Phase II trial of procarbazine, lomustine, and vincristine as initial therapy for patients with low-grade oligodendroglioma or oligoastrocytoma: efficacy and associations with chromosomal abnormalities

Brain Plasticity Profiling as a Key Support to Therapeutic Decision-Making in Low-Grade Glioma Oncological Strategies

The ability of neural circuits to compensate for damage to the central nervous system is called postlesional plasticity. In diffuse low-grade gliomas (LGGs), a crosstalk between the brain and the tumor activates modulations of plasticity, as well as tumor proliferation and migration, by means of paracrine and electrical intercommunications. Such adaptative mechanisms have a major impact on the benefits and risks of oncological treatments but are still disregarded by current neuro-oncological guidelines. In this review, the authors first aimed to highlight clinical, radiological, and oncological markers that robustly reflect the plasticity potentials and limitations in LGG patients, including the location of the tumor and the degree of critical white matter tract infiltration, the velocity of tumor expansion, and the reactional changes of neuropsychological performances over time. Second, the interactions between the potential/limitations of cerebral plasticity and the efficacy/tolerance of treatment options (i.e., surgery, chemotherapy, and radiotherapy) are reviewed. Finally, a longitudinal and multimodal treatment approach accounting for the evolutive profiles of brain plasticity is proposed. Such an approach integrates personalized predictive models of plasticity potentials with a step-by-step therapeutic decision making and supports onco-functional balanced strategies in patients with LGG, with the ultimate aim of optimizing overall survival and quality of life.

Therapies for IDH-Mutant Gliomas

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutant gliomas are a distinct type of primary brain tumors with unique characteristics, behavior, and disease outcomes. This article provides a review of standard of care treatment options and innovative, therapeutic approaches that are currently under investigation for these tumors.

RECENT FINDINGS

Extensive pre-clinical data and a variety of clinical studies support targeting IDH mutations in glioma using different mechanisms, which include direct inhibition and immunotherapies that target metabolic and epigenomic vulnerabilities caused by these mutations. IDH mutations have been recognized as an oncogenic driver in gliomas for more than a decade and as a positive prognostic factor influencing the research for new therapeutic methods including IDH inhibitors, DNA repair inhibitors, and immunotherapy.

Thirty years of progress in the management of low-grade gliomas

This paper reviews 30 years of developments in the area of low-grade gliomas. This includes the changes in diagnostics with the incorporation of 1p/19q and IDH mutations in the diagnostic classifier, the improved surgical techniques, improved delivery of radiotherapy and chemotherapy. More recently, the better understanding of the altered cellular processes has lead to the development of novel drugs that may alter completely alter the management of patients early in the course of their disease.

Benign Glioma

Benign glioma broadly refers to a heterogeneous group of slow-growing glial tumors with low proliferative rates and a more indolent clinical course. These tumors may also be described as "low-grade" glioma (LGG) and are classified as WHO grade I or II lesions according to the Classification of Tumors of the Central Nervous System (CNS) (Louis et al. in Acta Neuropathol 114:97-109, 2007). Advances in molecular genetics have improved understanding of glioma tumorigenesis, leading to the identification of common mutation profiles with significant treatment and prognostic implications. The most recent WHO 2016 classification system has introduced several notable changes in the way that gliomas are diagnosed, with a new emphasis on molecular features as key factors in differentiation (Wesseling and Capper in Neuropathol Appl Neurobiol 44:139-150, 2018). Benign gliomas have a predilection for younger patients and are among the most frequently diagnosed tumors in children and young adults (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). These tumors can be separated into two clinically distinct subgroups. The first group is of focal, well-circumscribed lesions that notably are not associated with an increased risk of malignant transformation. Primarily diagnosed in pediatric patients, these WHO grade I tumors may be cured with surgical resection alone (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). Recurrence rates are low, and the prognosis for these patients is excellent (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). Diffuse gliomas are WHO grade II lesions with a more infiltrative pattern of growth and high propensity for recurrence. These tumors are primarily diagnosed in young adult patients, and classically present with seizures (Pallud et al. Brain 137:449-462, 2014). The term "benign" is a misnomer in many cases, as the natural history of these tumors is with malignant transformation and recurrence as grade III or grade IV tumors (Jooma et al. in J Neurosurg 14:356-363, 2019). For all LGG, surgery with maximal safe resection is the treatment of choice for both primary and recurrent tumors. The goal of surgery should be for gross total resection (GTR), as complete tumor removal is associated with higher rates of tumor control and seizure freedom. Chemotherapy and radiation therapy (RT), while not typically a component of first-line treatment in most cases, may be employed as adjunctive therapy in high-risk or recurrent tumors and in some select cases. The prognosis of benign gliomas varies widely; non-infiltrative tumor subtypes generally have an excellent prognosis, while diffusely infiltrative tumors, although slow-growing, are eventually fatal (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). This chapter reviews the shared and unique individual features of the benign glioma including diffuse glioma, pilocytic astrocytoma and pilomyxoid astrocytoma (PMA), subependymal giant cell astrocytoma (SEGA), pleomorphic xanthoastrocytoma (PXA), subependymoma (SE), angiocentric glioma (AG), and chordoid glioma (CG). Also discussed is ganglioglioma (GG), a mixed neuronal-glial tumor that represents a notable diagnosis in the differential for other LGG (Wesseling and Capper 2018). Ependymomas of the brain and spinal cord, including major histologic subtypes, are discussed in other chapters.

Current and promising treatment strategies in glioma

Gliomas are the most common primary central nervous system tumors; despite recent advances in diagnosis and treatment, glioma patients generally have a poor prognosis. Hence there is a clear need for improved therapeutic options. In recent years, significant effort has been made to investigate immunotherapy and precision oncology approaches. The review covers well-established strategies such as surgery, temozolomide, PCV, and mTOR inhibitors. Furthermore, it summarizes promising therapies: tumor treating fields, immune therapies, tyrosine kinases inhibitors, IDH(Isocitrate dehydrogenase)-targeted approaches, and others. While there are many promising treatment strategies, none fundamentally changed the management of glioma patients. However, we are still awaiting the outcome of ongoing trials, which have the potential to revolutionize the treatment of glioma.

