Carboplatin chemotherapy for progressive intramedullary spinal cord low-grade gliomas in children: three case studies and a review of the literature

Rare Neuronal, Glial and Glioneuronal Tumours in Adults

Rare glial, neuronal and glioneuronal tumours in adults form a heterogeneous group of rare, primary central nervous system tumours. These tumours, with a glial and/or neuronal component, are challenging in terms of diagnosis and therapeutic management. The novel classification of primary brain tumours published by the WHO in 2021 has significantly improved the diagnostic criteria of these entities. Indeed, diagnostic criteria are nowadays multimodal, including histological, immunohistochemical and molecular (i.e., genetic and methylomic). These integrated parameters have allowed the specification of already known tumours but also the identification of novel tumours for a better diagnosis.

Clinical and molecular characterization of a multi-institutional cohort of pediatric spinal cord low-grade gliomas

Background

The mitogen-activated protein kinases/extracelluar signal-regulated kinases pathway is involved in cell growth and proliferation, and mutations in BRAF have made it an oncogene of interest in pediatric cancer. Previous studies found that BRAF mutations as well as KIAA1549–BRAF fusions are common in intracranial low-grade gliomas (LGGs). Fewer studies have tested for the presence of these genetic changes in spinal LGGs. The aim of this study was to better understand the prevalence of BRAF and other genetic aberrations in spinal LGG.

Methods

We retrospectively analyzed 46 spinal gliomas from patients aged 1–25 years from Children’s Hospital Colorado (CHCO) and The Hospital for Sick Children (SickKids). CHCO utilized a 67-gene panel that assessed BRAF and additionally screened for other possible genetic abnormalities of interest. At SickKids, BRAF^V600E was assessed by droplet digital polymerase chain reaction and immunohistochemistry. BRAF fusions were detected by fluorescence in situ hybridization, reverse transcription polymerase chain reaction, or NanoString platform. Data were correlated with clinical information.

Results

Of 31 samples with complete fusion analysis, 13 (42%) harbored KIAA1549–BRAF. All 13 (100%) patients with confirmed KIAA1549–BRAF survived the entirety of the study period (median [interquartile range] follow-up time: 47 months [27–85 months]) and 15 (83.3%) fusion-negative patients survived (follow-up time: 37.5 months [19.8–69.5 months]). Other mutations of interest were also identified in this patient cohort including BRAF^V600E, PTPN11, H3F3A, TP53, FGFR1, and CDKN2A deletion.

Conclusion

KIAA1549–BRAF was seen in higher frequency than BRAF^V600E or other genetic aberrations in pediatric spinal LGGs and experienced lower death rates compared to KIAA1549–BRAF negative patients, although this was not statistically significant.

Surgical Management of Intramedullary Spinal Cord Tumors

Intramedullary spinal cord tumors (IMSCT) comprise a rare subset of CNS tumors that have distinct management strategies based on histopathology. These tumors often present challenges in regards to optimal timing for surgery, invasiveness, and recurrence. Advances in microsurgical techniques and technological adjuncts have improved extent of resection and outcomes with IMSCT. Furthermore, adjuvant therapies including targeted immunotherapies and image-guided radiation therapy have witnessed rapid development over the past decade, further improving survival for many of these patients. In this review, we provide an overview of types, epidemiology, imaging characteristics, surgical management strategies, and future areas of research for IMSCT.

