Skull base chondrosarcoma: evidence-based treatment paradigms

A systematic review and meta-analysis of radiotherapy and particle beam therapy for skull base chondrosarcoma: TRP-chondrosarcoma 2024

Introduction

Chondrosarcoma is a rare malignant bone tumor. Particle beam therapy (PT) can concentrate doses to targets while reducing adverse events. A meta-analysis based on a literature review was performed to examine the efficacy of PT and photon radiotherapy for skull base chondrosarcoma.

Methods

The meta-analysis was conducted using 21 articles published from 1990 to 2022.

Results

After PT, the 3- and 5-year overall survival (OS) rates were 94.1% (95% confidence interval [CI]: 91.0-96.2%) and 93.9% (95% CI: 90.6-96.1%), respectively, and the 3- and 5-year local control rates were 95.4% (95% CI: 92.0-97.4%) and 90.1% (95% CI: 76.8-96.0%), respectively. Meta-regression analysis revealed a significant association of PT with a superior 5-year OS rate compared to three-dimensional conformal radiotherapy (p < 0.001). In the studies used in the meta-analysis, the major adverse event of grade 2 or higher was temporal lobe necrosis (incidence 1-18%, median 7%).

Conclusion

PT for skull base chondrosarcoma had a good outcome and may be a valuable option among radiotherapy modalities. However, high-dose postoperative irradiation of skull base chondrosarcoma can cause adverse events such as temporal lobe necrosis.

Brain and Spinal Cord Tumors Among the Life-Threatening Health Problems: An Introduction

As one of the global concerns, cancers, including brain and spinal cord tumors, are responsible for mortalities and irreversible morbidities in the affected patients. Although advancements in molecular pathology and imaging of tumors may have influenced the incidence rate due to higher diagnosis in early stages, exposure to environmental risk factors could be another explanation for increased incidence of these tumors over the past decades. Similar to many other tumors, the CNS tumors begin in cellular dimension with activation of different molecular pathways. Several genetic, epigenetic, and immunologic pathways and processes are already discovered to play roles in pathophysiology of these tumors, which mostly will eventually become symptomatic. Each of these tumors may exhibit imaging characteristics, making it possible to list a series of differential diagnosis before histopathologic examination. Advances in molecular pathology have resulted in better understanding and categorization of CNS tumors, leading to better decision-making on the most appropriate therapeutic approach for each category, as well as proposing new therapeutic modalities to treat these tumors. As an introduction to the 2-volume book, this chapter addressed different types of human brain and spinal cord tumors based on the fifth version of WHO classification of CNS tumors.

Malignant Brain and Spinal Tumors Originating from Bone or Cartilage

Malignant bone tumors affecting the brain and spine are a rare and exceedingly difficult-to-treat group of diseases. Most commonly consisting of chordoma and chondrosarcoma, these tumors also include giant-cell tumors and osteosarcomas. This chapter will cover the background, epidemiology, genetics, molecular biology, histopathology, radiographic features, clinical manifestations, therapeutic approaches, and clinical management of each entity.

Clinical Characteristics and Prognostic Risk Factors of Parasellar Chondrosarcoma

Background: Parasellar chondrosarcomas are extremely rare. This study describes the characteristics of parasellar chondrosarcoma and analyzes the risk factors and prognosis based on the resection degree. Methods: Fifteen patients with pathologically diagnosed parasellar chondrosarcoma were retrospectively analyzed for the clinical data, surgical methods, and prognosis to identify relationships between the surgical resection degree, tumor recurrence, and imaging characteristics. Results: Twelve patients had eye dysfunction and ptosis. Differentiation from other parasellar tumors by imaging is difficult. The preoperative Karnofsky Performance Scale (KPS) score positively correlated with the tumor resection degree (p = 0.026) and negatively correlated with the maximum tumor diameter (p = 0.001). Tumor recurrence negatively correlated with the resection degree (p = 0.009). The postoperative KPS score positively correlated with the preoperative KPS score (p < 0.001) and tumor resection degree (p = 0.026), and negatively correlated with the maximum tumor diameter (p = 0.016) and age (p = 0.047). An improved KPS score positively correlated with the tumor resection degree (p = 0.039). Patients who underwent total resection of the chondrosarcoma had longer progression-free survival than those who underwent partial resection (p = 0.0322). Conclusion: Parasellar chondrosarcomas are difficult to resect completely. Preoperative KPS score is an important factor for the degree of resection. KPS score, age, maximum tumor diameter, and resection degree may be important prognostic factors.

Asymptomatic Chondrosarcoma of the Skull base: A Case Report

Chondrosarcoma of the skull base is a malignant tumor of cartilage origin. Clinical manifestations are nonspecific, early can be asymptomatic. We report a case of asymptomatic chondrosarcoma of the skull base which is difficult to confirm the diagnosis. The patient underwent Type A resection of chondrosarcoma of the skull base through the left subtemporal fossa approach, with postoperative radiotherapy. And the patient achieved good postoperative recovery. Therefore, chondrosarcoma of the skull base is a rare malignant tumor with slow growth. Early detection, excision, and postoperative radiotherapy can achieve a good therapeutic effect.

Aggressive Mesenchymal chondrosarcoma of the maxilla: Case report

Introduction

Chondrosarcomas of the head and neck are extremely rare, accounting for approximatively 0.1% of all head and neck malignant tumors. Mesenchymal chondrosarcomas are particularly aggressive, with a high propensity for recurrence.

Case report

We report the case of a 25 years old man with no prior medical history, who presented to our facility with an aggressive tumor of the left maxilla. Upon radiologic and histopathological examinations, the tumor was revealed to be a mesenchymal chondrosarcoma. The patient was treated using surgical excision of the tumor, neoadjuvant chemotherapy and adjuvant radiotherapy.

Conclusion

Due to the high risk of recurrence and the possibility of metastasis occurring long after the initial diagnosis, it is important that patients with mesenchymal chondrosarcomas receive close and regular follow-ups after treatment.

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Maxillary chondrosarcoma generally presents as a painless tissue mass in the nasal cavities.

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In our case, the patient presented with many symptoms on his first consultation due to the advanced stage of tumor extension which has invaded the ipsilateral nasal cavity, the nasopharynx, oropharynx the hard palate and which arrives at the orbit without invading it.

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This case underlines the interest of multidisciplinary consultation because thanks to the decision of a first chemotherapy, the patient could then benefit from a carcinological surgery.

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The interest of a regular long-term follow-up given the high risk of recurrence.

