Surgical management of incidentally discovered low-grade gliomas

Influence of supratotal resection on overall survival and progression of tumor in gliomas grade 2 and 3: a systematic review and meta-analysis

BACKGROUND

Recurrence after resection is a major factor in poor prognosis for grade 2 and 3 gliomas. The effect of Supratotal Resection (STR) on recurrence timing remains debated. This meta-analysis examines overall survival (OS) and tumor progression in grade 2 and 3 gliomas after supratotal resection.

METHODS

Studies on patients with grade II and III gliomas who underwent supratotal resection were included, with comparisons to subtotal, partial, and total resections. The primary outcomes were overall survival (OS) and tumor progression, while secondary outcomes included return-to-work (RTW) rates, malignant transformations and cognitive impairments.

RESULTS

We included 954 patients from 8 studies, mean age was 39 (± 16) years. The mean OS for patients undergoing supratotal resection was 17.45 (95% CI: 3.39 to 89.74, p < 0.05) compared to TR. The OR for RTW in the STR group versus TR group was 0.12 (95% CI: 0.01 to 1.28, p = 0.08). Tumor progression OR was, no statistical significantly, 0.15 (95% CI: 0.00 to 38.00, p = 0.5), and the likelihood of malignancy was reduced 0.03 (95% CI: 0.01 to 0.18, p < 0.01) compared to the TR group. In the immediate pos-operatory, when comparing STR with TR, the OR of language impairment was 5.47 (95% CI: 2.73 to 10.97, p < 0.01) and cognitive impairment was 0.38 (95% CI: 0.17 to 0.58). During the follow-up, the OR of language impairment was 0.68 (95% CI: 0.25 to 1.81, p = 0.44) and cognitive impairment was 0.34 (95% CI: 0.03 to 3.61, p = 0.37) comparing STR with TR.

CONCLUSION

Patients with grade 2 and 3 gliomas undergoing supratotal resection showed significantly higher overall survival, fewer malignant transformations and language impairments in immediate pos-operatory. While there was a trend towards higher return-to-work rates, progression of tumor and better cognitive status during the follow-up, it was not statistically significant. Further studies are needed for definitive conclusions.

CLINICAL TRIAL NUMBER

Not applicable.

Prognostic Factors of Low-Grade Gliomas in Adults

Adult low-grade gliomas are a rare and aggressive pathology of the central nervous system. Some of their characteristics contribute to the patient's life expectancy and to their management. This study aimed to characterize and identify the main prognostic factors of low-grade gliomas. The six-year retrospective study statistically analyzed the demographic, imaging, and morphogenetic characteristics of the patient group through appropriate parameters. Immunohistochemical tests were performed: IDH1, Ki-67, p53, and Nestin, as well as FISH tests on the CDKN2A gene and 1p/19q codeletion. The pathology was prevalent in females, with patients having an average age of 56.31 years. The average tumor volume was 41.61 cm³, producing a midline shift with an average of 7.5 mm. Its displacement had a negative impact on survival. The presence of a residual tumor resulted in decreased survival and is an independent risk factor for mortality. Positivity for p53 identified a low survival rate. CDKN2A mutations were an independent risk factor for mortality. We identified that a negative prognosis is influenced by the association of epilepsy with headache, tumor volume, and immunoreactivity to IDH1 and p53. Independent factors associated with mortality were midline shift, presence of tumor residue, and CDKN2A gene deletions and amplifications.

Modern surgical management of incidental gliomas

Purpose

Gliomas are the most common primary tumors of the central nervous system and are categorized by the World Health Organization into either low-grade (grades 1 and 2) or high-grade (grades 3 and 4) gliomas. A subset of patients with glioma may experience no tumor-related symptoms and be incidentally diagnosed. These incidental low-grade gliomas (iLGG) maintain controversial treatment course despite scientific advancements. Here we highlight the recent advancements in classification, neuroimaging, and surgical management of these tumors.

Methods

A review of the literature was performed. The authors created five subtopics of focus: histological criteria, diagnostic imaging, surgical advancements, correlation of surgical resection and survival outcomes, and clinical implications.

