Low-grade astrocytoma--a retrospective analysis of 102 patients

The 2021 WHO Classification of Tumors of the Central Nervous System: An update on pediatric low-grade gliomas and glioneuronal tumors

The 2021 5th edition of the WHO Classification of Tumors of the Central Nervous System reflects the discovery of genetic alterations underlying many central nervous system (CNS) neoplasms. Insights gained from technologic advances and novel applications in molecular diagnostics, including next‐generation sequencing and DNA methylation‐based profiling, coupled with the recognition of clinicopathologic correlates, have prompted substantial changes to CNS tumor classification; this is particularly true for pediatric low‐grade gliomas and glioneuronal tumors (pLGG/GNTs). The 2021 WHO now classifies gliomas, glioneuronal tumors and neuronal tumors into 6 families, three of which encompass pLGG/LGNTs: “Pediatric type diffuse low‐grade gliomas,” “circumscribed astrocytic gliomas,” and “glioneuronal and neuronal tumors.” Among these are six newly recognized tumor types: “diffuse astrocytoma, MYB or MYBL1‐altered”; “polymorphous low grade neuroepithelial tumor of the young (PLNTY)”; “diffuse low‐grade glioma‐MAPK altered”; “Diffuse glioneuronal tumor with oligodendroglioma‐like features and nuclear clusters (DGONC)”; “myxoid glioneuronal tumor (MGT)”; and “multinodular and vacuolating neuronal tumor (MVNT).” We review these newly recognized entities in the context of general changes to the WHO schema, discuss implications of the new classification for treatment of pLGG/LGNT, and consider strategies for molecular testing and interpretation.

Subventricular zone predicts high velocity of tumor expansion and poor clinical outcome in patients with low grade astrocytoma

OBJECTIVE

The aim of this study is to clarify the association between subventricular zone (SVZ) involvement and velocity of diametric expansion(VDE) in patients with low-grade astrocytoma and also assessed the clinical outcome of those patients.

MATERIALS AND METHODS

A total of 168 adult patients with newly diagnosed supratentorial low-grade astrocytoma were studied retrospectively.

RESULTS

There were 73 patients had SVZ involvement. Patients with SVZ involvement(7.16 ± 6.53 mm/y) had a higher VDE than patients without SVZ involvement(4.38 ± 5.35 mm/y). VDE was modeled as a categorical variable(＜4, ≥4 and, ＜8, ≥8 and, ＜12, ≥12 mm/y). Logistic regression showed that SVZ involvement was associated with high VDE after adjusting by confounding variables. On the univariate analysis, the results showed that tumor involved with SVZ, VDE ≥ 4 mm/y, VDE ≥ 8 mm/y, and VDE ≥ 8 mm/y were significant predictors of a shorter OS, progression-free survival (PFS) and malignant progression-free survival (MFS)(all p ＜0.05). The categorical variables of VDE (＜4 mm/y, ≥4 mm/y and, ＜8 mm/y, ≥8 mm/y and, ＜12 mm/y, ≥12 mm/y) were adjusted by confounding variables in multivariate analysis, respectively. The results indicated that VDE ≥ 8 mm/y, VDE ≥ 12 mm/y were worse prognostic factors for OS, while VDE ≥ 4 mm/y, VDE ≥ 8 mm/y and VDE ≥ 12 mm/y were related to shorter PFS and MFS. In addition, SVZ involvement was prognostic factors in predicting OS and PFS except MFS.

CONCLUSION

Our results demonstrated that SVZ involvement predicted high VDE and worse clinical outcome, and high VDE was associated with poor prognosis in patients with low-grade astrocytoma.

The role of radiotherapy in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

QUESTIONS

(1) What is the optimal role of external beam radiotherapy in the management of adult patients with newly diagnosed low-grade glioma (LGG) in terms of improving outcome (i.e., survival, complications, seizure control or other reported outcomes of interest)? (2) Which radiation strategies (dose, timing, fractionation, stereotactic radiation, brachytherapy, chemotherapy) improve outcomes compared to standard external beam radiation therapy in the initial management of low grade gliomas in adults? (3) Do specific factors (e.g., age, volume, extent of resection, genetic subtype) identify subgroups with better outcomes following radiation therapy than the general population of adults with newly diagnosed low-grade gliomas?