Lung toxicity of CCNU in the treatment of progressive gliomas

Background

Pulmonary fibrosis is a rare, but dangerous side effect of CCNU (lomustine). CCNU is a frequently used chemotherapeutic agent in the setting of recurrent or progressive glioblastoma. At present, CCNU is also administered in patients with newly diagnosed gliomas in combination with temozolomide. There is only little evidence if, and how, lung function should be monitored on treatment with CCNU.

Methods

We retrospectively collected data on patient characteristics, lung function analyses, and relevant toxicities among 166 brain tumor patients treated with CCNU at a German University Hospital and National Cancer Center.

Results

The patient collective mainly included patients with recurrent glioblastoma who received a mean number of 2.64 ± 1.57 cycles. There was overall no statistically significant change in parameters of pulmonary restriction among patients treated with CCNU. On an individual patient basis, a >10% decrease in the absolute vital capacity was primarily seen in patients with prior lung diseases and smokers. Other severe toxicities mainly included thrombocytopenia, leukopenia, nausea, and vomiting.

Conclusions

Our findings support to limit lung function analyses on CCNU to patients with gliomas and pulmonary risk factors. However, all patients should be closely followed for clinical symptoms of pulmonary restriction.

Optimal Combinations of Chemotherapy and Radiotherapy in Low-Grade Gliomas: A Mathematical Approach

Low-grade gliomas (LGGs) are brain tumors characterized by their slow growth and infiltrative nature. Treatment options for these tumors are surgery, radiation therapy and chemotherapy. The optimal use of radiation therapy and chemotherapy is still under study. In this paper, we construct a mathematical model of LGG response to combinations of chemotherapy, specifically to the alkylating agent temozolomide and radiation therapy. Patient-specific parameters were obtained from longitudinal imaging data of the response of real LGG patients. Computer simulations showed that concurrent cycles of radiation therapy and temozolomide could provide the best therapeutic efficacy in-silico for the patients included in the study. The patient cohort was extended computationally to a set of 3000 virtual patients. This virtual cohort was subject to an in-silico trial in which matching the doses of radiotherapy to those of temozolomide in the first five days of each cycle improved overall survival over concomitant radio-chemotherapy according to RTOG 0424. Thus, the proposed treatment schedule could be investigated in a clinical setting to improve combination treatments in LGGs with substantial survival benefits.

Oligodendroglioma: A Review of Management and Pathways

Anaplastic oligodendrogliomas are a type of glioma that occurs primarily in adults but are also found in children. These tumors are genetically defined according to the mutations they harbor. Grade II and grade III tumors can be differentiated most of the times by the presence of anaplastic features. The earliest regimen used for the treatment of these tumors was procarbazine, lomustine, and vincristine. The treatment modalities have shifted over time, and recent studies are considering immunotherapy as an option as well. This review assesses the latest management modalities along with the pathways involved in the pathogenesis of this malignancies.

Survival outcome and prognostic factors in anaplastic oligodendroglioma: a single-institution study of 95 cases

The aim of this study was to evaluate prognostic factors including surgical, radiographic, and histopathologic analyses in anaplastic oligodendroglioma (AO) patients. We reviewed the electronic records of 95 patients who underwent surgery and were diagnosed with AO for 20 years. The primary endpoints were progression-free survival (PFS) and overall survival (OS). Univariate and multivariable analyses included clinical, histopathological, and radiographic prognostic factors. Subgroup analysis was performed in isocitrate dehydrogenase (IDH1/2)-mutant and 1p/19q-codeleted patients. The median PFS and OS were 24.7 months and 50.8 months, respectively. The 1-, 3-, 5-, and 10-year PFS were 75.8%, 42.9%, 32.4%, and 16.4%, respectively. Furthermore, the 1-, 3-, 5-, and 10-year OS were 98.9%, 76.9%, 42.9%, and 29.7%, respectively. The median PFS and OS of the IDH1/2-mutant and 1p/19q-codeleted patients were 54.2 and 57.8 months, respectively. In univariate analyses, young age, frontal lobe, weak enhancement, gross total resection (GTR), low Ki-67 index, 1p/19q codeletion, and IDH1/2 mutations were associated with a favorable outcome. In multivariable analyses, IDH1/2 mutation was related to better PFS and OS. In subgroup analysis, GTR was associated with favorable outcomes.

Toxicity Profile of Procarbazine Lomustine and Vincristine Chemotherapy in Low-Grade Glioma - Retrospective Review

Background

The role of Procarbazine Lomustine and Vincristine (PCV) chemotherapy is already established in terms of improving survival in low-grade glioma (LGG). This improved survival has led to the increasing administration of PCV to LGG patients over the past years. However, like other chemotherapies, serious hematological and non-hematological toxicities may occur. The purpose of this study was to evaluate the toxicity profile of PCV and its clinical relevance in our practice. 

Materials and Methods

We reviewed 63 patients of LGG retrospectively who received chemotherapy PCV between January 2015 and January 2018 at Shaukat Khanum Memorial Cancer Hospital & Research Centre, Lahore.

Results

Significant hematological toxicity as grade 3 anemia, thrombocytopenia, and neutropenia occurred in 19%, 27%, and 46% respectively with PCV. Other toxicities such as neurotoxicity, vomiting and derangement of liver enzymes occurred in 3.2%, 19%, and 19% respectively. Patients who were on concurrent anticonvulsants had no increase in PCV toxicity. Survival was not impacted by hematological toxicities up to grade 3.

Conclusion

PCV chemotherapy is associated with major hematological, hepatic, and clinical toxicities (vomiting, constipation, and neuropathy). Hematological toxicities influenced the course of treatment in terms of delays and interruptions.

