Surgical treatment and neurological outcome of infiltrating intramedullary astrocytoma WHO II-IV: a multicenter retrospective case series

Astrocytomas of the spinal cord

Tumors of astrocytic origin represent one of the most frequent entities among the overall rare group of spinal cord gliomas. Initial clinical symptoms are often unspecific, and sensorimotor signs localizing to the spinal cord occur with progressing tumor growth. On MRI, a hyperintense intrinsic spinal cord signal on T2-weighted sequences with varying degrees of contrast enhancement raises suspicion for an infiltrative neoplasm. Blood and CSF analysis serves to exclude an infectious process, nutritional deficits, or metabolic disorders. When such other differential diagnoses have been ruled out, a neuropathological tissue-based analysis is warranted to confirm the diagnosis of a spinal cord astrocytoma and guide further patient management. As such, maximal safe resection forms the basis of any treatment. Meticulous preoperative planning is necessary to weigh the potential improvement in survival against the risk of functional deterioration. Intraoperative neuromonitoring and ultrasound may aid in achieving a more extensive resection. Depending on the assigned WHO tumor grade spanning from grade 1 to grade 4, the use of radiotherapy and chemotherapy might be indicated but also wait-and-scan approaches appear reasonable in tumors of lower grade. Close imaging follow-up is necessary given that recurrence inevitably occurs in astrocytomas of grades 2-4. Prognosis is so far dictated by tumor grade and histopathological findings, but also by age and clinical performance of the patient. Targeted therapies resting upon an in-depth tissue analysis are emerging in recurrent tumors, but no prospective study is available so far given the rarity of spinal cord astrocytomas.

Management and Outcome of Recurring Low-Grade Intramedullary Astrocytomas

Intramedullary astrocytomas (IMAs) are the second most frequent intramedullary tumors in adults. Low-grade IMAs (LG-IMA, WHO grade I and II) carry a better prognosis than high-grade IMAs (HG-IMAs). However, adjuvant treatment of LG-IMAs by radiotherapy (RT) and/or chemotherapy (CT) as well as treatment of tumor recurrences remains controversial. The aim of our study was to evaluate the postoperative outcome of LG-IMAs and the management of recurring tumors. We retrospectively reviewed a series of patients operated on for IMA from 1980 to 2022 in a single neurosurgical department. We retrieved 40 patients who received surgery for intramedullary astrocytomas, including 30 LG-IMAs (22 WHO grade I; 5 WHO grade II; 3 "low-grade") and 10 HG-IMAs (4 WHO grade III; 5 WHO grade IV; 1 "high-grade"). Of the patients with LG-IMAs, the extent of surgical resection was large (gross or subtotal resection >90%) in 30% of cases. Immediate postoperative radiotherapy and/or chemotherapy was proposed only to patients who underwent biopsy (n = 5), while others were initially followed-up. Over a median follow-up of 59 months (range = 13-376), 16 LG-IMA (53.3%) recurred with a mean delay of 28.5 months after surgery (range = 3-288). These included seven biopsies, five partial resections (PR), four subtotal resections (STR) but no gross total resections (GTR). Progression-free survival for LG-IMAs was 51.9% at 3 years and 35.6% at 5 and 10 years; overall survival was 96.3% at 3 years; 90.9% at 5 years and 81.9% at 10 years. There were no significant differences in terms of OS and PFS between WHO grade I and grade II tumors. However, "large resections" (GTR or STR), as opposed to "limited resections" (PR and biopsies), were associated with both better OS (p = 0.14) and PFS (p = 0.04). The treatment of recurrences consisted of surgery alone (n = 3), surgery with RT and/or CT (n = 2), RT with CT (n = 3), RT alone (n = 2) or CT alone (n = 2). In conclusion, although LG-IMAs are infiltrating tumors, the extent of resection (GTR or STR), but not WHO grading, is the main prognostic factor. The management of recurring tumors is highly variable with no conclusive evidence for either option.

Spinal Intradural Tumor Resection via Long-Segment Approaches and Clinical Long-Term Follow-Up

INTRODUCTION

Spinal intradural tumors account for 15% of all CNS tumors. Typical tumor entities include ependymomas, astrocytomas, meningiomas, and neurinomas. In cases of multiple affected segments, extensive approaches may be necessary to achieve the gold standard of complete tumor resection.

