Advances in the management of primary bone sarcomas of the skull base

Endoscopic transsphenoidal approach in resection of intracranial clivus chondrosarcoma: A case report

Intracranial primary chondrosarcomas are rare, accounting for <0.15% of all intracranial tumors, but exhibit a high risk of recurrence. Due to the rarity of this condition, it has proven difficult to establish efficacy-based treatment guidelines. The present study details a case of clivus chondrosarcoma exhibiting no recurrence following surgical resection using an endoscopic transsphenoidal approach and postoperative adjuvant radiotherapy. A 41-year-old female presented with primary symptoms of left eye esotropia, scotoma of the left nasal visual field and double vision. Preoperative cranial magnetic resonance imaging revealed a lesion on the clivus, which was initially diagnosed as chordoma. However, clivus chondrosarcoma was ultimately diagnosed based on intraoperative findings and postoperative histopathology. The tumor was totally resected and 25 doses of adjuvant radiotherapy with planning gross tumor volume (60 Gy) and planning clinical target volume (50 Gy) were administered for 5 weeks. The patient was discharged at 12 days post-surgery with no obvious postoperative complications. Over the 28-month follow-up period, there was no evidence of recurrence, which may be due to the successful use of combined gross total resection and adjuvant radiotherapy. Therefore, surgical resection using an endoscopic transsphenoidal approach and postoperative adjuvant radiotherapy is an effective method for treating intracranial clivus chondrosarcoma.

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.

A novel technique for safe percutaneous biopsy of a petrous apex lesion

Lesions within the skull base are the most challenging targets for percutaneous biopsy due to the likelihood of encountering a critical structure along any needle trajectory. Due to ICA proximity, the petrous apex is considered unsafe. We describe a novel percutaneous CT-guided approach for biopsying a petrous apex lesion via a contralateral mandibular condylar notch (subzygomatic approach). To our best knowledge, this approach has not been reported and can be safely employed with thorough planning.

Patient, Disease, and Treatment-Related Factors Affecting Progression-Free and Disease-Specific Survival in Recurrent Chondrosarcomas of the Skull Base

BACKGROUND

Recurrent skull base chondrosarcomas (CSA) are difficult to treat, and limited data are available to help guide subsequent therapy.

OBJECTIVE

To further characterize the natural history of CSA and identify treatment modalities that were most effective in prolonging progression-free (PFS) and disease-specific survival (DSS).

METHODS

We conducted a single-institution retrospective review of patients with recurrent skull base CSA from 1993 to 2021. Kaplan-Meier survival analyses for PFS and DSS were completed. Univariable and multivariable Cox proportional hazards regression models were used to identify patient-related, treatment-related, and disease-related factors that predicted PFS and DSS.

RESULTS

A total of 28 patients and 84 episodes of recurrence were included. One-year PFS was 70.6%, 5-year PFS was 28.9%, and 10-year DSS was 78.5%. The median time to first progression was 23.9 months (range, 2.8-282 months). In univariable Cox proportional hazards regression, male sex, higher grade histology, fourth or greater progression episode status, distal pattern of recurrence, and treatment of recurrence without surgery or with chemotherapy alone predicted worse PFS. Multivariable regression predicted shortened DSS in male patients (hazard ratio [HR] 0.16; P = .021) and higher-grade tumors (HR 0.22; P = .039). Treatment of recurrence with surgery was associated with, but did not significantly predict, improved DSS (HR 1.78; P = .11).

CONCLUSION

Several patient and disease-specific factors were associated with shorter PFS and DSS in recurrent skull base chondrosarcoma. For recurrences amenable to resection, surgery is recommended for treatment of recurrent CSA. Local recurrence management without surgery results in shorter PFS and DSS.

MRI-Based Radiomics Differentiates Skull Base Chordoma and Chondrosarcoma: A Preliminary Study

Simple Summary

In this study, we created a novel MRI-based machine learning model to differentiate skull base chordoma and chondrosarcoma with multiparametric signatures. While these tumors share common radiographic characteristics, clinical behavior is distinct. Therefore, distinguishing these tumors before initial surgical intervention would be useful, potentially impacting the surgical strategy. Although there are some limitations, such as the risk of overfitting and the lack of an extramural cohort for truly independent final validation, our machine learning model distinguishing chordoma from chondrosarcoma yielded superior diagnostic accuracy to that achieved by 20 board-certified neurosurgeons.