Gene signatures based on therapy responsiveness provide guidance for combined radiotherapy and chemotherapy for lower grade glioma

For a long time, the guidance for adjuvant chemoradiotherapy for lower grade glioma (LGG) lacks instructions on the application timing and order of radiotherapy (RT) and chemotherapy. We, therefore, aimed to develop indicators to distinguish between the different beneficiaries of RT and chemotherapy, which would provide more accurate guidance for combined chemoradiotherapy. By analysing 942 primary LGG samples from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases, we trained and validated two gene signatures (Rscore and Cscore) that independently predicted the responsiveness to RT and chemotherapy (Rscore AUC = 0.84, Cscore AUC = 0.79) and performed better than a previous signature. When the two scores were combined, we divided patients into four groups with different prognosis after adjuvant chemoradiotherapy: RSCS (RT-sensitive and chemotherapy-sensitive), RSCR (RT-sensitive and chemotherapy-resistant), RRCS (RT-resistant and chemotherapy-sensitive) and RRCR (RT-resistant and chemotherapy-resistant). The order and dose of RT and chemotherapy can be adjusted more precisely based on this patient stratification. We further found that the RRCR group exhibited a microenvironment with significantly increased T cell inflammation. In silico analyses predicted that patients in the RRCR group would show a stronger response to checkpoint blockade immunotherapy than other patients.

Management for Different Glioma Subtypes: Are All Low-Grade Gliomas Created Equal?

Following the identification of key molecular alterations that provided superior prognostication and led to the updated 2016 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification, the understanding of glioma behavior has rapidly evolved. Mutations in isocitrate dehydrogenase (IDH) 1 and 2 are present in the majority of adult grade 2 and 3 gliomas, and when used in conjunction with 1p/19q codeletion for classification, the prognostic distinction between grade 2 versus grade 3 is diminished. As such, the previously often used term of "low-grade glioma," which referred to grade 2 gliomas, has now been replaced by the phrase "lower-grade glioma" to encompass both grade 2 and 3 tumors. Additional molecular characterization is ongoing to even further classify this heterogeneous group of tumors. With such a colossal shift in the understanding of lower-grade gliomas, management of disease is being redefined in the setting of emerging molecular-genetic biomarkers. In this article, we review recent progress and future directions regarding the surgical, radiotherapeutic, chemotherapeutic, and long-term management of adult lower-grade gliomas.

Seizure response to temozolomide chemotherapy in patients with WHO grade II oligodendroglioma: a single-institution descriptive study

Background

Tumor-related epilepsy (TRE) is common in patients with low-grade oligodendrogliomas. TRE is difficult to control despite multiple antiepileptic drugs (AEDs) in up to 30% of patients. Chemotherapy has been used for treatment to avoid potential radiotherapy-related neurotoxicity. This study evaluates the effect of temozolomide on seizure frequency in a homogeneous group with World Health Organization (WHO) grade II oligodendrogliomas.

Methods

A retrospective analysis was conducted of adult patients with WHO grade II oligodendrogliomas and TRE followed at Memorial Sloan Kettering between 2005 and 2015 who were treated with temozolomide alone either as initial treatment or for disease progression. All had seizures 3 months prior to starting temozolomide. Seizure frequency was reviewed every 2 cycles and at the end of temozolomide treatment. Seizure reduction of ≥50% compared to baseline was defined as improvement.

Results

Thirty-nine individuals met inclusion criteria. Median follow-up since starting temozolomide was 6 years (0.8-13 years). Reduction in seizure frequency occurred in 35 patients (89.7%). Improvement was independent of AED regimen adjustments or prior antitumor treatment in 16 (41%); of these, AED dosage was successfully reduced or completely eliminated in 10 (25.6%). Twenty-five patients (64.1%) remained on a stable AED regimen. The majority (n = 32, 82%) had radiographically stable disease, 5 (12.8%) had objective radiographic response, and 2 (5.2%) had disease progression.

Conclusions

Temozolomide may result in reduced seizure frequency, and permit discontinuation of AEDs in patients with WHO II oligodendroglioma. Improvement was observed irrespective of objective tumor response on MRI, emphasizing the importance of incorporating seizure control in assessing response to tumor-directed therapy.

Case Report: Clinical Outcome and Image Response of Two Patients With Secondary High-Grade Glioma Treated With Chemoradiation, PCV, and Cannabidiol

We describe two patients with a confirmed diagnosis of high-grade gliomas (grades III/IV), both presenting with O6-methylguanine-DNA methyltransferase (MGMT) methylated and isocitrate dehydrogenase (IDH-1) mutated who, after subtotal resection, were submitted to chemoradiation and followed by PCV, a multiple drug regimen (procarbazine, lomustine, and vincristine) associated with cannabidiol (CBD). Both patients presented with satisfactory clinical and imaging responses at periodic evaluations. Immediately after chemoradiation therapy, one of the patients presented with an exacerbated and precocious pseudoprogression (PSD) assessed by magnetic resonance imaging (MRI), which was resolved in a short period. The other patient presented with a marked remission of altered areas compared with the post-operative scans as assessed by MRI. Such aspects are not commonly observed in patients only treated with conventional modalities. This observation might highlight the potential effect of CBD to increase PSD or improve chemoradiation responses that impact survival. Further investigation with more patients and critical molecular analyses should be performed.

Chemotherapy Treatment and Trials in Low-Grade Gliomas

There is currently no universally accepted standard of care treatment for low-grade gliomas, a molecularly heterogeneous group of tumors with similarly heterogeneous clinical outcomes. Risk stratification by clinical and molecular features is useful to help determine which patients benefit the most from adjuvant treatment. The addition of combination chemotherapy with procarbazine, lomustine, and vincristine confers survival advantage, as likely does temozolomide, but radiochemotherapy may not be appropriate for all patients owing to its toxicity profile. We review the approach to treatment in patients with low-grade gliomas with an emphasis on the clinical trials focusing on adjuvant chemotherapy in this population.

The Korean Society for Neuro-Oncology (KSNO) Guideline for WHO Grade II Cerebral Gliomas in Adults: Version 2019.01

BACKGROUND

There was no practical guideline for the management of patients with central nervous system tumor in Korea for many years. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has developed the guideline for glioblastoma. Subsequently, the KSNO guideline for World Health Organization (WHO) grade II cerebral glioma in adults is established.

METHODS

The Working Group was composed of 35 multidisciplinary medical experts in Korea. References were identified by searching PubMed, MEDLINE, EMBASE, and Cochrane CENTRAL databases using specific and sensitive keywords as well as combinations of keywords regarding diffuse astrocytoma and oligodendroglioma of brain in adults.

