Impact of Treatment Modalities upon Survival Outcomes in Skull Base and Clival Chordoma: An NCDB Analysis

Objectives  Skull base chordomas are locally aggressive malignant tumors derived from the notochord remnant. There are limited large-scale studies examining the role and extent of surgery and radiation therapy. Design  Analysis of the National Cancer Database (NCDB) was performed to evaluate the survival outcomes of various treatments, and to assess for predictors of overall survival (OS). Participants  This is a retrospective, population-based cohort study of patients diagnosed with a clival/skull base chordoma between 2004 and 2015 in the NCDB. Main Outcome Measures  The primary outcome was overall survival (OS). Results  In all, 468 cases were identified. Forty-nine percent of patients received surgery and 20.7% had positive margins. Mean age at diagnosis was 48.4 years in the surgical cohort, and 55% were males. Of the surgical cohort, 33.8% had negative margins, 20.7% had positive margins, and 45.5% had unknown margin status. Age ≥ 65 (hazard ratio [HR]: 3.07; 95% confidence interval [CI]: 1.63-5.76; p  < 0.001), diagnosis between 2010 and 2015 (HR: 0.49; 95% CI: 0.26-0.90; p  = 0.022), tumor size >5 cm (HR: 2.29; 95% CI: 1.26-4.15; p  = 0.007), and government insurance (HR: 2.28; 95% CI: 1.24-4.2; p  = 0.008) were independent predictors of OS. When comparing surgery with or without adjuvant radiation, no survival differences were found, regardless of margin status ( p  = 0.66). Conclusion  Surgery remains the mainstay of therapy. Advanced age (>65 years), large tumor size, and government insurance were predictors of worse OS. Whereas negative margins and the use of adjuvant radiation did not appear to impact OS, these may very well reduce local recurrences. A multidisciplinary approach is critical in achieving optimal outcomes in this challenging disease.

Surgical Outcomes of Clival Chordoma Through Endoscopic Endonasal Approach: A Single-Center Experience

OBJECTIVE

Clival chordoma is a locally aggressive tumor with low metastatic potential. In the past decade, endoscopic endonasal approach (EEA) for clival chordoma has had a higher resection rate and a lower morbidity rate than transcranial approaches. Here, we present our initial single-center experience after EEA of clival chordomas.

PATIENTS AND METHODS

This study retrospectively analyzed 17 consecutive patients with clival chordoma who received EEA in our department between March 2015 and September 2021. The operation was performed by a single surgeon with EEA. The clinical and pathological characteristics were analyzed along with the surgical outcomes and complications.

RESULTS

A total of 17 consecutive patients with clival chordoma received EEA with a median follow-up of 29.2 months (range 1-79). Gross total resection (GTR) was performed in 7 cases (41%), subtotal resection (STR) in 7 case (41%) and partially resection (PR) in 3 cases (18%). Cerebrospinal fluid leakage occurred in 2 cases (12%) and meningitis developed in 3 patients (18%) which were all successfully treated with intravenous antibiotics without any complications. There were no perioperative deaths or new focal neurological deficits postoperatively. Four in 7 patients with STR have had radiotherapy while the other three chose to be monitored. Till the last follow-up, three patients in STR group who received radiotherapy (3 in 4) had no tumor regrowth, while one in STR group with radiotherapy (1 in 4) showed tumor progression. Two patients in STR group without radiotherapy (2 in 3) showed stable tumor while the left one (1 in 3) showed tumor progression. One patient in the PR group died of tumor progression 2 years postoperation and the other one showed tumor progression and died of lung cancer 1 year postoperation. In addition, 1 in 7 patients with GTR had tumor recurrence in situ after 10 months and developed surgical pathway seeding in the spinal canal in C1 after 16 months. No recurrence occurred in the other 6 cases with GTR during the follow-up.

CONCLUSION

Although more cases are needed, our case series showed EEA is a safe and reliable method for clival chordoma with high resection rates and low morbidity rates. GTR without tumor residuum would improve the outcome.

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.

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.

Radial Forearm Free Tissue Transfer to Clival Defect

Introduction  Reconstruction of craniocervical junction (CCJ) defects after endoscopic endonasal skull base surgery (ESBS) remains challenging, despite advancements in vascularized intranasal and regional flaps. Microvascular free tissue transfers have revolutionized reconstruction in open skull base surgery but have been utilized rarely in ESBS. We describe the use of a radial forearm free flap (RFFF) for reconstruction of a recalcitrant CCJ defect after resection of a clival chordoma.