TARGET POPULATION

These recommendations apply to adults with newly diagnosed diffuse LGG.

RECOMMENDATIONS

OUTCOMES IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level I Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong progression free survival, irrespective of extent of resection. Level II Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults as an equivalent alternative to observation in preserving cognitive function, irrespective of extent of resection. Level III Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults to improve seizure control in patients with epilepsy and subtotal resection. Level III Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong overall survival in patients with subtotal resection. Level III Consideration of the risk of radiation induced morbidity, including cognitive decline, imaging abnormalities, metabolic dysfunction and malignant transformation, is recommended when the delivery of radiotherapy is selected in the management of newly diagnosed low-grade glioma in adults. STRATEGIES OF RADIOTHERAPY IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA: Level I Lower dose radiotherapy is recommended as an equivalent alternative to higher dose immediate postoperative radiotherapy (45-50.4 vs. 59.4-64.8 Gy) in the management of newly diagnosed low-grade glioma in adults with reduced toxicity. Level III Delaying radiotherapy until recurrence or progression is recommended as an equivalent alternative to immediate postoperative radiotherapy in the management of newly diagnosed low-grade glioma in adults but may result in shorter time to progression. Level III The addition of chemotherapy to radiotherapy is not recommended over whole brain radiotherapy alone in the management of low-grade glioma, as it provides no additional survival benefit. Level III Limited-field radiotherapy is recommended over whole brain radiotherapy in the management of low-grade glioma. Level III Either stereotactic radiosurgery or brachytherapy are recommended as acceptable alternatives to external radiotherapy in selected patients. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level II It is recommended that age greater than 40 years, astrocytic pathology, diameter greater than 6 cm, tumor crossing the midline and preoperative neurological deficit be considered as negative prognostic indicators when predicting overall survival in adult low grade glioma patients treated with radiotherapy. Level II It is recommended that smaller tumor size, extent of surgical resection and higher mini-mental status exam be considered as positive prognostic indicators when predicting overall survival and progression free survival in patients in adult low grade glioma patients treated with radiotherapy. Level III It is recommended that seizures at presentation, presence of oligodendroglial histological component and 1p19q deletion (along with additional relevant factors-see Table 1) be considered as positive prognostic indicators when predicting response to radiotherapy in adults with low grade gliomas. Level III It is recommended that increasing age, decreasing performance status, decreasing cognition, presence of astrocytic histological component (along with additional relevant factors (see Tables 1, 2) be considered as negative prognostic indicators when predicting response to radiotherapy.

Prognostic factors and survival patterns in pediatric low-grade gliomas over 4 decades

BACKGROUND

This study reports changes in long-term survival after the introduction of modern imaging in pediatric patients with low-grade gliomas (LGGs).

METHODS

Records from 351 consecutive pediatric patients diagnosed with LGG between 1970 and 2009 at Mayo Clinic Rochester were reviewed and divided into diagnosis before (group I: 1970 to 1989) and after (group II: 1990 to 2009) postoperative magnetic resonance imaging became regularly used in pediatric LGG.

RESULTS

Median progression-free survival (PFS) and overall survival (OS) were not reached. Overall, 10-year PFS was 62% and OS was 90%. On multivariate analysis, improved PFS was associated with gross total resection (GTR; P<0.0001) and postoperative radiation therapy (RT; P<0.0001). In those undergoing less than GTR, PFS was improved with RT, nearing rates of patients receiving GTR (P=0.12). On multivariate analysis, higher OS was associated with GTR (P<0.0001) and pilocytic histology (P=0.03). Group II had fewer headaches, fewer sensory/motor symptoms, less postoperative RT, and more GTRs. OS and PFS were not different between the groups.