Radiosensitizing Effect of Celastrol by Inhibiting G2/M Phase Arrest Induced by the c-myc Gene of Human SW1353 Chondrosarcoma Cells: Network and Experimental Analyses

Objective

Studies have unveiled that the components of Tripterygium wilfordii Hook F (TWHF) such as celastrol could attenuate apoptosis and proliferation of various tumor cells. This study is focused on the radiosensitization effect and apoptotic pathways of celastrol via the inhibition of the c-myc gene and the influence of which combined with radiotherapy on the proliferation, apoptosis, invasion, and metastasis of chondrosarcoma cells.

Methods

A variety of bioinformatic tools were applied to explore the expression level and prognosis of the c-myc gene in different tumor cells and chondrosarcoma cells. We used pharmacology network to analyze the components, pathways, targets, molecular functions of TWHF and explore the relevant effective components over the MYC gene. Clone formation assay, CCK-8 assay, flow cytometry, and transwell migration assay were applied to detect the effects of celastrol on the expression of c-myc gene, cell apoptosis, and cell cycle. Radiation therapy was used to observe the radiosensitization effect of celastrol on chondrosarcoma.

Results

This study shows that the c-myc gene is overexpressed in various tumor cells and bone tumor cells to varying degrees. Celastrol can significantly inhibit the expression of the c-myc gene, induce G2/M phase arrest through regulation of G2/M phase-related proteins, and promote SW1353 cell apoptosis through the mitochondrial signaling pathway. In addition, we also found that the use of triptorubin to inhibit c-myc gene expression in combination with radiotherapy can increase the osteosarcoma cells' apoptosis rate through the mitochondrial signaling pathway significantly.

Conclusions

Our study validated the radiosensitization effect of celastrol through knocking down the expression of the c-myc gene to induce G2/M phase arrest and provides a new idea for the treatment of refractory or recurrent chondrosarcoma that is not sensitive to radiotherapy.

Activation of efficient DNA repair mechanisms after photon and proton irradiation of human chondrosarcoma cells

Although particle therapy with protons has proven to be beneficial in the treatment of chondrosarcoma compared to photon-based (X-ray) radiation therapy, the cellular and molecular mechanisms have not yet been sufficiently investigated. Cell viability and colony forming ability were analyzed after X-ray and proton irradiation (IR). Cell cycle was analyzed using flow cytometry and corresponding regulator genes and key players of the DNA repair mechanisms were measured using next generation sequencing, protein expression and immunofluorescence staining. Changes in metabolic phenotypes were determined with nuclear magnetic resonance spectroscopy. Both X-ray and proton IR resulted in reduced cell survival and a G2/M phase arrest of the cell cycle. Especially 1 h after IR, a significant dose-dependent increase of phosphorylated γH2AX foci was observed. This was accompanied with a reprogramming in cellular metabolism. Interestingly, within 24 h the majority of clearly visible DNA damages were repaired and the metabolic phenotype restored. Involved DNA repair mechanisms are, besides the homology directed repair (HDR) and the non-homologous end-joining (NHEJ), especially the mismatch mediated repair (MMR) pathway with the key players EXO1, MSH3, and PCNA. Chondrosarcoma cells regenerates the majority of DNA damages within 24 h. These molecular mechanisms represent an important basis for an improved therapy.

Determinants of Survival in Skull Base Chondrosarcoma: A National Cancer Database Study

OBJECTIVE

Chondrosarcomas of the skull base are rare tumors most commonly treated surgically with or without adjuvant radiation therapy. Using the National Cancer Database (NCDB), we analyzed overall survival (OS), treatment modalities, and prognosticators.

METHODS

The NCDB was queried for all cases of histologically confirmed skull base chondrosarcoma treated between 2004 and 2015, excluding patients with more than 1 malignant tumor, on palliative care, receiving unrelated concurrent treatments, or having less than 1 month of follow-up. The χ² test for categorical variables, Cox proportional hazards models, and Kaplan-Meier log-rank analysis were used to test associations with the use of adjuvant radiation, OS, and survival time.

RESULTS

A total of 498 patients with skull base chondrosarcoma were identified in the NCDB. Of them, 224 (45.0%) and 198 (39.8%) were treated with either surgery alone or surgery with adjuvant radiation therapy, respectively. Patients more likely to undergo surgery with adjuvant radiation had higher tumor grade (P = 0.008), later year of diagnosis (P = 0.002), positive surgical margins (P < 0.001), and treatment at an academic institution (P = 0.02). Patient, tumor, and socioeconomic factors associated with worse OS on multivariate analysis included the Charlson/Deyo Comorbidity Score ≥2 (P = 0.017), as well as clear cell (P = 0.02) and dedifferentiated (P = 0.006) histology. Age, tumor grade, tumor size, treatment modality, insurance status, facility type, and urban/rural population did not show a statistically significant impact on OS.

CONCLUSION

The mainstay of treatment for skull base chondrosarcoma is surgery, with consideration of adjuvant radiation. This study demonstrated worse overall survival associated with more frail patients and aggressive histology types. It is important to consider these factors when planning the clinical management of these patients.

Determinants of survival in sinonasal and skull base chondrosarcoma: An analysis of the National Cancer Database

BACKGROUND

Chondrosarcomas are rare, malignant chondroid tumors that can occur in the sinonasal and skull base regions. Surgery is a mainstay of treatment, but complete resection can be challenging because of the close proximity of critical neurovascular structures. Because of their rarity and relatively indolent nature, optimal treatment regimens are not established. Our objective was to assess determinants of survival for sinonasal and skull base chondrosarcomas utilizing the National Cancer Database (NCDB).

METHODS

The NCDB (2004-2017) was queried for cases of sinonasal and skull base chondrosarcoma. Multivariate hazard regression modeling was used to identify significant predictors of 60-month and 120-month overall survival (OS).

RESULTS

Seven hundred thirty-six cases met inclusion criteria. OS for all treatment types was 84.7% [SE±0.02] at 60 months and 75.6% [SE±0.02] at 120 months. Surgery with or without adjuvant treatment was found to associate with highest OS at 60 and 120 months. For patients receiving adjuvant radiation during treatment, proton therapy had significantly better OS at 60 months (95.4% [SE±0.03] vs 82.3% [SE±0.03], -²  = 5.27; p = 0.02) and 120 months (85.1% [SE±0.08] vs 72.8% [SE±0.05], -²  = 4.11; p = 0.04) compared with conventional external beam. After adjustment for primary site, multivariate Cox regression modeling (n = 561) identified cofactors significantly associated with variation in mortality risk at 60 and 120 months, including age, Charlson-Deyo total score ≥ 3, insurance provision status, and tumor grade.

CONCLUSIONS

Sinonasal and skull base chondrosarcoma are primarily treated with surgery with favorable OS. Adjuvant treatment may be required and proton radiation was associated with improved 60-month and 120-month survival compared with conventional radiation.