Case Report  A 54-year-old female who underwent ESBS for a clival chordoma complicated by a C1–C2 epidural abscess after proton beam therapy presented with pneumocephalus 4 years after her resection ( Fig. 1 ). At the CCJ, she developed a 1-cm skull-base defect. An occult cerebrospinal fluid (CSF) leak persisted despite an extracranial pericranial flap and a lateral nasal wall flap. Her definite reconstruction was a RFFF inset through a transmaxillary approach. Using a maxillary vestibular incision, anterior, lateral, and medial maxillotomies allowed the introduction of the flap into the nasal cavity and the passage of the RFFF pedicle across the posterior maxillary wall, into the premassateric space and to the facial vessels at the mandible. An endonasal inset supplemented with transoral suturing of the distal end of the flap to the posterior oropharynx halted further CSF egress. Vascularization of the flap was confirmed with intraoperative indocyanine green angiography and postoperative computed tomography (CT) angiography and magnetic resonance imaging (MRI).

Conclusion  A RFFF inset through a transmaxillary approach to the facial vessels has an adequate reconstructive surface and pedicle to cover the central and posterior fossa skull base after ESBS ( Fig. 2 ).

The link to the video can be found at: https://youtu.be/rQ5vJKyD5qg .

[Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 3. Analysis of surgical treatment outcomes in 127 patients]

Until recently, tumors of the clival region and ventral posterior cranial fossa were considered hard-to-reach and often inoperable via standard transcranial approaches. The introduction of minimally invasive methods combined with the endoscopic technique into neurosurgical practice has enabled removal of hard-to-reach tumors, including midline tumors of the ventral posterior cranial fossa.

OBJECTIVE

To improve and introduce the extended endoscopic endonasal posterior (transclival) approach into clinical practice and to analyze the results of its application in surgical treatment of midline skull base tumors extending into the ventral posterior cranial fossa.

MATERIAL AND METHODS

During the period from 2008 to the present, we have operated 127 patients with various skull base tumors located in the clival region and ventral posterior cranial fossa (60 males and 67 females); the patients' age was 3 to 74 years. The distribution of tumors by histology was as follows: 96 (75.6%) chordomas, 9 (7.1%) pituitary adenomas, 8 (6.3%) meningiomas, 3 (2.33%) cholesteatomas, 2 (1.6%) craniopharyngiomas, 3 (2.33%) fibrotic dysplasia, and 6 (4.7%) other tumors (giant cell tumor, glioma of the neurohypophysis, osteoma, plasmacytoma, carcinoid tumors, chondroma). The tumor size was as follows: 36 (28.35%) giant (more than 60 mm) tumors, 71 (55.9%) large (35-59 mm) tumors, 19 (14.96%) medium (21-35 mm) tumors, and 1 (0.79%) small (less than 20 mm) tumor. Intraoperative monitoring of the cranial nerves was performed (20 cranial nerves were identified) in 10 cases.

RESULTS

The extent of chordoma resection was as follows: total removal - 63 (65.62%) cases, subtotal removal - 23 (23.96%) cases, and partial removal - 10 (10.42%) cases. Pituitary adenomas were resected totally in 6 cases, subtotally in 1 case, and partially in 2 cases. Meningioma was removed subtotally in 4 cases, partially in 3 cases, and less than 50% in 1 case. Other tumors (cholesteatoma, craniopharyngioma, fibrous dysplasia, giant cell tumor, glioma of the neurohypophysis, osteoma, plasmacytoma, carcinoid tumors, chondroma) were removed totally in 7 cases and subtotally in 7 cases. Postoperative cerebrospinal fluid leakage occurred in 9 (7.2%) cases, and meningitis developed in 12 (9.4%) cases. Oculomotor disorders occurred in 17 (13.4%) patients; in 10 of these patients, the disorders regressed within 4 to 38 days after surgery; in 7 patients the oculomotor disorders did not regress. A lethal outcome occurred in 2 (1.57%) cases.

CONCLUSION

The extended endoscopic endonasal posterior (transclival) approach, being minimally invasive, enables removal of various midline skull base tumors with/without involvement of the clivus with high radicalness, low risk of postoperative complications, and low lethality. Until recently, these tumors were considered almost inoperable.

International consensus statement on endoscopic skull-base surgery: executive summary

BACKGROUND

Endoscopic skull-base surgery (ESBS) is a rapidly growing discipline that often combines the expertise of otolaryngology-head and neck surgeons and neurosurgeons to provide care for these challenging conditions. As the field has grown, so too has the literature evaluating this surgical approach and the challenges and complications associated with these interventions. An international, multidisciplinary effort to critically evaluate and grade the current literature on ESBS has resulted in the International Consensus Statement on Endoscopic Skull Base Surgery (ICAR:SB). This Executive Summary highlights the key findings of the ICAR:SB document.

METHODS

Following the prior methodology of the ICAR statements, the ICAR:SB document consists of 98 topics in ESBS that underwent a systematic review. When sufficient evidence exists, an evidence-based review with recommendation (EBRR) or evidence-based review (EBR) was created and then underwent an iterative review process until consensus was achieved. This Executive Summary recapitulates these findings.

