Effect of neoadjuvant temozolomide upon volume reduction and resection of diffuse low-grade glioma

Advanced targeted microsphere embolization for arteriovenous malformations: state-of-the-art and future directions

BACKGROUND

Arteriovenous malformations (AVMs) present a significant therapeutic challenge, as current treatment modalities frequently fail to achieve complete and rapid obliteration and are associated with substantial morbidity in both the short and long term. This underscores the critical need for innovative therapeutic strategies that enable efficient AVM obliteration while minimizing patient risk. The current review aims to comprehensively assess the role of ATME in AVM management, examining its clinical efficacy, associated risks and benefits, and the economic and ethical implications to provide valuable foundation for future studies and guiding development in treatment strategies for AVMs.

RESULTS

Advanced targeted microsphere embolization (ATME) has emerged as a promising therapeutic option, initially developed for the localized treatment of AVMs and unresectable tumors, including liver cancer. By providing targeted delivery, ATME offers potential advantages over conventional approaches in achieving effective local control.

CONCLUSIONS

ATME are safe and effective for vascular disease and cancer. Although evidence for microspheres in AVMs is scarce, results are promising. Future research could refine eligibility criteria, evaluate treatment techniques, and optimize ATME.

Postoperative NEOadjuvant TEMozolomide followed by chemoradiotherapy versus upfront chemoradiotherapy for glioblastoma multiforme (NEOTEM) trial: Interim results

Background

Glioblastoma multiforme (GBM) is an aggressive brain tumor with poor survival rates despite current treatments. The standard of care (SOC) includes surgery, followed by radiotherapy plus concurrent and adjuvant chemotherapy with temozolomide (TMZ). This phase II trial assessed the safety and efficacy of neoadjuvant TMZ (nTMZ) before and during chemoradiotherapy in newly diagnosed GBM patients.

Methods

Newly diagnosed GBM patients who underwent maximal safe resection were randomized into 2 groups. One received nTMZ before standard chemoradiotherapy and adjuvant TMZ (intervention). The other received standard chemoradiotherapy followed by adjuvant TMZ (control). Primary endpoints were progression-free survival (PFS) at 6 and 12 months. Secondary endpoints included overall survival, radiological and clinical responses, and adverse events.

Results

Of 35 patients, 16 were in the intervention group and 19 in the control group. Median PFS was 9 months (95% CI: 3.93-14.06) versus 3 months (95% confidence interval [CI]: 1.98-4.01) in the control and intervention groups (P = .737), with a high progression rate (73.4%) during nTMZ treatment. The 6-month PFS rates were 58% versus 25% (P = .042), and 12-month PFS rates were 26% versus 25% (P = .390) in the control and intervention groups, respectively. Patients with unmethylated O6-methylguanine-DNA methyltransferase (MGMT) and those with good performance status (PS) had significantly worse PFS with nTMZ.  However, those who underwent larger extent of resection exhibited significantly better PFS  with nTMZ. Adverse events were similar between groups.

Conclusions

Neoadjuvant TMZ before SOC chemoradiotherapy did not improve outcomes for newly diagnosed GBM patients and is unsuitable for those with unmethylated MGMT and good PS. However, It may benefit patients with near or gross total resection. Further research is needed to refine GBM treatment strategies.

Oncological, cognitive, and employment outcomes in a series of patients with IDH-mutated glioma resected following neoadjuvant chemotherapy

PURPOSE

Maximal safe tumor resection is the first line of treatment for IDH-mutated gliomas. However, when upfront surgical resection is deemed unsatisfactory due to tumor size and location, chemotherapy could represent an interesting alternative for reducing glioma extension and allowing for a safer and more efficient removal.

METHODS

We performed a retrospective study (June 2011 to December 2021) on patients with IDH-mutated gliomas undergoing chemotherapy with a neoadjuvant intent, followed by surgical excision in awake conditions. MRI-imaging follow-up was conducted every 3-6 months. Neuropsychological assessments (NPSA) were performed for all patients before surgery, during post-operative period, and at later follow-up, and patients were periodically interviewed about their clinical and job status.

RESULTS

We included 6 patients who underwent awake surgery after neoadjuvant chemotherapy (temozolomide in 5 cases, PCV in 1 case) for an IDH-mutated glioma (3 oligodendrogliomas and 3 astrocytomas). Median tumor volume reduction was 47%, allowing for complete resection in one patient, subtotal resection in 4 patients, and partial resection in 1 patient. No major adverse effects were observed under chemotherapy. At the 4 months NPSA, a worsening of flexibility was observed in 2 patients (verbal fluencies in one case and trail making test in the other). Three out of the four patients working full time before procedure resumed their job full time, after a 7 to 10 months delay.