METHODS

We performed a bicentric, retrospective cohort study of all patients equal to or older than 14 years who underwent multi-segment surgical treatment for spinal intradural tumors between 2007 and 2023 with approaches longer than four segments without instrumentation. We assessed the surgical technique and the clinical outcome regarding signs of symptomatic spinal instability. Children were excluded from our cohort.

RESULTS

In total, we analyzed 33 patients with a median age of 44 years and interquartile range IQR of 30-56 years, including the following tumors: 21 ependymomas, one subependymoma-ependymoma mixed tumor, two meningiomas, two astrocytomas, and seven patients with other entities. The median length of the approach was five spinal segments with a range of 4-14 and with the foremost localization in the cervical or thoracic spine. Laminoplasty was the most chosen approach (72.2%). The median time to follow-up was 13 months IQR (4-56 months). Comparing pre- and post-surgery outcomes, 72.2% of the patients (n = 24) reported pain improvement after surgery. The median modified McCormick scores pre- and post surgery were equal to II IQR (I-II) and II IQR (I-III), respectively.

DISCUSSION

We achieved satisfying results with long-segment approaches. In general, patients reported pain improvement after surgery and received similar low modified McCormick scores pre- and post surgery and did not undergo secondary dorsal fixation. Thus, we conclude that intradural tumor resection via extensive approaches does not seem to impair long-term spinal stability in our cohort.

Diffuse Midline H3K27-Altered Gliomas in the Spinal Cord: A Systematic Review

PURPOSE

To systematically review the clinical features, management, and outcomes of diffuse midline H3K27-altered gliomas of the spinal cord (DMG-SCs).

METHODS

PubMed, Ovid EMBASE, Scopus, and Web of Science were searched from database inception to 23 September 2023 for histologically confirmed cases of DMG-SC. Patient demographics, tumor characteristics, management information, and survival outcomes were extracted and analyzed.

RESULTS

A total of 279 patients from 39 studies were collected. Patients were mostly male (61%), with an average age of 32 years. Patients were treated with surgery, radiotherapy, and chemotherapy combined (31%) or surgery only (24%), and extent of resection was most often subtotal (38%). Temozolomide was the most common chemotherapeutic agent (81%). Radiation therapy was delivered with mean dose of 47 Gy in 23 fractions. At mean follow-up time of 21 months, 13% of patients were alive. Average median overall survival was 24 months (range of 13 to 40 months) with a median progression-free survival of 14 months. Historical WHO grades of 2 or 3 appeared to exhibit a longer average median overall survival time than that of grade 4 DMG-SCs (32 vs. 23 months, p = 0.009).

CONCLUSIONS

Outcomes for DMG-SCs are poor overall but appear to be favorable compared to intracranial DMGs. Despite the recent WHO 2021 grade 4 classification for all DMGs, given the differences in overall survival reported based on historical grading systems, future studies on DMG-SCs are needed to further define if DMG-SCs may represent a heterogeneous group of tumors with different prognoses.

Neurological Outcome and Respiratory Insufficiency in Intramedullary Tumors of the Upper Cervical Spine

Background and Objectives: Intramedullary spinal cord tumors (IMSCT) are rare entities. A location in the upper cervical spine as a highly eloquent region carries the risk of postoperative neurological deficits, such as tetraparesis or respiratory dysfunction. Evidence for respiratory dysfunction is scarce. This study aimed to describe these highly eloquent tumors' early and late postoperative clinical course. Materials and Methods: This is a single-center retrospective cohort study. We included 35 patients with IMSCT at levels of the craniocervical junction to C4 who underwent surgical treatment between 2008 and 2022. The authors analyzed the patients' preoperative status, tumor- and surgery-specific characteristics, and follow-up functional status. Results: The study cohort included twenty-two patients with grade II ependymoma (62.9%), two low-grade astrocytomas (5.7%), two glioblastomas (5.7%), six hemangioblastomas (17.1%), two metastases (5.7%), and one patient with partially intramedullary schwannoma (2.9%). Gross total resection was achieved in 76% of patients. Early dorsal column-related symptoms (gait ataxia and sensory loss) and motor deterioration occurred in 64% and 44% of patients. At a follow-up of 3.27 ± 3.83 years, 43% and 33% of patients still exhibited postoperative sensory and motor deterioration, respectively. The median McCormick Scale grade was 2 in the preoperative and late postoperative periods, respectively. Only three patients (8.6%) developed respiratory dysfunction, of whom, two patients, both with malignant IMSCT, required prolonged invasive ventilation. Conclusions: More than 60% of the patients with IMSCT in the upper cervical cord developed new neurological deficits in the immediate postoperative period, and more than 40% are permanent. However, these deficits are not disabling in most cases since most patients maintain functional independence as observed by unchanged low McCormick scores. The rate of respiratory insufficiency is relatively low and seems to be influenced by the rapid neurological deterioration in high-grade tumors.