RESULTS

This summary complies the EBR and EBRR from the ICAR:SB document in the management of numerous skull-base pathologies including cerebrospinal fluid rhinorrhea, intradural tumors, sinonasal malignancies, and clival tumors, as well as the key issues of reconstruction after and the complications associated with ESBS.

CONCLUSION

The ICAR:SB Executive Summary recaps the evidenced-based recommendations concerning the advantages, limitations and challenges of ESBS in the management of diverse skull-base pathologies. Although multifactorial in nature, the overall level of evidence in ESBS is modest. This represents an opportunity to address these knowledge gaps moving forward.

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.

Clival chordoma: long-term clinical outcome in a single center

The treatment of clival chordoma remains highly challenging. This difficulty is enhanced by the very small likelihood of a successful complete surgical resection or nonsurgical treatment of chordoma. Additionally, no effective means of interdisciplinary treatment for chordoma have been identified. With this background, we analyzed data of patients who underwent multidisciplinary treatment for clival chordoma at our institution during the last 25 years.This retrospective study evaluated patients treated at a single center from 1992 to 2017.During the study period, 24 patients underwent 24 surgeries. Twenty-two surgical resections (including 1 initial surgery and 1 surgery for recurrence) were deemed maximally safe cyto-reductive resections (92%); the remaining 2 surgeries were deemed incomplete (8%), which were histologically confirmed in all but in 1 case (which involved radionecrosis). The complications were divided into endocrinologic, neurologic, and other complications. In 1 case (4%), surgery led to immediate dyspnea followed by death on the following day; in another case (4%), ischemic infarction led to sudden death. In 3 cases (13%), patients exhibited improvements of neurologic (visual or oculomotor) deficits that had been observed prior to surgery. The following new postoperative neurologic deficits were observed: oculomotor deficits in 4 cases, dizziness in 2 cases, and cranial nerve-attributed dysphagia in 3 cases. About 19 patients underwent adjuvant postoperative radiotherapy following the initial surgery (dose: 54.5 Gy in all cases). The mean and median follow-up durations were 50 ± 53 and 48.5 months, respectively. A Kaplan-Meier analysis estimated a median survival duration of 50.2 months (95% confidence interval 27.9-72.4 months).These findings highlight the importance of interdisciplinary treatment strategies, particularly those combining maximally safe cyto-reductive tumor resection and adjusted radiotherapy and other treatment options, for patients with relatively good conditions.

Iatrogenic seeding of skull base chordoma following endoscopic endonasal surgery

OBJECTIVE

Iatrogenic tumor seeding after open surgery for chordoma has been well described in the literature. The incidence and particularities related to endoscopic endonasal surgery (EES) have not been defined.

METHODS

The authors retrospectively reviewed their experience with EES for clival chordoma, focusing on cases with iatrogenic seeding. The clinical, radiographic, pathological, and molecular characterization data were reviewed.

RESULTS

Among 173 EESs performed for clival chordomas at the authors' institution between April 2003 and May 2016, 2 cases complicated by iatrogenic seeding (incidence 1.15%) were identified. The first case was a 10-year-old boy, who presented 21 months after an EES for a multiply recurrent clival chordoma with a recurrence along the left inferior turbinate, distinct from a right petrous apex recurrence. Both appeared as a T2-hypertintense, T1-isointense, and heterogeneously enhancing lesion on MRI. Resection of the inferior turbinate recurrence and debulking of the petrous recurrence were both performed via a purely endoscopic endonasal approach. Unfortunately, the child died 2 years later due progression of disease at the primary site, but with no sign of progression at the seeded site. The second patient was a 79-year-old man with an MRI-incompatible pacemaker who presented 19 months after EES for his clival chordoma with a mass involving the floor of the left nasal cavity that was causing an oro-antral fistula. On CT imaging, this appeared as a homogeneously contrast-enhancing mass eroding the hard palate inferiorly, the nasal septum superiorly, and the nasal process of the maxilla, with extension into the subcutaneous tissue. This was also treated endoscopically (combined transnasal-transoral approach) with resection of the mass, and repair of the fistula by using a palatal and left lateral wall rotational flap. Adjuvant hypofractionated stereotactic CyberKnife radiotherapy was administered using 35 Gy in 5 fractions. No recurrence was appreciated endoscopically or on imaging at the patient's last follow-up, 12 months after this last procedure. In both cases, pathological investigation of the original tumors revealed a fairly aggressive biology with 1p36 deletions, and high Ki-67 levels (10%-15%, and > 20%, respectively). The procedures were performed by a team of right-handed surgeons (otolaryngology and neurosurgery), using a 4-handed technique (in which the endoscope and suction are typically passed through the right nostril, and other instruments are passed through the left nostril without visualization).

