Machine learning-based models for outcome prediction in skull base and spinal chordomas: a systematic review and meta-analysis

BACKGROUND

Chordomas are primary bone lesions originating from embryonic notochord remnants, most commonly developing along the skull base and spine. Managing chordomas is challenging due to the complex surgical approaches and significant resistance to chemotherapy and radiation. Consequently, the prognosis for chordoma treatment is unfavorable. We aimed to systematically assess the outcomes of machine learning (ML) models in predicting progression, recurrence, and survival in chordoma patients.

METHODS

We conducted a systematic search on January 28, 2025, in PubMed, Embase, Scopus, and Web of Science. ML models that forecast skull base and spinal chordomas and report concordance index (C-index), area under the curve (AUC), accuracy (ACC), sensitivity, or specificity were included. A random-effects meta-analysis was performed using R with the "meta" and "mada" packages. The risk of bias (RoB) was assessed using the QUADAS-2 tool.

RESULTS

Fifteen studies involving 3525 chordomas were included. The meta-analysis exhibited a pooled C-index of 0.81 (0.79-0.83), an AUC of 0.86 (95% CI: 0.83-0.9), and an ACC of 0.8 (95% CI: 0.75-0.85). The meta-analysis showed a pooled sensitivity of 0.74 (95% CI: 0.71-0.77), a specificity of 0.78 (95% CI: 0.74-0.81), and a diagnostic odds ratio (DOR) of 12.1 (95% CI: 7.1-20.6).

CONCLUSION

Our results indicated that ML models demonstrated robust predictive performance across various outcomes in chordomas, with pooled C-index, AUC, and ACC values ranging from 0.80 to 0.86 in relation to models that forecast progression, recurrence, or survival.

CLINICAL TRIAL NUMBER

Not applicable.

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.

Comparative overall survival analysis of chordomas of the base of the skull from the Surveillance, Epidemiology, and End Results (SEER) program between 2000 and 2020

Chordomas of the skull base are rare, slow growing, locally invasive cancers with limited long-term survival analysis reported in the literature. We seek to provide comparative survival analysis of patients on a long-term (20-year) basis using population-level data. The Surveillance, Epidemiology, and End Results (SEER) program was queried for cases of chordoma relegated to the base of the skull, diagnosed between 2000 and 2020. Demographic, disease, and treatment information were analyzed using Cox proportional hazards and log-rank comparisons. 630 patients with chordoma of the skull base were identified. Age ≤ 49 years at diagnosis was associated with increased five-, 10-, and 20-year overall survival (hazard ratio (HR) = 0.39, 0.33, and 0.30, respectively; p < 0.001 for all). Treatment with surgery and adjuvant radiotherapy was associated with increased five-, 10-, and 20-year survival (HR = 0.71, 0.79, and 0.79, respectively; p < 0.001 for all). On univariate analysis, widowed patients had decreased survival (20-year overall survival = 34.8% [15.3%-34.8%] compared to married patients (74.4% [68.1%-80.8%]. Surgery remains the primary treatment associated with increased survival among patients with chordoma of the skull base, with adjuvant radiotherapy serving a complimentary role. Demographic factors such as marital status are also associated with changes in survival.

Hematoporphyrin derivative-mediated photodynamic techniques for the diagnosis and treatment of chordoma

BACKGROUND

Chordoma is a rare congenital low-grade malignant tumor characterized by infiltrative growth. It often tends to compress important intracranial nerves and blood vessels, making its surgical treatment extremely difficult. Besides, the efficacy of radiotherapy and chemotherapy is limited. The photosensitizer hematoporphyrin derivative (HPD) can emit red fluorescence under 405 nm excitation and produce reactive oxygen species for tumor therapy under 630 nm excitation. Herein, we investigated the effects of the photosensitizer hematoporphyrin derivative (HPD) on different cell lines of chordoma and xenograft tumors under 405 nm and 630 nm excitation.

METHODS

The photosensitizer hematoporphyrin derivative (HPD) and Two different chordoma cell lines (U-CH1, JHC7) were used for the test. The in vitro experiments were as follows: (1) the fluorescence intensity emitted by chordoma cells excited by different 405 nm light intensities was observed under a confocal microscope; (2) the Cell Counting Kit-8 (CCK-8) assay was performed to detect the effects of different photosensitizer concentrations and 630 nm light energy densities on the activity of chordoma cells. In the in vivo experiments, (3) Fluorescence visualization of chordoma xenograft tumors injected with photosensitizer via tail vein under 405 nm excitation; (4) Impact of 630 nm excitation of photosensitizer on the growth of chordoma xenograft tumors.

RESULTS

(1) The photosensitizers in chordoma cells and chordoma xenografts of nude mice were excited by 405 nm to emit red fluorescence; (2) 630 nm excitation photosensitizer reduces chordoma cell activity and inhibits chordoma xenograft tumor growth in chordoma nude mice.

CONCLUSION

Photodynamic techniques mediated by the photosensitizer hematoporphyrin derivatives can be used for the diagnosis and treatment of chordoma.

Speech and Swallowing Outcomes of Surgically Managed Cervical Chordoma: A Case Series

OBJECTIVES

Cervical chordoma is a rare, low-grade primary bone tumor occurring in the axial skeleton. Due to challenges in surgical exposure caused by anatomic location, patients may experience dysfunction in speech and swallowing. The objective of this study was to characterize speech and swallowing outcomes for patients undergoing surgical resection of cervical chordoma. Moreover, we detail in-depth two cases with similar initial presentations to compare prognostic factors and management strategies.

METHODS

Eleven patients with histologically confirmed cervical chordoma treated between 1993 and 2020 were included in this retrospective case series. Outcomes measured included overall survival, disease-free survival, need for enteral feeds, as well as results of modified barium swallow study (MBSS) and fiberoptic laryngoscopy.

RESULTS

The mean age at diagnosis was 55.9 years. The patient population was 81.8% male. Mean survival after diagnosis was 96 months. Four (36.4%) patients required post-operative MBSS and demonstrated aspiration. All four of these patients presented with tumors in the superior cervical spine and received surgeries utilizing anterior approaches. Of the four, 2 required enteral feeds long-term. Four (36.4%) patients endorsed dysphonia. One patient developed post-operative right vocal fold paresis. The remaining three patients experienced stable dysphonia pre- and post-operatively. Additionally, three (27%) patients required tracheostomy placement, two of which remained in place long-term.

CONCLUSIONS

Dysphagia is a common side effect of cervical chordoma resection. It is associated with the use of an anterior approach during resection and with tumors located in the superior cervical spine. Patients with postoperative dysphagia should receive early multidisciplinary swallow rehabilitation.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3706-3712, 2024.

Incidence and centralization of chordoma in the Netherlands: A nationwide study between 1991 and 2020

INTRODUCTION

Chordomas are rare malignant bone tumors arising in the axial skeleton, with an incidence of 0.3-0.88 per million inhabitants. We studied the annual incidence rate and centralization of treatment for chordoma in the Netherlands.

METHODS

We retrieved pathology excerpts from the PALGA nationwide Dutch Pathology Registry between 1991 and 2019 for patients with a chordoma to calculate incidence rates. From pathology reports we extracted patient age at diagnosis, sex, year of diagnosis, localization of primary tumor, histologic chordoma subtype (conventional including chondroid, poorly differentiated or dedifferentiated), center of diagnosis (bone tumor referral center (BTC) or other hospital), and partial identification of the BTCs.

RESULTS

A total of 420 individual chordoma patients were identified in the given time period. The incidence of chordoma increased from 0.593 per million inhabitants between 1991-1995 to 1.111 from 2015-2019 (P = 0.001). Median age at diagnosis was 63 years (range 1-95), 252 patients (60%) were male. The proportion of samples analyzed in a BTC either primarily or secondary, as a consultation, revision or referral, increased significantly from 29.3% to 84.4% (P < 0.001). Most primary and secondary samples were analyzed at the Leiden University Medical Center (LUMC, 54.4% and 57% respectively).

CONCLUSIONS

This study shows an increase in the standardized incidence of pathology proven chordoma in the Netherlands. We observed an increase in samples being analysed in the specialized BTCs as well, which is in line with current guidelines and will hopefully lead to more accurate diagnoses and optimal treatment plans for chordoma patients in specialized treatment centers.