RESULTS

Whenever radiological feature suggests lower grade glioma, the maximal safe resection if feasible is recommended globally. After molecular and histological examinations, patients with diffuse astrocytoma, isocitrate dehydrogenase (IDH)-wildtype without molecular feature of glioblastoma should be primarily treated by standard brain radiotherapy and adjuvant temozolomide chemotherapy (Level III) while those with molecular feature of glioblastoma should be treated following the protocol for glioblastomas. In terms of patients with diffuse astrocytoma, IDH-mutant and oligodendroglioma (IDH-mutant and 1p19q codeletion), standard brain radiotherapy and adjuvant PCV (procarbazine+lomustine+vincristine) combination chemotherapy should be considered primarily for the high-risk group while observation with regular follow up should be considered for the low-risk group.

CONCLUSION

The KSNO's guideline recommends that WHO grade II gliomas should be treated by maximal safe resection, if feasible, followed by radiotherapy and/or chemotherapy according to molecular and histological features of tumors and clinical characteristics of patients.

Procarbazine, CCNU and vincristine (PCV) versus temozolomide chemotherapy for patients with low-grade glioma: a systematic review

Low-grade gliomas (LGG) encompass a heterogeneous group of tumors that are clinically, histologically and molecularly diverse. Treatment decisions for patients with LGG are directed toward improving upon the natural history while limiting treatment-associated toxiceffects. Recent evidence has documented a utility for adjuvant chemotherapy with procarbazine, CCNU (lomustine), and vincristine (PCV) or temozolomide (TMZ). We sought to determine the comparative utility of PCV and TMZ for patients with LGG, particularly in context of molecular subtype. A literature search of PubMed was conducted to identify studies reporting patient response to PCV, TMZ, or a combination of chemotherapy and radiation therapy (RT). Eligibility criteria included patients 16 years of age and older, notation of LGG subtype, and report of progression-free survival (PFS), overall survival (OS), and treatment course. Level I, II, and III data were included. Adjuvant therapy with PCV resulted in prolonged PFS and OS in patients with newly diagnosed high-risk LGG. This benefit was accrued most significantly by patients with tumors harboring 1p/19q codeletion and IDH1 mutation. Adjuvant therapy with temozolomide was associated with lower toxicity than therapy with PCV. In patients with LGG with an unfavorable natural history, such as with intact 1p/19q and wild-type IDH1, RT/TMZ plus adjuvant TMZ may be the best option. Patients with biologically favorable high-risk LGG are likely to derive the most benefit from RT and adjuvant PCV.

Therapeutic Interventions in Adult Low-Grade Gliomas

Treating adult low-grade gliomas (LGGs) is particularly challenging due to the highly infiltrative nature of this type of brain cancer. Although surgery, radiotherapy, and chemotherapy are the mainstay treatment modalities for LGGs, the optimal combination management plan for a particular patient based on individual symptoms and the risk of treatment-induced toxicity remains unclear. This review highlights the competency and limitations of standard treatment options while providing an essential therapeutic update regarding current clinical trials aimed at implementing targeted therapies with morbidity rates lower than those for current LGG treatments and also augmenting the killing of cancerous cells while maintaining an improved quality of life.

Procarbazine, lomustine and vincristine toxicity in low-grade gliomas

Background

Procarbazine, lomustine, and vincristine (pcv) significantly improve survival outcomes in lgg (low-grade gliomas). Administration of pcv to lgg patients increased tremendously over the past years as it went from 2 patients per year between 2005 and 2012 to 23 patients in 2015 only in our centre. However, serious hematological and non-hematological adverse events may occur. The purpose of this study was to evaluate the toxicity of pcv and its clinical relevance in our practice.

Methods

We retrospectively reviewed the charts of 57 patients with lgg who received pcv at the Centre hospitalier de l'Université de Montréal between 1 January 2005 and 27 July 2016.

Results

Procarbazine, lomustine, and vincristine were associated with severe hematological toxicity as clinically significant grade 3 anemia, neutropenia, and thrombocytopenia occurred in 7%, 10%, and 28% of patients, respectively. Other frequent adverse events such as the increase of liver enzymes, cutaneous rash, neurotoxicity, and vomiting occurred in 65%, 26%, 60%, and 40% of patients, respectively. Patients with prophylactic trimethoprim/sulfamethoxazole had more grade 3 hematological toxicity with pcv, especially anemia (p = 0.040) and thrombocytopenia (p = 0.003) but we found no increase in pcv toxicity in patients on concurrent anticonvulsants. Patients with grade 3 neutropenia had a significantly lower survival (median survival 44.0 months vs. 114.0 months, p = 0.001). Patients who were given pcv at diagnosis had more grade 3 anemia than those who received it at subsequent lines of treatment (p = 0.042).

Conclusion

Procarbazine, lomustine, and vincristine increase survival in lgg but were also associated with major hematologic, hepatic, neurologic, and cutaneous toxicity. Anti-Pneumocystis jiroveci pneumonia (pjp) prophylaxis, but not anticonvulsants, enhances hematologic toxicity.

Is less more? Comparing chemotherapy alone with chemotherapy and radiation for high-risk grade 2 glioma: An analysis of the National Cancer Data Base

BACKGROUND

The addition of chemotherapy to adjuvant radiotherapy (chemotherapy and radiation therapy [CRT]) improves overall survival (OS) for patients with high-risk grade 2 gliomas; however, the impact of chemotherapy alone (CA) is unknown. This study compares the OS of patients with high-risk grade 2 gliomas treated with CA versus CRT.

METHODS

Patients with high-risk grade 2 gliomas (subtotal resection or age ≥ 40 years) with oligodendrogliomas, astrocytomas, or mixed tumors were identified with the National Cancer Data Base. Patients were grouped into CA and CRT cohorts. Univariate analyses and multivariate analyses (MVAs) were performed. Propensity score (PS) matching was also implemented. The Kaplan-Meier method was used to analyze OS.