Genomic Landscape of Intramedullary Spinal Cord Gliomas

Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms that have limited treatment options and are associated with high rates of morbidity and mortality. To better understand the genetic basis of these tumors we performed whole exome sequencing on 45 tumors and matched germline DNA, including twenty-nine spinal cord ependymomas and sixteen astrocytomas. Though recurrent somatic mutations in IMSCTs were rare, we identified NF2 mutations in 15.7% of tumors (ependymoma, N = 7; astrocytoma, N = 1), RP1 mutations in 5.9% of tumors (ependymoma, N = 3), and ESX1 mutations in 5.9% of tumors (ependymoma, N = 3). We further identified copy number amplifications in CTU1 in 25% of myxopapillary ependymomas. Given the paucity of somatic driver mutations, we further performed whole-genome sequencing of 12 tumors (ependymoma, N = 9; astrocytoma, N = 3). Overall, we observed that IMSCTs with intracranial histologic counterparts (e.g. glioblastoma) did not harbor the canonical mutations associated with their intracranial counterparts. Our findings suggest that the origin of IMSCTs may be distinct from tumors arising within other compartments of the central nervous system and provides the framework to begin more biologically based therapeutic strategies.

Surgical outcomes of pediatric spinal cord astrocytomas: systematic review and meta-analysis

OBJECTIVE

Pediatric spinal astrocytomas are rare spinal lesions that pose unique management challenges. Therapeutic options include gross-total resection (GTR), subtotal resection (STR), and adjuvant chemotherapy or radiation therapy. With no randomized controlled trials, the optimal management approach for children with spinal astrocytomas remains unclear. The aim of this study was to conduct a systematic review and meta-analysis on pediatric spinal astrocytomas.

METHODS

The authors performed a systematic review of the PubMed/MEDLINE electronic database to investigate the impact of histological grade and extent of resection on overall survival among patients with spinal cord astrocytomas. They retained publications in which the majority of reported cases included astrocytoma histology.

RESULTS

Twenty-nine previously published studies met the eligibility criteria, totaling 578 patients with spinal cord astrocytomas. The spinal level of intramedullary spinal cord tumors was predominantly cervical (53.8%), followed by thoracic (40.8%). Overall, resection was more common than biopsy, and GTR was slightly more commonly achieved than STR (39.7% vs 37.0%). The reported rates of GTR and STR rose markedly from 1984 to 2015. Patients with high-grade astrocytomas had markedly worse 5-year overall survival than patients with low-grade tumors. Patients receiving GTR may have better 5-year overall survival than those receiving STR.

CONCLUSIONS

The authors describe trends in the management of pediatric spinal cord astrocytomas and suggest a benefit of GTR over STR for 5-year overall survival.

A reproducible model of intramedullary spinal cord tumor in rats bearing RG2 cells

Intramedullary spinal cord tumors (IMSCTs) are lethal diseases to many patients. The lack of adequate animal model has hampered the development of novel treatments. In the current study, a rodent intramedullary glioma model is established to study IMSCT progression. Fischer 344 rats received a intramedullary implantation of RG2 glioma cells. The neurological state of each rat was evaluated on daily basis using the Basso, Beattie and Bresnahan (BBB) scale. Rats implanted with RG2 cells developed significant hind limb paraplegia 20 days after implantation. Magnetic resonance imaging (MRI) scans after three weeks revealed significant intramedullary RG2 tumors in the rats. Forty days post implantation, rats were sacrificed for histopathological examination. Neuro-imaging and HE staining cross sections confirmed intramedullary RG2 glioma cells invading to the spinal cord. Thus, our model displayed many of the same invasive characteristics as human IMSCTs. This model should be a reliable and reproducible methodology to correlate well with the features of human IMSCT.

[Contribution of temozolomide chemotherapy for intramedullary grade II spinal cord astrocytomas in adults: Our experience]

INTRODUCTION

Grade II intramedullary astrocytomas are rare tumors. Despite a well-defined role of adjuvant temozolomide chemotherapy for brain gliomas, the contribution of this therapy for intramedullary gliomas is not yet clearly defined.

METHOD

We retrospectively analyzed the data of 5 adult patients treated with temozolomide between 2008 and 2015 for a grade II intramedullary astrocytoma with progression after surgery.

