scholarly journals Maximum 11C-methionine PET uptake as a prognostic imaging biomarker for newly diagnosed and untreated astrocytic glioma

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Kosuke Nakajo ◽  
Takehiro Uda ◽  
Toshiyuki Kawashima ◽  
Yuzo Terakawa ◽  
Kenichi Ishibashi ◽  
...  
Keyword(s):  
Cox Regression ◽  
Surgical Excision ◽  
University Hospital ◽  
World Health ◽  
Imaging Biomarker ◽  
Normal Brain ◽  
Newly Diagnosed ◽  
Who Grade ◽  
Astrocytic Glioma ◽  
Grade Ii

AbstractThis study aimed whether the uptake of amino tracer positron emission tomography (PET) can be used as an additional imaging biomarker to estimate the prognosis of glioma. Participants comprised 56 adult patients with newly diagnosed and untreated World Health Organization (WHO) grade II–IV astrocytic glioma who underwent surgical excision and were evaluated by 11C-methionine PET prior to the surgical excision at Osaka City University Hospital from July 2011 to March 2018. Clinical and imaging studies were retrospectively reviewed based on medical records at our institution. Preoperative Karnofsky Performance Status (KPS) only influenced progression-free survival (hazard ratio [HR] 0.20; 95% confidence interval [CI] 0.10–0.41, p < 0.0001), whereas histology (anaplastic astrocytoma: HR 5.30, 95% CI 1.23–22.8, p = 0.025; glioblastoma: HR 11.52, 95% CI 2.27–58.47, p = 0.0032), preoperative KPS ≥ 80 (HR 0.23, 95% CI 0.09–0.62, p = 0.004), maximum lesion-to-contralateral normal brain tissue (LN max) ≥ 4.03 (HR 0.24, 95% CI 0.08–0.71, p = 0.01), and isocitrate dehydrogenase (IDH) status (HR 14.06, 95% CI 1.81–109.2, p = 0.011) were factors influencing overall survival (OS) in multivariate Cox regression. OS was shorter in patients with LN max ≥ 4.03 (29.3 months) than in patients with LN max < 4.03 (not reached; p = 0.03). OS differed significantly between patients with IDH mutant/LN max < 4.03 and patients with IDH mutant/LN max ≥ 4.03. LN max using 11C-methionine PET may be used in prognostic markers for newly identified and untreated WHO grade II–IV astrocytic glioma.

scholarly journals Maximum Lesion-To-Contralateral Normal Brain Tissue Ratio of 11C-Methionine PET as a Prognostic Imaging Biomarker for Newly Diagnosed and Untreated Astrocytic Glioma

2021 ◽  
Author(s):  
Kosuke Nakajo ◽  
Takehiro Uda ◽  
Toshiyuki Kawashima ◽  
Yuzo Terakawa ◽  
Kenichi Ishibashi ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Cox Regression ◽  
Surgical Excision ◽  
World Health ◽  
Imaging Biomarker ◽  
Normal Brain ◽  
Newly Diagnosed ◽  
Normal Brain Tissue ◽  
Astrocytic Glioma ◽  
Contralateral Normal Brain

Abstract Purpose: This study aimed whether the uptake of amino tracer positron emissiontomography (PET) can be used as an additional imaging biomarker to estimatethe prognosis of glioma.Methods: Participants comprised 56 adult patients with newly diagnosed and untreated World Health Organization (WHO) gradeⅡ-Ⅳ astrocytic glioma who underwent surgical excision and were evaluated by 11C-methionine PET prior to the surgical excision at Osaka City University Hospital from July 2011 to March 2018. Clinical and imaging studies were retrospectively reviewed based on medical records at our institution.Results: Preoperative Karnofsky Performance Status (KPS) only influenced progression-free survival (PFS) (hazard ratio [HR] 0.20; 95% confidence interval [CI] 0.10-0.41, p<0.0001), whereas histology (anaplastic astrocytoma: HR 5.30, 95%CI 1.23-22.8, p=0.025; glioblastoma: HR 11.52, 95%CI 2.27-58.47, p=0.0032), preoperative KPS≥80 (HR 0.23, 95%CI 0.09-0.62, p=0.004), maximum lesion-to-contralateral normal brain tissue (LN max)≥4.03 (HR 0.24, 95%CI 0.08-0.71, p=0.01), and isocitrate dehydrogenase (IDH) status (HR 14.06, 95%CI 1.81-109.2, p=0.011) were factors influencing overall survival (OS) in multivariate Cox regression. OS was shorter in patients with LN max≥ 4.03 (29.3 months) than in patients with LN max<4.03 (not reached; p=0.03). OS differed significantly between patients with IDH mutant/LN max<4.03 and patients with IDH mutant/LN max ≥4.03.Conclusions: LN max using 11C-methionine PET may be used in prognostic markers for newly identified and untreated WHO gradeⅡ-Ⅳ astrocytic glioma.

