistic regression analysis. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analyses were performed to evaluate the performance of the clinical model (CM), FRM and CRM. Through analysis, we found that blood supply was the only significantly different clinical factor in the CM. For the FRM, the area under the receiver operating characteristic curve (AUC) of the TS was 0.925, and the calibration curves were consistent across the TS. In the CRM, the AUC of the TS was 0.929, the calibration curve analysis was consistent for both the TS and the VS, and the DCA showed that the net benefit was greater at a threshold probability of > 0% for both the TS and the VS. Our proposed FRM can help clinicians better predict PSBC progression preoperatively, and the use of the CRM can lead to the development of more appropriate protocols to improve patients' PFS after surgery.

Proton Therapy for Spinal Tumors: A Consensus Statement From the Particle Therapy Cooperative Group

PURPOSE

Proton beam therapy (PBT) plays an important role in the management of primary spine tumors. The purpose of this consensus statement was to summarize safe and optimal delivery of PBT for spinal tumors.

METHODS AND MATERIALS

The Particle Therapy Cooperative Group Skull Base/Central nervous system/Sarcoma Subcommittee consisting of radiation oncologists and medical physicists with specific expertise in spinal irradiation developed expert recommendations discussing treatment planning considerations and current approaches in the treatment of primary spinal tumors.

RESULTS

Computed tomography simulation: factors that require significant consideration include (1) patient comfort, (2) setup reproducibility and stability, and (3) accessibility of appropriate beam angles.

SPINE STABILIZATION HARDWARE

If present, hardware should be placed with cross-links well above/below the level of the primary tumor to reduce the metal burden at the level of the tumor bed. New materials that can reduce uncertainties include polyether-ether-ketone and composite polyether-ether-ketone-carbon fiber implants.

FIELD ARRANGEMENT

Appropriate beam selection is required to ensure robust target coverage and organ at risk sparing. Commonly, 2 to 4 treatment fields, typically from posterior and/or posterior-oblique directions, are used.

TREATMENT PLANNING METHODOLOGY

Robust optimization is recommended for all pencil beam scanning plans (the preferred treatment modality) and should consider setup uncertainty (between 3 and 7 mm) and range uncertainty (3%-3.5%). In the presence of metal hardware, use of an increased range uncertainty up to 5% is recommended.

CONCLUSIONS

The Particle Therapy Cooperative Group Skull Base/Central nervous system/Sarcoma Subcommittee has developed recommendations to enable centers to deliver PBT safely and effectively for the management of primary spinal tumors.

Intensity Modulated Carbon Ion Radiation Therapy Using Pencil Beam Scanning Technology for Patients With Unresectable Sacrococcygeal Chordoma

Purpose

To investigate the safety and efficacy of intensity modulated carbon ion radiation therapy (IM-CIRT) using pencil beam scanning technology for patients with unresectable sacrococcygeal chordoma (SC).

Methods and Materials

A total of 35 patients with unresectable SC were retrospectively analyzed, including 54.3% (19/35) recurrent cases. In 68.6% (24/35) cases, tumor was located in S2 or above, and all cases were treated with hypofractionated IM-CIRT. The median dose was 70.4 Gy (range, 69-80 Gy) (relative biologic effectiveness) in 16 fractions (range, 16-23 fractions), typically delivered over 5 fractions per week.

Results

The 3-year overall survival, cause-specific survival, progression-free survival, locoregional progression-free survival, and distant metastasis-free survival rates with a median follow-up time of 42 months (range, 12-91 months) for the entire cohort were 93.2%, 96.3%, 61.8%, 80%, and 77.3%, respectively. Multivariate analysis revealed that gross tumor volume (hazard ratio, 3.807; 95% CI, 1.044-13.887; P = .043) was the only significant prognostic factor for progression-free survival and the dose for the gross tumor volume ≥70.4 Gy (relative biologic effectiveness) was relevant with significantly better locoregional progression-free survival (hazard ratio, 0.190; 95% CI, 0.038-0.940; P = .042). No significant prognostic factor for overall survival, cause-specific survival, and distant metastasis-free survival and no severe (ie, grade ≥3) acute toxicity were identified. Severe late toxicities occurred in 3 patients (8.57%): pain (1 patient), motor neuropathy (1 patient), and skin ulcer (1 patient). Furthermore, no severe toxicity related to urinary function or defecation was observed following IM-CIRT. Pain grades improved or remained unchanged in 85.7% of patients.

Conclusions

IM-CIRT produced acceptable 3-year outcomes without substantial late adverse effects, especially urinary and anorectal complications for SC, and did not appear to increase pain. IM-CIRT at high doses using hypofractionated radiation therapy may improve outcomes for local control and seems to be feasible even for postoperative recurrent SC.

Clinical-proteomic classification and precision treatment strategy of chordoma

Chordoma is a rare and heterogeneous mesenchymal malignancy, with distinct clinical and biological behaviors. Till now, its comprehensive clinical-molecular characteristics and accurate molecular classification remain obscure. In this research, we enroll 102 patients with chordoma and describe their clinical, imageological, and histopathological features. Through tandem mass tag-based proteomic analysis and nonnegative matrix factorization clustering, we classify chordoma into three molecular subtypes: bone microenvironment-dominant, mesenchymal-derived, and mesenchymal-to-epithelial transition-mediated pattern. The three subtypes exhibit discrete clinical prognosis and distinct biological attributes of osteoclastogenesis and immunogenicity, oxidative phosphorylation, and receptor tyrosine kinase activation, suggesting targeted therapeutic strategies of denosumab, S-Gboxin, and anlotinib, respectively. Notably, these approaches demonstrate positive treatment outcomes for each subtype in vitro and in vivo. Altogether, this work sheds light on the clinical-proteomic characteristics of chordoma and provides a candidate precision treatment strategy for chordoma according to molecular classification, underscoring their potential for clinical application.