Activation of Wnt Pathway Suppresses Growth of MUG-Chor1 Chordoma Cell Line

Chordoma as a malignant bone tumor, occurs along the axial skeleton and does not have an effective therapy. Brachyury, which is a crucial player for the formation of early embryonic notochord, is abundantly found in both sporadic and familial chordoma. During embryonic development, Brachyury expression was reported to be regulated by the Wnt pathway. The objective of the study is to investigate the role of Wnt signaling in a human chordoma cell line in terms of proliferation, survival, and invasiveness. We tried to elucidate the signaling events that regulate Chordoma cancer. In this regard, Wnt pathway was activated or inhibited using various strategies including small molecules, siRNA-based knockdown and overexpression applications. The results indicated the negative regulatory effect of Wnt signaling activity on proliferation and migration capacity of the chordoma cells. It was revealed that when GSK3β was inhibited, the Wnt pathway was activated and negatively regulated T/Bra expression. Activity of the Wnt pathway caused cell cycle arrest, reduced migration potential of the cells, and led to cell death. Therefore, the present study suggests that the Wnt pathway plays a key role in suppressing the proliferation and invasive characteristics of human chordoma cells and has a great potential as a therapeutic target in further clinical studies.

Bibliometric Insights in Advances of Chordoma: Global Trends and Research Development in the Last Decade

Chordoma is a rare tumor, but has a serious effect on the quality of life of patients. This study aims to assess the overall knowledge structure and trends in the development of chordoma research using a bibliometric analysis and visualization tool. Research datasets were acquired from the Web of Science. VOS viewer and CiteSpace visualization software were used to demonstrate collaborations and correlations. Annual trends in publications, distribution, H-index status, co-authorship status, and research hotspots were analyzed. A total of 1844 publications from 2012 to 2022 were included. The number of chordoma-related publications increased year by year. The United States contributed the most publications (717) and had the highest total citations (10130) and H-index (50), followed by China. The United States was also the country most frequently involved in international cooperation. The most productive organization involved in chordoma research was Massachusetts General Hospital. World Neurosurgery (114) published the most papers on chordoma. Hornicek FJ was the most productive author over the last decade (41). Initially, diagnosis and the location of onset captured the attention of the research society. Quality of life, risk factors, disability, minimally invasive surgical techniques, molecular targeted therapy, and radiotherapy technology are the research hotspots in recent years. Indeed, this study provides important insights into the overall landscape of chordoma research and also contributes to the further investigation of the international frontier of chordoma.

Predicting overall survival in chordoma patients using machine learning models: a web-app application

OBJECTIVE

The goal of this study was to evaluate the efficacy of machine learning (ML) techniques in predicting survival for chordoma patients in comparison with the standard Cox proportional hazards (CoxPH) model.

METHODS

Using a Surveillance, Epidemiology, and End Results database of consecutive newly diagnosed chordoma cases between January 2000 and December 2018, we created and validated three ML survival models as well as a traditional CoxPH model in this population-based cohort study. Randomly, the dataset was divided into training and validation datasets. Tuning hyperparameters on the training dataset involved a 1000-iteration random search with fivefold cross-validation. Concordance index (C-index), Brier score, and integrated Brier score were used to evaluate the performance of the model. The receiver operating characteristic (ROC) curves, calibration curves, and area under the ROC curves (AUC) were used to assess the reliability of the models by predicting 5- and 10-year survival probabilities.

RESULTS

A total of 724 chordoma patients were divided into training (n = 508) and validation (n = 216) cohorts. Cox regression identified nine significant prognostic factors (p < 0.05). ML models showed superior performance over CoxPH model, with DeepSurv having the highest C-index (0.795) and the best discrimination for 5- and 10-year survival (AUC 0.84 and 0.88). Calibration curves revealed strong correlation between DeepSurv predictions and actual survival. Risk stratification by DeepSurv model effectively discriminated high- and low-risk groups (p < 0.01). The optimized DeepSurv model was implemented into a web application for clinical use that can be found at https://hust-chengp-ml-chordoma-app-19rjyr.streamlitapp.com/ .

CONCLUSION

ML algorithms based on time-to-event results are effective in chordoma prediction, with DeepSurv having the best discrimination performance and calibration.

Primary Skull Base Chordomas: A Clinicopathological Analysis of 94 Patients

OBJECTIVE

To investigate prognostic factors in patients with primary skull base chordoma (PSBC) to guide future therapeutic advances.

METHODS

This retrospective cohort study of 94 PSBC patients was conducted in 2 institutions from January 2006 to December 2013. Independent predictors for progression-free survival (PFS) and overall survival were established with multivariate Cox regression analysis.

RESULTS

Age (P = 0.006), extent of resection (P = 0.037), and radiotherapy (RT) (P = 0.027) were established as independent predictors for PFS in PSBC patients. Similarly, age (P = 0.002), extent of resection (P = 0.048), and RT (P = 0.015) were established as independent predictors for overall survival. Meta-analysis manifested that lower MIB-1 correlated with longer PFS in skull base chordoma patients (P < 0.001). RT doubled the 5-year PFS rate from 28.6 ± 12.1% to 61.6 ± 10.7% (P = 0.031) and increased the 5-year overall survival rate from 54.5 ± 13.8% to 84.2 ± 8.4% (P = 0.020) in the subtotal resection/partial resection and MIB-1 labeling index (STR/PR+MIB-1 LI) <2% subgroup. In contrast, in the STR/PR+MIB-1 LI ≥2% subgroup, the survival benefit of RT remained uncertain. Further analysis revealed no survival difference between different RT modalities in STR/PR PSBC patients.

CONCLUSIONS

In PSBC patients, age, extent of resection, and adjuvant RT all are independent predictors for PFS. Lower MIB-1 LI is associated with longer PFS in PSBC patients. Adjuvant RT is necessary for PSBC patients who undergo STR/PR with MIB-1 LI <2%. Patients who undergo GTR or STR/PR with MIB-1 LI ≥2% seem nonresponsive to RT.

High-Throughput/High Content Imaging Screen Identifies Novel Small Molecule Inhibitors and Immunoproteasomes as Therapeutic Targets for Chordoma

Chordomas account for approximately 1-4% of all malignant bone tumors and 20% of primary tumors of the spinal column. It is a rare disease, with an incidence estimated to be approximately 1 per 1,000,000 people. The underlying causative mechanism of chordoma is unknown, which makes it challenging to treat. Chordomas have been linked to the T-box transcription factor T (TBXT) gene located on chromosome 6. The TBXT gene encodes a protein transcription factor TBXT, or brachyury homolog. Currently, there is no approved targeted therapy for chordoma. Here, we performed a small molecule screening to identify small chemical molecules and therapeutic targets for treating chordoma. We screened 3730 unique compounds and selected 50 potential hits. The top three hits were Ribociclib, Ingenol-3-angelate, and Duvelisib. Among the top 10 hits, we found a novel class of small molecules, including proteasomal inhibitors, as promising molecules that reduce the proliferation of human chordoma cells. Furthermore, we discovered that proteasomal subunits PSMB5 and PSMB8 are increased in human chordoma cell lines U-CH1 and U-CH2, confirming that the proteasome may serve as a molecular target whose specific inhibition may lead to better therapeutic strategies for chordoma.

Clival Chordomas in the Endoscopic Endonasal Era: Comparison With Management With Open Skull Base Approaches

BACKGROUND

The most significant paradigm shift in surgical management of skull base chordomas has been the adoption of the endoscopic endonasal approach, but the impact on patient outcomes compared with open skull base approaches remains unclear.

OBJECTIVE

To compare a large series of patients treated by a single surgeon using primarily endoscopic endonasal approaches with previously published outcomes by the same surgeon using open skull base approaches.

METHODS

Between 2006 and 2020, 68 patients with skull base chordoma underwent resection using primarily endoscopic endonasal approaches. Outcomes and complications were compared with previously published results of resection of chordomas from 1991 to 2005 using open skull base approaches.

RESULTS

Compared with the prior cohort, the current principally endoscopic cohort demonstrated similar rates of OS ( P = .86) and progression-free survival ( P = .56), but patients undergoing first-time resection had significantly higher rates of radical resection (82.9% compared with 64.3%, P = .05) and required fewer staged surgeries (9.8% compared with 33.3%, P = .01).

CONCLUSION

There was no difference in survival rates for patients treated in the current era, primarily using endoscopic endonasal techniques, compared with previously published results using open skull-base approaches by the same surgeon. Although use of endoscopic endonasal approach resulted in higher rates of radical resection, patients undergoing first-time resection and fewer staged surgeries were required.

