Diffuse gliomas and secondary glioblastomas (GBMs) that develop from low-grade gliomas are a common and incurable class of brain tumor. Mutations in the metabolic enzyme glioblastomas (IDH1) represent a distinguishing feature of low-grade gliomas and secondary GBMs. IDH1 mutations are one of the most common and earliest detectable genetic alterations in low-grade diffuse gliomas, and evidence supports this mutation as a driver of gliomagenesis. Here, the authors highlight the biological consequences of IDH1 mutations in gliomas, the clinical and therapeutic/diagnostic implications, and the molecular subtypes of these tumors. They also explore, in brief, the non-IDH1–mutated gliomas, including primary GBMs, and the molecular subtypes and drivers of these tumors. A fundamental understanding of the diversity of GBMs and lower-grade gliomas will ultimately allow for more effective treatments and predictors of survival.
Sameer Agnihotri, Kenneth D. Aldape and Gelareh Zadeh
Matthew D. Smyth, Lawrence Pitts, Robert K. Jackler and Kenneth D. Aldape
Case report and review of the literature
Robert J. Bohinski, Ehud Mendel, Kenneth D. Aldape and Laurence D. Rhines
✓ Solitary fibrous tumor is a spindle cell tumor deriving from mesenchymal cells that arises most commonly in the pleura. Only very recently has this tumor been reported in the spine. A solitary fibrous tumor strongly resembles other spindle cell neoplasms of the spine and may be an unrecognized entity if not routinely considered in the differential diagnosis of spinal neoplasms. The authors report an unusual intra- and extramedullary location for a solitary fibrous tumor of the cervical spine. Findings in this case and a comprehensive review of the literature indicate that solitary fibrous tumors can originate from various spinal anatomical substrates and mimic both intra- and extramedullary tumor types.
Margaret Wrensch, James L. Fisher, Judith A. Schwartzbaum, Melissa Bondy, Mitchel Berger and Kenneth D. Aldape
In this paper the authors highlight recent findings from molecular epidemiology studies of glioma origin and prognosis and suggest promising paths for future research. The reasons for variation in glioma incidence according to time period of diagnosis, sex, age, ancestry and ethnicity, and geography are poorly understood, as are factors that affect prognosis. High-dose therapeutic ionizing irradiation and rare mutations in highly penetrant genes associated with certain rare syndromes—the only two established causes of glioma—can be called upon to explain few cases. Both familial aggregation of gliomas and the inverse association of allergies and immune-related conditions with gliomas have been shown consistently, but the explanations for these associations are inadequately developed or unknown. Several bio-markers do predict prognosis, but only evaluation of loss of 1p and 19q in oligodendroglial tumors are incorporated in clinical practice. Ongoing research focuses on classifying homogeneous groups of tumors on the basis of molecular markers and identifying inherited polymorphisms that may influence survival or risk. Because most cases of glioma have yet to furnish either an environmental or a genetic explanation, the greatest potential for discovery may lie in genomic studies in conjunction with continued evaluation of environmental and developmental factors. Large sample sizes and multidisciplinary teams with expertise in neuropathology, genetics, epidemiology, functional genomics, bioinformatics, biostatistics, immunology, and neurooncology are required for these studies to permit exploration of potentially relevant pathways and modifying effects of other genes or exposures, and to avoid false-positive findings. Improving survival rates for patients harboring astrocytic tumors will probably require many randomized clinical trials of novel treatment strategies.
Susan L. McGovern, Kenneth D. Aldape, Mark F. Munsell, Anita Mahajan, Franco DeMonte and Shiao Y. Woo
Despite a favorable outcome for most patients with WHO Grade I meningiomas, a subset of these patients will have recurrent or progressive disease that advances to a higher grade and requires increasingly aggressive therapy. The goal of this study was to identify clinical characteristics associated with the recurrence of benign meningiomas and their acceleration to atypical and malignant histological types.
Records of 216 patients with WHO Grade I, II, or III meningioma that were initially treated between 1965 and 2001 were retrospectively reviewed. Median follow-up was 7.2 years.
Patients with non–skull base cranial meningiomas (82 of 105 [78%]) were more likely to have undergone a gross-total resection than patients with skull base meningiomas (32 of 78 [41%]; p < 0.001). Consequently, patients with Grade I non–skull base cranial meningiomas had better 5-year recurrence-free survival (69%) than patients with Grade I skull base meningiomas (56%) or Grade II or III tumors at any site (50%; p = 0.005). Unexpectedly, patients with non–skull base tumors who experienced a recurrence (8 of 22 [36%]) were more likely than patients with skull base tumors (1 of 19 [5%]) to have a higher grade tumor at recurrence (p = 0.024). Furthermore, the median MIB-1 labeling index of Grade I non–skull base cranial meningiomas (2.60%) was significantly higher than that of Grade I skull base tumors (1.35%; p = 0.016).