Spinal chordoma and chondrosarcoma treatment experiences - a 20-year retrospective study from databases of two medical centers

The research retrospectively analyzed cases of spinal chordoma and chondrosarcoma involving patients who received treatment at the two hospitals between 2001 and 2023. Among the 48 patients studied (39 chordoma and 9 chondrosarcoma cases), the average age was 53.9 ± 15.8 years, with a range of 17 to 86 years. Out of these patients, 43 underwent excision surgery and were categorized based on tumor margin into negative (R0) or microscopically positive (R1) margin (n = 14) and macroscopically positive (R2) margin (n = 29) groups. The mean overall survival (OS) for R0/R1 and R2 groups was 156.5 ± 19.3 and 79.2 ± 11.9 months, respectively (p value = 0.012). The mean progression-free survival (PFS) for R0/R1 and R2 was 112.9 ± 24.4 and 25.5 ± 5.5 months (p value < 0.001). The study showed that regardless of whether patients in the R0/R1 or R2 groups received radiation therapy (RT) or not, there was no significant improvement in OS or PFS. Specifically, the OS and PFS for the RT only group were 75.9 ± 16.6 and 73.3 ± 18.0 months. In conclusion, the recommended treatment approach for spinal chordoma and chondrosarcoma remains en bloc resection surgery with an appropriate margin. Patients who are unsuitable for or decline surgery may find a beneficial disease control rate with traditional external beam photon/proton therapy.

The landscape of drug sensitivity and resistance in sarcoma

Sarcomas are rare malignancies with over 100 distinct histological subtypes. Their rarity and heterogeneity pose significant challenges to identifying effective therapies, and approved regimens show varied responses. Novel, personalized approaches to therapy are needed to improve patient outcomes. Patient-derived tumor organoids (PDTOs) model tumor behavior across an array of malignancies. We leverage PDTOs to characterize the landscape of drug resistance and sensitivity in sarcoma, collecting 194 specimens from 126 patients spanning 24 distinct sarcoma subtypes. Our high-throughput organoid screening pipeline tested single agents and combinations, with results available within a week from surgery. Drug sensitivity correlated with clinical features such as tumor subtype, treatment history, and disease trajectory. PDTO screening can facilitate optimal drug selection and mirror patient outcomes in sarcoma. We could identify at least one FDA-approved or NCCN-recommended effective regimen for 59% of the specimens, demonstrating the potential of our pipeline to provide actionable treatment information.

Skull Base Chordoma and Chondrosarcoma: Neuroradiologist's Guide to Diagnosis, Surgical Management, and Proton Beam Therapy

Skull base chordomas and chondrosarcomas are distinct types of rare, locally aggressive mesenchymal tumors that share key principles of imaging investigation and multidisciplinary care. Maximal safe surgical resection is the treatment choice for each, often via an expanded endoscopic endonasal approach, with or without multilayer skull base repair. Postoperative adjuvant radiation therapy is frequently administered, usually with particle therapy such as proton beam therapy (PBT). Compared with photon therapy, PBT enables dose escalation while limiting damage to dose-limiting neurologic structures, particularly the brainstem and optic apparatus, due to energy deposition being delivered at a high maximum with a rapid decrease at the end of the penetration range (Bragg peak phenomenon). Essential requirements for PBT following gross total or maximal safe resection are tissue diagnosis, minimal residual tumor after resection, and adequate clearance from PBT dose-limiting structures. The radiologist should understand surgical approaches and surgical techniques, including multilayer skull base repair, and be aware of evolution of postsurgical imaging appearances over time. Accurate radiologic review of all relevant preoperative imaging examinations and of intraoperative and postoperative MRI examinations plays a key role in management. The radiology report should reflect what the skull base surgeon and radiation oncologist need to know, including distance between the tumor and PBT dose-limiting structures, tumor sites that may be difficult to access via the endoscopic endonasal route, the relationship between intradural tumor and neurovascular structures, and tumor sites with implications for postresection stability. ©RSNA, 2024 Supplemental material is available for this article.

Skull Base Chordoma in a Young Lady - A Tale of Mismanagement and Redemption: A Case Report and Review of Literature

Skull base chordomas are a rare entity that requires multidisciplinary decision-making for management. We report a case wherein the patient was initially mismanaged at a peripheral centre, and was then redeemed by a multidisciplinary tumor board decision-making and specialized surgical procedures. We also present a brief review of the therapeutic options.

Hypoxic Upregulation of IER2 Increases Paracrine GMFG Signaling of Endoplasmic Reticulum Stress-CAF to Promote Chordoma Progression via Targeting ITGB1

Currently, the oncogenic mechanism of endoplasmic reticulum stress-CAF (ERS-CAF) subpopulation in chordoma remains unknown. Here, single-cell RNA sequencing, spatial transcriptomics, GeoMx Digital Spatial Profiler, data-independent acquisition proteomics, bulk RNA-seq, and multiplexed quantitative immunofluorescence are used to unveil the precise molecular mechanism of how ERS-CAF affected chordoma progression. Results show that hypoxic microenvironment reprograms CAFs into ERS-CAF subtype. Mechanistically, this occurrs via hypoxia-mediated transcriptional upregulation of IER2. Overexpression of IER2 in CAFs promotes chordoma progression, which can be impeded by IER2 knockdown or use of ERS inhibitors. IER2 also induces expression of ERS-CAF marker genes and results in production of a pro-tumorigenic paracrine GMFG signaling, which exert its biological function via directly binding to ITGB1 on tumor cells. ITGB1 inhibition attenuates tumor malignant progression, which can be partially reversed by exogenous GMFG intervention. Further analyses reveal a positive correlation between ITGB1high tumor cell counts and SPP1+ macrophage density, as well as the spatial proximity of these two cell types. Clinically, a significant correlation of high IER2/ITGB1 expression with tumor aggressive phenotype and poor patient survival is observed. Collectively, the findings suggest that ERS-CAF regulates SPP1+ macrophage to aggravate chordoma progression via the IER2/GMFG/ITGB1 axis, which may be targeted therapeutically in future.