Impact of silencing eEF2K expression on the malignant properties of chordoma

BACKGROUND

Eukaryotic elongation factor 2 kinase (eukaryotic elongation factor 2 kinase, eEF2K) is a calcium calmodulin dependent protein kinase that keeps the highest energy consuming cellular process of protein synthesis under check through negative regulation. eEF2K pauses global protein synthesis rates at the translational elongation step by phosphorylating its only kown substrate elongation factor 2 (eEF2), a unique translocase activity in ekaryotic cells enabling the polypeptide chain elongation. Therefore, eEF2K is thought to preserve cellular energy pools particularly upon acute development of cellular stress conditions such as nutrient deprivation, hypoxia, or infections. Recently, high expression of this enzyme has been associated with poor prognosis in an array of solid tumor types. Therefore, in a growing number of studies tremendous effort is being directed to the development of treatment methods aiming to suppress eEF2K as a novel therapeutic approach in the fight against cancer.

METHODS

In our study, we aimed to investigate the changes in the tumorigenicity of chordoma cells in presence of gene silencing for eEF2K. Taking a transient gene silencing approach using siRNA particles, eEF2K gene expression was suppressed in chordoma cells.

RESULTS

Silencing eEF2K expression was associated with a slight increase in cellular proliferation and a decrease in death rates. Furthermore, no alteration in the sensitivity of chordoma cells to chemotherapy was detected in response to the decrease in eEF2K expression which intriguingly promoted suppression of cell migratory and invasion related properties.

CONCLUSION

Our findings indicate that the loss of eEF2K expression in chordoma cell lines results in the reduction of metastatic capacity.

A chronicle review of new techniques that facilitate the understanding and development of optimal individualized therapeutic strategies for chordoma

Chordoma is a rare malignant bone tumor that mainly occurs in the sacrum and the clivus/skull base. Surgical resection is the treatment of choice for chordoma, but the local recurrence rate is high with unsatisfactory prognosis. Compared with other common tumors, there is not much research and individualized treatment for chordoma, partly due to the rarity of the disease and the lack of appropriate disease models, which delay the discovery of therapeutic strategies. Recent advances in modern techniques have enabled gaining a better understanding of a number of rare diseases, including chordoma. Since the beginning of the 21st century, various chordoma cell lines and animal models have been reported, which have partially revealed the intrinsic mechanisms of tumor initiation and progression with the use of next-generation sequencing (NGS) techniques. In this study, we performed a systematic overview of the chordoma models and related sequencing studies in a chronological manner, from the first patient-derived chordoma cell line (U-CH1) to diverse preclinical models such as the patient-derived organoid-based xenograft (PDX) and patient-derived organoid (PDO) models. The use of modern sequencing techniques has discovered mutations and expression signatures that are considered potential treatment targets, such as the expression of Brachyury and overactivated receptor tyrosine kinases (RTKs). Moreover, computational and bioinformatics techniques have made drug repositioning/repurposing and individualized high-throughput drug screening available. These advantages facilitate the research and development of comprehensive and personalized treatment strategies for indicated patients and will dramatically improve their prognoses in the near feature.

Adjuvant stereotactic radiosurgery with or without postoperative fractionated radiation therapy in adults with skull base chordomas: a systematic review

OBJECTIVE

The objective of this retrospective study was to compare the survival of patients with biopsy-proven skull base chordoma who had undergone stereotactic radiosurgery (SRS) with versus without prior fractionated radiation therapy (RT).

METHODS

Relevant articles from database inception to September 2021 were retrieved from the PubMed, Scopus, Web of Science, and Cochrane databases for a systematic review of treatment protocols. Studies were included if they 1) involved adult patients (age ≥ 18 years) with histologically and radiologically confirmed chordomas located within the clival skull base region and treated with SRS; 2) reported data on clinical features, SRS protocols, and outcomes; and 3) were written in the English language. Studies were excluded if they 1) were literature reviews, case reports, technical notes, abstracts, or autopsy reports; 2) did not clearly differentiate the data of patients with chordomas from the data of patients with different tumors or the data of patients with chordomas in locations other than the skull base; or 3) lacked histological confirmation or treatment and outcome data. Extracted data included the following: study author and publication year, patient age and sex, symptoms, cranial nerve involvement, invaded structures, lesion size, treatment modality, surgical details, histopathological type, RT modality, SRS parameters, complications, postradiosurgery outcomes, complications, and survival outcomes.

RESULTS

After the selection process, 15 articles describing 130 patients met the study eligibility criteria, including 94 patients who had undergone postresection SRS (NoRT group) and 36 who had undergone postresection fractionated RT and subsequent SRS (RT group). The NoRT and RT groups were comparable in age (51.3 vs 47.4 years, respectively), sex (57.1% vs 58.3% male), tumor volume (9.5 vs 11.2 cm3), SRS treatment parameters (maximum dose: 35.4 vs 42.2 Gy, marginal dose: 19.6 vs 20.6 Gy, treatment isodose line: 60.2% vs 65.2%), and SRS adverse effects (10.9% vs 17.6%). For the entire cohort, the 3-, 5-, and 10-year progression-free survival (PFS) rates were 23%, 9%, and 3%, respectively, and the overall survival (OS) rates were 94%, 82%, and 76%, respectively. In the NoRT group, SRS was adjuvant treatment after resection in 38 patients (40.4%), salvage treatment for recurrent tumor treated with resection alone in 10 (10.6%), and not specified in 46 (48.9%). In the RT group, SRS was boost treatment in 9 patients (25.0%), salvage treatment after recurrence in 22 (61.1%), and not specified in 5 (13.9%). There was no difference between the two groups in terms of median PFS (24.0 months [Q1 34.0, Q3 15.0] vs 23.8 months [34.0, 18.0], respectively; p = 0.8) or median OS (293.0 months [not reached, 137.4] vs not reached [not reached, 48.0], respectively; p = 0.36). The adverse radiation effect rates were comparable between the groups (10.9% vs 17.6%, respectively; p = 0.4).

CONCLUSIONS

The role of SRS in the management of skull base chordomas is still evolving. This systematic literature review of biopsy-proven chordoma revealed that tumor control and survival rates for SRS alone after chordoma surgery were not inferior to those encountered after SRS plus fractionated RT.

High systemic inflammation score is associated with adverse survival in skull base chordoma

Background

The systemic inflammation score (SIS), based on preoperative lymphocyte to monocyte ratio (LMR) and albumin (ALB), was recently developed and is demonstrated to be a novel prognostic indicator in several cancers. However, data discussing the utility of SIS in chordoma are lacking. We aimed to investigate the distribution and the prognostic role of SIS in primary skull base chordoma patients undergoing surgery.

Material and methods

Preoperative SIS was retrospectively collected from 183 skull base chordoma patients between 2008 and 2014 in a single center. Its associations with clinical features and overall survival (OS) were further analyzed. The SIS-based nomogram was developed and evaluated by the concordance index (C-index), time-dependent receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA).

Results

The numbers of patients in the SIS 2, 1, and 0 group were 29 (15.8%), 60 (32.8%), 94 (51.4%), respectively. High SIS was associated with older age (p = 0.008), brainstem involvement of tumors (p = 0.039), and adverse OS (p < 0.001). Importantly, multivariate Cox analysis showed that high SIS independently predicts adverse OS. Furthermore, the nomogram based on SIS and clinical variables showed eligible performance for OS prediction in both training and validation cohorts.

Conclusions

The SIS is a promising, simple prognostic biomarker, and the SIS-based nomogram serves as a potential risk stratification tool for outcome in skull base chordoma patients.

Metastatic skull base chordoma: A systematic review

Objective/Hypothesis

To investigate the clinical features, management strategies and outcomes for patients with metastatic primary skull base chordomas.

Study Design

Systematic review.

Methods

A systematic search through Pubmed/Medline, Web of Science, and EBSCOhost (CINAHL) was conducted without restriction on dates. After study screening and full-text assessment, two authors independently extracted all data using a pre-established abstraction form.

Results

Forty cases were included from 38 studies. The average age (standard deviation [SD]) of the sample at presentation was 28.5 (23.3) and was equally distributed across genders. The average time (SD) between initial diagnosis to local recurrence was 40.1 (60.3) months. The average time (SD) from primary tumor detection to the diagnosis of metastatic disease was 55.2 (49.0) months. The most common subsite for metastatic spread were the lungs (32.5%). Of the 33 patients with data on outcomes, 48.5% were found to have expired by the time of publication. The median overall survival was estimated to be 84 months (95% confidence interval [CI] 62.3-105.7).

Conclusions

The most common subsites for metastatic spread of skull base chordoma were the lungs and bone. Overall survival for patients in the current cohort was a median of 84 months, with no significant differences noted when stratifying by the extent of surgery or the site of metastases.

Level of Evidence

3a.