Conclusions

Alternating studies suggest that these tumors may experience higher mutational rates than their counterparts. Significant progress in management of gliomas, regardless of the grade, has been made through modern neurosurgical treatment modalities, diagnostic neuroimaging, and a better understanding of the genetic composition of these tumors. An optimal treatment approach for patients with newly diagnosed iLGG remains ill-defined despite multiple studies arguing in favor of safe maximal resection. Our review emphasizes the not so benign nature of incidental low grade glioma and further supports the need for future studies to evaluate survival outcomes following surgical resection.

The clinical characteristics and outcomes of incidentally discovered glioblastoma

OBJECTIVE

With an increase in the number of imaging examinations and the development of imaging technology, a small number of glioblastomas (GBMs) are identified by incidental radiological images. These incidentally discovered glioblastomas (iGBMs) are rare, and their clinical features are not well understood. Here, we investigated the clinical characteristics and outcomes of iGBM.

METHODS

Data of newly diagnosed iGBM patients who were treated at our institution between August 2005 and October 2019 were reviewed. An iGBM was defined as a GBM without a focal sign, discovered on radiological images obtained for reasons unrelated to the tumor. Kaplan-Meier analysis was performed to calculate progression-free survival (PFS) and overall survival (OS).

RESULTS

Of 315 patients with newly diagnosed GBM, four (1.3%) were classified as having iGBM. Health screening was the most common reason for tumor discovery (75.0%). The preoperative Karnofsky performance status score was 100 in three patients. Tumors were found on the right side in three cases. The mean volume of preoperative enhanced tumor lesion was 16.8 cm³. The median duration from confirmation of an enhanced lesion to surgery was 13.5 days. In all cases, either total (100%) or subtotal (95-99%) resections were achieved. The median PFS and OS were 10.5 and 20.0 months, respectively.

CONCLUSIONS

The iGBMs were often small and in the right non-eloquent area, and the patients had good performance status. We found that timely therapeutic intervention provided iGBM patients with favorable outcomes. This report suggests that early detection of GBM may lead to a better prognosis.

Prevalence of incidental meningiomas and gliomas on MRI: a meta-analysis and meta-regression analysis

BACKGROUND

The chance of incidentally detecting brain tumors is increasing as the utilization of magnetic resonance imaging (MRI) becomes more prevalent. In this background, knowledge is accumulating in relation to the prediction of their clinical sequence. However, their prevalence-especially the prevalence of glioma-has not been adequately investigated according to age, sex, and region.

METHOD

We systematically reviewed the articles according to the PRISMA statement and calculated the prevalence of meningiomas and diffuse gliomas in adults using a generalized linear mixed model. Specifically, the differences related to age, sex, and region were investigated.

RESULTS

The pooled prevalence of incidental meningiomas in MRI studies was 0.52% (95% confidence interval (CI) [0.34-0.78]) in 37,697 individuals from 36 studies. A meta-regression analysis showed that the prevalence was significantly higher in elderly individuals, women, and individuals outside Asia; this remained statistically significant in the multivariate meta-regression analysis. The prevalence reached to 3% at 90 years of age. In contrast, the prevalence of gliomas in 30,918 individuals from 18 studies was 0.064% (95%CI [0.040 - 0.104]). The meta-regression analysis did not show a significant relationship between the prevalence and age, male sex, or region. The prevalence of histologically confirmed glioma was 0.026% (95%CI [0.013-0.052]).

CONCLUSIONS

Most of meningiomas, especially those in elderlies, remained asymptomatic, and their prevalence increased with age. However, the prevalence of incidental gliomas was much lower and did not increase with age. The number of gliomas that developed and the number that reached a symptomatic stage appeared to be balanced.

Pediatric and Adult Low-Grade Gliomas: Where Do the Differences Lie?