RESULTS

Five patients from 19 to 70 years of age (median, 37years) underwent a second surgery for the progression of a grade II intramedullary astrocytoma (median progression-free survival 26months [8-90]). All tumors remained grade II. Due to a second clinical or/and radiological tumor progression, the patients were treated with temozolomide after a 37months median progression-free survival (5-66). All patients received at minimum 12 cycles (mean 14 ± 5; range 12-24) of temozolomide (150-200mg/m²/day, 5days/28days). All patients were alive after a 10-year median follow-up after diagnosis (6-13). All patients were able to walk except one, who was previously in McCormick autonomy grade IV before chemotherapy. The McCormick autonomy rating after temozolomide was stable for 4 patients and improved for 1 patient. The treatment was delayed once for hematological toxicity.

CONCLUSION

Temozolomide stabilized all 5 patients without any major toxicity. Based on this experience that needs to be confirmed, we consider that temozolomide should be envisaged within the therapeutic arsenal for progressive intramedullary grade II astrocytomas.

Management of holocord pilocytic astrocytomas in children and adolescents: an update

Holocord intramedullary low-grade astrocytomas in children and adolescents - involving most or all of the cervical and thoracic spinal cord - are a rare finding. Most of the tumors seem to be pilocytic astrocytomas. Surgical management strategies might not be as clear as in small and circumscribed intramedullary tumors. On the basis of 20 previously published cases and 3 own patients, we summarize and discuss possible treatment options and their risks and benefits. Surgery should be performed soon after establishment of the diagnosis, which per se is often delayed despite a long-standing presence of attributable symptoms or signs in most cases. Following multilevel laminotomy, excellent results can be achieved by electrophysiologically guided microsurgical tumor removal in a single-staged or multistaged approach. The surgical goal is resection as gross total as possible provided intraoperative monitoring indicates preservation of function. Small tumor remnants often remain stable in the due course. In case of unresectable regrowth or recurrence, chemotherapy or radiotherapy are the adjuvant treatment options.

Primary intramedullary tumors of the spinal cord

STUDY DESIGN

Clinically based systematic review.

OBJECTIVE

To define optimal clinical care for primary intramedullary spinal cord tumors using a systematic review with expert opinion.

METHODS

Focused questions on the treatment of primary intramedullary spinal cord tumors were refined by a panel of spine oncology surgeons, medical and radiation oncologist. Keyword were searched through Medline database and pertinent abstracts and manuscripts obtained. The quality of literature was rated as high, moderate, low, or very low. Using the GRADE evidence based review system the proposed questions were answered using the literature review and expert opinion. These treatment recommendations were then rated as either strong or weak based on the quality of evidence and clinical expertise.

RESULTS

The literature searches revealed low and very low quality evidence with no prospective or randomized studies. The MEDLINE search engine returned 9000 articles which was restricted to articles about human subjects and written in the English language. The subsequent search resulted in a return of: "spinal cord tumor" (5053), "ependymoma" (580), "astrocytoma" (420), and "glioma" (235) articles. Seventeen articles referenced timing of surgical intervention and symptomatology for intramedullary spinal cord tumors. One hundred fifty-eight chemotherapy and 183 radiation therapy articles for intramedullary spinal cord tumors were reviewed.

CONCLUSION

The most important factor in determining the IMSCT patient's long-term neurologic and functional outcome after surgery is the patient's preoperative neurologic status. However, this must be taken in the context of the underlying tumor histology. Therefore, resection is reserved for progressive neurologic decline and serial monitoring for asymptomatic individuals. Adjuvant therapy is an option for high grade astrocytomas (WHO grades 3-4).

Survival and functional outcome of childhood spinal cord low-grade gliomas. Clinical article

OBJECT

Intramedullary spinal cord low-grade gliomas (LGGs) are rare CNS neoplasms in pediatric patients, and there is little information on therapy for and outcome of these tumors in this population. Furthermore, most patient series combine adult and pediatric patients or high- and low-grade tumors, resulting in controversial data regarding optimal treatment of these children. To clarify these issues, the authors performed a regional population-based study of spinal cord LGGs in pediatric patients.