Prognostic molecular biomarkers in chordomas: A systematic review and identification of clinically usable biomarker panels

Introduction and objective

Despite the improvements in management and treatment of chordomas over time, the risk of disease recurrence remains high. Consequently, there is a push to develop effective systemic therapeutics for newly diagnosed and recurrent disease. In order to tailor treatment for individual chordoma patients and develop effective surveillance strategies, suitable clinical biomarkers need to be identified. The objective of this study was to systematically review all prognostic biomarkers for chordomas reported to date in order to classify them according to localization, study design and statistical analysis.

Methods

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically reviewed published studies reporting biomarkers that correlated with clinical outcomes. We included time-to-event studies that evaluated biomarkers in skull base or spine chordomas. To be included in our review, the study must have analyzed the outcomes with univariate and/or multivariate methods (log-rank test or a Cox-regression model).

Results

We included 68 studies, of which only 5 were prospective studies. Overall, 103 biomarkers were analyzed in 3183 patients. According to FDA classification, 85 were molecular biomarkers (82.5%) mainly located in nucleus and cytoplasm (48% and 27%, respectively). Thirty-four studies analyzed biomarkers with Cox-regression model. Within these studies, 32 biomarkers (31%) and 22 biomarkers (21%) were independent prognostic factors for PFS and OS, respectively.

Conclusion

Our analysis identified a list of 13 biomarkers correlating with tumor control rates and survival. The future point will be gathering all these results to guide the clinical validation for a chordoma biomarker panel. Our identified biomarkers have strengths and weaknesses according to FDA's guidelines, some are affordable, have a low-invasive collection method and can be easily measured in any health care setting (RDW and D-dimer), but others molecular biomarkers need specialized assay techniques (microRNAs, PD-1 pathway markers, CDKs and somatic chromosome deletions were more chordoma-specific). A focused list of biomarkers that correlate with local recurrence, metastatic spread and survival might be a cornerstone to determine the need of adjuvant therapies.

Intraoperative Magnetic Resonance Imaging Assisted Endoscopic Endonasal Resection of Clival Chordomas

BACKGROUND

Cranial base chordomas are typically indolent and usually appear as encapsulated tumors. They slowly grow by infiltrating the bone, along with the lines of least resistance. Due to its relationship with important neurovascular structures, skull base chordoma surgery is challenging.

OBJECTIVE

The usefulness of intraoperative magnetic resonance imaging (IO-MRI) in achieving the goal of surgery, is evaluated in this study.

METHODS

Between March 2018 and March 2020, 42 patients were operated on for resection of skull base chordomas in our institution. All of them were operated on under IO-MRI. Patients were analyzed retrospectively for identifying common residue locations, complications and early post-operative outcomes.

RESULTS

In 22 patients (52,4%) gross total resection was achieved according to the final IO-MRI. In 20 patients (47,6%) complete tumor removal was not possible because of extension to the petrous bone (8 patients), pontocerebellar angle (6 patients), prepontine cistern (4 patients), temporobasal (1 patient), cervical axis (1 patient). In 13 patients, the surgery was continued after the first IO-MRI control was performed, which showed a resectable residual tumor. 7 of these patients achieved total resection according to the second IO-MRI, in the other 6 patients all efforts were made to ensure maximal resection of the tumor as much as possible without morbidity. Repeated IO-MRI helped achieve gross total resection in 7 patients (53.8%).

CONCLUSIONS

Our study proves that the use of IO-MRI is a safe method that provides the opportunity to show the degree of resection in skull base chordomas and to evaluate the volume and location of the residual tumor intraoperatively. Hence IO-MRI can improve the life expectancy of patients because it provides an opportunity for both gross total resection and maximal safe resection in cases where total resection is not possible.

Multivariate Analysis and Validation of the Prognostic Factors for Skull Base Chordoma

Background: Skull base chordoma is a rare tumor with low-grade malignancy and a high recurrence rate, the factors affecting the prognosis of patients need to be further studied. For that, we investigated prognostic factors of skull base chordoma through the database of the Surveillance, Epidemiology, and End Results (SEER) program, and validated in an independent data set from the Xiangya Hospital.

Methods: Six hundred and forty-three patients diagnosed with skull base chordoma were obtained from the SEER database (606 patients) and the Xiangya Hospital (37 patients). Categorical variables were selected by Chi-square test with a statistical difference. Survival curves were constructed by Kaplan–Meier analysis and compared by log-rank test. Univariate and multivariate Cox regression analyses were used to explore the prognostic factors. Propensity score matching (PSM) analysis was undertaken to reduce the substantial bias between gross total resection (GTR) and subtotal resection (STR) groups. Furthermore, clinical data of 37 patients from the Xiangya Hospital were used as validation cohorts to check the survival impacts of the extent of resection and adjuvant radiotherapy on prognosis.

Results: We found that age at diagnosis, primary site, disease stage, surgical treatment, and tumor size was significantly associated with the prognosis of skull base chordoma. PSM analysis revealed that there was no significant difference in the OS between GTR and STR (p = 0.157). Independent data set from the Xiangya Hospital proved no statistical difference in OS between GTR and STR groups (p = 0.16), but the GTR group was superior to the STR group for progression-free survival (PFS) (p = 0.048). Postoperative radiotherapy does not improve OS (p = 0.28), but it can prolong PFS (p = 0.0037). Nomograms predicting 5- and 10-year OS and DSS were constructed based on statistically significant factors identified by multivariate Cox analysis. Age, primary site, tumor size, surgical treatment, and disease stage were included as prognostic predictors in the nomograms with good performance.

Conclusions: We identified age, tumor size, surgery, primary site, and tumor stage as main factors affecting the prognosis of the skull base chordoma. Resection of the tumor as much as possible while ensuring safety, combined with postoperative radiotherapy may be the optimum treatment for skull base chordoma.

Combinatorial Natural Killer Cell-based Immunotherapy Approaches Selectively Target Chordoma Cancer Stem Cells

Chordoma is a rare tumor derived from notochord remnants that has a propensity to recur and metastasize despite conventional multimodal treatment. Cancer stem cells (CSC) are implicated in chordoma's resistant and recurrent behavior; thus strategies that target CSCs are of particular interest. Using in vitro cytotoxicity models, we demonstrated that anti-programmed death-ligand 1 (N-601) and anti-epidermal growth factor receptor (cetuximab) antibodies enhanced lysis of chordoma cells by healthy donor and chordoma patient NK cells through antibody-dependent cellular cytotoxicity (ADCC). Treatment of NK cells with an IL-15 superagonist complex (N-803) increased their cytotoxicity against chordoma cells, which was further enhanced by treatment with N-601 and/or cetuximab. PD-L1-targeted chimeric antigen receptor NK cells (PD-L1 t-haNKs) were also effective against chordoma cells. CSCs were preferentially vulnerable to NK cell killing in the presence of N-601 and N-803. Flow cytometric analysis of a chordoma CSC population showed that CSCs expressed significantly more NK activating ligand B7-H6 and PD-L1 than non-CSCs, thus explaining a potential mechanism of selective targeting. These data suggest that chordoma may be effectively targeted by combinatorial NK cell-mediated immunotherapeutic approaches and that the efficacy of these approaches in chordoma and other CSC-driven tumor types should be investigated further in clinical studies.

Outcomes and issues of 12 chordomas treated in a single center

Background

Chordomas stem from notochordal vestiges and rank as low-grade bone malignancies although fraught with high risk of recurrence. This study assesses the clinical outcomes of twelve chordoma cases treated in our clinic, in an effort to shed light on the often under-represented pool of results deriving from non-referral centers.

Methods

We reviewed the clinicopathological traits of all chordoma patients registered in our center since 1991. Major endpoints were overall survival (OS) and progression-free survival (PFS) estimated using the Kaplan–Meier and Nelson–Aalen methods.

Results

Twelve patients, aged on average 47.9 years, were treated for primary or recurrent disease. Seven had chordomas originating in the cranium, 5 in the spine, including a bifocal tumor, and the mean time lapse between the beginning of symptoms and diagnosis was 15.4 months, marked by dull ache. Subtotal resection was achieved in 5 cases, incomplete in 5, while in 2, only biopsy was accomplished. Conformal radiotherapy was administered to 5 and stereotactic radiosurgery to 2 in the setting of recurrence. Protons were used once and targeted agents induced no clinical response in 3 patients. Median OS and PFS were 36 and 12 months, respectively, with the best outlook linked to maximal resection, spinal location, and good preoperative functional status. In all, 6 patients died of chordoma, 4 are alive, and 1 was lost. Relapse was the rule for most cases, except 2, and pulmonary metastases were ascertained in 1.

Conclusions

Our cases were typical of chordomas, implying that inadequate surgical margins and successive recurrence are negative determinants of prognosis and that interinstitutional cooperation counterbalances shortages in non-referral institutes.