scholarly journals Maximum Lesion-to-contralateral Normal Brain Tissue Ration of 11C-methionine PET as a Prognostic Imaging Biomarker for Newly Diagnosed and Untreated Astrocytic Glioma

2021 ◽  
Author(s):  
Kosuke Nakajo ◽  
Takehiro Uda ◽  
Toshiyuki Kawashima ◽  
Yuzo Terakawa ◽  
Kenichi Ishibashi ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Cox Regression ◽  
Surgical Excision ◽  
World Health ◽  
Imaging Biomarker ◽  
Normal Brain ◽  
Newly Diagnosed ◽  
Normal Brain Tissue ◽  
Astrocytic Glioma ◽  
Contralateral Normal Brain

Abstract Purpose: This study aimed whether the uptake of amino tracer positron emission tomography (PET) can be used as an additional imaging biomarker to estimate the prognosis of glioma.Methods: Participants comprised 56 adult patients with newly diagnosed and untreated World Health Organization (WHO) gradeⅡ-Ⅳ astrocytic glioma who underwent surgical excision and were evaluated by 11C-methionine PET prior to the surgical excision at Osaka City University Hospital from July 2011 to March 2018. Clinical and imaging studies were retrospectively reviewed based on medical records at our institution.Results: Preoperative Karnofsky Performance Status (KPS) only influenced progression-free survival (PFS) (hazard ratio [HR] 0.20; 95% confidence interval [CI] 0.10-0.41, p<0.0001), whereas histology (anaplastic astrocytoma: HR 5.30, 95%CI 1.23-22.8, p=0.025; glioblastoma: HR 11.52, 95%CI 2.27-58.47, p=0.0032), preoperative KPS≥80 (HR 0.23, 95%CI 0.09-0.62, p=0.004), maximum lesion-to-contralateral normal brain tissue (LN max)≥4.03 (HR 0.24, 95%CI 0.08-0.71, p=0.01), and isocitrate dehydrogenase (IDH) status (HR 14.06, 95%CI 1.81-109.2, p=0.011) were factors influencing overall survival (OS) in multivariate Cox regression. OS was shorter in patients with LN max≥ 4.03 (29.3 months) than in patients with LN max<4.03 (not reached; p=0.03). OS differed significantly between patients with IDH mutant/LN max<4.03 and patients with IDH mutant/LN max ≥4.03.Conclusions: LN max using 11C-methionine PET may be used in prognostic markers for newly identified and untreated WHO gradeⅡ-Ⅳ astrocytic glioma.

scholarly journals The Role of Extent of Resection in IDH1 Wild-Type or Mutant Low-Grade Gliomas

Neurosurgery ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. 808-814 ◽  
Author(s):  
Toral Patel ◽  
Evan D Bander ◽  
Rachael A Venn ◽  
Tiffany Powell ◽  
Gustav Young-Min Cederquist ◽  
...  
Keyword(s):  
Cox Regression ◽  
Extent Of Resection ◽  
World Health ◽  
Low Grade ◽  
Wild Type ◽  
Who Grade ◽  
Cox Regression Analysis ◽  
Low Grade Gliomas ◽  
Grade Ii ◽  
The Impact