CONCLUSIONS

Although uncommon, iatrogenic seeding occurs during EES for clival chordomas, probably because of decreased visualization during tumor removal combined with mucosal trauma and exposure of subepithelial elements (either inadvertently or because of mucosal flaps). In addition, tumors with more aggressive biology (1p36 deletions, elevated Ki-67, or both) are probably at a higher risk and require increased vigilance on surveillance imaging and endoscopy. Further prospective studies are warranted to evaluate the authors' proposed strategies for decreasing the incidence of iatrogenic seeding after EES for chordomas.

A panoramic view of the skull base: systematic review of open and endoscopic endonasal approaches to four tumors

Endoscopic endonasal surgery has been established as the safest approach to pituitary tumors, yet its role in other common skull base lesions has not been established. To answer this question, we carried out a systematic review of reported series of open and endoscopic endonasal approaches to four major skull base tumors: olfactory groove meningiomas (OGM), tuberculum sellae meningiomas (TSM), craniopharyngiomas (CRA), and clival chordomas (CHO). Data from 162 studies containing 5,701 patients were combined and compared for differences in perioperative mortality, gross total resection (GTR), cerebrospinal fluid (CSF) leak, neurological morbidity, post-operative visual function, post-operative anosmia, post-operative diabetes insipidus (DI), and post-operative obesity/hyperphagia. Weighted average rates for each outcome were calculated using relative study size. Our findings indicate similar rates of GTR and perioperative mortality between open and endoscopic approaches for all tumor types. CSF leak was increased after endoscopic surgery. Visual function symptoms were more likely to improve after endoscopic surgery for TSM, CRA, and CHO. Post-operative DI and obesity/hyperphagia were significantly increased after open resection in CRA. Recurrence rates per 1,000 patient-years of follow-up were higher in endoscopy for OGM, TSM, and CHO. Trends for open and endoscopic surgery suggested modest improvement in all outcomes over time. Our observations suggest that endonasal endoscopy is a safe alternative to craniotomy and may be preferred for certain tumor types. However, endoscopic surgery is associated with higher rates of CSF leak, and possibly increased recurrence rates. Prospective study with long-term follow-up is required to verify these preliminary observations.

Clival chordomas: A pathological, surgical, and radiotherapeutic review

BACKGROUND

The purpose of this study was to discuss the optimal management of patients with clival chordomas and provide an up-to-date review of the field.

METHODS

A schematic description of the anatomy of the clivus and its surrounding structures is provided based on the modular classification of the surgical corridors used in endoscopic skull base surgery. Postoperative radiotherapy (RT) techniques are described.

RESULTS

The optimal treatment is gross total resection. Recent advances in endoscopic endonasal skull base surgery have allowed very high rates of macroscopic and radiographic complete tumor resection in spite of the challenging location of these lesions. When the tumor location or extension is too lateral or inferior to be effectively resected with an endoscopic approach, an open approach or a combination of endoscopic and open approaches in stages should be considered. Postoperative RT is usually indicated because the likelihood of recurrence is high in spite of complete surgical resection. The main site of recurrence is local and late recurrences are relatively common. The probability of cure is approximately 50% at 10 years and significantly increases when complete tumor resection has been achieved.

CONCLUSION

The preferred treatment for patients with clival chordoma is gross total resection (via endoscopic endonasal surgery when possible) followed by postoperative RT. Treatment at experienced multidisciplinary cranial base centers is key to minimize complications and to enhance the probability of total removal of the tumors.

Metastatic disease to the clivus mimicking clival chordomas

Objectives/Hypothesis A comprehensive review of the literature of clival metastases and presentation of two additional cases. Study Design Literature review and report of two cases. Methods A literature review of the MEDLINE database (1950 to January 19, 2013) was performed to identify all cases of patients with metastatic disease to the clivus. Additionally, two novel cases are presented. Results In total, 47 cases were identified in the literature, including the two cases presented in this study. Metastatic disease to the clivus is the initial presenting symptom of the primary malignancy in 36% (13/36) of the cases. When there was a history of malignancy, the median interval of time to clival metastases was 24 months (range 1 to 172 months). Clinical symptoms manifested often as cranial neuropathies, with at least abducens palsies as the initial presenting symptom in 61.9% (26/42) of patients. Tumor pathology was diverse, but several pathologies were seen more commonly: prostate carcinoma (18.1%, 9/47), hepatocellular carcinoma (10.6%, 5/47), and thyroid follicular carcinoma (8.5%, 4/47). Conclusion Although clival metastases are extremely rare, they are an important part of the differential of clival masses as they can be the presenting symptom of distant malignancy. Level of Evidence 4.