Misdiagnosis of primary dumbbell chordoma of the cervical spine

AIM

This study aimed to analyze the clinical characteristics and outcomes of patients with primary dumbbell chordoma of the cervical spine and to summarize the causes of misdiagnosis.

METHODS

The clinical data of patients were retrospectively collected. The diagnostic process, surgical procedures, and outcomes were analyzed, then the difference was compared between dumbbell and non-dumbbell chordomas of the cervical spine.

RESULTS

This study included six patients with primary dumbbell chordoma (one male and five females) with a mean age of 32.2 ± 24.5 years (range: 5-61 years). Five cases with no computed tomography (CT) examination before the first operation were misdiagnosed, and on magnetic resonance imaging (MRI), primary dumbbell chordoma showed the following specific features: extensive invasion of the surrounding soft tissues with an obscure boundary (≥5 cm), intervertebral disc sparing, and hemorrhagic necrosis, furthermore, the CT features included atypical destructive vertebral lesions, minimal intralesional calcification, and neural foraminal enlargement. After comparison with non-dumbbell chordomas, it show statistical difference (p < 0.05) in terms of calcification, foramen enlargement, FNA, misdiagnosis rate but with different recurrent rate.

CONCLUSION

Primary dumbbell chordomas of the cervical spine can easily be misdiagnosed as neurogenic tumors. Preoperative CT-guided fine-needle aspiration puncture biopsy helps make an accurate diagnosis. Gross total excision with postoperative radiotherapy has been proven effective in reducing the recurrence rate.

Endoscopic Endonasal Approach for Clival Chordomas in Elderly Patients: Clinical Characteristics, Patient Outcome, and Recurrence Rate

Introduction  The endoscopic endonasal route has demonstrated to be the approach of choice for a large majority of clival chordomas (CCs). However, its results in elderly patients are under-evaluated in the literature. The aim of this study is to assess the surgical outcome for these patients, determining the factors associated with a larger tumor resection in this population. Materials and Methods  Our institutional database of CC has been retrospectively reviewed, to identify all cases over 65 years old, operated through an endoscopic endonasal approach (EEA). Preoperative clinical and radiological features were considered, as well as surgical results, morbidity, and patients' outcome at follow-up. Results  Out of our series of 143 endoscopic surgical procedures for CC, 34 (23.8%) were in patients older than 65 and 10 in older than 75 (7.0%). Gross tumor removal was achieved in 22 cases (64.7%). Complications consisted of 2 (5.9%) postoperative cerebrospinal leaks, 1 (2.9%) meningitis, 1 (2.9%) permanent cranial nerve VI palsy, 1 (2.9%) pneumonia, and 2 (5.9%) urinary infections. In 39.1% of cases, the preoperative ophthalmoplegia improved or resolved. Twenty-seven patients (79.4%) underwent radiation therapy. At follow-up (37.7 ± 44.9 months), 13 patients (38.2%) showed a recurrence/progression and 13 (38.3%) deceased. Conclusion  EEA can be a useful approach in elderlies, balancing the large tumor removal with an acceptable morbidity rate, even if higher than that for general CC population. However, patient selection remains crucial. A multidisciplinary evaluation is important to assess not only their medical conditions, but also their social and familiar conditions.

Proteogenomic characterization of skull-base chordoma

Skull-base chordoma is a rare, aggressive bone cancer with a high recurrence rate. Despite advances in genomic studies, its molecular characteristics and effective therapies remain unknown. Here, we conduct integrative genomics, transcriptomics, proteomics, and phosphoproteomics analyses of 187 skull-base chordoma tumors. In our study, chromosome instability is identified as a prognostic predictor and potential therapeutic target. Multi-omics data reveals downstream effects of chromosome instability, with RPRD1B as a putative target for radiotherapy-resistant patients. Chromosome 1q gain, associated with chromosome instability and upregulated mitochondrial functions, lead to poorer clinical outcomes. Immune subtyping identify an immune cold subtype linked to chromosome 9p/10q loss and immune evasion. Proteomics-based classification reveals subtypes (P-II and P-III) with high chromosome instability and immune cold features, with P-II tumors showing increased invasiveness. These findings, confirmed in 17 paired samples, provide insights into the biology and treatment of skull-base chordoma.

Immunologic and Targeted Molecular Therapies for Chordomas: A Narrative Review

Chordomas are rare sarcomas arising from notochordal tissue and occur most commonly in the spine. The standard of care for chordomas without evidence of metastatic disease generally consists of en bloc resection followed by adjuvant radiotherapy. However, long-term (20-year) survival rates are approximately 30%. Chordomas are generally considered as chemo resistant. Therefore, systemic therapies have rarely been employed. Novel immunotherapies, including antibody therapy and tumor vaccines, have shown promise in early trials, leading to extended progression-free survival and symptom relief. However, the outcomes of larger trials using these vectors are heterogeneous. The aim of this review is to summarize novel chordoma treatments in immune-targeted therapies. The current merits, trial outcomes, and toxicities of these novel immune and targeted therapies, including those targeting vascular endothelial growth factor receptor (VEGFR) targets and the epidermal growth factor receptor (EGFR), will be discussed.