METHODS

All pediatric patients with LGGs treated during the MR imaging era (1985-2007) were identified in the comprehensive database of the Hospital for Sick Children in Toronto. Data on demographics, pathology, treatment details, and outcomes were collected.

RESULTS

Spinal cord LGGs in pediatric patients constituted 29 (4.6%) of 635 LGGs. Epidemiological and clinical data in this cohort were different than in patients with other spinal tumors and strikingly similar to data from pediatric patients with intracranial LGGs. The authors observed an age peak at 2 years and a male predominance in patients with these tumors. Histological testing revealed a Grade I astrocytoma in 86% of tumors. Although 5-year progression-free survival for the entire group was 48 +/- 9%, all patients were alive at a median follow-up of 8.2 years. Five-year progression-free survival was 88 +/- 13% for patients undergoing gross-total resection and 34 +/- 11% for those undergoing all other therapies, respectively (p = 0.02). Chemotherapy and radiation therapy showed similar efficacy, achieving sustained tumor control in most patients. However, this excellent survival rate was associated with an 83% rate of significant neurological and orthopedic sequelae.

CONCLUSIONS

This study provides basic data on the incidence, clinical course, and outcome of spinal cord LGGs in pediatric patients. The similarities between spinal and intracranial LGGs in pediatric patients showing excellent survival but high morbidity suggest that a less aggressive approach may be the preferable treatment option for these patients.

Holocord pilocytic astrocytoma--case report and review of the literature

Intramedullary glial neoplasms affecting the entire cord from the cervicomedullary junction to the conus are termed "holocord tumors" and those diagnosed as pilocytic astrocytoma are rare. Herein, we present a 13-year-old girl with a tumor extending from the cervicomedullary junction to the conus which was partially resected in a four-stage approach. Histopathological examination of all specimens resulted in diagnosis of a pilocytic astrocytoma. Although no signs of atypia were present, an elevated proliferative activity of endothelial vessels was noted. Residual parts of the tumor showed progress making additional surgery necessary. Therapy and its consequences are discussed and an overview of the literature of these rare longitudinally extensive intramedullary lesions is given.

Microsurgical removal of intramedullary spinal cord gliomas in a rat spinal cord decreases onset to paresis, an animal model for intramedullary tumor treatment

OBJECTIVE

Intramedullary spinal cord tumors (IMSCT) pose significant challenges given their recurrence rate and limited treatment options. Using our previously described rat model of IMSCT, we describe a technique for microsurgical tumor resection and present the functional and histopathological analysis of tumor progression.

METHODS

Twenty-four Fischer 344 rats were randomized into two groups. All animals received a 5-microl intramedullary injection of 9L gliosarcoma cells. Animals were evaluated daily for signs of paralysis using the Basso, Beattie, and Bresnahan (BBB) scale. Group 1 continued with daily assessments using the BBB scale following tumor implantation, but received no further treatment. Group 2 underwent surgical removal of intramedullary tumor on postoperative day five. At a BBB score less than 5 (e.g., functional paraplegia), all animals of both groups were killed and sent for histopathological analysis.

RESULTS

Group 1 had a median onset of functional hind limb paraplegia at 15 +/- 1.0 days. Group 2 had a median onset of hind limb paresis at 53 +/- 0.46 days. Hematoxylin-eosin cross-sections confirmed the presence of intramedullary 9L tumor invading the spinal cord in both groups.

CONCLUSION

Animals with 9L IMSCTs consistently developed hind limb paraplegia in a reliable and reproducible manner. Animals undergoing microsurgical resection of IMSCT had a significant delay in the onset of functional paraplegia compared to the untreated controls. These findings suggest that this model may mimic the behavior of IMSCTs following operative resection in humans and thus may be used to examine efficacy of new treatment options for high-grade intramedullary tumors.