CONCLUSIONS

This large series of pediatric LGG patients with long-term follow-up found no significant changes in OS or PFS over time. Overall, GTR was associated with improved OS and PFS. RT was associated with an improvement in PFS, with the greatest benefit seen in patients undergoing less than GTR.

Outcomes of multidisciplinary management in pediatric low-grade gliomas

PURPOSE

To evaluate the outcomes in pediatric low-grade gliomas managed in a multidisciplinary setting.

METHODS AND MATERIALS

We conducted a single-institution retrospective study of 181 children with Grade I-II gliomas. Log-rank and stepwise Cox proportional hazards models were used to analyze freedom from progression (FFP) and overall survival (OS).

RESULTS

Median follow-up was 6.4 years. Thirty-four (19%) of patients had neurofibromatosis Type 1 (NF1) and because of their favorable prognosis were evaluated separately. In the 147 (81%) of patients without NF1, actuarial 7-year FFP and OS were 67 ± 4% (standard error) and 94 ± 2%, respectively. In this population, tumor location in the optic pathway/hypothalamus was associated with worse FFP (39% vs. 76%, p < 0.0003), but there was no difference in OS. Age ≤5 years was associated with worse FFP (52% vs. 75%, p < 0.02) but improved OS (97% vs. 92%, p < 0.05). In those with tissue diagnosis, gross total resection (GTR) was associated with improved 7-year FFP (81% vs. 56%, p < 0.02) and OS (100% vs. 90%, p < 0.03). In a multivariate model, only location in the optic pathway/hypothalamus predicted worse FFP (p < 0.01). Fifty patients received radiation therapy (RT). For those with less than GTR, adjuvant RT improved FFP (89% vs. 49%, p < 0.003) but not OS. There was no difference in OS between patient groups given RT as adjuvant vs. salvage therapy. In NF1 patients, 94% of tumors were located in the optic pathway/hypothalamus. With a conservative treatment strategy in this population, actuarial 7-year FFP and OS were 73 ± 9% and 100%, respectively.

CONCLUSIONS

Low-grade gliomas in children ≤5 years old with tumors in the optic pathway/hypothalamus are more likely to progress, but this does not confer worse OS because of the success of salvage therapy. When GTR is not achieved, adjuvant RT improves FFP but not OS. Routine adjuvant RT can be avoided and instead reserved as salvage.

Survival and long-term health and cognitive outcomes after low-grade glioma

Long-term morbidity for children with low-grade glioma (LGG) requires exposure-specific characterization. Overall survival (OS) and progression-free survival (PFS) were estimated for 361 children diagnosed with LGG between 1985 and 2007 at a single institution. Five-year survivors (n = 240) received risk-based clinical assessment. Cumulative incidence of late effects 15 years from diagnosis were estimated. Risk factors for adverse health were identified using Fine and Gray's approach to Cox's proportional hazards model, accounting for death as a competing risk. OS at 15 years was 86% (95% confidence interval [CI] 82%-90%), and PFS was 55% (95% CI 51%-58%). Among the 240 5-year survivors, the 5-, 10-, and 15-year cumulative incidence of adverse outcomes included blindness: 10%, 13%, and 18%, respectively; hearing loss: 8%, 14%, and 22%; obesity/overweight: 18%, 35%, and 53%; hyperinsulinism: 1%, 5%, and 24%; growth hormone deficiency: 13%, 27%, and 29%;thyroid hormone deficiency: 16%, 28%, and 33%; and adrenocorticotropic hormone (ACTH) deficiency: 12%, 22%, and 26%. Multivariable models demonstrated radiation therapy to be a significant independent predictor of hearing loss, growth hormone deficiency, abnormal thyroid function, and ACTH deficiency. Diencephalic location was a statistically significant independent risk factor for blindness, growth hormone deficiency, abnormal thyroid function, and ACTH deficiency. Among the 182 5-year survivors assessed for intellectual function, 34% had an intelligence quotient (IQ) below average (<85), associated with younger age at diagnosis, epilepsy, and shunt placement. Survivors of childhood LGG experience substantial long-term adverse effects that continue to increase well beyond the 5-year survival time point.