Prognostic factors and overall survival in pelvic Ewing's sarcoma and chordoma: A comparative SEER database analysis

Background

This study aimed to develop and validate nomograms to predict overall survival (OS) for pelvic Ewing's sarcoma (EWS) and chordoma, identify prognostic factors, and compare outcomes between the two conditions.

Methods

We identified patients diagnosed with pelvic EWS or chordoma from the SEER database (2001-2019). Independent risk factors were identified using univariate and multivariate Cox regression analyses, and these factors were used to construct nomograms predicting 3-, 5-, and 10-year OS. Validation methods included AUC, calibration plots, C-index, and decision curve analysis (DCA). Kaplan-Meier curves and log-rank tests compared survival differences between low- and high-risk groups.

Results

The study included 1175 patients (EWS: 611, chordoma: 564). Both groups were randomly divided into training (70 %) and validation (30 %) cohorts. OS was significantly higher for chordoma. Multivariate analysis showed year of diagnosis, income, stage, and surgery were significant for EWS survival, while age, time to treatment, stage, and surgery were significant for chordoma survival. Validation showed the nomograms had strong predictive performance and clinical utility.

Conclusions

The nomograms reliably predict overall survival (OS) in pelvic EWS and chordoma, helping to identify high-risk patients early and guide preventive measures. The study also found that survival rates are significantly higher for chordoma, highlighting different prognostic profiles between EWS and chordoma.

Hypofractionated proton and carbon ion beam radiotherapy for sacrococcygeal chordoma (ISAC): An open label, randomized, stratified, phase II trial

INTRODUCTION

Sacrococcygeal chordomas have high recurrence rates and are challenging to treat.

METHODS

In this phase II prospective, randomized, stratified trial, the safety and feasibility of hypofractionated ion radiation therapy were investigated. The primary focus was monitored through the incidence of Grade 3-5 NCI-CTC-AE toxicity. Secondary endpoints included local progression-free (LPFS) and overall survival (OS).

RESULTS

The study enrolled 82 patients with primary (87 %) and recurrent (13 %) inoperable or incompletely resected sacral chordomas from January 2013 to July 2022, divided equally into proton therapy (Arm A) and carbon ion beam therapy (Arm B) groups, each receiving a total dose of 64 Gy (RBE) in 16 fractions, 5-6 fractions per week. Overall 74 % of patients received no previous surgery and 66 % of tumors were confirmed by a brachyury staining. The mean and median Gross Tumor Volume at the time of treatment (GTV) was 407 ml and 185 ml, respectively. The median follow-up of the surviving patients was 44.7 months, and the 2-year and 4-year OS rates were 96 % and 81 %, respectively. Factors such as smaller GTV and younger age trended towards better OS. The LPFS after 2-year and 4-year was 84 % and 70 %, respectively. Male gender emerged as a significant predictor of LPFS. There was no significant difference between the treatment groups. We observed five grade 4 wound healing disorders (6 %).

CONCLUSION

The initial response rates were promising; however local control was not sustained. More comparative research on fractionation schemes is essential to refine treatment approaches for inoperable sacral chordoma.

A single-center experience of the upright proton therapy for skull-base chordomas and chondrosarcomas: Updated results

AIM

To access efficacy and safety of the upright proton therapy for the skull-base chordomas and chondrosarcomas.

MATERIALS AND METHODS

The study encompasses single-center experience of proton therapy in chordomas (CA) and chondrosarcomas (CSA) of skull-base localization. We evaluate overall survival, local control and toxicity. Tumor response was assessed in accordance with RANO criteria. Treatment-related toxicity was evaluated with the help of CTCAE v 5.0 scale.

RESULTS

Proton therapy in the upright position was utilized for 51pts (patients) with CA-CSA (40 pts with chordoma and 11pts with chondrosarcoma) at the A. Tsyb Medical Radiological Research Center in 2016-2023. Median tumor volume constituted 30 cm3 (IQR (interquartile range) 15-41 cm3). Median total dose was 70 GyRBE. Median number of fractions was 35. Overall survival (OS) at 1-, 2- and 3-year rates reached 98.0 %, 88.6 % and 82.7 %, respectively. Median follow-up time was 36 months. The 1-, 2- and 3-year local control (LC) rates constituted, respectively, 98 %, 78.6 % and 66.3 %. Prior surgery showed statistically significant association with better prognosis (p = 0.023). Brainstem-to-tumor dose coverage compromise became the major pattern of LC failure (p = 0.03). The late radiation toxicity reactions included temporal lobe necrosis grade 2 in 2 pts, xerostomia grade 1 in 1pt, radiation cataract grade 2 in 1pt and persistent headache grade 2 in 4 pts. Severe late toxicity reactions were observed in 2 cases (4 %): 1 myelitis grade 3 and brainstem damage grade 5 in 1pt.

CONCLUSION

Local control was achieved in the majority of patients receiving the scanning-beam upright proton therapy for skull-base CA-CSA. The LC rates after a surgery-radiotherapy combination treatment were higher compared with irradiation alone. Pattern of failure is mostly brainstem-tumor dose compromise. The high OS and LC rates were accompanied by low toxicity incidence. Even in complex case of the skull base CA-CSA upright proton therapy shows promising clinical outcomes.