Operative nuances and surgical limits of the endoscopic approach to clival chordomas and chondrosarcomas: A single-center experience of 72 patients

OBJECTIVE

Gross total resection (GTR) is the mainstay therapy for chordomas and chondrosarcomas to have the best prognosis. The aims of this study were to specify the limits of EEA, emphasize the need for additional combined approaches for tumors beyond these limitations for high resection rates, discuss the prognostic factors and operative nuances that affect GTR, and present the causes and characteristics of early and late recurrences.

METHODS

We retrospectively analyzed the endoscopic endonasal surgeries in the Pituitary Research Center and Neurosurgery Department of the Kocaeli University Faculty of Medicine, Turkey between January 2004 and December 2019. We retrospectively reviewed the medical data, radiological images, and surgical videos of patients, and 72 patients with chordoma and chondrosarcoma were included in the study.

RESULTS

Based on pathology reports, 72 patients (seven pediatric) were identified, to whom 91 endoscopic operations were performed. We determined the surgical limitations for each clival segment as superior, middle, and inferior. Then, we divided these into three subgroups according to whether the tumor shows dural invasion (extradural chordoma, large extradural - minimal intradural component, and minimal extradural - large intradural component). The tumors of 19 (26.4%), 25 (26.4%), and nine (12.5%) patients originated from the superior, middle, and inferior clivus, respectively. Nineteen (26.4%) patients had panclival involvement. GTR was performed in 47 (65.3%) the patients. The GTR rate in patients with panclival tumors was 47.3% (9/19). The experience, lateralization, dural involvement, and origin of the clivus affecting GTR were analyzed. Extradural - intradural extensions were verified as negative predictor factors for GTR, whereas tumors located in the superior (OR: 16.710, p=0.030) and middle (OR: 11.154, p=0.023) segments were positive predictive factors for GTR.

CONCLUSION

An increasing experience in endoscopic surgery significantly increases the GTR rates by widening the surgical limitations. Due to dense bone infiltration and adhesion to critical neurovascular structures, recurrence rates are high despite performing GTR. Although surgery and adjuvant treatments improve the 5-year survival of patients, the mortality rates remain high. Therefore, surgery of these tumors should be performed by experienced centers. In addition to surgical and adjuvant therapies, targeted molecular and translational biological therapies are also needed for chordomas and chondrosarcomas in the future.

Effects of a combined therapy of bortezomib and ionizing radiation on chondrosarcoma three-dimensional spheroid cultures

Chondrosarcomas represent a heterogeneous group of primary bone cancers that are characterized by hyaline cartilaginous neoplastic tissue and are predominantly resistant to radiation and chemotherapy. However, adjuvant radiotherapy is often recommended in inoperable cases or after incomplete resections. To improve the efficiency of treatment, the present study tested a combination therapy with ionizing radiation (IR) and the proteasome inhibitor bortezomib. Using a three-dimensional (3D) spheroid model, 0-20 Gy of IR was applied to chondrosarcoma cells and healthy human chondrocytes. Following combined treatment with IR and bortezomib, the cell cycle distribution, apoptotic induction, the survivin pathway, autophagy and DNA damage were evaluated. Both cell types exhibited a slight decrease in viability following increasing doses of IR; the chondrosarcoma cells demonstrated a significant dose-dependent increase in the expression levels of the DNA damage marker histone H2AX phosphorylation at serine 139 (γH2AX). The combination treatment with bortezomib significantly decreased the cell viability after 48 h compared with that in irradiated cells. High-dose IR induced a G2/M phase arrest, which was accompanied by a decrease in the number of cells at the G1 and S phase. Co-treatment with bortezomib changed the distribution of the cell cycle phases. The mRNA expression levels of the proapoptotic genes Bcl-2-associated X protein (Bax) and Bak were significantly increased by bortezomib treatment and combination therapy with IR. In addition, the combination therapy resulted in a synergistic decrease of the expression levels of survivin and its corresponding downstream pathway molecules, including heat shock protein 90, X-linked inhibitor of apoptosis protein, smad 2 and smad 3. Comparative analyses of γH2AX at 1 and 24 h post-IR revealed efficient DNA repair in human chondrosarcoma cells. Therefore, additional bortezomib treatment may only temporarily improve the radiation sensitivity of chondrosarcoma cells. However, the inhibition of the survivin pathway by the combined treatment with IR and bortezomib, observed in the present study, revealed a novel aspect in the tumor biology of chondrosarcoma 3D spheroid cultures and may represent a potential target for therapy.

[Interdisciplinary surgery to the central skull base-current status]

Hintergrund

Die Schädelbasis stellt eine chirurgisch hochkomplexe Einheit dar und ist häufig nur über kombinierte Zugangswege erreichbar. Neu entwickelte Operationstechniken mit Verwendung von mikrochirurgischen Visualisierungsverfahren und aktiven Instrumenten („powered instruments“) sowie „Multi-Port-Zugänge“ ermöglichen neue, weniger traumatische Operationskorridore. Hierfür ist eine enge interdisziplinäre Zusammenarbeit zwischen dem Chirurgen aus dem Fachgebiet der Hals-Nasen-Ohren-Heilkunde sowie dem Neurochirurgen notwendig. Die aktuell etablierten Zugangsverfahren zur zentralen Schädelbasis werden aufgrund eigener klinischer Erfahrungen und unter Berücksichtigung der Entität systematisiert und in Bezug auf die aktuelle Studienlage erörtert.

Material und Methode

Es erfolgte eine retrospektive, qualitative und deskriptive Auswertung der Operationsberichte einzelner Patienten, die in der Zeit zwischen 2006 und 2019 mit Pathologien an der zentralen Schädelbasis chirurgisch gemeinsam von der Neurochirurgie und der Hals-Nasen-Ohren-Heilkunde/Kopf- und Halschirurgie behandelt wurden.

Ergebnisse

Die chirurgischen Zugangswege zur zentralen Schädelbasis ließen sich nachfolgend kategorisieren, teilweise auch in Kombination derselben, als sog. Multi-Port-Zugänge: transnasal-transsphenoidal, subfrontal, subtemporal, transzygomatisch, transpterygonal, transpetrös, translabyrinthär und subokzipital. Maßgebend für die Wahl des Zugangswegs waren die Lokalisation und Art der Pathologie, sowie der mögliche Anspruch auf Funktionserhalt und Komplettentfernung.

Schlussfolgerung

Aufgrund der Komplexität der Strukturen der zentralen Schädelbasis, der unterschiedlichsten Tumorentitäten und der benötigten Fachkompetenz unterschiedlicher Facharztdisziplinen bleibt die Chirurgie der zentralen Schädelbasis eine Herausforderung, der man sich nur an speziellen, nach den Kriterien der Gesellschaft für Schädelbasischirurgie e. V. zertifizierten Kompetenzzentren stellen sollte.