RESULTS

A total of 1054 patients with high-risk grade 2 gliomas were identified: 496 (47.1%) received CA, and 558 (52.9%) received CRT. Patients treated with CA were more likely (all P values < .05) to have oligodendroglioma histology (65.5% vs 34.2%), exhibit a 1p/19q codeletion (22.8% vs 7.5%), be younger (median age, 47.0 vs 48.0 years), and receive treatment at an academic facility (65.2% vs 50.3%). The treatment type was not a significant predictor for OS (P = .125) according to the MVA; a tumor size > 6 cm, astrocytoma histology, and older age were predictors for worse OS (all P values < .05). After 1:1 PS matching (n = 331 for each cohort), no OS difference was seen (P = .696) between the CA and CRT cohorts at 5 (69.3% vs 67.4%) and 8 years (52.8% vs 56.7%).

CONCLUSIONS

No long-term OS difference was seen in patients with high-risk grade 2 gliomas treated with CA versus CRT. These findings are hypothesis-generating, and prospective clinical trials comparing these treatment paradigms are warranted. Cancer 2018;124:1169-78. © 2017 American Cancer Society.

SEOM clinical guideline of diagnosis and management of low-grade glioma (2017)

Diffuse infiltrating low-grade gliomas include oligodendrogliomas and astrocytomas, and account for about 5% of all primary brain tumors. Treatment strategies for these low-grade gliomas in adults have recently changed. The 2016 World Health Organization (WHO) classification has updated the definition of these tumors to include their molecular characterization, including the presence of isocitrate dehydrogenase (IDH) mutation and 1p/19p codeletion. In this new classification, the histologic subtype of grade II-mixed oligoastrocytoma has also been eliminated. The precise optimal management of patients with low-grade glioma after resection remains to be determined. The risk–benefit ratio of adjuvant treatment must be weighed for each individual.

Treatment Strategies for Low-Grade Glioma in Adults

Diffuse low-grade gliomas include oligodendrogliomas and astrocytomas. The recent 2016 WHO classification has now updated the definition of these tumors to include molecular characterization, including the presence of isocitrate dehydrogenase mutation and 1p/19q codeletion. In this new classification, the histologic subtype of grade II mixed oligoastrocytoma has been eliminated. Treatment recommendations are currently evolving, mainly because of a change in the prognostic factors that are based on molecular and cytogenetic features. Standard of care includes maximal safe surgical resection. Prior randomized clinical trials stratified treatment arms on the basis of extent of resection and age, with patients stratified into low risk (age younger than 40 years and gross total resection) and high risk (age older than 40 years or subtotal resection). Patients who are low risk may undergo routine magnetic resonance imaging surveillance after resection. On the basis of recently published data, it is now recommended that high-risk patients undergo a combination of both radiation and chemotherapy after surgery. These studies, however, do not address the management of patients with low-grade gliomas in the era of genomic medicine. These treatments can also have great impact on quality of life, and therefore treatment recommendations should be done on an individual basis taking into account the current pathology classification, age, extent of resection, quality of life, and patient preference.

Chemotherapy for adult low-grade gliomas: clinical outcomes by molecular subtype in a phase II study of adjuvant temozolomide

Background

Optimal adjuvant management of adult low-grade gliomas is controversial. Recently described tumor classification based on molecular subtype has the potential to individualize adjuvant therapy but has not yet been evaluated as part of a prospective trial.

Methods

Patients aged 18 or older with newly diagnosed World Health Organization grade II low-grade gliomas and gross residual disease after surgical resection were enrolled in the study. Patients received monthly cycles of temozolomide for up to 1 year or until disease progression. For patients with available tissue, molecular subtype was assessed based upon 1p/19q codeletion and isocitrate dehydrogenase-1 R132H mutation status. The primary outcome was radiographic response rate; secondary outcomes included progression-free survival (PFS) and overall survival (OS).

Results

One hundred twenty patients were enrolled with median follow-up of 7.5 years. Overall response rate was 6%, with median PFS and OS of 4.2 and 9.7 years, respectively. Molecular subtype was associated with rate of disease progression during treatment (P<.001), PFS (P=.007), and OS (P<.001). Patients with 1p/19q codeletion demonstrated a 0% risk of progression during treatment. In an exploratory analysis, pretreatment lesion volume was associated with both PFS (P<.001) and OS (P<.001).

Conclusions

While our study failed to meet the primary endpoint for objective radiographic response, patients with high-risk low-grade glioma receiving adjuvant temozolomide demonstrated a high rate of radiographic stability and favorable survival outcomes while meaningfully delaying radiotherapy. Patients with 1p/19q codeletion are potential candidates for omission of adjuvant radiotherapy, but further work is needed to directly compare chemotherapy with combined modality therapy.

Probing the phosphatidylinositol 3-kinase/mammalian target of rapamycin pathway in gliomas: A phase 2 study of everolimus for recurrent adult low-grade gliomas

BACKGROUND

Activation of the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway is common in patients with low-grade gliomas (LGGs), but agents that inhibit this pathway, including mTOR inhibitors, have not been studied in this population.

METHODS

Fifty-eight patients with pathologic evidence of recurrence after they had initially been diagnosed with World Health Organization (WHO) grade II gliomas were enrolled into a prospective phase 2 clinical trial and received daily everolimus (RAD001) for 1 year or until progression. Tissue at the time of enrollment was analyzed for markers of PI3K/mTOR pathway activation. Thirty-eight patients underwent serial multiparametric magnetic resonance imaging, with the tumor volume and the perfusion metrics (the fractional blood volume [fBV] for capillary density and the transfer coefficient [K_ps ] for vascular permeability) measured during treatment. The primary endpoint was progression-free survival at 6 months (PFS-6) in patients with WHO II disease at enrollment.

RESULTS

For patients with WHO II gliomas at enrollment, the PFS-6 rate was 84%, and this met the primary endpoint (P < .001 for an improvement from the historical rate of 17%). Evidence of PI3K/mTOR activation by immunohistochemistry for phosphorylated ribosomal S6^Ser240/244 (p-S6^Ser240/244 ) was associated with worse progression-free survival (PFS; hazard ratio [HR], 3.03; P = .004) and overall survival (HR, 12.7; P = .01). Tumor perfusion decreased after 6 months (median decrease in fBV, 15%; P = .03; median decrease in K_ps , 12%; P = .09), with greater decreases associated with improved PFS (HR for each 10% fBV decrease, 0.71; P = .01; HR for each 10% K_ps decrease, 0.82; P = .04).