Clival chordomas and chondrosarcomas in Denmark-Outcomes in 33 patients following the national centralization of treatment in 2010

PURPOSE

This 13-year consecutive case series aims to provide a comprehensive overview of all patients operated for clival chordomas and clival chondrosarcomas in Denmark since the centralization of treatment in 2010, comparing outcomes to international series.

METHODS

This was a retrospective review of 33 patients with clival tumors, comprising 22 chordomas and 11 chondrosarcomas, who were treated at Copenhagen University Hospital between years 2010 and 2023. Data were collected from digital patient records and pathology reports.

RESULTS

The symptoms leading to diagnosis primarily included double vision, headaches, and dizziness. In general, patients were in good health, with a mean Charlson Comorbidity Index score of 1.6. The complication rate of the index surgery was 51.5%. Adjuvant radiotherapy was applied in 51.5% of the cases. In patients with clival chordomas, the mean age was 51.1 years, ranging from 16 to 83 years. At the time of diagnosis, the mean tumor volume was 20.9 cm3 and the five-year overall survival rates were 79.1% (95% confidence interval (CI): 62.4-100). In patients with chondrosarcomas, the mean age was 48.2 years, ranging from 15 to 76 years. At the time of diagnosis, the mean tumor volume was 22.3 cm3 and the five-year overall survival 90% (95% CI: 73.2-100).

CONCLUSION

The centralized treatment of clival tumors in Denmark demonstrates incidence, survival, and complication rates comparable to those found in other international series. Given the variations in treatment strategies, tumor localizations across series, and small sample sizes, the further analysis of larger compiled multicenter datasets for clival tumors could provide more solid evidence regarding the management of these rare tumors.

Not Every Size Fits All: Surgical Corridors for Clival and Cervical Chordomas-A Systematic Review of the Literature and Illustrative Cases

Introduction. Clival chordomas represent a rare but clinically significant subset of skull base tumors, characterized by a locally aggressive nature and a location in proximity to vital neurovascular structures. Surgical resection, often combined with adjuvant therapies, remains the cornerstone of clival chordoma treatment, and various approaches and techniques have evolved to maximize tumor removal while preserving neurological function. Recent advancements in skull base surgery, imaging, and adjuvant therapies have improved outcomes by reducing morbidity and thus enhancing long-term survival. Methods and Results. We have conducted a systematic review on PubMed/Medline following PRISMA guidelines regarding indications, the extent of resection (EOR), and complication rates. Then, we present three illustrative cases from our personal experience, which started 25 years ago with CVJ instrumentation procedures and 15 years ago with anterior decompressive transmucosal procedures performed with the aid of an operative microscope, an endoscope, and neuroradiological monitoring. Conclusions. Traditionally, the transoral approach (TOA) is the most frequently used corridor for accessing the lower clivus and the anterior craniovertebral junction (CVJ), without the need to mobilize or retract neural structures; however, it is associated with a high rate of complications. The endonasal approach (EEA) provides access to the anterior CVJ as well as to the lower, middle, and superior clivus, decreasing airway and swallowing morbidity, preserving palatal function, decreasing postoperative pain, and reducing the incidence of tracheostomy. The submandibular retropharyngeal approach (SRA) allows unique access to certain cervical chordomas, which is better suited when the lesion is located below the clivus and in the midline.

Exceptionally giant neglected sacral chordoma in a post-poliotic residual paralysis patient - a rare case scenario

Chordoma is a rare malignant tumour with an incidence of 0.1 case per 1 lakh population per year. The sacrococcygeal region is the most common site to be involved. Herein, we are reporting a case of sacral chordoma, who is a 32-year-old male patient, a known case of post-polio residual paralysis on the left lower limb, who presented with complaint of pain in the lower back and gluteal region for 2 years with swelling in the gluteal region for 1 year, which was gradually increasing in size for 1 year with associated weight loss. MRI revealed an ill-defined lytic expansile altered signal intensity lesion involving S3 to S5 and coccygeal vertebral bodies measuring 13.2 × 16.2 × 14 cm (ap × tr × cc) with adjacent large lobulated heterogeneous soft tissue component and showed multiple coarse calcifications. The lesion anteriorly displaced and abutted the rectum and was deriving its blood supply from branches of bilateral internal iliac arteries. The patient was planned and underwent wide-margin resection (middle sacrectomy with R0 margins with preservation of both S2 and right S3 nerve roots). Histologic Grade was reported to be G2, moderately differentiated, high grade. Pathologic stage classification was reported as pT3a. Postoperatively patient had the same neurological status and was discharged on advice to do full weight bearing walking and self-intermittent catheterisation and laxatives. He was on routine follow up and improved well symptomatically.

Clinical characteristics and predisposing factors of lung metastasis in sacral chordoma: a cross-sectional cohort study of 221 cases

Introduction

Limited studies are available on the topic of lung metastasis in sacral chordoma. The primary objective of this study was to investigate the prevalence, characteristics, associated factors, and prognosis of lung metastasis in sacral chordoma.

Methods

A total of 221 cases with primary sacral chordoma, all of whom underwent surgical resection at our center, were included in this study. Comprehensive demographic information, imaging findings, and oncological evaluations were collected and thoroughly analyzed. The diagnosis of lung metastasis in the majority of cases was established through radiographic examinations.

Results

The prevalence of lung metastasis in the cohort was 19.5%, with the lung emerging as the predominant site of distant metastasis. Recurrent chordoma cases exhibited a significantly higher lung metastasis rate in comparison to newly diagnosed chordoma cases (33.33% and 12.76%, p=0.0005). Patients with lung metastasis had a larger tumor size, a higher proportion of previous sacral chordoma surgeries and a greater likelihood of postoperative recurrence. Associated factors of lung metastasis were tumor size, postoperative recurrence and radiotherapy. Patients with lung metastasis exhibited decreased median overall survival (91 vs. 144 months for those without lung metastasis, p<0.05) and recurrence-free survival (27 vs. 68 months, p<0.001) times.