Outcomes and Patterns of Care in Adult Skull Base Chondrosarcoma Patients in the United States

BACKGROUND

Chondrosarcomas of the skull base are rare intracranial tumors of chondroid origin. The rarity of these lesions has made it difficult to form a consensus on optimal treatment regimens. The aim of this study was to provide a comprehensive analysis of prognostic factors, treatment modalities, and survival outcomes in patients with chondrosarcoma of the skull base.

METHODS

Patients with diagnosis codes for chondrosarcoma of the skull base were queried from the National Cancer Database for the years 2004-2016. Outcomes were investigated using Cox univariate and multivariate regression analyses, and survival curves were generated for comparative visualization.

RESULTS

A total of 718 patients with chondrosarcoma of the skull base were identified. Mean overall survival (OS) in these patients was 10.7 years. Older age and presence of metastases were associated with worsened OS. Of patients, 83.3% received surgical intervention, and both partial resection and radical resection were associated with significantly improved OS (P < 0.001). Neither radiotherapy nor chemotherapy improved OS; however, patients who received proton-based radiation and patients who received high-dose radiation (≥6000 cGy) had significantly improved OS compared with patients who received traditional radiation.

CONCLUSIONS

In the largest study to our knowledge of skull base chondrosarcoma to date, both partial resection and radical resection significantly improved OS, thus supporting the goal of maximal safe resection to preserve vital neurovascular structures without sacrificing outcome. In patients who received radiotherapy, proton-based modalities and high-dose radiation were associated with increased OS.

Chondrosarcoma of the parapharyngeal space: Case report and literature review of an extremely rare location

Chondrosarcoma of the head and neck region is a rare disease, representing approximately 0.1% of all head and neck neoplasms. Parapharyngeal location is extremely rare and low-grade ones are even rarer. Surgery alone or followed by adjuvant radiotherapy is the treatment of choice. In this article, we report a case of a 67-year-old male with low-grade parapharyngeal chondrosarcoma who presented with a 3-month history of dysphagia. A cervical magnetic resonance imaging was performed that shows a well-defined mass located at the right parapharyngeal space, causing medial deviation of the mucosal space. Surgical resection of the tumor without neck dissection followed by adjuvant radiotherapy was undertaken with a favorable response. The purpose of this article is to add our case to the limited literature for good management of parapharyngeal chondrosarcomas.

Chondrosarcoma of the Skull Base: A Case Study and Literature Review

Chondrosarcomas (CSs) are rare malignant tumors composed of cells derived from the transformed chondrocytes. Only 2% of the total cases of CS are found at the skull base, thus representing a 0.1-0.2% prevalence. We present the case of a patient with CS at the middle cranial fossa who was admitted for surgery to the Burdenko National Medical Research Center of Neurosurgery. In addition, we engage in a review of the literature to discuss the current approaches to the diagnostics and surgery of CS and delve deep into its embryo- and oncogenesis.

Dosimetric analysis of local failures in skull-base chordoma and chondrosarcoma following pencil beam scanning proton therapy

Background

Despite combined modality treatment involving surgery and radiotherapy, a relevant proportion of skull-base chordoma and chondrosarcoma patients develop a local recurrence (LR). This study aims to analyze patterns of recurrence and correlate LR with a detailed dosimetric analysis.

Methods

222 patients were treated with proton radiotherapy for chordoma (n = 151) and chondrosarcoma (n = 71) at the PSI between 1998 and 2012. All patients underwent surgery, followed by pencil-beam scanning proton therapy to a mean dose of 72.5 ± 2.2Gy_RBE. A retrospective patterns of recurrence analysis was performed: LR were contoured on follow-up MRI, registered with planning-imaging and the overlap with initial target structures (GTV, PTV_high-dose, PTV_low-dose) was calculated. DVH parameters of planning structures and recurrences were calculated and correlated with LR using univariate and multivariate cox regression.

Results

After a median follow-up of 50 months, 35 (16%) LR were observed. Follow-up MRI imaging was available for 27 (77%) of these recurring patients. Only one (3.7%) recurrence was located completely outside the initial PTV (surgical pathway recurrence). The mean proportions of LR covered by the initial target structures were 48% (range 0–86%) for the GTV, 70% (range 0–100%) for PTV_high and 83% (range 0–100%) for PTV_low. In the univariate analysis, the following DVH parameters were significantly associated with LR: GTV(V < 66Gy_RBE, p = 0.01), GTV(volume, p = 0.02), PTV_high(max, p = 0.02), PTV_high(V < 66Gy_RBE, p = 0.03), PTV_high(V < 59Gy_RBE, p = 0.02), PTV_high(volume, p = 0.01) and GTV(D95, p = 0.05). In the multivariate analysis, only histology (chordoma vs. chondrosarcoma, p = 0.01), PTV_high(volume, p = 0.05) and GTV(V < 66Gy_RBE, p = 0.02) were independent prognostic factors for LR.

Conclusion

This study identified DVH parameters, which are associated with the risk of local recurrence after proton therapy using pencil-beam scanning for patients with skull-base chordoma and chondrosarcoma.

Radiation therapy strategies for skull-base malignancies

INTRODUCTION

The management of skull base malignancies continues to evolve with improvements in surgical technique, advances in radiation delivery and novel systemic agents.

METHODS

In this review, we aim to discuss in detail the management of common skull base pathologies which typically require multimodality therapy, focusing on the radiotherapeutic aspects of care.

RESULTS

Technological advances in the administration of radiation therapy have led to a wide variety of different treatment strategies for the treatment of skull base malignances, with outcomes summarized herein.

CONCLUSION

Radiation treatment plays a key and critical role in the management of patients with skull base tumors. Recent advancements continue to improve the risk/benefit ratio for radiotherapy in this setting.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

High LET Radiation Overcomes In Vitro Resistance to X-Rays of Chondrosarcoma Cell Lines

Chondrosarcomas are malignant tumors of the cartilage that are chemoresistant and radioresistant to X-rays. This restricts the treatment options essential to surgery. In this study, we investigated the sensitivity of chondrosarcoma to X-rays and C-ions in vitro. The sensitivity of 4 chondrosarcoma cell lines (SW1353, CH2879, OUMS27, and L835) was determined by clonogenic survival assays and cell cycle progression. In addition, biomarkers of DNA damage responses were analyzed in the SW1353 cell line. Chondrosarcoma cells showed a heterogeneous sensitivity toward irradiation. Chondrosarcoma cell lines were more sensitive to C-ions exposure compared to X-rays. Using D10 values, the relative biological effectiveness of C-ions was higher (relative biological effectiveness = 5.5) with cells resistant to X-rays (CH2879) and lower (relative biological effectiveness = 3.7) with sensitive cells (L835). C-ions induced more G2 phase blockage and micronuclei in SW1353 cells as compared to X-rays with the same doses. Persistent unrepaired DNA damage was also higher following C-ions irradiation. These results indicate that chondrosarcoma cell lines displayed a heterogeneous response to conventional radiation treatment; however, treatment with C-ions irradiation was more efficient in killing chondrosarcoma cells, compared to X-rays.