Abstract

Chordoma and chondrosarcoma share common radiographic characteristics yet are distinct clinically. A radiomic machine learning model differentiating these tumors preoperatively would help plan surgery. MR images were acquired from 57 consecutive patients with chordoma (N = 32) or chondrosarcoma (N = 25) treated at the University of Tokyo Hospital between September 2012 and February 2020. Preoperative T1-weighted images with gadolinium enhancement (GdT1) and T2-weighted images were analyzed. Datasets from the first 47 cases were used for model creation, and those from the subsequent 10 cases were used for validation. Feature extraction was performed semi-automatically, and 2438 features were obtained per image sequence. Machine learning models with logistic regression and a support vector machine were created. The model with the highest accuracy incorporated seven features extracted from GdT1 in the logistic regression. The average area under the curve was 0.93 ± 0.06, and accuracy was 0.90 (9/10) in the validation dataset. The same validation dataset was assessed by 20 board-certified neurosurgeons. Diagnostic accuracy ranged from 0.50 to 0.80 (median 0.60, 95% confidence interval 0.60 ± 0.06%), which was inferior to that of the machine learning model (p = 0.03), although there are some limitations, such as the risk of overfitting and the lack of an extramural cohort for truly independent final validation. In summary, we created a novel MRI-based machine learning model to differentiate skull base chordoma and chondrosarcoma from multiparametric signatures.

Primary Skull Base Chondrosarcomas: A Systematic Review

Simple Summary

Primary skull base chondrosarcomas (SBCs) may carry significant tumor-burden by causing severe cranial nerve neuropathies. Current treatment strategies mainly focus on surgical resection and radiotherapy protocols, with a wide range of findings in terms of efficacy and safety. The aim of our systematic review was to comprehensively analyze the current literature on primary SBCs, describing clinical and radiological characteristics, available management strategies, treatment outcomes, and prognoses. We found that most primary SBCs show benign slow-growing patterns but may cause neurological deficits by compressing critical neurovascular structures. Open surgical approaches favor maximal resection with acceptable complication rates, but only a few studies reported the use of newer endoscopic approaches. Proton-based, photon-based, and carbon-based radiotherapy protocols may also allow safe and effective local tumor control as adjuvant treatments or stand-alone strategies in patients not eligible to undergo surgery. Overall, primary SBCs’ prognoses proved to be favorable and comparable to benign skull base neoplasms.

Abstract

Background: Primary skull base chondrosarcomas (SBCs) can severely affect patients’ quality of life. Surgical-resection and radiotherapy are feasible but may cause debilitating complications. We systematically reviewed the literature on primary SBCs. Methods: PubMed, EMBASE, Scopus, Web-of-Science, and Cochrane were searched following the PRISMA guidelines to include studies of patients with primary SBCs. Clinical characteristics, management strategies, and treatment outcomes were analyzed. Results: We included 33 studies comprising 1307 patients. Primary SBCs mostly involved the middle-fossa (72.7%), infiltrating the cavernous-sinus in 42.4% of patients. Cranial-neuropathies were reported in 810 patients (62%). Surgical-resection (93.3%) was preferred over biopsy (6.6%). The most frequent open surgical approaches were frontotemporal-orbitozygomatic (17.6%) and pterional (11.9%), and 111 patients (21.3%) underwent endoscopic-endonasal resection. Post-surgical cerebrospinal-fluid leaks occurred in 36 patients (6.5%). Radiotherapy was delivered in 1018 patients (77.9%): photon-based (41.4%), proton-based (64.2%), and carbon-based (13.1%). Severe post-radiotherapy complications, mostly hypopituitarism (15.4%) and hearing loss (7.1%) were experienced by 251 patients (30.7%). Post-treatment symptom-improvement (46.7%) and reduced/stable tumor volumes (85.4%) showed no differences based on radiotherapy-protocols (p = 0.165; p = 0.062). Median follow-up was 67-months (range, 0.1–376). SBCs recurrences were reported in 211 cases (16.1%). The 5-year and 10-year progression-free survival rates were 84.3% and 67.4%, and overall survival rates were 94% and 84%. Conclusion: Surgical-resection and radiotherapy are effective treatments in primary SBCs, with acceptable complication rates and favorable local tumor control.