CONCLUSIONS

Patients with recurrent LGGs demonstrated a high degree of disease stability during treatment with everolimus. PI3K/mTOR activation, as measured by immunohistochemistry for p-S6, was associated with a worse prognosis. Tumor vascular changes were observed that were consistent with the antiangiogenic effects of mTOR inhibitors. These results support further study of everolimus for LGGs. Cancer 2017;123:4631-4639. © 2017 American Cancer Society.

Procarbazine, Lomustine, and Vincristine (PCV) Regimen for Central Nervous System Tumors

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net. The information presented in this review is based on published data and clinical expertise and includes information not included in the product labeling. Incorporation of such published data provides a more robust assessment of the drugs and assists pharmacists in evaluation of orders for off-label use of these agents.

Management of diffuse low-grade gliomas in adults - use of molecular diagnostics

Diffuse WHO grade II gliomas are histologically and genetically heterogeneous. The 2016 WHO classification redefines grade II gliomas with respect to morphological and molecular tumour alterations: grade II oligodendrogliomas are defined by the presence of whole-arm codeletion in chromosomal arms 1p/19q, whereas isocitrate dehydrogenase (IDH) mutations define subclasses of astrocytoma. Although histological grade remains useful, the prognoses of patients with glioma are more tightly associated with molecular alterations than with grade, and chromosomal and gene array technologies are becoming increasingly beneficial in understanding tumour genetic heterogeneity. The indolent nature of the disease often creates subtle neurological symptoms that can be overlooked or misunderstood, resulting in delayed diagnosis. Seizures often herald the diagnosis, especially in patients who have IDH mutations, which are associated with an increased production of 2-hydroxyglutarate. Treatment paradigms have shifted, owing to new diagnostic criteria and new clinical trial evidence. Patients benefit more from chemoradiation than radiation alone, especially those with tumour IDH1 Arg132His mutations; gross total resection of the tumour, including tumours with IDH mutations, is associated with prolonged survival. Initial observation remains appropriate in patients whose rate of disease growth is not yet completely defined; such patients could include those with completely resected disease and those with 1p/19q codeleted tumours.

Malignant transformation of low-grade gliomas in patients undergoing adjuvant therapy

Low-grade gliomas (LGG) comprise nearly 15-20 % of all central nervous system glial tumors. Several factors have been recognized as playing role in LGG malignant transformation (MT). A breakthrough analysis of a multidisciplinary group pointed that temozolomide may play a role in MT of LGGs. We analyzed the prevalence of MT in LGG patients submitted to adjuvant therapy (AT). We analyzed the medical charts of 43 patients with LGG submitted to surgery or biopsy and attending at Hospital do Servidor Público Estadual de São Paulo (São Paulo, Brazil), consecutively diagnosed from 1995 to 2013. 43 patients (24 women and 19 men) were evaluated, with mean age of 45.3 years. According to histology, 30 were astrocytomas (70 %), 12 (27 %) were oligodendrogliomas, and 1 (3 %) were mixed glioma. Mean follow-up time was 4.2 years with the standard deviation of 2.1. Twenty-eight patients did not receive adjuvant therapy and 15 received adjuvant therapy. From 43 patients with complete follow-up, 21 (48 %) experienced malignant transformation. Among such patients, nine were users of AT. Forty-eight percent of patients presented MT, being 60 % in the AT group and 42.8 % without AT. Our analysis revealed a high prevalence of MT in patients undergoing AT, higher than in patients without AT.

Temozolomide low-dose chemotherapy in newly diagnosed low-grade gliomas: activity, safety, and long-term follow-up

PURPOSE

To explore the efficacy and toxicity of an extended schedule of temozolomide (50 mg/mq 1 week on/1 week off) in a population of newly diagnosed low-grade gliomas (LGG).

METHODS

Primary endpoints were progression-free survival (PFS) at 12 and 24 months and response rate evaluated with Response Assessment in Neuro-Oncology Criteria. Secondary endpoints were clinical benefit (reduction of seizures frequency), reduction of steroid, and modifications of Karnofsky Performance Status.

RESULTS

From 2006 to 2009, we enrolled 14 consecutive patients with newly diagnosed LGG: 8 grade II astrocytomas, 2 oligodendroglioma, and 4 oligo-astrocytoma. Temozolomide was administered for 18 cycles (mean) per patient (range 3-24 cycles). In 57.5% (n = 8), we observed stable disease, 28.5% (n = 4) presented a minor response, and 14% (n = 2) showed progression. Five patients presented early progression during the first year of treatment and the study was stopped. A relevant clinical benefit was observed in 85% of patients (seizure control). After 6 years of follow-up, only 4 patients died. Prolonged PFS was associated with 1p-19q codeletion over 1p-19q intact (35 vs 4 months; p<0.04) and IDH1 mutation over IDH1 wild-type (36 vs 6 months; p<0.009).

CONCLUSIONS

The study was interrupted for the high rate of progression observed in the first 14 patients enrolled. However, our results show that an extended low dose of temozolomide presents interesting activity with objective response and clinical benefit, but does not seem to prevent progression in patients presenting unfavorable molecular prognostic factors.

Current Management of Adult Diffuse Infiltrative Low Grade Gliomas

Diffuse infiltrative low grade gliomas (LGG) account for approximately 15 % of all gliomas. The prognosis of LGG differs between high-risk and low-risk patients notwithstanding varying definitions of what constitutes a high-risk patient. Maximal safe resection optimally is the initial treatment. Surgery that achieves a large volume resection improves both progression-free and overall survival. Based on results of three randomized clinical trials (RCT), radiotherapy (RT) may be deferred in patients with low-risk LGG (defined as age <40 years and having undergone a complete resection), although combined chemoradiotherapy has never been prospectively evaluated in the low-risk population. The recent RTOG 9802 RCT established a new standard of care in high-risk patients (defined as age >40 years or incomplete resection) by demonstrating a nearly twofold improvement in overall survival with the addition of PCV (procarbazine, CCNU, vincristine) chemotherapy following RT as compared to RT alone. Chemotherapy alone as a treatment of LGG may result in less toxicity than RT; however, this has only been prospectively studied once (EORTC 22033) in high-risk patients. A challenge remains to define when an aggressive treatment improves survival without impacting quality of life (QoL) or neurocognitive function and when an effective treatment can be delayed in order to preserve QoL without impacting survival. Current WHO histopathological classification is poorly predictive of outcome in patients with LGG. The integration of molecular biomarkers with histology will lead to an improved classification that more accurately reflects underlying tumor biology, prognosis, and hopefully best therapy.