Abstract BACKGROUND Maximizing extent of resection (EOR) improves outcomes in adults with World Health Organization (WHO) grade II low-grade gliomas (LGG). However, recent studies demonstrate that LGGs bearing a mutation in the isocitrate dehydrogenase 1 (IDH1) gene are a distinct molecular and clinical entity. It remains unclear whether maximizing EOR confers an equivalent clinical benefit in IDH mutated (mtIDH) and IDH wild-type (wtIDH) LGGs. OBJECTIVE To assess the impact of EOR on malignant progression-free survival (MPFS) and overall survival (OS) in mtIDH and wtIDH LGGs. METHODS We performed a retrospective review of 74 patients with WHO grade II gliomas and known IDH mutational status undergoing resection at a single institution. EOR was assessed with quantitative 3-dimensional volumetric analysis. The effect of predictor variables on MPFS and OS was analyzed with Cox regression models and the Kaplan–Meier method. RESULTS Fifty-two (70%) mtIDH patients and 22 (30%) wtIDH patients were included. Median preoperative tumor volume was 37.4 cm3; median EOR of 57.6% was achieved. Univariate Cox regression analysis confirmed EOR as a prognostic factor for the entire cohort. However, stratifying by IDH status demonstrates that greater EOR independently prolonged MPFS and OS for wtIDH patients (hazard ratio [HR] = 0.002 [95% confidence interval {CI} 0.000-0.074] and HR = 0.001 [95% CI 0.00-0.108], respectively), but not for mtIDH patients (HR = 0.84 [95% CI 0.17-4.13] and HR = 2.99 [95% CI 0.15-61.66], respectively). CONCLUSION Increasing EOR confers oncologic and survival benefits in IDH1 wtLGGs, but the impact on IDH1 mtLGGs requires further study.

scholarly journals CODEL: phase III study of RT, RT + TMZ, or TMZ for newly diagnosed 1p/19q codeleted oligodendroglioma. Analysis from the initial study design

2020 ◽  
Author(s):  
Kurt A Jaeckle ◽  
Karla V Ballman ◽  
Martin van den Bent ◽  
Caterina Giannini ◽  
Evanthia Galanis ◽  
...  
Keyword(s):  
Cox Regression ◽  
Progression Free Survival ◽  
Initial Study ◽  
Phase Iii ◽  
World Health ◽  
Newly Diagnosed ◽  
Who Grade ◽  
Phase Iii Study ◽  
Grade 3 ◽  
Health Organization

Abstract Background We report the analysis involving patients treated on the initial CODEL design. Methods Adults (&gt;18) with newly diagnosed 1p/19q World Health Organization (WHO) grade III oligodendroglioma were randomized to radiotherapy (RT; 5940 centigray ) alone (arm A); RT with concomitant and adjuvant temozolomide (TMZ) (arm B); or TMZ alone (arm C). Primary endpoint was overall survival (OS), arm A versus B. Secondary comparisons were performed for OS and progression-free survival (PFS), comparing pooled RT arms versus TMZ-alone arm. Results Thirty-six patients were randomized equally. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients progressed, versus 37.5% (9/24) on the RT arms. PFS was significantly shorter in TMZ-alone patients compared with RT patients (hazard ratio [HR] = 3.12; 95% CI: 1.26, 7.69; P = 0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) on the RT arms. OS did not statistically differ between arms (comparison underpowered). After adjustment for isocitrate dehydrogenase (IDH) status (mutated/wildtype) in a Cox regression model utilizing IDH and RT treatment status as covariables (arm C vs pooled arms A + B), PFS remained shorter for patients not receiving RT (HR = 3.33; 95% CI: 1.31, 8.45; P = 0.011), but not OS ((HR = 2.78; 95% CI: 0.58, 13.22, P = 0.20). Grade 3+ adverse events occurred in 25%, 42%, and 33% of patients (arms A, B, and C). There were no differences between arms in neurocognitive decline comparing baseline to 3 months. Conclusions TMZ-alone patients experienced significantly shorter PFS than patients treated on the RT arms. The ongoing CODEL trial has been redesigned to compare RT + PCV versus RT + TMZ.

Adjuvant radiation versus observation with salvage radiation after gross-total resection of WHO grade II meningiomas: a propensity score–adjusted analysis

2021 ◽  
pp. 1-8
Author(s):  
Arbaz A. Momin ◽  
Pranay Soni ◽  
Jianning Shao ◽  
Amy S. Nowacki ◽  
John H. Suh ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Cox Regression ◽  
Adjuvant Radiation ◽  
Newly Diagnosed ◽  
Total Resection ◽  
Who Grade ◽  
Free Survival ◽  
Cox Regression Analysis ◽  
Initial Recurrence ◽  
Grade Ii