CONCLUSION

Neoadjuvant chemotherapy followed by maximal safe resection can be offered to patients affected by IDH-mutated gliomas for whom upfront surgery would be inadequate. More studies are necessary given the limited size of our sample.

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.

The Concept of «Peritumoral Zone» in Diffuse Low-Grade Gliomas: Oncological and Functional Implications for a Connectome-Guided Therapeutic Attitude

Diffuse low-grade gliomas (DLGGs) are heterogeneous and poorly circumscribed neoplasms with isolated tumor cells that extend beyond the margins of the lesion depicted on MRI. Efforts to demarcate the glioma core from the surrounding healthy brain led us to define an intermediate region, the so-called peritumoral zone (PTZ). Although most studies about PTZ have been conducted on high-grade gliomas, the purpose here is to review the cellular, metabolic, and radiological characteristics of PTZ in the specific context of DLGG. A better delineation of PTZ, in which glioma cells and neural tissue strongly interact, may open new therapeutic avenues to optimize both functional and oncological results. First, a connectome-based “supratotal” surgical resection (i.e., with the removal of PTZ in addition to the tumor core) resulted in prolonged survival by limiting the risk of malignant transformation, while improving the quality of life, thanks to a better control of seizures. Second, the timing and order of (neo)adjuvant medical treatments can be modulated according to the pattern of peritumoral infiltration. Third, the development of new drugs specifically targeting the PTZ could be considered from an oncological (such as immunotherapy) and epileptological perspective. Further multimodal investigations of PTZ are needed to maximize long-term outcomes in DLGG patients.

Effect of neoadjuvant iodine-125 brachytherapy upon resection of glioma

Background

A more extensive surgical resection of glioma contributes to improved overall survival (OS) and progression-free survival (PFS). However, some patients miss the chance of surgical resection when the tumor involves critical structures.

Purpose

The present study aimed to assess the feasibility of neoadjuvant ¹²⁵I brachytherapy followed by total gross resection for initially inoperable glioma.

Methods

Six patients diagnosed with inoperable glioma due to invasion of eloquent areas, bihemispheric diffusion, or large tumor volume received ¹²⁵I brachytherapy. Surgical resection was performed when the tumor shrank, allowing a safe resection, assessed by the neurosurgeons. Patients were followed up after surgery.

Results

Shrinkage of the tumor after adjuvant ¹²⁵I brachytherapy enabled a total gross resection of all six patients. Four patients were still alive at the last follow-up, with the longest survival time of more than 50 months, two of which returned to everyday life with a KPS of 100. Another two patients had neurological injuries with KPSs of 80 and 50, respectively. One patient with grade II glioma died 34 months, and another with grade IV glioma died 40 months after the combined therapy.

Conclusions

In the present study, the results demonstrated that ¹²⁵I brachytherapy enabled a complete resection of patients with initially unresectable gliomas. ¹²⁵I brachytherapy may offer a proper neoadjuvant therapy method for glioma.

The Role of Neoadjuvant Therapy to Improve the Extent of Resection in "Unresectable" Gliomas

BACKGROUND

Surgical resection plays a pivotal role in the management of glial tumors and a greater extent of resection (EOR) should be the goal in most surgeries to improve overall survival. Many factors may limit the EOR. A potential role for preoperative chemotherapy to decrease the volume and/or infiltration of gliomas, thereby facilitating a safe radical resection, has been recently suggested. This review aims to provide an overview of the current state of neoadjuvant therapy in the field of glioma surgery.

METHODS

A systematic review was conducted according to PRISMA guidelines to identify articles of low- and high-grade gliomas that received neoadjuvant chemotherapy prior to surgery to improve the EOR from 2000 to 2020. Full-text articles that addressed this subject were included for evaluation.

RESULTS

Case reports and clinical trials have been published for the use of chemotherapy as a neoadjuvant therapy to improve surgical resection in low-grade gliomas. More scarce information exists regarding this strategy for high-grade glioma surgery.

CONCLUSIONS

Neoadjuvant chemotherapy has played a role in overcoming obstacles that limit the EOR in patients with complex gliomas, especially low-grade gliomas.

The Ethical Dilemma in the Surgical Management of Low Grade Gliomas According to the Variable Availability of Resources and Surgeon Experience

Low grade gliomas (LGGs) affect young individuals in the prime of life. Management may alternatively include biopsy and observation or surgical resection. Recent evidence strongly favors maximal and supramaximal resection of LGGs in optimizing survival metrics. Awake craniotomy with cortical mapping and electrical stimulation along with other preoperative and intraoperative surgical adjuncts, including intraoperative magnetic resonance and diffusion tensor imaging, facilitates maximization of resection and eschews precipitating neurological deficits. Intraoperative imaging permits additional resection of identified residual to be completed within the same surgical session, improving extent of resection and consequently progression free and overall survival. These resources are available in only a few centers throughout the United States, raising an ethical dilemma as to where patients harboring LGGs should most appropriately be treated.