Radiation plus Procarbazine, CCNU, and Vincristine in Low-Grade Glioma

BACKGROUND

Grade 2 gliomas occur most commonly in young adults and cause progressive neurologic deterioration and premature death. Early results of this trial showed that treatment with procarbazine, lomustine (also called CCNU), and vincristine after radiation therapy at the time of initial diagnosis resulted in longer progression-free survival, but not overall survival, than radiation therapy alone. We now report the long-term results.

METHODS

We included patients with grade 2 astrocytoma, oligoastrocytoma, or oligodendroglioma who were younger than 40 years of age and had undergone subtotal resection or biopsy or who were 40 years of age or older and had undergone biopsy or resection of any of the tumor. Patients were stratified according to age, histologic findings, Karnofsky performance-status score, and presence or absence of contrast enhancement on preoperative images. Patients were randomly assigned to radiation therapy alone or to radiation therapy followed by six cycles of combination chemotherapy.

RESULTS

A total of 251 eligible patients were enrolled from 1998 through 2002. The median follow-up was 11.9 years; 55% of the patients died. Patients who received radiation therapy plus chemotherapy had longer median overall survival than did those who received radiation therapy alone (13.3 vs. 7.8 years; hazard ratio for death, 0.59; P=0.003). The rate of progression-free survival at 10 years was 51% in the group that received radiation therapy plus chemotherapy versus 21% in the group that received radiation therapy alone; the corresponding rates of overall survival at 10 years were 60% and 40%. A Cox model identified receipt of radiation therapy plus chemotherapy and histologic findings of oligodendroglioma as favorable prognostic variables for both progression-free and overall survival.

CONCLUSIONS

In a cohort of patients with grade 2 glioma who were younger than 40 years of age and had undergone subtotal tumor resection or who were 40 years of age or older, progression-free survival and overall survival were longer among those who received combination chemotherapy in addition to radiation therapy than among those who received radiation therapy alone. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00003375.).

Low-grade and anaplastic oligodendroglioma

Anaplastic oligodendrogliomas have long attracted interest because of their sensitivity to chemotherapy, in particular in the subset of 1p/19q co-deleted tumors. Recent molecular studies have shown that all 1p/19q co-deleted tumors have IDH mutations and most of them also have TERT mutations. Because of the presence of similar typical genetic alterations in astrocytoma and glioblastoma, the current trend is to diagnose these tumors on the basis of their molecular profile. Further long-term follow-up analysis of both EORTC and RTOG randomized studies on (neo)adjuvant procarbazine, lomustine, vincristine (PCV) chemotherapy have shown that adjuvant chemotherapy indeed improves outcome, and this is now standard of care. It is also equally clear that benefit to PCV chemotherapy is not limited to the 1p/19q co-deleted cases; potential other predictive factors are IDH mutations and MGMT promoter methylation. Moreover, a recent RTOG study on low-grade glioma also noted an improved outcome after adjuvant PCV chemotherapy, thus making (PCV) chemotherapy now standard of care for all 1p/19q co-deleted tumors regardless of grade. It remains unclear whether temozolomide provides the same survival benefit, as no data from well-designed clinical trials on adjuvant temozolomide in this tumor type are available. Another question that remains is whether one can safely leave out radiotherapy as part of initial treatment to avoid cognitive side-effects of radiotherapy. The current data suggest that delaying radiotherapy and treatment with chemotherapy only may be detrimental for overall survival.

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.

Radiation therapy and grade II/III oligodendroglial tumors

Radiotherapy has been a longstanding treatment option for low-grade glioma. Improvements in tumor control and radiation-related toxicity may be attributed to advances in neuroimaging as well as radiotherapy planning and delivery. The discovery of various molecular prognostic factors have aided in patient selection for radiotherapy. These prognostic and predictive factors may also play a key role in determining which patients are likely to benefit most from combined systemic therapy and radiation.

Combined IDH1 mutation and MGMT methylation status on long-term survival of patients with cerebral low-grade glioma

OBJECTIVE

The management of low-grade glioma (LGG) still remains controversial because the effectiveness of early and extensive resection is unclear, and the use of radiation therapy or chemotherapy is not well-defined. In particular, the importance of prognostic factors for survival remains a matter of discussion. The purpose of this study was to validate prognostic factors for survival in patients with LGG.

MATERIALS AND METHODS

A consecutive series of 55 patients with WHO grade II LGG treated in our institute between 1983 and 2013 were retrospectively reviewed to determine the prognostic factors for survival. All data were retrospectively analyzed from the aspect of baseline characteristics, pathological findings, genetic change, surgical treatments, adjuvant therapies, and survival time. Cox multivariate analysis was performed to determine the prognostic factors for survival.

RESULTS

There were 28 patients with diffuse astrocytoma (DA), 21 patients with oligodendroglioma (OG), and 6 patients with oligoastrocytoma (OA) diagnosed on initial surgery. The median overall survival was 193 months and fifteen patients (27.3%) died. A mutation in isocitrate dehydrogenase-1 (IDH1) was found in 72.9% of LGG, and this mutation was positively correlated with methylation of O6-methylguanine-DNA methyltransferase (MGMT) (p=0.02). A better prognosis was significantly associated with combined IDH1 mutation and MGMT methylation status (both positive vs both negative, HR 0.079 [95% CI 0.008-0.579], p=0.012), as well as histology (OG vs DA and OA, HR 0.158 [95% CI 0.022-0.674], p=0.011) and tumor size (<6 cm vs ≥6 cm, HR 0.120 [95% CI 0.017-0.595], p=0.008).

CONCLUSIONS

Tumor histology, size and IDH-mutation status are important predictors for prolonged overall survival in patients with LGG and may provide a reliable tool for standardizing future treatment strategies.

