Favorable long-term outcome of low-grade oligodendrogliomas irrespective of 1p/19q status when treated without radiotherapy

Rise of oligodendroglioma hypermutator phenotype from a subclone harboring TP53 mutation after TMZ treatment

Oligodendrogliomas characterized and defined by 1p/19q co-deletion are slowly growing tumors showing better prognosis than astrocytomas. TP53 mutation is rare in oligodendrogliomas while the vast majority of astrocytomas harbor the mutation, making TP53 mutation mutually exclusive with 1p/19q codeletion in lower grade gliomas virtually. We report a case of 51-year-old woman with a left fronto-temporal oligodendroglioma that contained a small portion with a TP53 mutation, R248Q, at the initial surgery. On a first, slow-growing recurrence 29 months after radiation and nitrosourea-based chemotherapy, the patient underwent TMZ chemotherapy. The recurrent tumor responded well to TMZ but developed a rapid progression after 6 cycles as a malignant hypermutator tumor with a MSH6 mutation. Most of the recurrent tumor lacked typical oligodendroglioma morphology that was observed in the primary tumor, while it retained the IDH1 mutation and 1p/19q co-deletion. The identical TP53 mutation observed in the small portion of the primary tumor was universal in the recurrence. This case embodied the theoretically understandable clonal expansion of the TP53 mutation with additional mismatch repair gene dysfunction leading to hypermutator phenotype. It thus indicated that TP53 mutation in oligodendroglioma, although not common, may play a critical role in the development of hypermutator after TMZ treatment.

A single institution retrospective analysis on survival based on treatment paradigms for patients with anaplastic oligodendroglioma

Introduction

Anaplastic oligodendrogliomas are high-grade gliomas defined molecularly by 1p19q co-deletion. There is no curative therapy, and standard of care includes surgical resection followed by radiation and chemotherapy. However, the benefit of up-front radiation with chemotherapy compared to chemotherapy alone has not been demonstrated in a randomized control trial. Given the potential long-term consequences of radiation therapy, such as cognitive impairment, arteriopathy, endocrinopathy, and hearing/visual impairment, there is an effort to balance longevity with radiation toxicity.

Methods

We performed a retrospective single institution analysis of survival of patients with anaplastic oligodendroglioma over 20 years.

Results

159 patients were identified as diagnosed with an anaplastic oligodendroglioma between 1996 and 2016. Of those, 40 patients were found to have AO at original diagnosis and had documented 1p19q co-deletion with a median of 7.1 years of follow-up (range: 0.6–16.7 years). After surgery, 45 % of patients were treated with radiation and chemotherapy at diagnosis, and 50 % were treated with adjuvant chemotherapy alone. The group treated with chemotherapy alone had a trend of receiving more cycles of chemotherapy than patients treated with radiation and chemotherapy upfront (p = 0.051). Median overall survival has not yet been reached. The related risk of progression in the upfront, adjuvant chemotherapy only group was almost 5-fold higher than the patients who received radiation and chemotherapy (hazard ratio = 4.85 (1.74–13.49), p = 0.002). However, there was no significant difference in overall survival in patients treated with upfront chemotherapy compared to patients treated upfront with chemotherapy and radiation (p = 0.8). Univariate analysis of age, KPS, extent of resection, or upfront versus delayed radiation was not associated with improved survival.

Conclusions

Initial treatment with adjuvant chemotherapy alone, rather than radiation and chemotherapy, may be an option for some patients with anaplastic oligodendroglioma, as it is associated with similar overall survival despite shorter progression free survival.

Tumor recurrence patterns after surgical resection of intracranial low-grade gliomas

INTRODUCTION

Tumor recurrence patterns after resection of intracranial low-grade gliomas (LGG) generally remain obscured. The objective of the present retrospective study was their multifaceted analysis, evaluation of associated factors, and assessment of impact on prognosis.

METHODS

Study group comprised 81 consecutive adult patients (46 men and 35 women; median age, 37 years) with recurrent diffuse astrocytomas (DA; 51 cases) and oligodendrogliomas (OD; 30 cases). The median length of follow-up after primary surgery was 6.7 years.