An Integrated Management Paradigm for Skull Base Chordoma Based on Clinical and Molecular Characteristics

Objective  Previous work categorized skull base chordoma (SBC) into three genetic risk groups based on 1p36 and homozygous 9p21(p16) deletions, accounting for a wide variability in prognosis (A = low-risk, B = intermediate-risk, C = high-risk). However, it remains unclear how these groups could guide management. Study Design  By integrating surgical outcome and adjuvant radiation (AdjXRT) information with genetic data on 152 tumors, we sought to develop an evidence-based management algorithm for SBC. Results  Gross total resections (GTRs) were associated with improved progression free survival (PFS) in all genetic groups. For Group C tumors, GTR and AdjXRT independently contributed to PFS (multivariate Cox proportional hazard ratio [HR] = 0.14, p  = 0.002, and HR = 0.40, p  = 0.047, respectively). For Group B tumors, AdjXRT improved outcomes only when GTR was not feasible (log-rank p  = 0.008), but not following GTR (log-rank p  = 0.54). However, 24 of 25 Group A tumors underwent GTR, and AdjXRT for these did not confer any benefit (log-Rank p  = 0.285). The high GTR rates in Group A could be explained by smaller tumor sizes (mean = 0.98cc/4.08cc/4.92cc for Group A/B/C, respectively, p  = 0.031) and lack of invasiveness. Group A tumors were also more frequently diagnosed in young people ( p  = 0.002) as asymptomatic lesions ( p  = 0.001), suggesting that they could be precursors to tumors in higher risk groups. Conclusion  Genotypic grouping by 1p36 and homozygous 9p21(p16) deletions can predict prognosis in SBC and guide management. GTR remains the cornerstone of SBC treatment and can be sufficient without AdjXRT in low and intermediate risk tumors. Low-risk tumors are associated with a less invasive phenotype, which makes them more amenable to GTR.

Proteomics Analysis Identified ASNS as a Novel Biomarker for Predicting Recurrence of Skull Base Chordoma

Background

The prognostic factors of skull base chordoma associated with outcomes of patients after surgery remain inadequately identified. This study was designed to identify a novel prognostic factor for patients with skull base chordoma.

Method

Using a proteomic technique, the tumor biomarkers that were upregulated in the rapid-recurrence group of chordoma were screened and then narrowed down by bioinformatic analysis. Finally one potential biomarker was chosen for validation by immunohistochemistry using tissue microarray (TMA). A total of 187 patients included in TMA were randomly divided into two cohorts, the training cohort included 93 patients and the validation cohort included 94 patients. Kaplan-Meier survival analysis was used to assess the patients’ survival. Univariable and multivariable Cox regression analysis were used to identify prognostic factors predicting recurrence-free survival (RFS). CCK-8 assay, clonal formation assay and transwell assay were used to test the effect of asparagine synthetase (ASNS) on the proliferation, migration and invasion in chordoma cell lines.

Results

Among 146 upregulated proteins, ASNS was chosen as a potential prognostic biomarker after bioinformatics analysis. The H-scores of ASNS ranged from 106.27 to 239.58 in TMA. High expression of ASNS was correlated with shorter RFS in both the training cohort (p = 0.0093) and validation cohort (p < 0.001). Knockdown of ASNS by small interfering RNA (siRNA) inhibited the growth, colony formation, migration and invasion of chordoma cells in vitro.

Conclusion

This study indicates that high expression of ASNS is correlated with poor prognosis of patients with skull base chordoma. ASNS may be a useful prognostic factor for patients with skull base chordoma.

AZD8055 enhances in vivo efficacy of afatinib in chordomas

Chordomas are primary bone tumors that arise in the cranial base, mobile spine, and sacrococcygeal region, affecting patients of all ages. Currently, there are no approved agents for chordoma patients. Here, we evaluated the anti-tumor efficacy of small molecule inhibitors that target oncogenic pathways in chordoma, as single agents and in combination, to identify novel therapeutic approaches with the greatest translational potential. A panel of small molecule compounds was screened in vivo against patient-derived xenograft (PDX) models of chordoma, and potentially synergistic combinations were further evaluated using chordoma cell lines and xenograft models. Among the tested agents, inhibitors of EGFR (BIBX 1382, erlotinib, and afatinib), c-MET (crizotinib), and mTOR (AZD8055) significantly inhibited tumor growth in vivo but did not induce tumor regression. Co-inhibition of EGFR and c-MET using erlotinib and crizotinib synergistically reduced cell viability in chordoma cell lines but did not result in enhanced in vivo activity. Co-inhibition of EGFR and mTOR pathways using afatinib and AZD8055 synergistically reduced cell viability in chordoma cell lines. Importantly, this dual inhibition completely suppressed tumor growth in vivo, showing improved tumor control. Together, these data demonstrate that individual inhibitors of EGFR, c-MET, and mTOR pathways suppress chordoma growth both in vitro and in vivo. mTOR inhibition increased the efficacy of EGFR inhibition on chordoma growth in several preclinical models. The insights gained from our study potentially provide a novel combination therapeutic strategy for patients with chordoma. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Characteristics and overall survival in pediatric versus adult skull base chordoma: a population-based study

PURPOSE

Less than 5% of chordomas occur in pediatric patients. While many studies have explored the treatment and outcomes of skull base chordomas, few have focused on the differences between pediatric and adult populations. The aim of this study is to analyze the epidemiological variables and clinical outcomes between pediatric and adult skull base chordomas using a large-sample, population-based cancer database.

METHODS

The National Cancer Database was queried between 2004 and 2015 for skull base chordomas. We stratified patients as pediatric (<18 years) and adults (≥18 years). We compared several clinical covariates between the two groups.

RESULTS

Our cohort consisted of 658 patients, 61 pediatric (9.3%), and 597 adults (90.7%). Pediatric patients were more likely to have larger tumor size (41.4 ± 15.7 mm versus 34.1 ± 15.8 mm, p < 0.01) and universally treated at academic facilities. There was no significant difference in overall survival.

CONCLUSIONS

Pediatric skull base chordomas are rare tumors that are managed with aggressive surgical resection, followed by radiation. While there may be difference between tumor presentation, outcomes between pediatric and adult patients are similar.

Numerical Simulation of Nasal Airflow Aerodynamics, and Warming and Humidification in Models of Clival Chordoma Pre and Post-Endoscopic Endonasal Surgery

OBJECTIVES

To study the effect of endoscopic endonasal surgery on nasal function for the treatment of clival chordoma.

METHODS

Pre and post-operative computed tomography (CT) scans of a case of chordoma treated with an endoscopic endonasal approach (EEA) were collected retrospectively, and models of the nasal cavity were reconstructed so that a subsequent numerical simulation of nasal airflow characteristics, warming, and humidification could be conducted.

RESULTS

Middle turbinectomy resulted in redistribution of airflow within the nasal cavity, and the most significant changes occurred in the middle section. Consistent with the results of airflow evaluation, it was found that the change in nasal anatomical structure significantly reduced warming and humidification. Nasal humidification decreased substantially when postoperative loss of mucosa was taken into consideration. The H₂O mass fraction of pharynx in inspiration phase were significantly correlated with airway surface-to-volume ratio (SVR).

CONCLUSIONS

The EEA for chordoma significantly affected nasal function. Attention should be paid to the protection of nasal structure and the associated mucosa.

Randomized, Double-Blind, Placebo-Controlled Phase II Study of Yeast-Brachyury Vaccine (GI-6301) in Combination with Standard-of-Care Radiotherapy in Locally Advanced, Unresectable Chordoma

BACKGROUND

Brachyury is a transcription factor overexpressed in chordoma and is associated with chemotherapy resistance and epithelial-to-mesenchymal transition. GI-6301 is a recombinant, heat-killed Saccharomyces cerevisiae yeast-based vaccine targeting brachyury. A previous phase I trial of GI-6301 demonstrated a signal of clinical activity in chordomas. This trial evaluated synergistic effects of GI-6301 vaccine plus radiation.

MATERIALS AND METHODS

Adults with locally advanced, unresectable chordoma were treated on a randomized, placebo-controlled trial. Patients received three doses of GI-6301 (80 × 107 yeast cells) or placebo followed by radiation, followed by continued vaccine or placebo until progression. Primary endpoint was overall response rate, defined as a complete response (CR) or partial response (PR) in the irradiated tumor site at 24 months. Immune assays were conducted to evaluate immunogenicity.