Effects of neonatal handling on central noradrenergic and nitric oxidergic systems and reproductive parameters in female rats

Early-life environmental events that disrupt the mother-pup relationship may induce profound long-lasting changes on several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces sexual behavior and induces anovulatory estrous cycles in female rats. On the afternoon of proestrus, neonatally handled females show a reduced surge of luteinizing hormone (LH) and an increased content of gonadotropin-releasing hormone in the medial preoptic area (MPOA). In order to detect the possible causes for the reduced ovulation and sexual behavior, the present study aimed to analyze the effects of neonatal handling on noradrenaline (NA) and nitric oxide (NO) levels in the MPOA on the afternoon of proestrus. Neonatal handling reduced MHPG (NA metabolite) levels and MHPG/NA ratio in the MPOA, indicating decreased NAergic activity. Additionally, neonatal handling decreased NO levels, as measured by the metabolites (NO(x)), nitrite and nitrate in the same period. We may conclude that the neonatal handling procedure decreased activity of the NAergic and NOergic systems in the MPOA during proestrus, which is involved in the control of LH and FSH secretion, and this may possibly explain the anovulatory estrous cycles and reduced sexual behavior of the neonatally handled female rats.

Successful treatment of childhood intramedullary spinal cord astrocytomas with irinotecan and cisplatin

Childhood spinal cord astrocytomas are rare diseases, and their management is controversial. We report here our successful experience using irinotecan and cisplatin in three consecutive infants with progressing intramedullary astrocytomas. The first patient was a 16-month-old girl who presented with a grade III intramedullary astrocytoma that rapidly progressed after surgery and adjuvant chemotherapy. Weekly irinotecan (50 mg/m(2)) and cisplatin (30 mg/m(2)) for four consecutive weeks (one cycle) for a total of four cycles (I/C regimen) was used in order to avoid or delay radiotherapy. Radiological complete remission was achieved 10 months after completion of therapy, and 3.5 years after diagnosis the patient remains disease free. The second patient was a 19-month-old boy with a C3-T4 grade II intramedullary astrocytoma who received up-front vincristine and carboplatin for two months but remained clinically symptomatic. A followup MRI showed a larger tumor, and the patient was switched to the I/C regimen. A marked clinical improvement occurred after the first cycle, and MRI showed a very good partial remission at the end of therapy. At 16 months after diagnosis, the patient remains disease free. The third patient was a 10-month-old girl with a C2-T3 grade II intramedullary astrocytoma. She presented with severe pain that became steroid dependent during the month she was treated with the vincristine-carboplatin regimen. When she was switched to the I/C regimen, the clinical symptoms responded within days. MRI at the end of therapy showed a significant reduction in tumor size, and one year after diagnosis the patient remains symptom free. Using this I/C regimen for childhood intramedullary astrocytoma, we obtained remarkable clinicoradiological responses while avoiding the use of radiotherapy.

Intramedullary spinal cord tumors in children

INTRODUCTION

Pediatric intramedullary spinal cord tumors are rare and make up only a small percentage of all central nervous system neoplasms.

DISCUSSION

These neoplasms are predominantly benign histologically, regardless of size, with a large percentage being astrocytomas or gangliogliomas. Ependymomas, which are common in adults, are relatively uncommon in children. Contemporary management of these tumors has generated much controversy. These neoplasms occur primarily in the cervical region, with pain or a motor deficit as the chief complaint. Surgery on these neoplasms can safely be performed using modern surgical adjuncts such as the ultrasonic aspirator, contact laser and neurophysiological monitoring. A radical resection of these tumors results in a good long-term outcome, since the majority are histologically benign. Adjuvant radiation therapy should only be administered for high-grade or malignant tumors.

CONCLUSION

The majority of spinal cord tumors are benign; however, malignant tumors have a dismal outcome and surgery in these children should be limited to a conservative debulking. An attempt should be made for radical surgery in hope of avoiding radiation and chemotherapy for the benign tumors. Spinal deformity is a concern in these patients since 35% of children may require a stabilization procedure.