RESULTS

Early (within 2 years after primary surgery) and non-early (> 2 years after primary surgery) recurrence was noted in 23 (28%) and 58 (72%) cases, respectively. Fast (≤ 6 months) and slow ( > 6 months) radiological progression of relapse was noted in 31 (38%) and 48 (59%) cases, respectively. Tumor recurrence was local and non-local in 71 (88%) and 10 (12%) cases, respectively. Recurrence patterns have differed in OD, IDH1-mutant DA, and IDH wild-type DA. Early onset, fast radiological progression, and non-local site of relapse had statistically significant negative impact on overall survival of patients and were often associated with malignant transformation of the tumor (38 cases). However, in subgroup with extent of resection ≥ 90% (56 cases) no differences in recurrence characteristics were found between 3 molecularly defined groups of LGG.

CONCLUSIONS

Recurrence patterns after resection of LGG show significant variability, differ in distinct molecularly defined types of tumors, and demonstrate definitive impact on prognosis. Aggressive resection at the time of primary surgery may result in more favorable characteristics of recurrence at the time of its development.

Eighty percent survival rate at 15 years for 1p/19q co-deleted oligodendroglioma treated with upfront chemotherapy irrespective of tumor grade

INTRODUCTION

Chromosomes 1p/19q co-deletion is a robust molecular marker for the diagnosis of oligodendroglial tumors, and has been included in the 2016 WHO modified classification. Although treatment for oligodendroglioma is controversial, upfront chemotherapy is regarded as one of the treatment option for low-grade tumor. We have treated all the 1p/19q co-deleted oligodendrogliomas, both grades II and III, with upfront chemotherapy without conventional radiotherapy for 20 years. The clinical experience from this trial may be suggestive for understanding of the biological features of oligodendroglioma with 1p/19q co-deletion toward precision medicine.

METHODS

This is a long-term retrospective data of the non-selected patients with 1p/19q co-deleted oligodendrogliomas uniformly treated with up-front chemotherapy. Seventy consecutive patients (48 with grade II and 22 with grade III tumors) were included.

RESULTS

The median follow-up period was 13 years. The 5-, 10-, and 15-year progression-free survival (PFS) rates were 85.7%, 54.8%, and 31.5%, respectively, and the median PFS was 146 months. In most cases, tumor recurrence was remained local and could be controlled by salvage surgery and/or chemotherapy. The 5-, 10-, and 15-year overall survival (OS) rates were 96.8%, 88.7%, and 80.0%, respectively, and the median OS was not reached. These survival data compared favorably with previous large clinical studies employing radiotherapy. Tumor grades based on World Health Organization classification, extent of surgery, and age affected neither PFS nor OS. Most patients were able to return to their premorbid social life.

CONCLUSIONS

The long-term results drawn from 20-years of single institution experience show that the patients with 1p/19q co-deleted oligodendrogliomas can be successfully treated with up-front chemotherapy alone without compromising OS.

Clair WH, Lightner DD, Villano JL. Comprehensive evaluation of treatment and outcomes of low-grade diffuse gliomas

Background

Low-grade gliomas affect younger adults and carry a favorable prognosis. They include a variety of biological features affecting clinical behavior and treatment. Having no guidelines on treatment established, we aim to describe clinical and treatment patterns of low-grade gliomas across the largest cancer database in the United States.

Methods

We analyzed the National Cancer Database from 2004 to 2015, for adult patients with a diagnosis of World Health Organization grade II diffuse glioma.

Results

We analyzed 13,621 cases with median age of 41 years. Over 56% were male, 88.4% were white, 6.1% were black, and 7.6% Hispanic. The most common primary site location was the cerebrum (79.9%). Overall, 72.2% received surgery, 36.0% radiation, and 27.3% chemotherapy. Treatment combinations included surgery only (41.5%), chemotherapy + surgery (6.6%), chemotherapy only (3.1%), radiation + chemotherapy + surgery (10.7%), radiation + surgery (11.5%), radiation only (6.1%), and radiotherapy + chemotherapy (6.7%). Radiation was more common in treatment of elderly patients, 1p/19q co-deletion (37.3% versus 24.3%, p<0.01), and tumors with midline location. Median survival was 11 years with younger age, 1p/19q co-deletion, and cerebrum location offered survival advantage.

Conclusions

Tumor location, 1p/19q co-deletion, and age were the main determinants of treatment received and survival, likely reflecting tumor biology differences. Any form of treatment was preferred over watchful waiting in the majority of the patients (86.1% versus 8.1%). Survival of low-grade gliomas is higher than previously reported in the majority of clinical trials and population-based analyses. Our analysis provides a real world estimation of treatment decisions, use of molecular data, and outcomes.