Skull Base Chordomas and Chondrosarcomas

Skull base chordomas account for less than 0.2% and chondrosarcomas for less than 0.15% of all intracranial tumors. Although their clinical and imaging presentations are similar, they derive from different origins. Chordomas arise from embryonic remnants of the primitive notochord and chondrosarcomas from primitive mesenchymal cells or from the embryonic rest of the cranial cartilaginous matrix. Both entities are characterized by infiltration and destruction of the surrounding bone and soft tissue and a high locoregional recurrence rate. Chondrosarcomas, when treated with similar complex strategies, display a much better prognosis than chordomas. The overall survival is approximately 65% for chordomas and 80% for chondrosarcomas at 5 years and 30 and 50%, respectively, at 10 years. Chordomas are divided into the following 3 histological types: classical (conventional), chondroid, and dedifferentiated. Chondrosarcomas have conventional, mesenchymal, clear cell, and dedifferentiated subgroups. Both tumor entities often present with nonspecific symptoms, and headaches are the most reported initial symptom. Computed tomography and magnetic resonance imaging are required to determine the tumor localization and the extent of tumor growth. The treatment philosophy is to maximize tumor resection, minimize morbidity, and preserve function. Neurosurgical approaches commonly used for the resection of intracranial chordomas and chondrosarcomas are transsphenoidal, transbasal, cranio-orbitozygomatic, transzygomatic extended middle fossa, transcondylar, and transmaxillary approaches. Chordomas and chondrosarcomas are not sensitive to chemotherapy and there are no approved drugs for their treatment. The present treatment concept is a combination of surgical resection with a maximal excision and preserving patients' quality of life by adjuvant radiotherapy for both chordomas and chondrosarcomas.

Endoscopic Endonasal Approach to the Ventral Jugular Foramen: Anatomical Basis, Technical Considerations, and Clinical Series

BACKGROUND

Surgical exposure of the jugular foramen (JF) is challenging given its complex regional anatomy and proximity to critical neurovascular structures.

OBJECTIVE

To describe the anatomical basis, surgical technique, and outcomes of a group of patients who underwent the endoscopic endonasal approach to the JF.

METHODS

Five silicon-injected anatomical specimens were prepared for dissection. Additionally, a chart review was conducted through our patient database, searching for endonasal exposure of the JF. Demographic data, clinical presentation, pathological findings, extent of resection in the JF, and occurrence of complications were analyzed.

RESULTS

The endonasal exposure of the JF requires 3 sequential steps: a transpterygoid, a "far-medial," and an "extreme-medial" approach. Mobilization or transection of the cartilaginous portion of the eustachian tube (ET) is necessary. In the clinical series, cranial neuropathies were the presenting symptoms in 16 patients (89%). Eighteen tumors (10 chondrosarcomas, 7 chordomas, 1 adenocarcinoma) extended secondarily into the JF. Total tumor resection was achieved in 10 patients (56%), near total (≥90%) in 6 (33%), and subtotal (<90%) in 2 (11%). ET dysfunction (75% of cases), transient palatal numbness (17%), cerebrospinal fluid leakage (17%), and lower cranial nerve palsy (17%) were the most common postoperative complications. There were no carotid artery or jugular vein injuries.

CONCLUSION

The endoscopic endonasal approach to the JF requires mobilization or transection of the cartilaginous portion of the ET. This maneuver provides a safe infrapetrosal surgical route to the JF. It may be considered a valid option, in well-selected cases, for resection of malignant and recurrent cranial base tumors.

Endoscopic Endonasal Surgery for Cranial Base Chondrosarcomas

BACKGROUND

Microsurgical resection via open approaches is considered the main treatment modality for cranial base chondrosarcomas (CBCs). The use of endoscopic endonasal approaches (EEAs) has been rarely reported.

OBJECTIVE

To present the endoscopic endonasal experience with CBCs at our institution.

METHODS

Retrospective review of the medical records of 35 consecutive patients who underwent EEA for CBC resection between January 2004 and April 2013. Surgical outcomes and variables that might affect extent of resection, complications, and recurrence were analyzed.

RESULTS

Forty-eight operations were performed (42 EEAs and 6 open approaches). Gross-total resection was achieved in 22 patients (62.9%), near total (≥90% tumor resection) in 11 (31.4%). Larger tumors were associated with incomplete resection in univariate and multivariate analysis ( P = .004, .015, respectively). In univariate analysis, tumors involving the lower clivus and cerebellopontine angle were associated with increased number of complications, especially postoperative cerebrospinal fluid leak ( P = .015) and new cranial neuropathy ( P = .037), respectively. Other major complications included 2 cases of meningitis and deep venous thrombosis, and 1 case of hydrocephalus and carotid injury. Involvement of the lower clivus, parapharyngeal space, and cervical spine required a combination of approaches to maximize tumor resection ( P = .017, .044, .017, respectively). No predictors were significantly associated with increased risk of recurrence. The average follow-up time was 44.6 ± 31 months.

CONCLUSIONS

EEAs may be considered a good option for managing CBCs without significant posterolateral extension beyond the basal foramina and can be used in conjunction with open approaches for maximal resection with acceptable morbidity.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.

Surgery and protontherapy in Grade I and II skull base chondrosarcoma: A comparative retrospective study

Objective

Skull base chondrosarcoma is a rare tumour usually treated by surgery and proton therapy. However, as mortality rate is very low and treatment complications are frequent, a less aggressive therapeutic strategy could be considered. The objective of this study was to compare the results of surgery only vs surgery and adjuvant proton therapy, in terms of survival and treatment adverse effects, based on a retrospective series.

Methods

Monocentric retrospective study at a tertiary care centre. All patients treated for a skull base grade I and II chondrosarcoma were included. We collected data concerning surgical and proton therapy treatment and up-to-date follow-up, including Common Terminology Criteria for Adverse Events (CTCAE) scores.

Results

47 patients (23M/24F) were operated on between 2002 and 2015; mean age at diagnosis was 47 years-old (10–85). Petroclival and anterior skull base locations were found in 34 and 13 patients, respectively. Gross total resection was achieved in 17 cases (36%) and partial in 30 (64%). Adjuvant proton therapy (mean total dose 70 GyRBE,1.8 GyRBE/day) was administered in 23 cases. Overall mean follow-up was 91 months (7–182). Of the patients treated by surgery only, 8 (34%) experienced residual tumour progression (mean delay 51 months) and 5 received second-line proton therapy. Adjuvant proton therapy was associated with a significantly lower rate of relapse (11%; p = 0.01). There was no significant difference in 10-year disease specific survival between patients initially treated with or without adjuvant proton therapy (100% vs 89.8%, p = 0.14). Difference in high-grade toxicity was not statistically significant between patients in both groups (25% (7) vs 11% (5), p = 0.10). The most frequent adverse effect of proton therapy was sensorineural hearing loss (39%).