Computational design of improved standardized chemotherapy protocols for grade II oligodendrogliomas

Here we put forward a mathematical model describing the response of low-grade (WHO grade II) oligodendrogliomas (LGO) to temozolomide (TMZ). The model describes the longitudinal volumetric dynamics of tumor response to TMZ of a cohort of 11 LGO patients treated with TMZ. After finding patient-specific parameters, different therapeutic strategies were tried computationally on the 'in-silico twins' of those patients. Chemotherapy schedules with larger-than-standard rest periods between consecutive cycles had either the same or better long-term efficacy than the standard 28-day cycles. The results were confirmed in a large trial of 2000 virtual patients. These long-cycle schemes would also have reduced toxicity and defer the appearance of resistances. On the basis of those results, a combination scheme consisting of five induction TMZ cycles given monthly plus 12 maintenance cycles given every three months was found to provide substantial survival benefits for the in-silico twins of the 11 LGO patients (median 5.69 years, range: 0.67 to 68.45 years) and in a large virtual trial including 2000 patients. We used 220 sets of experiments in-silico to show that a clinical trial incorporating 100 patients per arm (standard intensive treatment versus 5 + 12 scheme) could demonstrate the superiority of the novel scheme after a follow-up period of 10 years. Thus, the proposed treatment plan could be the basis for a standardized TMZ treatment for LGO patients with survival benefits.

Chemotherapy and diffuse low-grade gliomas: a survey within the European Low-Grade Glioma Network

BACKGROUND

Diffuse low-grade gliomas (DLGGs) are rare and incurable tumors. Whereas maximal safe, functional-based surgical resection is the first-line treatment, the timing and choice of further treatments (chemotherapy, radiation therapy, or combined treatments) remain controversial.

METHODS

An online survey on the management of DLGG patients was sent to 28 expert centers from the European Low-Grade Glioma Network (ELGGN) in May 2015. It contained 40 specific questions addressing the modalities of use of chemotherapy in these patients.

RESULTS

The survey demonstrated a significant heterogeneity in practice regarding the initial management of DLGG patients and the use of chemotherapy. Interestingly, radiation therapy combined with the procarbazine, CCNU (lomustine), and vincristine regimen has not imposed itself as the gold-standard treatment after surgery, despite the results of the Radiation Therapy Oncology Group 9802 study. Temozolomide is largely used as first-line treatment after surgical resection for high-risk DLGG patients, or at progression.

CONCLUSIONS

The heterogeneity in the management of patients with DLGG demonstrates that many questions regarding the postoperative strategy and the use of chemotherapy remain unanswered. Our survey reveals a high recruitment potential within the ELGGN for retrospective or prospective studies to generate new data regarding these issues.

An attempt to conceptualize the individual onco-functional balance: Why a standardized treatment is an illusion for diffuse low-grade glioma patients

In the era of evidence-based medicine, clinicians aim to establish standards of care from randomized studies. Following, personalized medicine has emerged, as new individualized biomarkers could help to predict sensitivity to specific treatment. In this paper, we show that, for diffuse low-grade glioma, some specificities - dual goal of both survival and functional gain, long duration of the disease with multistep treatments, multiparametric evaluation of the onco-functional balance of each treatment modality - call for a change of paradigm. After summarizing how to weight the benefits and risks of surgery, chemotherapy and radiotherapy, we show that the overall efficacy of a treatment modality cannot be assessed per se, as it depends on its integration in the whole sequence. Then, we revisit the notion of personalized medicine: instead of decision-making based solely on molecular profile, we plead for a recursive algorithm, allowing a dynamic evaluation of the onco-functional balance, integrating many individual characteristics of the patient's tumor and brain function.

Survey on current practice within the European Low-Grade Glioma Network: where do we stand and what is the next step?

Diffuse low-grade glioma form a rare entity affecting young people. Despite advances in surgery, chemotherapy, and radiation therapy, diffuse low-grade glioma are still incurable. According to current guidelines, maximum safe resection, when feasible, is the first line of treatment. Apart from surgery, all other treatment modalities (temozolomide, procarbazine-CCNU-vincristine regimen, and radiation therapy) are handled very differently among different teams, and this in spite of recent results of several phase 3 studies. Based on a European survey, this paper aimed to get a picture of this heterogeneity in diffuse low-grade glioma management, to identify clinically relevant questions raised by this heterogeneity of practice, and to propose new methodological frameworks to address these questions.