OBJECTIVE After gross-total resection (GTR) of a newly diagnosed WHO grade II meningioma, the decision to treat with radiation upfront or at initial recurrence remains controversial. A comparison of progression-free survival (PFS) between observation and adjuvant radiation fails to account for the potential success of salvage radiation, and a direct comparison of PFS between adjuvant and salvage radiation is hampered by strong selection bias against salvage radiation cohorts in which only more aggressive, recurrent tumors are included. To account for the limitations of traditional PFS measures, the authors evaluated radiation failure-free survival (RFFS) between two treatment strategies after GTR: adjuvant radiation versus observation with salvage radiation, if necessary. METHODS The authors performed a retrospective review of patients who underwent GTR of newly diagnosed WHO grade II meningiomas at their institution between 1996 and 2019. They assessed traditional PFS in patients who underwent adjuvant radiation, postoperative observation, and salvage radiation. For RFFS, treatment failure was defined as time from initial surgery to failure of first radiation. To assess the association between treatment strategy and RFFS while accounting for potential confounders, a multivariable Cox regression analysis adjusted for the propensity score (PS) and inverse probability of treatment weighted (IPTW) Cox regression analysis were performed. RESULTS A total of 160 patients underwent GTR and were included in this study. Of the 121 patients who underwent observation, 32 (26.4%) developed recurrence and required salvage radiation. PFS at 3, 5, and 10 years after observation was 75.1%, 65.6%, and 45.5%, respectively. PFS at 3 and 5 years after salvage radiation was 81.7% and 61.3%, respectively. Of 160 patients, 39 received adjuvant radiation, and 3- and 5-year PFS/RFFS rates were 86.1% and 59.2%, respectively. In patients who underwent observation with salvage radiation, if necessary, the 3-, 5-, and 10-year RFFS rates were 97.7%, 90.3%, and 87.9%, respectively. Both PS and IPTW Cox regression models demonstrated that patients who underwent observation with salvage radiation treatment, if necessary, had significantly longer RFFS (PS model: hazard ratio [HR] 0.21, p < 0.01; IPTW model: HR 0.21, p < 0.01). CONCLUSIONS In this retrospective, nonrandomized study, adjuvant radiation after GTR of a WHO II meningioma did not add significant benefit over a strategy of observation and salvage radiation at initial recurrence, if necessary, but results must be considered in the context of the limitations of the study design.

scholarly journals Extracranial metastases in secondary glioblastoma multiforme: a case report

BMC Neurology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jessica Rossi ◽  
Lucia Giaccherini ◽  
Francesco Cavallieri ◽  
Manuela Napoli ◽  
Claudio Moratti ◽  
...  
Keyword(s):  
Brain Lesion ◽  
Rare Event ◽  
Subsequent Development ◽  
World Health ◽  
Who Grade ◽  
Systemic Involvement ◽  
Grade Ii ◽  
The Stability ◽  
Health Organization ◽  
Extracranial Metastases

Abstract Background Glioblastoma (GBM) is known for its devastating intracranial infiltration and its unfavorable prognosis, while extracranial involvement is a very rare event, more commonly attributed to IDH wild-type (primary) GBM evolution. Case presentation We present a case of a young woman with a World Health Organization (WHO) grade II Astrocytoma evolved to WHO grade IV IDH mutant glioblastoma, with subsequent development of lymphatic and bone metastases, despite the favorable biomolecular pattern and the stability of the primary brain lesion. Conclusions Our case highlights that grade II Astrocytoma may evolve to a GBM and rarely lead to a secondary metastatic diffusion, which can progress quite rapidly; any symptoms referable to a possible systemic involvement should be carefully investigated.

scholarly journals Short-term outcomes associated with temozolomide vs. PCV chemotherapy for 1p/19q-codeleted WHO grade III anaplastic oligodendrogliomas: a national evaluation

2020 ◽  
Author(s):  
Nayan Lamba ◽  
Malia McAvoy ◽  
Vasileios K. Kavouridis ◽  
Timothy R. Smith ◽  
Mehdi Touat ◽  
...  
Keyword(s):  
Cox Regression ◽  
Long Term Results ◽  
National Database ◽  
Newly Diagnosed ◽  
First Line ◽  
Short Term ◽  
Who Grade ◽  
Cox Regression Analysis ◽  
Pcv Chemotherapy ◽  
Grade Iii