RESULTS

Between May 2015 and September 2019, 24 patients enrolled on the first randomized phase II study in chordoma. There was one PR in each arm; no CRs were observed. Median progressive-free survival for vaccine and placebo arms was 20.6 months (95% confidence interval [CI], 5.7-37.5 months) and 25.9 months (95% CI, 9.2-30.8 months), respectively. Hazard ratio was 1.02 (95% CI, 0.38-2.71). Vaccine was well tolerated with no vaccine-related serious adverse events. Preexisting brachyury-specific T cells were detected in most patients in both arms. Most patients developed T-cell responses during therapy, with no difference between arms in frequency or magnitude of response.

CONCLUSION

No difference in overall response rate was observed, leading to early discontinuation of this trial due to low conditional power to detect statistical difference at the planned end of accrual.

IMPLICATIONS FOR PRACTICE

Chordoma is a rare neoplasm lacking effective systemic therapies for advanced, unresectable disease. Lack of clinically actionable somatic mutations in chordoma makes development of targeted therapy quite challenging. While the combination of yeast-brachyury vaccine (GI-6301) and standard radiation therapy did not demonstrate synergistic antitumor effects, brachyury still remains a good target for developmental therapeutics in chordoma. Patients and their oncologists should consider early referral to centers with expertise in chordoma (or sarcoma) and encourage participation in clinical trials.

GSK-3β Regulates the Expression of P21 to Promote the Progression of Chordoma

Purpose

Chordoma is a rare malignant bone tumor transformed from the remnants of notochord. It is characterized as highly aggressive and locally invasive, difficult to be completely removed by surgery, and has a poor clinical prognosis. Glycogen synthase kinase 3 beta (GSK-3β) is involved in many cellular processes. GSK-3β overexpression has been shown to promote the development of many cancers, according to previous studies. However, the role of GSK-3β in chordoma remains unclear.

Methods

Immunohistochemistry (IHC) and Western blotting (WB) were performed on clinical specimens to measure GSK-3β expression in chordoma, and immunofluorescence and quantitative real-time polymerase chain reaction (QRT-PCR) were performed to examine the expression of GSK-3β and P21 in cell lines. Cell proliferation was detected by the CCK-8 assay and colony formation analysis, cell migration and invasion checked by Transwell experiments, and cell apoptosis was determined by Annexin V/propidium iodide staining. P21 was predicted as a downstream target gene of GSK-3β using STRING and UNIHI databases. Moreover, we used immunoprecipitation to confirm that GSK-3β and P21 interacted with each other. The double luciferase reporter gene assay showed that GSK-3β could regulate the promoter activity of P21. Finally, the role of the GSK-3β -P21 pathway in chordoma tumorigenesis was analyzed in vivo in nude mice.

Results

Our study showed that GSK-3β was significantly higher in chordoma tissues than in paracancer tissues, and siRNA knockdown of GSK-3β inhibited chordoma cell proliferation and promoted cell apoptosis. Additionally, our research found that GSK-3β bound and downregulated the expression of the P21 gene, and the expression of silencing P21 partially reversed the inhibitory effect of knockdown GSK-3β on chordoma. Furthermore, xenografts showed that knockdown GSK-3β inhibited the formation of chordomas in vivo.

Conclusion

Our results indicated that the GSK-3β-P21 axis may be an important signaling pathway for the occurrence and development of chordoma, providing a new therapeutic target for the clinical treatment of this disorder.

Sacral and thoracic chordoma with pulmonary metastases: A case report and review of the literature

Chordoma is a sporadic type of cancer that affects the spine and is particularly challenging to treat due to the paucity of reported cases and scientific literature. In particular, primary chordomas affecting both the sacral and thoracic vertebrae are extremely rare. We herein report a rare case of chordoma in the sacral and thoracic vertebrae with pulmonary metastasis, along with a literature review. The objective of the present study was to explore treatment options and long-term outcomes in patients with metastatic chordoma. Posterior decompression was performed for the thoracic tumor, followed by extended resection of the sacral tumor. The symptoms of the patient were relieved after surgery, and the postoperative Nurick score decreased from grade 3 to grade 2, while the postoperative McCormick score was I. Therefore, complete chordoma excision and internal spinal fixation may effectively reduce tumor recurrence and metastasis.

Mean platelet volume and platelet distribution width serve as prognostic biomarkers in skull base chordoma: a retrospective study

Background

Increasing studies have demonstrated that activated platelets play an essential role in tumour progression. However, the level and prognostic role of platelet indices in chordoma patients remain unclear. The aim of the current study was to characterize the prognostic performance of platelet count (PLT), mean platelet volume (MPV) and platelet distribution width (PDW) in skull base chordoma patients.

Methods

187 primary skull base chordoma patients between January 2008 and September 2014 were enrolled in this retrospective study. The optimal cut-off values were determined by X-tile software, and the correlations between PLT, MPV, PDW and clinicopathological features were further analysed. Kaplan-Meier curve and Cox regression analysis were used for survival analysis.

Results

The values of preoperative PTL, MPV and PDW ranged from 104 to 501 × 10⁹/L, 6.7 to 14.2 fl, and 7.8 to 26.2%, respectively. Elevated PLT was associated with larger tumour volume (p = 0.002). Kaplan-Meier survival analysis revealed that increased MPV and PDW were associated with shorter overall survival (p = 0.022 and 0.008, respectively). Importantly, multivariate Cox analysis demonstrated that elevated PDW was an independent unfavourable predictive factor for overall survival (hazard ratio (HR), 2.154, 95% confidence interval (CI), 1.258–3.688, p = 0.005).

Conclusions

Our data show that elevated MPV and PDW are associated with poor outcomes in skull base chordoma and that PDW may be helpful to identify patients with high risk.

Microsurgical versus endoscopic trans-sphenoidal approaches for clivus chordoma: a pooled and meta-analysis

Chordoma is a rare slow-growing neoplastic bone lesion. However, they show an invasive local growth and high recurrence rate, leading to an overall survival rate of 65% at 5 years and 35% at 10 years. We conducted a pooled and meta-analysis comparing recurrence rate, post-operative-complications, and survival in patients undergoing either microsurgical (MA) or endoscopic approaches (EA). Search of literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify surgical series of clivus chordomas published between January 1990 and March 2018 on Pubmed, Scopus, and Cochrane. Two different statistical analyses have been performed: a pooled analysis and a single-arm meta-analysis of overall recurrence rate and subgroup meta-analysis of complications in the subgroups open surgery and endoscopic surgery. After full-text screening, a total of 58 articles were included in the pooled analysis and 27 studies were included for the study-level meta-analysis. Pooled analysis-the extent of resection was the only association that remained significant (subtotal: HR = 2.18, p = 0.004; partial: HR = 4.40, p < 0.001). Recurrence was more prevalent among the surgical patients (45.5%) compared to endoscopic ones (23.7%). Meta-analysis-results of the cumulative meta-analysis showed an overall rate of recurrence of 25.6%. MA recurrence rate was 31.8% (99% CI 14-52.8), EA recurrence rate was 19.4% (5.4-39.2). CSF leak rate for the endoscopic group was 10.3% (99%CI 5-17.3) and 9.5% (99%CI 1.2-24.6) for the open surgery group. The partial removal versus total removal has an influence on recurrence rate (p < 0.001). MA recurrence rate was 31.8%; EA recurrence rate was 19.4%. The extent of resection is confirmed as a statistically significant factor affecting the risk for recurrence both with the pooled analysis and with the meta-analysis. Meta-analysis demonstrated that older patients tend to recur more than young patients, especially in surgical group.

Chordoma: update on disease, epidemiology, biology and medical therapies

PURPOSE OF REVIEW

Chordoma is an exceedingly rare subtype of bone sarcoma. This review aims to provide a comprehensive insight into chordoma epidemiology, and an update on the recent advances in disease, biology and medical therapies.

RECENT FINDINGS

The incidence of chordoma is approximately 0.08/100 000 and the 5-year overall age-adjusted relative survival is 72% in the United States and 61% in Europe. Over the last years, significant steps forwards have been done in the comprehension of chordoma complexity, with insights gained into the biology and morphology of this disease. New entities have been described and potentially druggable molecular targets identified. This is becoming all the more relevant today, as new potentially active agents are under development.

SUMMARY

Chordoma is a complex disease because of its rarity, biological heterogeneity and peculiar clinical behaviour. Despite the progress done, the outcome in this disease remains unsatisfactory and the identification of active systemic treatments remains an urgent, unmet medical need.