Clinical management of grade III oligodendroglioma

Oligodendrogliomas represent the third most common type of glioma, comprising 4%-15% of all gliomas and can be classified by degree of malignancy into grade II and grade III, according to WHO classification. Only 30% of oligodendroglial tumors have anaplastic characteristics. Anaplastic oligodendroglioma (AO) is often localized as a single lesion in the white matter and in the cortex, rarely in brainstem or spinal cord. The management of AO is deeply changed in the recent years. Maximal safe surgical resection followed by radiotherapy (RT) was considered as the standard of care since paramount findings regarding molecular aspects, in particular co-deletion of the short arm of chromosome 1 and the long arm of chromosome 19, revealed that these subsets of AO, benefit in terms of overall survival (OS) and progression-free survival (PFS), from the addition of chemotherapy to RT. Allelic losses of chromosomes 1p and 19q occur in 50%-70% of both low-grade and anaplastic tumors, representing a strong prognostic factor and a powerful predictor of prolonged survival. Several other molecular markers have potential clinical significance as IDH1 mutations, confirming the strong prognostic role for OS. Malignant brain tumors negatively impacts on patients' quality of life. Seizures, visual impairment, headache, and cognitive disorders can be present. Moreover, chemotherapy and RT have important side effects. For these reasons, "health-related quality of life" is becoming a topic of growing interest, investigating on physical, mental, emotional, and social well-being. Understanding the impact of medical treatment on health-related quality of life will probably have a growing effect both on health care strategies and on patients.

Prediction of anaplastic transformation in low-grade oligodendrogliomas based on magnetic resonance spectroscopy and 1p/19q codeletion status

The aim of this study was to assess whether combining multimodal magnetic resonance imaging (MRI) with the determination of the 1p/19q codeletion status could improve the ability to predict anaplastic transformation in low-grade oligodendrogliomas. Twenty patients with grade II oligodendrogliomas were followed-up using multimodal MR [proton MR spectroscopy (MRS), perfusion, and conventional MR imaging]. All patients diagnoses were histologically proven, and 1p/19q codeletion status was analyzed for all patients. Median follow-up was 30.5 ± 11.4 months. Anaplastic transformation was observed in six patients. The only MRI feature that was associated with anaplastic transformation was an elevation of the choline/creatine ratio >2.4 which was observed in 4 out of 6 patients with anaplastic transformation versus 1 out of 14 patients without anaplastic transformation. In patients without 1p/19q codeletion, an elevation of the choline/creatine ratio >2.4 was associated with the occurrence of anaplastic transformation in all cases (4 out of 4 patients), with a mean time of 12 months. In contrast, in patients with a 1p/19q codeletion, no anaplastic transformation was observed in the patient who had an elevation of >2.4 of the choline/creatine ratio and two patients demonstrated an anaplastic transformation without any elevation of this ratio.Prospective validation in a larger series is needed, yet the present study suggests that combining data from in vivo proton MRS and genetic analysis could be a promising strategy to predict time to anaplastic transformation at the individual level in patients with low-grade oligodendrogliomas and may help deciding when chemotherapy and/or radiotherapy should be initiated in these tumors.

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.

Neurocognitive Function Following Therapy for Low-Grade Gliomas

Low-grade gliomas (LGGs) are a heterogenous group of primary brain neoplasms that most commonly occur in children and young adults, characterized by a slow, indolent course and overall favorable prognosis. Standard therapies used to treat LGGs have included surgical resection, radiotherapy, chemotherapy, or a combination thereof. Given the anticipated long survival and typical young age of patients with LGG, the long-term sequelae of therapy require special attention, especially as they affect neurocognitive function and quality of life. We review the complex interplay of baseline and treatment-related factors that perturb neurocognition as well as the effect of each treatment modality on altering neurocognitive outcomes in this patient population.

Radiation Therapy Oncology Group 9802: Controversy or Consensus in the Treatment of Newly Diagnosed Low-Grade Glioma?

Treatment of newly diagnosed or suspected low-grade glioma (LGG) is one of the most controversial areas in neuro-oncology. The heterogeneity of these tumors, concern regarding morbidity of treatment, and absence of proven overall survival benefit from any known treatment have resulted in a lack of consensus regarding the timing and extent of surgery, timing of radiotherapy (RT), and role of chemotherapy. The long-term results of Radiation Therapy Oncology Group (RTOG) 9802, a phase III randomized trial comparing RT alone with RT and 6 cycles of adjuvant procarbazine, CCNU, vincristine (PCV), demonstrated an unprecedented 5.5-year improvement in median overall survival with the addition of PCV chemotherapy in high-risk patients with LGG. These results are practice changing and define a new standard of care for these patients. However, in the intervening decade since the trial was completed, novel molecular markers as well as newer chemotherapy agents such as temozolomide have been developed, which make these results difficult to incorporate into clinical practice. This review summarizes the evidence for and against the role of upfront RT and PCV in newly diagnosed patients with LGG.

Clinical value of O-(2-[(18)F]-fluoroethyl)-L-tyrosine positron emission tomography in patients with low-grade glioma

Progress in morphological imaging has facilitated the diagnosis of low-grade glioma (LGG) and plays a decisive role in therapeutic decisions. To date, the method of choice is contrast-enhanced MRI including T1-/T2-weighted and FLAIR sequences. However, tumor delineation and the differentiation between neoplastic and normal brain tissue can be difficult when using morphological MRI and may complicate the identification of anaplastic foci for biopsy and further treatment planning. Furthermore, therapy monitoring and the differentiation of tumor recurrence from unspecific post-therapeutic changes in the tissue are challenging. Additional information about tumor metabolism may be very helpful for the diagnostic assessment of LGG and can be provided by PET. In recent years, the PET amino acid tracer O-(2-[(18)F]-fluoroethyl)-L-tyrosine ((18)F-FET) has been clinically validated for brain tumor diagnosis. This tracer has logistical advantages over the widely used PET tracer (11)C-methyl-L-methionine due to the longer half-life of the (18)F-label (109 vs 20 minutes, respectively). Additionally, it has been demonstrated that both tracers provide comparable diagnostic information. The authors provide an overview of the recent literature regarding the value of various clinical applications of (18)F-FET PET in patients with LGG.