Conclusion

Long-term disease specific survival was not significantly lower in patients without adjuvant proton therapy, but they experienced less adverse effects. We believe a surgery only strategy could be discussed, delaying as much as possible proton therapy in cases of relapse. Further prospective studies are needed to validate this more conservative strategy in skull base chondrosarcoma.

The Differences Between Intracranial Mesenchymal Chondrosarcoma and Conventional Chondrosarcoma in Clinical Features and Outcomes

OBJECTIVE

To report differences in clinical features and outcomes between intracranial mesenchymal chondrosarcoma (MCS) and conventional chondrosarcoma (CCS).

METHODS

Clinical data of patients with primary intracranial MCS and CCS were retrospectively extracted and analyzed to compare differences between MCS and CCS.

RESULTS

Seventy-four patients with intracranial chondrosarcoma (61 cases with MCS and 13 cases with CCS) were included. Compared with patients with CCS, patients with MCS presented at a younger mean age (21.1 years vs. 34.5 years, P < 0.001) and had a poor mean preoperative Karnofsky performance scale score (64.6 vs. 77.8, P = 0.014). Compared with CCS, MCS was less often located in the skull base (38.5% vs. 96.7%, P < 0.001) and had a larger tumor volume (87.8 cm³ vs. 26.7 cm³, P < 0.001). Rates of gross total resection in MCS and CCS subgroups were 41.1% (n = 25) and 46.2% (n = 6), respectively; rates of adjuvant radiotherapy postoperatively were 44.2% (n = 27) and 46.2% (n = 6), respectively. After mean follow-up of 41.7 months, 1-year, 3-year, and 5-year overall survival and progression-free survival of MCS were significantly shorter than overall survival and progression-free survival of CCS. Multivariate analysis revealed that tumor pathology and extent of surgery were independent predictors for tumor recurrence.

CONCLUSIONS

Clinical features of MCS are quite different from CCS. Treatment strategies used for CCS do not yield satisfactory outcomes for MCS. Treatment of MCS should be aggressive and individualized.

Chondrosarcoma in the Petrous Apex: Case Report and Review

Introduction  Surgical treatment of petrous apex chondrosarcoma is challenging due to the location of the tumor. Using an endoscopic technique for tumor resection is favored since it provides a minimally invasive approach. Case Presentation  A 57 years old female was admitted for acute onset of left abducens nerve palsy and occasional headache mainly on the left side of the retro-orbital area with some radiation to the left occiput. Magnetic resonance imaging (MRI) and computed tomography (CT), at the time of admission, were showed lytic lesion on the left petrous apex and left part of the clivus. Results of metastatic workup were negative. The surgical procedure considered was expanded endoscopic endonasal transclival approach to the left of the petrous apex and reconstruction with a pedicled nasoseptal flap with image guidance system. The pathology confirmed chondrosarcoma on myxoid background. The surgical procedure was uncomplicated. The abducens nerve palsy was resolved in few weeks and no new deficits occurred. Postoperative MRI showed complete resection of the tumor. Conclusion  Expanded endoscopic endonasal transclival approach to petrous apex and reconstruction appears to be safe and feasible technique, capable of achieving total removal of identified lesions near the petrous apex. Nonetheless, future studies with a greater number of patients are crucial to confirm and consolidate this initial impression.

Sellar chondrosarcoma presenting with amenorrhea: A case report

RATIONALE

Intracranial chondrosarcomas are rare entities and most of which arise off the midline. Chondrosarcomas that occur in the sellar region are extremely rare, and to the best of our knowledge, there is no reporting about sellar chondrosarcoma with amenorrhea as the onset symptom.

PATIENT CONCERNS

A 45-year-old woman presented with a 7-month history of amenorrhea and a 3-month history of progressive visual loss in the left eye.

DIAGNOSIS

The patient was diagnosed with recurrent sellar chondrosarcoma arising from intrasellar with extensive tumor invasion into bilateral sphenoid sinuses.

INTERVENTIONS

Twice endonasal transsphenoidal tumorectomies were performed followed with a stereotactic radiotherapy and hormone replacement therapy.

OUTCOMES

The patient's condition was stable and her visual symptoms improved, the hormones returned to normal, and no recurrence was noted on MRI after six months.

LESSONS

Sellar chondrosarcomas with the onset of endocrine dysfunctions are extremely rare, which may be misdiagnosed as pituitary adenoma and the definitive diagnosis depends on histopathological and immunohistochemical evidence. The first choice of treatment is surgery with the goal of complete resection, and postoperative adjuvant radiotherapy should be highlighted.

Proposed Treatment Paradigm for Intracranial Chondrosarcomas Based on Multidisciplinary Coordination

OBJECTIVES

There was no consensus regarding the treatment of intracranial chondrosarcoma (CSA). The study aimed to evaluate the adverse factors for progression-free survival (PFS) and overall survival (OS) and to propose a treatment strategy for CSA.

METHODS

The clinical chart and radiographic data of 106 consecutive cases (mesenchymal and conventional CSA in 18 and 88 patients, respectively) of surgically treated CSAs were retrospectively reviewed.

RESULTS

Gross total resection was achieved in 43 patients (40.6%), and adjuvant radiotherapy was administered in 45 patients. After a mean follow-up duration of 47.8 months, 38 patients (37.3%) experienced recurrence. PFS and disease-specific OS at 5 years was 57.7% and 74.4%. Independent adverse factors for PFS were previous surgery (hazard ratio [HR] 2.261; P = 0.028), increased lesion size (HR, 1.298; P = 0.026), extent of surgical resection (HR, 3.226; P < 0.001), malignant pathology (HR, 2.018; P = 0.003), and postoperative radiotherapy (HR, 3.246; P = 0.001). The stereotactic radiosurgery subgroup presented best 5-year PFS of 88.9%, and a linear accelerator prolonged the mean PFS time (57.0 months) compared with no radiation (38.1 months). In the incomplete resection subgroup (n = 63), radiotherapy significantly benefited tumor control (HR, 2.101; P = 0.016). Extent of surgical resection (HR, 1.797; P = 0.026) and malignant disease (HR, 1.717; P = 0.030) were associated with OS.

CONCLUSIONS

Intracranial CSAs were not completely amendable by surgery alone. Gross total resection as far as possible plus radiation were necessary for mesenchymal CSA and conventional CSA with active growth or residual tumor. Stereotactic radiosurgery was an alternative if proton therapy was unavailable. A future study with a large cohort is required to verify our findings.