AbstractPURPOSEThe optimal chemotherapy regimen between temozolomide (TMZ) and procarbazine, lomustine, and vincristine (PCV) remains uncertain for newly-diagnosed anaplastic oligodendroglioma (AO). We therefore addressed this question using a national database.METHODSPatients newly-diagnosed with 1p/19q-codeleted W.H.O. grade III AO between 2010-2016 were identified from the National Cancer Database. Predictors of receiving first-line single-agent TMZ vs. multi-agent PCV were assessed by multivariable logistic regression. Overall survival (OS) was estimated by Kaplan-Meier techniques and evaluated by multivariable Cox regression.RESULTS1,360 AO patients were identified: 74.5% (n=1,013) treated with TMZ, 9.6% (n=131) with PCV, and 15.9% (n=216) with no chemotherapy in the first-line setting. In multivariable logistic analysis, PCV utilization increased from 2010 to 2016 (OR=1.38/year, 95%CI: 1.22-1.56, p<0.001) and was less commonly utilized in privately insured patients (OR=0.38 vs. uninsured, 95%CI: 0.15-0.97, p=0.04). In survival analyses (33.1% reached endpoint), there was no difference in unadjusted OS between TMZ (5yr-OS 60.1%, 95%CI: 55.9-64.1) and PCV (5yr-OS 61.1%, 95%CI: 45.6-73.5; p=0.42). There remained no OS difference between TMZ and PCV in the 75.9% (n=1,032) of AO patients that also received radiotherapy (p=0.51), in the Cox regression analysis adjusted by age, extent of resection, and radiotherapy (TMZ vs. PCV HR=1.31, 95%CI: 0.83-2.08, p=0.24), and in subgroup analyses that incorporate KPS or MGMT status.CONCLUSIONSIn a national database of AOs managed in the ‘real-world’ setting, there is no difference in the short-term mortality between first-line TMZ and PCV chemotherapy. These findings provide preliminary data while we await the long-term results from the CODEL trial.

scholarly journals Huge heterogeneity in survival in a subset of adult patients with resected, wild-type isocitrate dehydrogenase status, WHO grade II astrocytomas

2019 ◽  
Vol 130 (4) ◽  
pp. 1289-1298 ◽  
Author(s):  
Gaëtan Poulen ◽  
Catherine Gozé ◽  
Valérie Rigau ◽  
Hugues Duffau
Keyword(s):  
Radiation Therapy ◽  
Malignant Transformation ◽  
Isocitrate Dehydrogenase ◽  
Adult Patients ◽  
World Health ◽  
Wild Type ◽  
Who Grade ◽  
Grade Ii ◽  
The Individual

OBJECTIVEWorld Health Organization grade II gliomas are infiltrating tumors that inexorably progress to a higher grade of malignancy. However, the time to malignant transformation is quite unpredictable at the individual patient level. A wild-type isocitrate dehydrogenase (IDH-wt) molecular profile has been reported as a poor prognostic factor, with more rapid progression and a shorter survival compared with IDH-mutant tumors. Here, the oncological outcomes of a series of adult patients with IDH-wt, diffuse, WHO grade II astrocytomas (AII) who underwent resection without early adjuvant therapy were investigated.METHODSA retrospective review of patients extracted from a prospective database who underwent resection between 2007 and 2013 for histopathologically confirmed, IDH-wt, non–1p19q codeleted AII was performed. All patients had a minimum follow-up period of 2 years. Information regarding clinical, radiographic, and surgical results and survival were collected and analyzed.RESULTSThirty-one consecutive patients (18 men and 13 women, median age 39.6 years) were included in this study. The preoperative median tumor volume was 54 cm3 (range 3.5–180 cm3). The median growth rate, measured as the velocity of diametric expansion, was 2.45 mm/year. The median residual volume after surgery was 4.2 cm3 (range 0–30 cm3) with a median volumetric extent of resection of 93.97% (8 patients had a total or supratotal resection). No patient experienced permanent neurological deficits after surgery, and all patients resumed a normal life. No immediate postoperative chemotherapy or radiation therapy was given. The median clinical follow-up duration from diagnosis was 74 months (range 27–157 months). In this follow-up period, 18 patients received delayed chemotherapy and/or radiotherapy for tumor progression. Five patients (16%) died at a median time from radiological diagnosis of 3.5 years (range 2.6–4.5 years). Survival from diagnosis was 77.27% at 5 years. None of the 21 patients with a long-term follow-up greater than 5 years have died. There were no significant differences between the clinical, radiological, or molecular characteristics of the survivors relative to the patients who died.CONCLUSIONSHuge heterogeneity in the survival data for a subset of 31 patients with resected IDH-wt AII tumors was observed. These findings suggest that IDH mutation status alone is not sufficient to predict risk of malignant transformation and survival at the individual level. Therefore, the therapeutic management of AII tumors, in particular the decision to administer early adjuvant chemotherapy and/or radiation therapy following surgery, should not solely rely on routine molecular markers.