Two thirds of pediatric gliomas are classified as low-grade (LGG), while in adults only around 20% of gliomas are low-grade. However, these tumors do not only differ in their incidence but also in their location, behavior and, subsequently, treatment. Pediatric LGG constitute 65% of pilocytic astrocytomas, while in adults the most commonly found histology is diffuse low-grade glioma (WHO II), which mostly occurs in eloquent regions of the brain, while its pediatric counterpart is frequently found in the infratentorial compartment. The different tumor locations require different skillsets from neurosurgeons. In adult LGG, a common practice is awake surgery, which is rarely performed on children. On the other hand, pediatric neurosurgeons are more commonly confronted with infratentorial tumors causing hydrocephalus, which more often require endoscopic or shunt procedures to restore the cerebrospinal fluid flow. In adult and pediatric LGG surgery, gross total excision is the primary treatment strategy. Only tumor recurrences or progression warrant adjuvant therapy with either chemo- or radiotherapy. In pediatric LGG, MEK inhibitors have shown promising initial results in treating recurrent LGG and several ongoing trials are investigating their role and safety. Moreover, predisposition syndromes, such as neurofibromatosis or tuberous sclerosis complex, can increase the risk of developing LGG in children, while in adults, usually no tumor growth in these syndromes is observed. In this review, we discuss and compare the differences between pediatric and adult LGG, emphasizing that pediatric LGG should not be approached and managed in the same way as adult LCG.

Brain low-grade gliomas with high-grade spinal localization. Report of a clinical case and systematic literature review

INTRODUCTION

Oncological aggressiveness and the ability to present distant localizations are known in high-grade gliomas (HGGs), but the knowledge about the possible aggressiveness of LGGs is scarce, especially concerning possible spinal localization.

EVIDENCE ACQUISITION

A systematic search of LGGs with spinal localization on the three primary online databases (PubMed/MEDLINE, Embase, and Cochrane) was conducted. We included adult patients with histological diagnosis of intracranial LGG and specified WHO grade showing a remote spinal localization during follow-up. Additionally, we present a case of a left temporal LGG presenting a spinal localization fourteen years after the first appearance. We compared the survival rates of LGGs in our series with those of LGGs without spinal localizations.

EVIDENCE SYNTHESIS

Seven articles dealing with the subject and eight patients were considered (including our case), with a mean age at diagnosis of 42.25 years (range 26-69 years). The mean latency between a diagnosis of intracranial LGGs and a spinal localization occurrence was 7.37 years (range 2-14 years), and an increased WHO grade of the spinal localization compared to the brain LGG was observed in all patients. There was no sign of intracranial progression at the time of spinal glioma diagnosis in four cases, including ours. Survival at ten years was 28% against a 10-year survival rate of 65-71% for LGGs without distant localization, as reported in the literature.

CONCLUSIONS

Spinal metastasis of intracranial LGGs is an adverse prognostic factor. Surgical violation of ventricles can play a role in the pathophysiology of CSF spread of tumor cells in LGGs.

The benefit of early surgery on overall survival in incidental low grade glioma patients: a multicenter study

BACKGROUND

The role of surgery for incidentally discovered diffuse low-grade gliomas (iLGGs) is debatable and poorly documented in current literature.

OBJECTIVE

The aim was to identify factors that influence survival for patients that underwent surgical resection of iLGGs in a large multicenter population.

METHODS

Clinical, radiological, and surgical data were retrospectively analyzed in 267 patients operated for iLGG from 4 neurosurgical Centers. Univariate and multivariate analyses were performed to identify predictors of overall survival (OS) and tumor recurrence (TR).

RESULTS

The OS rate was 92.41%. The 5- and 10-year estimated OS rates were 98.09% and 93.2% respectively. OS was significantly longer for patients with a lower preoperative tumor volume (p=0.001) and higher extent of resection (EOR) (p=0.037), regardless the WHO defined molecular class (p=0.2). In the final model, OS was influenced only by the preoperative tumor volume (p=0.006), while TR by early surgery (p=0.028). A negative association was found between preoperative tumor volumes and EOR (rs = -0.44, p<0.001).The median preoperative tumor volume was 15 cm 3. The median EOR was 95%. Total or supratotal resection of FLAIR abnormality was achieved in 61.62% of cases.Second surgery was performed in 26.22%. The median time between surgeries was 5.5 years. Histological evolution to high grade glioma was detected in 22.85% of cases (16/70). Permanent mild deficits were observed in 3.08% of cases.

CONCLUSIONS

This multicenter study confirms the results of previous studies investigating surgical management of iLGGs and thereby strengthens the evidence in favour of early surgery for these lesions.