Ten years of battle with multiple recurrences of pediatric skull base chondrosarcoma: A case report

In children and adolescents presenting with skull base sarcoma, treatment strategies will face challenging decisions due to the unique chemoresistant pathologies, limitations imposed by the not-yet fully mature anatomical structures, and the small surgical site.

Clinical Outcomes Following Dose-Escalated Proton Therapy for Skull-Base Chordoma

Purpose

To evaluate the effectiveness of external-beam proton therapy (PT) on local control and survival in patients with skull-base chordoma.

Materials and Methods

We reviewed the medical records of patients with skull-base chordoma treated with definitive or adjuvant high-dose PT and updated their follow-up when feasible. We assessed overall survival, disease-specific survival, local control, and freedom from distant metastasis. Radiotherapy toxicities were scored using the Common Terminology Criteria for Adverse Events, version 4.0.

Results

A total 112 patients were analyzed, of whom 105 (94%) received PT and 7 (6%) received combined proton-photon therapy between 2007 and 2019. Eighty-seven patients (78%) underwent a subtotal resection, 22 (20%) a gross total resection, and 3 (3%) a biopsy alone. The median radiotherapy dose was 73.8 Gy radiobiologic equivalent (GyRBE; range, 69.6-74.4). Ninety patients (80%) had gross disease at radiotherapy and 7 (6%) were treated for locally recurrent disease following surgery. Median follow-up was 4.4 years (range, 0.4-12.6); for living patients, it was 4.6 years (range, 0.4-12.6), and for deceased patients, 4.1 years (range, 1.2-11.2). At 5 years after radiotherapy, the actuarial overall survival, disease-specific survival, local control, and freedom from distant metastasis rates were 78% (n = 87), 83% (n = 93), 74% (n = 83), and 99% (n = 111), respectively. The median time to local progression was 2.4 years (range, 0.8-7). Local control and disease-specific survival by resection status was 95% versus 70% (P = 0.28) and 100% versus 80% (P = 0.06) for gross total, versus subtotal, resection or biopsy alone, respectively. There were no serious acute toxicities (grade ≥ 3) related to radiotherapy.

Conclusion

High-dose PT alone or after surgical resection for skull-base chordoma reaffirms the favorable 5-year actuarial local control rate compared with conventional techniques with acceptable late-complication–free survival. Outcomes following gross total resection and adjuvant PT were excellent. Further follow-up of this cohort is necessary to better characterize long-term disease control and late toxicities.

Incidence and survival rates and trends of skull Base chondrosarcoma: A Population-Based study

INTRODUCTION

Chondrosarcomas are extremely rare, locally invasive, and potentially mortal malignant cartilaginous tumors. In this study, we aimed to evaluate the incidence and survival rates and trends of skull base chondrosarcomas (SBC).

METHODS

Data from SBC patients between 1975 and 2017 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The age-adjusted incidence rates (AAR) were calculated for the overall cases and based on gender, age, race, and histology. Furthermore, the relative survival rates for one, three, and five years, and the rates stratified to the aforementioned selected variables were computed. Besides, we conducted a joint point regression analysis to calculate the annual percent change (APC) and its associated standard error (SE) for AAR and mortality.

RESULTS

The AAR rate of SBC was 0.019 per 100,000. Higher AAR rates were observed in patients who were in the 65-74-year-age-group, females, Caucasians, and had none mesenchymal subtype. The relative one-year, three-year and five-year-survival rates were 99.58 %, 93.67 %, and 89.10 %, respectively. Lower survival rates were noted in patients who were males, African Americans, and had a mesenchymal subtype. The trend analysis has shown a significant yearly increase (P < 0.001) in AAR of SBC (APC ± SE = 0.0005 %±0.0001), along with a significant yearly decline in mortality rates (APC ± SE= -0.0202 %±0.0029).

CONCLUSION

Despite the increase in AAR over time, there has been a significant decline in mortality rates over time, which might have been due to the advancement of treatment modalities, improvement in diagnostic imaging, and modification in disease grading.