The role of initial chemotherapy for the treatment of adults with diffuse low grade glioma : A systematic review and evidence-based clinical practice guideline

TARGET POPULATION

Adult patients (older than 18 years of age) with newly diagnosed World Health Organization (WHO) Grade II gliomas (Oligodendroglioma, astrocytoma, mixed oligoastrocytoma).

QUESTION

Is there a role for chemotherapy as adjuvant therapy of choice in treatment of patients with newly diagnosed low-grade gliomas?

RECOMMENDATIONS

LEVEL III

Chemotherapy is recommended as a treatment option to postpone the use of radiotherapy, to slow tumor growth and to improve progression free survival (PFS), overall survival (OS) and clinical symptoms in adult patients with newly diagnosed LGG.

QUESTION

Who are the patients with newly diagnosed LGG that would benefit the most from chemotherapy?

RECOMMENDATION

LEVEL III

Chemotherapy is recommended as an optional component alone or in combination with radiation as the initial adjuvant therapy for all patients who cannot undergo gross total resection (GTR) of a newly diagnosed LGG. Patient with residual tumor >1 cm on post-operative MRI, presenting diameter of >4 cm or older than 40 years of age should be considered for adjuvant therapy as well.

QUESTION

Are there tumor markers that can predict which patients can benefit the most from initial treatment with chemotherapy?

RECOMMENDATION

LEVEL III

The addition of chemotherapy to standard RT is recommended in LGG patients that carry IDH mutation. In addition, temozolomide (TMZ) is recommended as a treatment option to slow tumor growth in patients who harbor the 1p/19q co-deletion.

QUESTION

How soon should the chemotherapy be started once the diagnosis of LGG is confirmed?

RECOMMENDATION

There is insufficient evidence to make a definitive recommendation on the timing of starting chemotherapy after surgical/pathological diagnosis of LGG has been made. However, using the 12 weeks mark as the latest timeframe to start adjuvant chemotherapy is suggested. It is recommended that patients be enrolled in properly designed clinical trials to assess the timing of chemotherapy initiation once diagnosis is confirmed for this target population.

QUESTION

What chemotherapeutic agents should be used for treatment of newly diagnosed LGG?

RECOMMENDATION

There is insufficient evidence to make a recommendation of one particular regimen. Enrollment of subjects in properly designed trials comparing the efficacy of these or other agents is recommended so as to determine which of these regimens is superior.

QUESTION

What is the optimal duration and dosing of chemotherapy as initial treatment for LGG?

RECOMMENDATION

Insufficient evidence exists regarding the duration of any specific cytotoxic drug regimen for treatment of newly diagnosed LGG. Enrollment of subjects in properly designed clinical investigations assessing the optimal duration of this therapy is recommended.

QUESTION

Should chemotherapy be given alone or in conjunction with RT as initial therapy for LGG?

RECOMMENDATION

Insufficient evidence exists to make recommendations in this regard. Hence, enrollment of patients in properly designed clinical trials assessing the difference between chemotherapy alone, RT alone or a combination of them is recommended.

QUESTION

Should chemotherapy be given in addition to other type of adjuvant therapy to patients with newly diagnosed LGG?

RECOMMENDATION

Level II: It is recommended that chemotherapy be added to the RT in patients with unfavorable LGG to improve their progression free survival.

IDH1 mutation is prognostic for diffuse astrocytoma but not low-grade oligodendrogliomas in patients not treated with early radiotherapy

Despite accumulating knowledge regarding molecular backgrounds, the optimal management strategy for low-grade gliomas remains controversial. One reason is the marked heterogeneity in the clinical course. To establish an accurate subclassification of low-grade gliomas, we retrospectively evaluated isocitrate dehydrogenase-1 (IDH1) mutation in clinical specimens of diffuse astrocytomas (DA) and oligodendroglial tumors separately. No patients were treated with early radiotherapy, and modified PCV chemotherapy was used for postoperative residual tumors or recurrence in oligodendroglial tumors. Immunohistochemical evaluation of IDH status, p53 status, O(6)-methylguanine methyltransferase expression, and the MIB-1 index were performed. The 1p and 19q status was analyzed with fluorescence in situ hybridization. Ninety-four patients were followed for a median period of 8.5 years. For DAs, p53 was prognostic for progression- free survival (PFS) and IDH1 was significant for overall survival (OS) with multivariate analysis. In contrast, for oligodendroglial tumors, none of the parameters was significant for PFS or OS. Thus, the significance of IDH1 mutation is not clear in oligodendroglial tumors that are homogeneously indolent and chemosensitive. In contrast, DAs are heterogeneous tumors including some potentially malignant tumors that can be predicted by examining the IDH1 mutation status.