Discussion

Lung is the most common site of distant metastasis in sacral chordoma with an incidence rate nearly 20%. Larger tumor size and postoperative recurrence are risk factors for lung metastasis while radiotherapy is a protective factor. Occurrence of lung metastasis in sacral chordoma is a negative prognostic factor.

Conventional Spinal Chordomas: Investigation of SMARCB1/INI1 Protein Expression, Genetic Alterations in SMARCB1 Gene, and Clinicopathological Features in 89 Patients

The partial loss of SMARCB1/INI1 expression has recently been reported in skull base conventional chordomas, with possible therapeutic implications. We retrospectively analyzed 89 patients with conventional spinal chordomas to investigate the differences in the immunohistochemical expression of SMARCB1/INI1 and the underlying genetic alterations in the SMARCB1 gene. Moreover, we assessed the correlation of clinicopathological features (age, gender, tumor size, tumor location, surgical margins, Ki67 labelling index, SMARCB1/INI1 pattern, previous surgery, previous treatment, type of surgery, and the Charlson Comorbidity Index) with patient survival. Our cohort included 51 males and 38 females, with a median age at diagnosis of 61 years. The median tumor size at presentation was 5.9 cm. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) rates were 90.8% and 54.9%, respectively. Partial SMARCB1/INI1 loss was identified in 37 (41.6%) patients with conventional spinal chordomas (27 mosaic and 10 clonal). The most frequent genetic alteration detected was the monoallelic deletion of a portion of the long arm of chromosome 22, which includes the SMARCB1 gene. Partial loss of SMARCB1/INI1 was correlated with cervical-thoracic-lumbar tumor location (p = 0.033) and inadequate surgical margins (p = 0.007), possibly due to the high degree of tumor invasiveness in this site. Among all the considered clinicopathological features related to patient survival, only tumor location in the sacrococcygeal region and adequate surgical margins positively impacted DFS. In conclusion, partial SMARCB1/INI1 loss, mostly due to 22q deletion, was detected in a significant number of patients with conventional spinal chordomas and was correlated with mobile spine location and inadequate surgical margins.

Controversies in neuro-oncology: Focal proton versus photon radiation therapy for adult brain tumors

Radiation therapy (RT) plays a fundamental role in the treatment of malignant and benign brain tumors. Current state-of-the-art photon- and proton-based RT combines more conformal dose distribution of target volumes and accurate dose delivery while limiting the adverse radiation effects. PubMed was systematically searched from from 2000 to October 2023 to identify studies reporting outcomes related to treatment of central nervous system (CNS)/skull base tumors with PT in adults. Several studies have demonstrated that proton therapy (PT) provides a reduced dose to healthy brain parenchyma compared with photon-based (xRT) radiation techniques. However, whether dosimetric advantages translate into superior clinical outcomes for different adult brain tumors remains an open question. This review aims at critically reviewing the recent studies on PT in adult patients with brain tumors, including glioma, meningiomas, and chordomas, to explore its potential benefits compared with xRT.

Surgical management of skull base chordomas and chondrosarcomas: insights from a national cohort study

Objective

Skull base chordoma and chondrosarcoma are distinct sarcomas of the skull base but share significant therapeutic challenges due to their proximity to critical neurovascular structures, making surgical resection difficult. We sought to establish factors associated with outcome predictors in a national cohort of patients.

Methods and analysis

Data for all patients referred with a diagnosis of skull base chordoma or chondrosarcoma from April 2017 to December 2022 were obtained. We performed analyses of data pertaining to the first cohort of patients treated in the UK with proton beam therapy (PBT) to determine factors associated with obtaining gross total resection (GTR) and adequate clearance of the brainstem and optic apparatus.

Results

Of 230 patients with skull base chordoma or chondrosarcoma referred for PBT, 71% were accepted for PBT, with a wide regional variation between referring neurosurgical units (29%-93%). Of the first 75 consecutive patients treated with PBT, the only factor predictive of obtaining GTR was surgical resection at a unit with higher volumes of patients accepted for PBT (OR 1.32, 95% CI 1.11 to 1.63, p=0.004). Use of intraoperative MRI (OR 4.84, 95% CI 1.21 to 27.83, p=0.04) and resection at a higher volume unit (OR 1.29, 95% CI 1.07 to 1.64, p=0.013) were associated with increased rates of tumour clearance from the brainstem/optic apparatus.

Conclusions

Treatment at a higher volume centre was a key determinant of the optimal surgical outcome in this cohort. These data support the management of skull base chordomas and chondrosarcomas in higher volume centres where multidisciplinary experience can be accumulated.