Surgery for Diffuse WHO Grade II Gliomas: Volumetric Analysis of a Multicenter Retrospective Cohort From the German Study Group for Intraoperative Magnetic Resonance Imaging

Neurosurgery ◽  
2019 ◽  
Vol 86 (1) ◽  
pp. E64-E74 ◽  
Author(s):  
Moritz Scherer ◽  
Hajrulla Ahmeti ◽  
Constantin Roder ◽  
Florian Gessler ◽  
Christine Jungk ◽  
...  
Keyword(s):  
Regression Models ◽  
Cox Regression ◽  
Study Group ◽  
Incomplete Resection ◽  
Who Grade ◽  
German Study ◽  
Significant Survival ◽  
Idh Mutations ◽  
Grade Ii ◽  
Who Grade Ii Gliomas

Abstract BACKGROUND In diffuse WHO grade II gliomas (LGG), the extent of resection (EOR) required to achieve significant survival benefits remains elusive. OBJECTIVE To evaluate the association of residual volume (RV) and EOR with progression-free survival (PFS) or overall survival (OS) in LGG in a retrospective, multicenter series by the German study group of intraoperative MRI (GeSGIM). METHODS Consecutive cases were retrospectively assessed from 5 centers. Tumors were volumetrically quantified before and after surgery, and clinical data were analyzed, including IDH mutations and neurologic deficits. Kaplan–Meier estimates, accelerated failure time models (AFT), and multivariate Cox regression models were calculated to identify determinants of survival. RESULTS A total of 140 cases were analyzed. Gross total resection (GTR) was associated with significantly longer PFS compared to any incomplete resection (P = .009). A significant survival disadvantage was evident even for small (&gt;0-5 ml) residuals and increased for moderate (&gt;5-20 ml) and large remnants (&gt;20 ml) P = .001). Accordingly, PFS increased continuously for 20% incremental steps of EOR (P &lt; .001). AFT models supported the notion of a continuous association of RV and EOR with PFS. Multivariate Cox regression models confirmed RV (P = .01) and EOR (P = .005) as continuous prognosticators of PFS. Univariate analysis showed significant associations of RV and EOR with OS. CONCLUSION Our data support the hypothesis of a continuous relationship of RV and EOR with survival for LGG with superiority seen for GTR. Hence, GTR should be achieved whenever safely feasible, and resections should be maximized whenever tumor has to be left behind to spare function.

scholarly journals Mitotic Index Thresholds Do Not Predict Clinical Outcome for IDH-Mutant Astrocytoma

2019 ◽  
Vol 78 (11) ◽  
pp. 1002-1010 ◽  
Author(s):  
Rebecca A Yoda ◽  
Troy Marxen ◽  
Lauren Longo ◽  
Chibawanye Ene ◽  
Hans-Georg Wirsching ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Cox Regression ◽  
Predictive Accuracy ◽  
Homozygous Deletion ◽  
World Health ◽  
Mitotic Figure ◽  
Lower Grade ◽  
Histological Grading ◽  
Who Grade ◽  
Diagnostic Uncertainty

Abstract Current histological grading recommendations for isocitrate dehydrogenase (IDH)-mutant astrocytoma are imprecise and not reliably predictive of patient outcome, while somatic copy number alterations are emerging as important prognostic biomarkers. One explanation for this relative underperformance of histological grading is that current criteria to distinguish World Health Organization (WHO) grade III anaplastic astrocytomas from lower-grade diffuse astrocytomas (WHO grade II) are vague (“increased mitotic activity”). This qualitative approach ensures diagnostic uncertainty and a broad “gray zone” where both diffuse and anaplastic designations can reasonably be assigned. Thus, we hypothesized that interobserver variability and lack of defined mitotic thresholds for IDH-mutant astrocytomas underlies poor predictive accuracy of current histologic grading approaches. To test this hypothesis, we quantified total mitotic figures and maximum mitotic activity per 10 high-powered fields in an institutional cohort of IDH-mutant astrocytomas. In our cohort, there was no mitotic activity threshold that was reflective of progression-free or overall survival (OS). Furthermore, in a multivariate Cox regression model consisting of mitotic activity, molecular markers, and clinical characteristics, only CDKN2A homozygous deletion was identified as a relevant variant for poor OS. We conclude that lack of defined mitotic figure thresholds may not contribute to underperformance of histological grading for IDH-mutant astrocytomas.

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