Pediatric low-grade gliomas

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.

Outcome analysis of childhood low-grade astrocytomas

BACKGROUND

We aimed to determine the long-term natural history of low-grade astrocytomas (LGA) in children, with respect to pathology, and to evaluate influence of treatment on survival.

PATIENTS AND METHODS

A consecutive cohort of patients < or =21 years with surgically confirmed LGA from 1965 to 1996 was assembled. All available pathology specimens were reviewed, masked to original diagnosis, patient data, and neuroimaging.

RESULTS

Two hundred seventy-eight children (160 males; mean age 9.1 years; tumor location: 77 cerebrum, 62 cerebellum, 51 hypothalamic, 30 thalamus, 9 ventricle, 40 brainstem, and 9 spine) were assessed. Among 246 specimens reviewed, diagnoses were 135 pilocytic astrocytoma (PA), 27 diffuse astrocytoma (DA), 75 unclassifiable well-differentiated astrocytoma (NOS), and 9 subependymal giant cell astrocytoma. At 5 and 10 years from initial surgery, for all LGA overall survival (OS) was 87% and 83%, while progression-free survival (PFS) was 55% and 42%, respectively. Original pathology diagnoses did not predict PFS (P = 0.47), but reviewed diagnoses were significantly associated with PFS (P = 0.007). Reviewed diagnoses were highly associated with OS (P < 0.0001), with 5-year OS for PA 96%, DA 48%, and NOS 86%; these differences remained significant when stratified by location or extent of resection. Among patients with residual tumor after surgery, 5-year PFS was 48% with observation alone (n = 114), no different (P = 0.32) from that achieved with immediate irradiation (n = 86).

CONCLUSION

LGA, particularly PA, have excellent long-term OS. While tumor location and resection extent affect outcome, pathologic diagnosis when carefully interpreted significantly influences long-term survival. Immediate postoperative irradiation does not confer an advantage in delaying first progression in children with residual PA.

The role of up-front radiation therapy for incompletely resected pediatric WHO grade II low-grade gliomas

The purpose of this study was to assess the impact of early radiation therapy and extent of surgical resection on progression-free survival (PFS) and overall survival (OS) in children with WHO grade II low-grade gliomas (LGGs). We conducted a historical cohort study of 90 patients, ages 21 or younger, diagnosed with WHO grade II LGGs between 1970 and 1995. Median follow-up for surviving patients was 9.4 years (range, 0.5-22.6 years). Tests for variables correlating with OS and PFS were conducted by using log-rank tests and Cox proportional hazards models. Eleven patients underwent gross total resections (GTRs), 43 had subtotal resections, and 34 underwent biopsy only at diagnosis. Two patients underwent biopsy at time of recurrence. Of the 90 patients, 52 received radiation as part of their initial therapy following diagnosis (early-RT group). The overall five-year PFS and OS rates +/- SE were 56% +/- 5% and 90% +/- 3%, respectively. Ten-year PFS and OS rates were 42% +/- 6% and 81% +/- 5%, respectively. For patients older than three years and without GTRs, administration of early radiation did not appear to influence PFS or OS (P = 0.98 and P = 0.40, respectively; log-rank test). This was confirmed by multivariate analyses (P = 0.95 and P = 0.33 for PFS and OS, respectively). Of the 11 patients with GTRs, disease progressed in only two, and all were alive with no evidence of disease at last follow-up. Patients who underwent GTRs had significantly longer PFS (P = 0.02), but did not have significantly improved OS. Excellent long-term survival rates were achieved for children with WHO grade II LGGs. We were unable to demonstrate a benefit for administering radiation as part of initial treatment. An outcome benefit was seen with greater extent of resection.