Inhibition Of Glycogen Synthase Kinase 3 Beta Suppresses The Growth And Survival Of Skull Base Chordoma Cells By Downregulating Brachyury Expression

Purpose

Chordomas are locally aggressive tumors arising from notochordal remnants. Brachyury, a protein coded by T-gene, is crucial for chordoma cell proliferation. The aim of this study was to evaluate the effects of glycogen synthase kinase 3 beta (GSK3β) activity on brachyury expression and on the growth and survival of skull base chordoma cells.

Patients and methods

In this study, 16 paraffin-embedded specimens of primary skull base chordomas were analyzed for the expression of phosphorylated GSK3β and brachyury using immunohistochemistry. The UM-Chor1 cell line derived from a clival chordoma was treated with AR-A014418 (AR), an inhibitor of GSK3β, and brachyury expression was analyzed by qRT-PCR and Western blotting. The possible mechanism by which brachyury regulates the Wnt/β-catenin signaling pathway was investigated by immunocytochemistry. The effects of AR on cell proliferation as well as sensitivity to chemotherapeutic drugs were also examined.

Results

The results suggested that phosphorylated GSK3β and brachyury were upregulated in chordoma tissues. The GSK3β inhibitor (AR) decreased brachyury expression and suppressed the growth and survival of the chordoma cells, possibly via regulation of the Wnt/β-catenin signaling pathway. Moreover, AR increased the sensitivity of chordoma cells to chemotherapeutic drugs in vitro.

Conclusion

This study provides evidence for the clinical development of the GSK3β inhibitor (AR-A014418) as a potential chemotherapeutic adjuvant for the treatment of chordoma.

The preliminary results of proton and carbon ion therapy for chordoma and chondrosarcoma of the skull base and cervical spine

Purpose

To evaluate the short-term outcomes in terms of tumor control and toxicity of patients with skull base or cervical spine chordoma and chondrosarcoma treated with intensity-modulated proton or carbon-ion radiation therapy.

Methods

Between 6/2014 and 7/2018, a total of 91 patients were treated in our Center. The median age was 38 (range, 4–70) years. Forty-six (50.5%) patients were treated definitively for their conditions as initial diagnosis, 45 (49.5%) patients had recurrent tumors including 14 had prior radiotherapy. The median gross tumor volume was 37.0 (range, 1.6–231.7) cc. Eight patients received proton therapy alone, 28 patients received combined proton and carbon ion therapy, 55 patients received carbon-ion therapy alone.

Results

With a median follow-up time of 28 (range, 8–59) months, the 2-year local control (LC), progression free (PFS) and overall survival (OS) rates was 86.2, 76.8, and 87.2%, respectively. Those rates for patients received definitive proton or carbon-ion therapy were 86.7, 82.8, and 93.8%, respectively. On multivariate analyses, tumor volume of > 60 cc was the only significant factor for predicting PFS (p = 0.045), while re-irradiation (p = 0.012) and tumor volume (> vs < 60 cc) (p = 0.005) were significant prognosticators for OS. Grade 1–2 late toxicities were observed in 11 patients, and one patient developed Grade 3 acute mucositis.

Conclusions

Larger tumor volume and re-irradiation were related to inferior survival for this group of patients. Further follow-up is needed for long-term efficacy and safety.

Radiomic signature: A novel magnetic resonance imaging-based prognostic biomarker in patients with skull base chordoma

BACKGROUND AND PURPOSE

We used radiomic analysis to establish a radiomic signature based on anatomical magnetic resonance imaging (MRI) sequences and explore its effectiveness as a novel prognostic biomarker for skull base chordoma (SBC).

MATERIALS AND METHODS

In this retrospective study, radiomic analysis was performed using preoperative axial T₁ FLAIR, T₂-weighted, and enhanced T₁ FLAIR from a single hospital. The primary clinical endpoint was progression-free survival. A total of 1860 3-D radiomic features were extracted from manually segmented region of interest. Pearson correlation coefficient was used for feature dimensional reduction and a ridge regression-based Cox proportional hazards model was used to determine a radiomic signature. Afterwards, radiomic signature and nine other potential prognostic factors, including age, gender, histological subtype, dural invasion, blood supply, adjuvant radiotherapy, extent of resection, preoperative KPS, and postoperative KPS were analyzed to build a radiomic nomogram and a clinical model. Finally, we compared the nomogram with each prognostic factor/model by DeLong's test.

RESULTS

A total of 148 SBC patients were enrolled, including 64 with disease progression. The median follow-up time was 52 months (range 4-122 months). The Harrell's concordance index of the radiomic signature was 0.745 (95% CI, 0.709-0.781) for the validation cohort, and its discrimination accuracy in predicting progression risk at 5 years in the same cohort was 82.4% (95% CI, 72.6-89.7%).

CONCLUSIONS

The radiomics is a low-cost, non-invasive method to predict SBC prognosis preoperatively. Radiomic signature is a potential prognostic biomarker that may allow the individualized evaluation of patients with SBC.

Extreme lateral transodontoid approach to the ventral craniocervical junction: cadaveric dissection and case illustrations

OBJECTIVE

Surgical treatment of pathological processes involving the ventral craniocervical junction (CCJ) traditionally involves anterior and posterolateral skull base approaches. In cases of bilateral extension, when lesions extend beyond the midline to the contralateral side, a unilateral corridor may result in suboptimal resection. In these cases, the lateral extent of the tumor will prevent extirpation of the lesion via anterior surgical approaches. The authors describe a unilateral operative corridor developed along an extreme lateral trajectory to the anterior aspect of the clival and upper cervical dura, allowing exposure and resection of tumor on the contralateral side. This approach is used when the disease involves the bone structures inherent to stability at the anterior CCJ.

METHODS

To achieve exposure of the ventral CCJ, an extreme lateral transcondylar transodontoid (ELTO) approach was performed with transposition of the ipsilateral vertebral artery, followed by drilling of the C1 anterior arch. Resection of the odontoid process allowed access to the contralateral component of lesions across the midline to the region of the extracranial contralateral vertebral artery, maximizing resection.

RESULTS

Exposure and details of the surgical procedure were derived from anatomical cadavers. At the completion of cadaveric dissection, morphometric measurements of the relevant anatomical landmarks were obtained. Illustrative case examples for approaching ventral CCJ chordomas via the ELTO approach are presented.

CONCLUSIONS

The ELTO approach provides a safe and direct surgical corridor to treat complex lesions at the ventral CCJ with bilateral extension through a single operative corridor. This approach can be combined with other lateral approaches or posterior infratemporal approaches to remove more extensive lesions involving the rostral clivus, jugular foramen, and temporal bone.

Comprehensive Review of Cranial Chordomas Using National Databases in the USA

AIMS

The management of cranial chordomas is controversial. We provide a comprehensive review of the evolving patterns of care of cranial chordomas in the USA.

MATERIALS AND METHODS

We analysed the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2014 for clinical characteristics and long-term survival, and the National Surgical Quality Improvement Program (NSQIP) dataset between 2005 and 2016 for perioperative characteristics and surgical morbidity.

RESULTS

In total, 936 patients were identified from the NCDB, 405 patients from SEER and 64 patients from the NSQIP. Most patients were men (56.2, 54.8 and 57.8% in NCDB, SEER and NSQIP, respectively) and White (80.9 and 83.2% in NCDB and SEER, respectively). Surgery was the preferred treatment modality (87.3% in NCDB and 86.2% in SEER). Surgery was carried out alone (41.8% in NCDB and 40.7% in SEER) or in combination with radiation (42.1% in NCDB and 45.4% in SEER). Proton therapy was the most common type of radiation (32.2% in NCDB), particularly after 2011. The median operative time, median hospital length and postoperative morbidity were significantly higher in chordoma patients compared with patients who underwent other skull-base procedures. The 5-year survival rate was 79.8% in NCDB and 76.9% in SEER. There was a trend towards longer survival in patients receiving surgery and radiation, which has been increasingly used since 2004. Patients younger than 60 years had a decreased risk of mortality.

CONCLUSIONS

Our analysis reflects patterns of care in the USA. The use of surgery and radiation is increasing, with a trend towards longer survival. Surgery is complicated with long operative time, hospital stay and a higher rate of complications.

High Expression of TGF-β1 Predicting Tumor Progression in Skull Base Chordomas

OBJECTIVE

To investigate the expression characteristics and prognostic value of transforming growth factor β1 (TGF-β1) in primary skull base chordomas (SBCs).

METHODS

The mRNA expression levels of TGF-β1 were measured in 57 frozen samples from patients with primary SBCs. Clinical data collection, follow-up, correlations, and survival analyses were performed.