Systematic Review and Meta-Analysis of Particle Beam Therapy versus Photon Radiotherapy for Skull Base Chordoma: TRP-Chordoma 2024

[Objective] The aim of this study was to compare the efficacy of particle beam therapy (PT) with photon radiotherapy (RT) for treatment of skull base chordoma. [Methods] A systematic review was conducted for skull base chordoma treated with PT or photon RT reported from 1990 to 2022. Data were extracted for overall survival (OS) and progression-free survival (PFS), late adverse events, age, gender, gross total resection (GTR) rates, tumor volume, total irradiation dose, and treatment modality. Random-effects meta-regression analysis with the treatment modality as an explanatory variable was performed for each outcome to compare the modalities. [Results] A meta-analysis of 30 selected articles found 3- and 5-year OS rates for PT vs. photon RT or combined photon RT/proton beam therapy (PBT) of 90.8% (95% CI: 87.4-93.3%) vs. 89.5% (95% CI: 83.0-93.6%), p = 0.6543; 80.0% (95% CI: 75.7-83.6%) vs. 89.5% (95% CI: 83.0-93.6%), p = 0.6787. The 5-year PFS rates for PT vs. photon RT or photon RT/PBT were 67.8% (95% CI: 56.5-76.7%) vs. 40.2% (95% CI: 31.6-48.7%), p = 0.0004. A random-effects model revealed that the treatment modality (PT vs. photon RT or photon RT/PBT) was not a significant factor for 3-year OS (p = 0.42) and 5-year OS (p = 0.11), but was a significant factor for 5-year PFS (p < 0.0001). The rates of brain necrosis were 8-50% after PT and 0-4% after photon RT or photon RT/PBT. [Conclusion] This study shows that PT results in higher PFS compared to photon RT for skull base chordoma, but that there is a tendency for a higher incidence of brain necrosis with PT. Publication and analysis of further studies is needed to validate these findings.

Getting to the Core: Exploring the Embryonic Development from Notochord to Nucleus Pulposus

The intervertebral disc (IVD) is the largest avascular organ of the human body and plays a fundamental role in providing the spine with its unique structural and biomechanical functions. The inner part of the IVD contains the nucleus pulposus (NP), a gel-like tissue characterized by a high content of type II collagen and proteoglycans, which is crucial for the disc's load-bearing and shock-absorbing properties. With aging and IVD degeneration (IDD), the NP gradually loses its physiological characteristics, leading to low back pain and additional sequelae. In contrast to surrounding spinal tissues, the NP presents a distinctive embryonic development since it directly derives from the notochord. This review aims to explore the embryology of the NP, emphasizing the pivotal roles of key transcription factors, which guide the differentiation and maintenance of the NP cellular components from the notochord and surrounding sclerotome. Through an understanding of NP development, we sought to investigate the implications of the critical developmental aspects in IVD-related pathologies, such as IDD and the rare malignant chordomas. Moreover, this review discusses the therapeutic strategies targeting these pathways, including the novel regenerative approaches leveraging insights from NP development and embryology to potentially guide future treatments.

Primary lung chordoma: a case report

BACKGROUND

Chordoma, a rare malignant tumor arising from notochordal tissue, usually occurs along the spinal axis. Only a few published reports of primary lung chordomas exist. Herein, we present a case of primary lung chordoma and discuss important considerations for diagnosing rare chordomas.

CASE PRESENTATION

We report a case of primary lung chordoma in a 39-year-old male with a history of testicular mixed germ-cell tumor of yolk sac and teratoma. Computed tomography revealed slow-growing solid lesions in the left lower lobe. We performed wedge resection for suspected germ-cell tumor lung metastasis. Histologically, large round or oval cells with eosinophilic cytoplasm were surrounded by large cells with granular, lightly eosinophilic cytoplasm. Tumor cells were physaliphorous. Immunohistochemistry was positive for brachyury, S-100 protein, epithelial membrane antigen, vimentin, and cytokeratin AE1/AE3, suggesting pulmonary chordoma. Re-examination of the testicular mixed germ-cell tumor revealed no notochordal elements. Although some areas were positive for brachyury staining, hematoxylin and eosin (HE) staining did not show morphological features typical of chordoma. Complementary fluorescence in situ hybridization (FISH) of the lung tumor confirmed the absence of isochromosome 12p and 12p amplification. Thus, a final diagnosis of primary lung chordoma was established.

CONCLUSIONS

In patients with a history of testicular mixed germ cell tumors, comparison of histomorphology using HE and Brachyury staining of lung and testicular tumors, and analyzing isochromosome 12p and 12p amplification in lung tumors using FISH is pivotal for the diagnosis of rare lung chordomas.

Chordoma: Genetics and Contemporary Management

Chordomas, arising from notochord remnants, are rare neoplasms with aggressive growth patterns despite their histologically low-grade nature. This review explores their embryological origins, molecular markers like brachyury, and genetic alterations driving pathogenesis. Diagnosis relies on advanced imaging and biopsy confirmation due to overlapping features with chondrosarcoma. The WHO classification distinguishes conventional, dedifferentiated, and poorly differentiated chordomas, each with distinct prognostic implications. Recent genomic analyses uncovered recurrent mutations in PI3K signaling pathways and chromatin remodeling genes, informing prognostic models. Surgery remains the cornerstone of treatment, though adjuvant radiation complements surgical resection. Although chordomas are generally considered refractory to medical therapy, emerging targeted molecular strategies show potential promise in ongoing trials. This review aims to provide a concise yet comprehensive overview of chordomas, guiding clinicians in diagnosis, treatment, and prognostication for improved patient outcomes.

Impact of CDK Inhibitors on TBXT Expression in Chordoma Cell Lines Including the First Stable Cell Line of a High-Grade Chordoma

Chordomas are very rare malignant neoplasms of the bone occurring almost exclusively along the spine. As the tumours are thought to arise from notochordal remnants, the vast majority of chordomas express the TBXT gene, resulting in detectable nuclear amounts of its gene product brachyury. This T-Box transcription factor is commonly recognised as being essential in chordoma cells, and limiting TBXT expression is thought to be the key factor in controlling this tumour. Although the tumour is rare, distinct molecular differences and vulnerabilities have been described with regard to its location and the progression status of the disease, rendering it mandatory for novel cell lines to reflect all relevant chordoma subtypes. Here, we describe a novel chordoma cell line arising from the pleural effusion of a disseminated, poorly differentiated chordoma. This cell line, U-CH22, represents a highly aggressive terminal chordoma and, therefore, fills a relevant gap within the panel of available cell culture models for this orphan disease. CDK7 and CDK9 inhibition was lately identified as being effective in reducing viability in four chordoma cell lines, most likely due to a reduction in brachyury levels. In this study, we determined the capability of the CDK7 inhibitor THZ1 and the CDK1/2/5/9 inhibitor dinaciclib to reduce TBXT expression at mRNA and protein levels in a broad range of nine cell lines that are models of primary, recurrent, and metastasised chordoma of the clivus and the sacrum.