Indications for Treatment: Is Observation or Chemotherapy Alone a Reasonable Approach in the Management of Low-Grade Gliomas?

The treatment of newly diagnosed low-grade gliomas remains controversial. Recently published results from the long-term follow-up of Radiation Therapy Oncology Group (RTOG) trial 9802 demonstrated medically meaningful and statistically significant survival prolongation by adding chemotherapy with procarbazine, lomustine (CCNU), and vincristine after radiotherapy (RT) vs RT alone for "high"-risk patients (median 13.3 vs 7.8 years, hazard ratio = 0.59, P = 0.03). However, in the 17 years since that trial was launched, there have been advances in the understanding of low-grade gliomas biology and patient heterogeneity, an increased recognition of late neurocognitive injury from early RT, and the emergence of temozolomide as an alternative chemotherapy to procarbazine, lomustine (CCNU), and vincristine. These and other changes in the treatment landscape make the applicability of results from RTOG 9802 to all patients less clear. Moreover, in some patients, especially those at the lowest risk for early disease progression, deferred RT in favor of active surveillance or chemotherapy alone may remain a reasonable treatment approach.

Oligodendroglial tumors

Oligodendroglial tumors are relatively rare, comprising approximately 5% of all glial neoplasms. Oligodendroglial tumor patients have a better prognosis than those with astrocytic neoplasms, and patients with tumors that contain 1p/19q co-deletions or IDH-1 mutations appear to be particularly sensitive to treatment. In the past decade, scientists have made significant progress in the unraveling the molecular events that relate to the pathogenesis of these neoplasms. There is considerable excitement resulting from the recent reports from two large phase III randomized trials (European Organization for Research and Treatment of Cancer [EORTC] 26951 and Radiation Therapy Oncology Group [RTOG] 9402), which disclosed that patients with newly diagnosed 1p/19q co-deleted anaplastic oligodendroglial tumors have a 7+year increase in median overall survival following chemoradiation, as compared to radiation alone. This has stimulated a renewed interest in the development of new therapeutic strategies for treatment and potential cure of oligodendroglial tumors, based on an improved scientific understanding of the molecular events involved in the pathogenesis of these neoplasms. The goal of this document is to summarize the key translational developments and recent clinical therapeutic trial data, with a correlative perspective on current and future directions.

Adult low-grade glioma: 19-year experience at a single institution

OBJECTIVES

To determine prognostic factors and optimal timing of postoperative radiation therapy (RT) in adult low-grade gliomas.

METHODS

Records from 554 adults diagnosed with nonpilocytic low-grade gliomas at Mayo Clinic between 1992 and 2011 were retrospectively reviewed.

RESULTS

Median follow-up was 5.2 years. Histology revealed astrocytoma in 22%, oligoastrocytoma in 34%, and oligodendroglioma in 45%. Initial surgery achieved gross total resection in 31%, radical subtotal resection in 10%, subtotal resection (STR) in 21%, and biopsy only in 39%. Median overall survival (OS) and progression-free survival (PFS) were 11.4 and 4.1 years, respectively. On multivariate analysis, factors associated with lower OS included astrocytomas and use of postoperative RT. Adverse prognostic factors for PFS on multivariate analysis included tumor size, astrocytomas, STR/biopsy only and not receiving RT. Patients undergoing gross total resection/radical subtotal resection had the best OS and PFS. Comparing survival with the log-rank test demonstrated no association between RT and PFS (P=0.24), but RT was associated with lower OS (P<0.0001). In patients undergoing STR/biopsy only, RT was associated with improved PFS (P<0.0001) but lower OS (P=0.03). Postoperative RT was associated with adverse prognostic factors including age > 40 years, deep tumors, size≥5 cm, astrocytomas and STR/biopsy only. Patients delaying RT until recurrence experienced 10-year OS (71%) similar to patients never needing RT (74%; P=0.34).