Characterization and Treatment of Spinal Tumors

The prevalence of spinal tumors is rare in comparison to brain tumors which encompass most central nervous system tumors. Tumors of the spine can be divided into primary and metastatic tumors with the latter being the most common presentation. Primary tumors are subdivided based on their location on the spinal column and in the spinal cord into intramedullary, intradural extramedullary, and primary bone tumors. Back pain is a common presentation in spine cancer patients; however, other radicular pain may be present. Magnetic resonance imaging (MRI) is the imaging modality of choice for intradural extramedullary and intramedullary tumors. Plain radiographs are used in the initial diagnosis of primary bone tumors while Computed tomography (CT) and MRI may often be necessary for further characterization. Complete surgical resection is the treatment of choice for spinal tumors and may be curative for well circumscribed lesions. However, intralesional resection along with adjuvant radiation and chemotherapy can be indicated for patients that would experience increased morbidity from damage to nearby neurological structures caused by resection with wide margins. Even with the current treatment options, the prognosis for aggressive spinal cancer remains poor. Advances in novel treatments including molecular targeting, immunotherapy and stem cell therapy provide the potential for greater control of malignant and metastatic tumors of the spine.

Surgical approaches to intramedullary spinal cord astrocytomas in the age of genomics

Intramedullary astrocytomas represent approximately 30%–40% of all intramedullary tumors and are the most common intramedullary tumor in children. Surgical resection is considered the mainstay of treatment in symptomatic patients with neurological deficits. Gross total resection (GTR) can be difficult to achieve as astrocytomas frequently present as diffuse lesions that infiltrate the cord. Therefore, GTR carries a substantial risk of new post-operative deficits. Consequently, subtotal resection and biopsy are often the only surgical options attempted. A midline or paramedian sulcal myelotomy is frequently used for surgical resection, although a dorsal root entry zone myelotomy can be used for lateral tumors. Intra-operative neuromonitoring using D-wave integrity, somatosensory, and motor evoked potentials is critical to facilitating a safe resection. Adjuvant radiation and chemotherapy, such as temozolomide, are often administered for high-grade recurrent or progressive lesions; however, consensus is lacking on their efficacy. Biopsied tumors can be analyzed for molecular markers that inform clinicians about the tumor’s prognosis and response to conventional as well as targeted therapeutic treatments. Stratification of intramedullary tumors is increasingly based on molecular features and mutational status. The landscape of genetic and epigenetic mutations in intramedullary astrocytomas is not equivalent to their intracranial counterparts, with important difference in frequency and type of mutations. Therefore, dedicated attention is needed to cohorts of patients with intramedullary tumors. Targeted therapeutic agents can be designed and administered to patients based on their mutational status, which may be used in coordination with traditional surgical resection to improve overall survival and functional status.

Surgical treatment and outcomes of intramedullary tumors by minimally invasive approach: Answer

The surgical outcomes which evaluated in studies depend on preoperative condition, demographic data of patients, surgical approaches or treatment and local factors. Author argues that the neurological deterioration rate 4,2% which is reported in our study is marvelous and he exemplifies the other studies in literature. Neurosurgeons know that the clinical studies in literature do not compare only their results. Authors compare and evaluate studies with preoperative demographic data, surgical approach, local factors or others between their results. Therefore this detail explains paralogism of the author. The neurological deterioration rate is reported as smaller or similar in our study to the contrary of others due to all the preoperative demographical data were evaluated with others. We suppose the author alludes that the neurological deterioration rate is marvelous since he does not compare all of the demographical data in these clinical studies.