Cranial meningiomas that occur outside of the skull base are more likely to have a higher MIB-1 labeling index and recur with a higher grade than those within the skull base, suggesting that non–skull base cranial tumors may have a more aggressive biology than skull base tumors.
Alireza Mansouri, George Klironomos, Shervin Taslimi, Alex Kilian, Fred Gentili, Osaama H. Khan, Kenneth Aldape and Gelareh Zadeh
The objective of this study was to identify the natural history and clinical predictors of postoperative recurrence of skull base and non–skull base meningiomas.
The authors performed a retrospective hospital-based study of all patients with meningioma referred to their institution from September 1993 to January 2014. The cohort constituted both patients with a first-time presentation and those with evidence of recurrence. Kaplan-Meier curves were constructed for analysis of recurrence and differences were assessed using the log-rank test. Cox proportional hazard regression was used to identify potential predictors of recurrence.
Overall, 398 intracranial meningiomas were reviewed, including 269 (68%) non–skull base and 129 (32%) skull base meningiomas (median follow-up 30.2 months, interquartile range [IQR] 8.5–76 months). The 10-year recurrence-free survival rates for patients with gross-total resection (GTR) and subtotal resection (STR) were 90% and 43%, respectively. Skull base tumors were associated with a lower proliferation index (0.041 vs 0.062, p = 0.001), higher likelihood of WHO Grade I (85.3% vs 69.1%, p = 0.003), and younger patient age (55.2 vs 58.3 years, p = 0.01). Meningiomas in all locations demonstrated an average recurrence rate of 30% at 100 months of follow-up. Subsequently, the recurrence of skull base meningiomas plateaued whereas non–skull base lesions had an 80% recurrence rate at 230 months follow-up (p = 0.02). On univariate analysis, a prior history of recurrence (p < 0.001), initial WHO grade following resection (p < 0.001), and the inability to obtain GTR (p < 0.001) were predictors of future recurrence. On multivariate analysis a prior history of recurrence (p = 0.02) and an STR (p < 0.01) were independent predictors of a recurrence. Assessing only patients with primary presentations, STR and WHO Grades II and III were independent predictors of recurrence (p < 0.001 for both).
Patients with skull base meningiomas present at a younger age and have less aggressive lesions overall. Extent of resection is a key predictor of recurrence and long-term follow-up of meningiomas is necessary, especially for non–skull base tumors. In skull base meningiomas, recurrence risk plateaus approximately 100 months after surgery, suggesting that for this specific cohort, follow-up after 100 months can be less frequent.
Wael Hassaneen, Nicholas B. Levine, Dima Suki, Abhijit L. Salaskar, Alessandra de Moura Lima, Ian E. McCutcheon, Sujit S. Prabhu, Frederick F. Lang, Franco DeMonte, Ganesh Rao, Jeffrey S. Weinberg, David M. Wildrick, Kenneth D. Aldape and Raymond Sawaya
Multiple craniotomies have been performed for resection of multiple brain metastases in the same surgical session with satisfactory outcomes, but the role of this procedure in the management of multifocal and multicentric glioblastomas is undetermined, although it is not the standard approach at most centers.
The authors performed a retrospective analysis of data prospectively collected between 1993 and 2008 in 20 patients with multifocal or multicentric glioblastomas (Group A) who underwent resection of all lesions via multiple craniotomies during a single surgical session. Twenty patients who underwent resection of solitary glioblastoma (Group B) were selected to match Group A with respect to the preoperative Karnofsky Performance Scale (KPS) score, tumor functional grade, extent of resection, age at time of surgery, and year of surgery. Clinical and neurosurgical outcomes were evaluated.
In Group A, the median age was 52 years (range 32–78 years); 70% of patients were male; the median preoperative KPS score was 80 (range 50–100); and 9 patients had multicentric glioblastomas and 11 had multifocal glioblastomas. Aggressive resection of all lesions in Group A was achieved via multiple craniotomies in the same session, with a median extent of resection of 100%. Groups A and B were comparable with respect to all the matching variables as well as the amount of tumor necrosis, number of cysts, and the use of intraoperative navigation. The overall median survival duration was 9.7 months in Group A and 10.5 months in Group B (p = 0.34). Group A and Group B (single craniotomy) had complication rates of 30% and 35% and 30-day mortality rates of 5% (1 patient) and 0%, respectively.
Aggressive resection of all lesions in selected patients with multifocal or multicentric glioblastomas resulted in a survival duration comparable with that of patients undergoing surgery for a single lesion, without an associated increase in postoperative morbidity. This finding may indicate that conventional wisdom of a minimal role for surgical treatment in glioblastoma should at least be questioned.