[Perfusion measurement using the T2* contrast media dynamics in neuro-oncology. Physical basics and clinical applications]

Perfusion imaging in the central nervous system (CNS) is mostly performed using the first-pass dynamic susceptibility-weighted contrast-enhanced (DSC) MRI. The first-pass of a contrast bolus in brain tissue is monitored by a series of T2*-weighted MR images. The susceptibility effect of the paramagnetic contrast agent leads to a signal loss that can be converted, using the principles of the indicator dilution theory, into an increase of the contrast agent concentration. From these data, parameter maps of cerebral blood volume (CBV) and flow (CBF) can be derived. Regional CBF and CBV values can be obtained by region-of-interest analysis. This review article describes physical basics of DSC MRI and summarizes the literature of DSC MRI in neurooncological issues.Studies, all with relatively limited patient numbers, report that DSC MRI is useful in the preoperative diagnosis of gliomas, CNS-lymphomas, and solitary metastases, as well as in the differentiation of these neoplastic lesions from infections and tumor-like manifestations of demyelinating disease. Additionally, DSC MRI is suitable for determining glioma grade and regions of active tumor growth which should be the target of stereotactic biopsy. After therapy, DSC MRI helps better assessing the tumor response to therapy, residual tumor after therapy, and possible treatment failure and therapy-related complications, such as radiation necrosis. The preliminary results show that DSC MRI is a diagnostic tool depicting regional variations in microvasculature of normal and diseased brains.

Treatment outcomes and prognostic factors in patients with supratentorial low-grade gliomas

Low-grade gliomas account for 10-15% of all adult primary intracranial tumours. Currently, there is no consensus on the treatment strategy for low-grade gliomas. This study was designed to evaluate the treatment outcomes, prognostic factors and radiation-related late complications, as well as to assess whether or not post-operative radiotherapy has benefit on local control and overall survival in this population. We retrospectively reviewed 93 consecutive adult patients with supratentorial low-grade gliomas diagnosed at our institution from July 1985 to December 1997. All patients underwent surgical intervention and 60 of them received post-operative radiotherapy. With a median follow-up of 110 months for surviving patients, the 5-year overall and progression-free survival rates were 57% and 47%, respectively. 46 patients experienced local progression of disease during the follow-up period. In multivariate analysis, age at diagnosis, extent of surgery and post-operative Karnofsky performance status showed independent prognostic significance for progression-free and overall survival rates. Post-operative radiotherapy had independent prognostic value for progression-free survival. This analysis has changed our practice and we suggest that aggressive surgical resection and post-operative radiotherapy might be considered for patients with low-grade gliomas. Further efforts should be made to optimize radiotherapy techniques and to integrate new therapeutic modalities.

Astrocytomas in young dogs

Primary brain tumors are not commonly reported in young dogs; however, they are the second most common cancer in children. Astrocytomas are the majority of these tumors. This report presents three cases of astrocytomas in young dogs, indicating a possible higher incidence than what is currently held. When suspected, it is recommended that biopsy or surgical excision be performed to further characterize and grade the tumor and, if appropriate, guide treatment.

Treatment of low-grade diffuse astrocytomas by surgery and human fibroblast interferon without radiation therapy

Low-grade diffuse astrocytomas are slowly growing tumors with a relatively long overall survival. However, a substantial proportion undergoes dedifferentiation to a more malignant phenotype. Considerable controversy exists as to the best therapeutic management for patients with such tumors. Over the past decade, we have applied human fibroblast interferon (HFIF) therapy without radiation therapy to low-grade astrocytomas. We investigated 28 patients with WHO grade II astrocytomas of the cerebral hemispheres treated by surgery plus HFIF therapy. The overall response rate to the HFIF therapy was 36%. All side-effects of HFIF were transient, tolerable and manageable. The 5-year progression free survival and overall survival probabilities were 65% and 96%, respectively. Although our data from small cohort of patients may have modest value, our results suggest that HFIF may be useful in treating low-grade diffuse astrocytomas.