CONCLUSIONS

This study supports the association between aggressive surgical resection and better OS and PFS, and between postoperative RT and improved PFS in patients receiving STR/biopsy only. In addition, our findings suggest that delaying RT until progression is safe in patients who are eligible.

Differentiation between oligodendroglioma genotypes using dynamic susceptibility contrast perfusion-weighted imaging and proton MR spectroscopy

BACKGROUND AND PURPOSE

Oligodendrogliomas with 1p/19q chromosome LOH are more sensitive to chemoradiation therapy than those with intact alleles. The usefulness of dynamic susceptibility contrast-PWI-guided ¹H-MRS in differentiating these 2 genotypes was tested in this study.

MATERIALS AND METHODS

Forty patients with oligodendrogliomas, 1p/19q LOH (n = 23) and intact alleles (n = 17), underwent MR imaging and 2D-¹H-MRS. ¹H-MRS VOI was overlaid on FLAIR images to encompass the hyperintense abnormality on the largest cross-section of the neoplasm and then overlaid on CBV maps to coregister CBV maps with ¹H-MRS VOI. rCBVmax values were obtained by measuring the CBV from each of the selected ¹H-MRS voxels in the neoplasm and were normalized with respect to contralateral white matter. Metabolite ratios with respect to ipsilateral Cr were computed from the voxel corresponding to the rCBVmax value. Logistic regression and receiver operating characteristic analyses were performed to ascertain the best model to discriminate the 2 genotypes of oligodendrogliomas. Qualitative evaluation of conventional MR imaging characteristics (patterns of tumor border, signal intensity, contrast enhancement, and paramagnetic susceptibility effect) was also performed to distinguish the 2 groups of oligodendrogliomas.

RESULTS

The incorporation of rCBVmax value and metabolite ratios (NAA/Cr, Cho/Cr, Glx/Cr, myo-inositol/Cr, and lipid + lactate/Cr) into the multivariate logistic regression model provided the best discriminatory classification with sensitivity (82.6%), specificity (64.7%), and accuracy (72%) in distinguishing 2 oligodendroglioma genotypes. Oligodendrogliomas with 1p/19q LOH were also more associated with paramagnetic susceptibility effect (P < .05).

CONCLUSIONS

Our preliminary results indicate the potential of combing PWI and ¹H-MRS to distinguish oligodendroglial genotypes.

Hypoxia-inducible factor-1-regulated protein expression and oligodendroglioma patient outcome: comparison with established biomarkers and preoperative UCSF low-grade scoring system

Methods for predicting outcome for patients with oligodendrogliomas and anaplastic oligodendrogliomas (AOs) are limited. Hypoxia-inducible factor-1α (HIF-1α) controls many proteins involved in glycolysis and angiogenesis including VEGF, Glut-1, and CA-IX. We examined whether expression of HIF-1α and other hypoxia-regulated molecules (HRM) can predict overall (OS) and progression-free (PFS) survival. We correlated these data with more established biomarkers and a published preoperative scoring system. We prospectively collected tissue samples and followed outcomes of 50 patients with oligodendrogliomas and 32 with AOs. Tumor tissues were stained for measures of proliferative index, microvascular density, IDH-1 mutational status, and HRMs. We retrospectively analyzed preoperative imaging and clinical data based on the UCSF Scoring System (good prognostic indicators: Karnofsky Performance Scale (KPS) score > 80, age < 50 years, tumor diameter < 4 cm, noneloquent tumor location) and correlated these with immunohistochemical markers, 1p19q chromosomal status, and compared both with patient PFS and OS. Mean follow-up was 85.6 ± 41.4 months. HRMs showed higher expression in AOs than in oligodendrogliomas. Both 1p19q codeletion and IDH-1 mutation predict outcome of patients with both oligodendroglioma and AO. The UCSF score is a strong predictor for oligodendrogliomas patient outcome and is strengthened by IDH-1 and 1p19q status. Glut-1 may be useful in predicting PFS in AOs. Proliferation index >5 for oligodendrogliomas and KPS ≤ 80 for AOs predict a worse prognosis. Immunohistochemical markers of HRMs show a significantly higher expression in anaplastic variants of oligodendrogliomas and may contribute to the prediction of survival in these patients.