Prognostic nomogram in middle-aged and elderly patients with chordoma: A SEER-based study

BACKGROUND

Chordoma is a bone tumor that tends to occur in middle-aged and elderly people. It grows relatively slowly but is aggressive. The prognosis of middle-aged and elderly patients with chordoma is quite different from that of young patients with chordoma.

OBJECTIVES

The purpose of the research was to construct a nomogram to predict the Individualized prognosis of middle-aged and elderly (age greater than or equal to 40 years) patients with chordoma.

METHODS

In this study, we screened 658 patients diagnosed with chordoma from 1983 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. We determined the independently prognostic factors that affect the survival of patients by univariate and multivariate Cox proportional hazards model. Based on the independent prognostic factors, we constructed a nomogram to predict the overall survival (OS) rates of middle-aged and elderly patients with chordoma at 3 and 5 years. The validation of this nomogram was completed by evaluating the calibration curve and the C-index.

RESULTS

We screened a total of 658 patients and divided them into two cohort. Training cohort had 462 samples and validation cohort had 196 samples. The multivariate Cox proportional hazards model of the training group showed an association of age, tumor size, histology, primary site, surgery, and extent of disease with OS rates. Based on these results, we constructed the corresponding nomogram. The calibration curve and C-index showed the satisfactory ability of the nomogram in terms of predictive ability.

CONCLUSION

Nomogram can be an effective prognostic tool to assess the prognosis of middle-aged and elderly patients with chordoma and can help clinicians in medical decision-making and enable patients to receive more accurate and reasonable treatment.

A Prospective Phase I/II Clinical Trial of High-Dose Proton Therapy for Chordomas and Chondrosarcomas

Purpose

The purpose of this study was to evaluate the feasibility and safety of dose-escalated proton beam therapy for treating chordomas and chondrosarcomas of the skull base and spine. Methods: A prospective cohort of 54 patients (42 with chordomas and 12 with chondrosarcomas) was enrolled between 2010 and 2018. The primary endpoints were feasibility and <20% rate of acute grade ≥3 toxicity, and secondary endpoints included cancer-specific outcomes and toxicities. Patients were followed with magnetic resonance imaging or computed tomography at 3-month intervals. Proton beam therapy was delivered with doses up to 79.2 Gy using protons only, combination protons/intensity modulated radiation therapy (IMRT), or IMRT only.

Results

Feasibility endpoints were met, with only 2 out of 54 patient radiation therapy plans failing to meet dosimetric constraints with protons, and 4 out of 54 experiencing a delay or treatment break >5 days, none for toxicities related to treatment. There were no grade 4 acute toxicities and 1 grade 3 acute toxicity (sensory neuropathy). The only 2 grade 3 late toxicities recorded, osteoradionecrosis and intranasal carotid blowout (mild and not emergently treated), occurred in a single patient. We report overall survival as 83% at 5 years, with local failure-free survival and progression-free survival rates of 72% and 68%, respectively. Five patients developed distant disease, and among the 9/54 patients who died, 4 deaths were not attributed to treatment or recurrence.

Conclusions

Our findings suggest that high-dose proton therapy alone or in combination with IMRT is a safe and effective treatment option for chordomas and chondrosarcomas of the skull base and spine.

Chordoma cancer stem cell subpopulation characterization may guide targeted immunotherapy approaches to reduce disease recurrence

Introduction

Cancer stem cells (CSCs), a group of tumor-initiating and tumor-maintaining cells, may be major players in the treatment resistance and recurrence distinctive of chordoma. Characterizing CSCs is crucial to better targeting this subpopulation.

Methods

Using flow cytometry, six chordoma cell lines were evaluated for CSC composition. In vitro, cell lines were stained for B7H6, HER2, MICA-B, ULBP1, EGFR, and PD-L1 surface markers. Eighteen resected chordomas were stained using a multispectral immunofluorescence (mIF) antibody panel to identify CSCs in vivo. HALO software was used for quantitative CSC density and spatial analysis.

Results

In vitro, chordoma CSCs express more B7H6, MICA-B, and ULBP1, assessed by percent positivity and mean fluorescence intensity (MFI), as compared to non-CSCs in all cell lines. PD- L1 percent positivity is increased by >20% in CSCs compared to non-CSCs in all cell lines except CH22. In vivo, CSCs comprise 1.39% of chordoma cells and most are PD-L1+ (75.18%). A spatial analysis suggests that chordoma CSCs cluster at an average distance of 71.51 mm (SD 73.40 mm) from stroma.

Discussion

To our knowledge, this study is the first to identify individual chordoma CSCs and describe their surface phenotypes using in vitro and in vivo methods. PD-L1 is overexpressed on CSCs in chordoma human cell lines and operative tumor samples. Similarly, potential immunotherapeutic targets on CSCs, including B7H6, MICA-B, ULBP1, EGFR, and HER2 are overexpressed across cell lines. Targeting these markers may have a preferential role in combating CSCs, an aggressive subpopulation likely consequential to chordoma's high recurrence rate.