RESULTS

In the series of 57 patients (29 men and 28 women) with primary SBCs, the mean value of TGF-β1 mRNA was 1.713 with a median of 0.904. Twenty-four SBCs were soft type and 33 were hard type. The Mann-Whitney U test revealed that the expression level of TGF-β1 mRNA in hard type SBCs was significantly higher than the expression level found in the soft type (P = 0.03). The independent-samples median test suggested that the expression level of TGF-β1 mRNA in female patients' SBCs was significantly higher than that in male patients' SBCs (P = 0.01). Expression differences of TGF-β1 were not seen among different pathological subtypes, tumor blood supply, or degree of resection. The Spearman rank correlation coefficient clarified that TGF-β1 mRNA levels were not correlated with tumor diameter, preoperative Karnofsky Performance Status (KPS), postoperative KPS, follow-up KPS, age, or intraoperative blood loss. The multivariate Cox analysis revealed that pathological subtype (P = 0.008), expression level of TGF-β1 mRNA (P = 0.01), and tumor texture (P = 0.03) were all independent prognostic factors for tumor progression.

CONCLUSIONS

SBCs in female patients and SBCs with hard texture were prone to have high TGF-β1 mRNA expression. High expression of TGF-β1, hard tumor texture, and conventional subtype were all independent risk factors for tumor progression.

Successful use of tissue expander and pelvic sling to exclude small bowel for high-dose pelvic irradiation

OBJECTIVE

Our study seeks to describe our surgical technique of the use of a tissue expander and a pelvic sling in order to perform high-dose pelvic irradiation without incurring radiation toxicity to the small bowel. High-dose radiation therapy for pelvic tumours comes at a risk of radiation toxicity to the small bowel. Our study discusses our novel surgical technique of compartmentalising the abdomen and the pelvis through the use of a tissue expander and pelvic sling to avoid small bowel radiation toxicity.

METHODS

We present a patient with an unresectable sacral chordoma. We describe our surgical technique incorporating both a tissue expander and an absorbable pelvic mesh sling to successfully compartmentalise the abdomen from the pelvis.

RESULTS

The patient underwent an uneventful surgical procedure to place the tissue expander within the pelvis and deploy the pelvic mesh sling. Following surgery, a separation of at least 8 cm was achieved between bowel loops and the tumour. A dose of 70 Gy delivered over 35 fractions using intensity modulated radiotherapy (IMRT) was administered to the sacral chordoma, whilst managing to constrain the maximum bowel dose to 35.7 Gy. Surgery to remove the tissue expander was uneventful. The patient has not suffered any small bowel irradiation toxicity.

CONCLUSIONS

Our technique to exclude small bowel from the pelvis is effective and safe. This technique not only can be applied in the setting of unresectable sacral chordomas but also may be applicable to other pelvic cancers which require radiation therapy.

The clinical outcomes for chordomas in the cranial base and spine: A single center experience

Owing to the special growth pattern of chordomas and the limited treatment options currently available, the treatment of chordoma still remains difficult. In this study, we hope to further clarify the relationship between surgical treatment and radiotherapy of chordoma and disease progression.All patients with a primary histopathological diagnosis of clival or spinal chordomas recorded in our institution between 1976 and 2017 were examined.A total of 60 patients (location: skull base/clival, n = 24; vertebral column, n = 5; sacrum, n = 31) had a mean follow-up time of 7.7 years (range 12 months-35 years). Compared with patients who received subtotal resection (n = 5, 5-year and 10-year survival = 61% and 39%, respectively), the annual survival rate of patients who received total resection (n = 55, 5-year and 10-year survival = 67%, respectively) was significantly higher. The overall 10-year survival rate (58%) of patients treated with surgery alone was significantly different from those treated with a combination of surgery and radiation (73%). The long-term prognosis of sacral chordoma was the worst (10-year survival rate = 48%).The best treatment strategy for improved long-term survival in chordoma was a combination of surgical resection and radiation therapy. Adjuvant radiotherapy for chordoma significantly improves disease-free survival, although the long-term survival benefit remains to be determined. A worse prognosis and poor long-term survival are seen in sacral chordomas.

Prospective validation of a molecular prognostication panel for clival chordoma

OBJECTIVE

There are currently no reliable means to predict the wide variability in behavior of clival chordoma so as to guide clinical decision-making and patient education. Furthermore, there is no method of predicting a tumor's response to radiation therapy.

METHODS

A molecular prognostication panel, consisting of fluorescence in situ hybridization (FISH) of the chromosomal loci 1p36 and 9p21, as well as immunohistochemistry for Ki-67, was prospectively evaluated in 105 clival chordoma samples from November 2007 to April 2016. The results were correlated with overall progression-free survival after surgery (PFSS), as well as progression-free survival after radiotherapy (PFSR).

RESULTS

Although Ki-67 and the percentages of tumor cells with 1q25 hyperploidy, 1p36 deletions, and homozygous 9p21 deletions were all found to be predictive of PFSS and PFSR in univariate analyses, only 1p36 deletions and homozygous 9p21 deletions were shown to be independently predictive in a multivariate analysis. Using a prognostication calculator formulated by a separate multivariate Cox model, two 1p36 deletion strata (0%-15% and > 15% deleted tumor cells) and three 9p21 homozygous deletion strata (0%-3%, 4%-24%, and ≥ 25% deleted tumor cells) accounted for a range of cumulative hazard ratios of 1 to 56.1 for PFSS and 1 to 75.6 for PFSR.

CONCLUSIONS

Homozygous 9p21 deletions and 1p36 deletions are independent prognostic factors in clival chordoma and can account for a wide spectrum of overall PFSS and PFSR. This panel can be used to guide management after resection of clival chordomas.

Identification of therapeutic targets in chordoma through comprehensive genomic and transcriptomic analyses

Chordoma is a rare, orphan cancer arising from embryonal precursors of bone. Surgery and radiotherapy (RT) provide excellent local control, often at the price of significant morbidity because of the structures involved and the need for relatively high doses of RT; however, recurrence remains high. Although our understanding of the genetic changes that occur in chordoma is evolving rapidly, this knowledge has yet to translate into treatments. We performed comprehensive DNA (paired tumor/normal whole-exome and shallow whole-genome) and RNA (tumor whole-transcriptome) next-generation sequencing analyses of archival sacral and clivus chordoma specimens. Incorporation of transcriptomic data enabled the identification of gene overexpression and expressed DNA alterations, thus providing additional support for potential therapeutic targets. In three patients, we identified alterations that may be amenable to off-label FDA-approved treatments for other tumor types. These alterations include FGFR1 overexpression (ponatinib, pazopanib) and copy-number duplication of CDK4 (palbociclib) and ERBB3 (gefitinib). In a third patient, germline DNA demonstrated predicted pathogenic changes in CHEK2 and ATM, which may have predisposed the patient to developing chordoma at a young age and may also be associated with potential sensitivity to PARP inhibitors because of homologous recombination repair deficiency. Last, in the fourth patient, a missense mutation in IGF1R was identified, suggesting potential activity for investigational anti-IGF1R strategies. Our findings demonstrate that chordoma patients present with aberrations in overlapping pathways. These results provide support for targeting the IGF1R/FGFR/EGFR and CDK4/6 pathways as treatment strategies for chordoma patients. This study underscores the value of comprehensive genomic and transcriptomic analysis in the development of rational, individualized treatment plans for chordoma.

Proton therapy for skull base tumors: A review of clinical outcomes for chordomas and chondrosarcomas

BACKGROUND

Skull base chordomas and chondrosarcomas are rare tumors traditionally treated by surgical resection and adjuvant radiation therapy (RT). We will discuss data evaluating clinical outcomes of proton therapy in the treatment of skull base chordomas and chondrosarcomas.

METHODS

A literature review was performed using a MEDLINE search from January 1990 to January 2017.

RESULTS

The published data suggest that the dose intensification allowed by proton therapy has resulted in good clinical outcomes and a tolerable toxicity profile.

CONCLUSION

Proton therapy is a modern RT technique that has demonstrated improved preliminary clinical outcomes in the treatment of skull base chordomas and chondrosarcomas compared to conventional radiotherapy, and comparable to other advanced photon-based RT techniques.

The nerve of legal entrapment

Chordomas are a rare type of bone tumor that arises from the embryological remnant of the notochord. They originate at any point along the axial spine with the sacrum and the skull based region being the most commonly affected sites. Chordomas are slowly growing, indolent tumors, presenting insidiously, but also carry a high recurrence rate with a tendency to invade contiguous structure making their treatment challenging. The current standard of care for localized chordoma is aggressive cytoreductive surgery followed by high dose adjuvant radiotherapy. We present a unique case of a 72-year-old lawyer with a skull base chordoma invading into the hypoglossal canal and causing isolated hypoglossal nerve paralysis.