Petroclival Chondrosarcoma: A Multicenter Review of 55 Cases and New Staging System

OBJECTIVE

To analyze clinical outcomes after treatment of petroclival chondrosarcoma and to propose a novel staging system.

STUDY DESIGN

Retrospective case review, 1995 to 2015.

SETTING

Multicenter study.

PATIENTS

Consecutive patients with histopathologically proven petroclival chondrosarcoma.

INTERVENTION(S)

Microsurgery, endoscopic endonasal surgery, radiation therapy, observation.

MAIN OUTCOME MEASURES

Disease- and treatment-associated morbidity, recurrence, mortality.

RESULTS

Fifty-five patients (mean age 42 years; 56% women) presenting with primary or recurrent petroclival chondrosarcoma were analyzed. The mean duration of follow-up was 74 months. Among 47 primary cases, the most common presenting symptoms were headache (55%) and diplopia (49%) and the mean tumor size at diagnosis was 3.3 cm. Subtotal resection was performed in 33 (73%) patients and gross total resection in 12 (27%). Adjuvant postoperative radiation was administered in 30 (64%) cases. Preoperative cranial neuropathy improved in 13 (29%), worsened in 11 (24%), and remained stable in 21 (47%) patients; notably, 11 preoperative sixth nerve palsies resolved after treatment. Nine recurrences occurred at a mean of 42 months. The 1-, 3-, 5- and 10-year recurrence-free survival rate for all 45 patients who underwent primary microsurgery with or without adjuvant radiation therapy was 97%, 89%, 70%, and 56%, respectively. Higher tumor stage, larger categorical size (<4 versus ≥4 cm), lack of adjuvant radiation, and longer duration of follow-up were associated with greater risk of recurrence. The overall mortality rate was 2% for patients presenting with primary disease.Analyzing the cohort of 17 cases with 20 recurrences, 3 received salvage surgery alone, 5 radiation therapy alone, 11 multimodality treatment, and one patient has been observed. Tumor control was ultimately achieved in 15 of 17 patients with recurrent disease. One patient (6%) with grade 3 petroclival chondrosarcoma died as a result of rapidly progressive disease within 6 months of salvage treatment. The overall mortality rate was 6% for patients with recurrent disease.

CONCLUSION

Gross total or subtotal resection with adjuvant radiation provides durable tumor control with minimal morbidity in most patients. Surgery may improve preoperative cranial nerve dysfunction, particularly in the case of cranial nerve 6 paralysis.

Kinase Activity in Recurring Primary Skull Base Chordomas and Chondrosarcomas: Identification of Novel Pathways of Oncogenesis and Potential Drug Targets

BACKGROUND

Chordomas and chondrosarcomas can occur in the skull base. Currently, 45% of chordomas and 56% of chondrosarcomas recur within 5 years of surgery. The role of adjuvant therapy is highly debated. No pharmacotherapies have been approved by the U.S. Food and Drug Administration for chordomas or chondrosarcomas. High propensity for recurrence and lack of definitive adjuvant therapy necessitate additional basic science research to identify molecular anomalies associated with recurrent disease.

METHODS

We pooled tumor lysates from patients based on clinical criteria into 4 groups: primary chordomas, primary chordomas that recurred, primary chondrosarcomas, and primary chondrosarcomas that recurred. We used a peptide labeling method, isobaric tags for relative and absolute quantitation, to uniquely identify each tumor group. Phosphorylated peptides were identified and quantified via mass spectroscopy to determine and predict active kinases.

RESULTS

Six groups of phosphorylated peptides were associated with primary tumors that later recurred. Specific kinases associated with primary chordomas that recurred were FES and FER. Specific kinases associated with primary chondrosarcomas that recurred were FES, FER, SRC family kinases, PKC, ROCK, and mitogen-activated protein kinase signaling (JNK, ERK1, p38).

CONCLUSIONS

These data provide clinicians with a means to screen skull base chordomas and chondrosarcomas to help identify tumors with a propensity to recur. Many of these kinases can be efficaciously inhibited by Food and Drug Administration-approved drugs that have not yet been used in clinical trials for treatment of skull base chordomas or chondrosarcomas. Validation of kinases identified in this study may advance treatment options for patients with these tumors.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

Long term outcomes of patients with skull-base low-grade chondrosarcoma and chordoma patients treated with pencil beam scanning proton therapy

PURPOSE

To evaluate the long term tumor control and toxicity of skull base tumors treated with pencil beam scanning proton therapy (PT).

MATERIALS AND METHODS

PT was delivered to 151 (68%) and 71 (32%) chordoma and chondrosarcoma (ChSa) patients, respectively. Mean age of patients was 40.8±18.4years and the male to female ratio was 0.53. The postoperative tumor was abutting the brainstem or optic apparatus in 71 (32.0%) patients. The postoperative mean gross tumor volume (GTV) was 35.7±29.1cm(3). The delivered mean PT dose was 72.5±2.2GyRBE.

RESULTS

After a mean follow-up of 50 (range, 4-176) months, 35 local (15.8%) failures were observed between 10.9 and 85.4months. The estimated 7-year LC rate for chordoma (70.9%; CI95% 61.5-81.8) was significantly lower compared to the LC rate for ChSa patients (93.6%; 95%CI 87.8-99.9; P=0.014). The estimated 7-year distant metastasis-free- and overall survival rate was 91.6% (95%CI 91.6-98.6) and 81.7% (95%CI 74.7-89.5), respectively. On multivariate analysis, optic apparatus and/or brainstem compression, histology and GTV were independent prognostic factors for LC and OS. The 7-year high grade toxicity-free survival was 87.2 (95%CI 82.4-92.3).

CONCLUSIONS

PBS PT is an effective treatment for skull base tumors with acceptable late toxicity. Optic apparatus and/or brainstem compression, histology and GTV allow independent prediction of the risk of local failure and death in skull base tumor patients.

Systemic therapy for selected skull base sarcomas: Chondrosarcoma, chordoma, giant cell tumour and solitary fibrous tumour/hemangiopericytoma

This review highlights the data currently available on the activity of systemic therapy in chondrosarcoma, chordoma, giant cell tumour of the bone (GCTB) and solitary fibrous tumour, i.e., four rare sarcomas amongst mesenchymal malignancy arising from the skull base.

Skull base chondrosarcoma

Intracranial chondrosarcoma are rare tumours, accounting for approximately one in 1000 intracranial neoplasms. Although more common in the axial or appendicular skeleton, intracranial tumours present a challenging surgical and oncological problem. Chondrosarcoma have a predilection for the skull base and although commonly slow growing, Grade II and III lesions do occur. We present two illustrative patients from the Royal Melbourne Hospital, Australia, demonstrating dramatically differing presentation and clinical outcome and the diagnostic difficulties that may arise. A review of the literature regarding skull base chondrosarcoma is presented. We summarise the clinical, radiological and histological features. The evidence for surgical resection, radiotherapy and chemotherapy is presented and critically evaluated. Based on the available evidence, we advocate maximal safe resection, followed by radiotherapy for Grade II and III tumours. There is no current role for chemotherapy. Radical excision should not be attempted at the expense of neurological function.

Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension

OBJECT

Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions.

METHODS

Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas.

RESULTS

The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery.

CONCLUSIONS

Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.

Nuances in the treatment of malignant tumors of the clival and petroclival region

Introduction Malignancies of the clivus and petroclival region are mainly chordomas and chondrosarcomas. Although a spectrum of malignancies may present in this area, a finite group of commonly encountered malignant pathologies will be the focus of this review, as they are recognized to be formidable pathologies due to adjacent critical neurovascular structures and challenging surgical approaches.

Objectives The objective is to review the literature regarding medical and surgical management of malignant tumors of the clival and petroclival region with a focus on clinical presentation, diagnostic identification, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to the skull base.

Data Synthesis A literature review was conducted, searching for basic science and clinical evidence from PubMed, Medline, and the Cochrane Database. The selection criteria encompassed original articles including data from both basic science and clinical literature, case series, case reports, and review articles on the etiology, diagnosis, treatment, and management of skull base malignancies in the clival and petroclival region.

Conclusions The management of petroclival malignancies requires a multidisciplinary team to deliver the most complete surgical resection, with minimal morbidity, followed by appropriate adjuvant therapy. We advocate the combination of endoscopic and open approaches (traditional or minimally invasive) as required by the particular tumor followed by radiation therapy to optimize oncologic outcomes.

Chordoma and chondrosarcoma

Chordoma and chondrosarcoma represent 2 fundamentally different and challenging central skull base pathologies. Both are largely surgical diseases with varying outcomes based on completeness of resection. Adjuvant therapy is controversial, although radiation therapy is commonly employed postoperatively, and stereotactic radiosurgery is used either in primary management or treatment of local progression.

Comparing operative exposures of the le fort I osteotomy and the expanded endoscopic endonasal approach to the clivus

Objectives We compare surgical exposures to the clivus by Le Fort I osteotomy (LFO) and the expanded endoscopic endonasal approach (EEEA). Methods Ten cadaveric specimens were imaged with 1.25-mm computed tomography. After stereotactic navigation, EEEA was performed followed by LFO. Clival measurements included lateral and vertical limits to the midline lower extent of exposure (t test). Results For EEFA and LFO, respectively, maximal lateral exposure in millimeters (mean ± standard deviation) was 24.5 ± 3.7 and 24.5 ±  - 3.8 (p = 0.99) at the opticocarotid recess (OCR) and 25.1 ±  - 4.1 and 24.1 ±  - 3.0 (p = 0.53) at the foramen lacerum level; lateral reach at the hypoglossal canals was 39.0 ±  - 5.88 and 56.1 ±   - 5.3 (p = 0.0004); and vertical extension was 56.0 ±  - 4.1 and 56.3 ±  - 3.4 (p = 0.78). Conclusions For clival exposures, LFO and EEEA were similar craniocaudally and laterally at the levels of the OCR and foramen lacerum. LFO achieved greater exposure at the level of the hypoglossal canal.

Bilateral chondrosarcoma of the jugular foramen: literature review and personal experience

Chondrosarcomas (CS) are slow-growing malignant cartilaginous tumors with locally invasive behavior. They account for only 0.15% head and neck neoplasia. There have been no reports in the management of bilateral skull base CS in the literature to date. The synchronous presentation of bilateral CS of the jugular foramen (JF) was diagnosed in a 22-year-old woman with right abducens nerve palsy. Once evaluated the collateral intracranial venous discharge, the lesions were removed in two surgical stages through a bilateral petro-occipital trans-sigmoid (POTS) approach performing a bilateral closure of sigmoid sinus. The patient is disease free 15 years after surgery. No complications occurred. Diplopia improved after excision of the tumor on the right side. A review of relevant English literature was performed. The POTS approach to the JF proved to be safe and effective. Staged radical surgery alone, assessing intracranial venous flow at all stages of surgery, was a valid strategy for bilateral CS, achieving long-term disease control, avoiding early adjuvant radiotherapy, and carrying no complications.

Endoscopic endonasal resection of skull base chondrosarcomas: technique and early results

OBJECT

The authors of this study sought to report the technique and early clinical outcomes of a purely endonasal endoscopic approach for resection of petroclival chondrosarcomas.

METHODS

Between 2010 and 2014, 8 patients (4 men and 4 women) underwent endonasal endoscopic operations to resect petroclival chondrosarcomas at 2 institutions. The patients' mean age was 44.8 years (range 30-64 years). One of the patients had previously undergone radiation therapy and another a staged craniotomy. Using volumetric software, an independent neuroradiologist assessed the extent of the resections on MRI scans taken immediately after surgery and at the 3-month follow-up. Immediate complications and control of symptoms were also recorded. In addition, the authors reviewed the current literature on surgical treatment of chondrosarcoma.

RESULTS

The mean preoperative tumor diameter and volume were 3.4 cm and 9.8 cm(3), respectively. Six patients presented with cranial neuropathies. Endonasal endoscopic surgery achieved > 95% resection in 5 of the 8 patients and < 95% resection in the remaining 3 patients. One of the 6 neuropathies resolved, and the remaining 5 partially improved. One instance of postoperative CSF leakage required a reoperation for repair; no other complications associated with these operations were observed. All of the patients underwent adjuvant radiotherapy.

CONCLUSIONS

According to the authors' experience, the endoscopic endonasal route is a safe and effective approach for the resection of appropriately selected petroclival chondrosarcomas.

Chondrosarcomas of the head and neck

Chondrosarcoma represents approximately 11% of all primary malignant bone tumors. It is the second most common sarcoma arising in bone after osteosarcoma. Chondrosarcomas of the head and neck are rare and may involve the sinonasal tract, jaws, larynx or skull base. Depending on the anatomical location, the tumor can produce a variety of symptoms. Computed tomography and magnetic resonance imaging are the preferred imaging modalities. The histology of conventional chondrosarcoma is relatively straightforward; major challenges are the distinction between grade I chondrosarcomas and chondromas, and the differential diagnosis with chondroblastic osteosarcoma and chondroid chordoma. Surgery alone or followed by adjuvant radiotherapy is the treatment of choice. Radiotherapy alone has also been reported to be effective and can be considered if mutilating radical surgery is the only curative alternative. The 5-year survival for chondrosarcoma reaches 80%; distant metastases and/or local recurrences significantly worsen prognosis. The present review aims to summarize the current state of information about the biology, diagnosis and management of these rare tumors.