Intraoperative Ventricular Opening has No Effect on Complication Development Following BCNU Wafer Implantation for Malignant Glioma

OBJECTIVE

To evaluate the safety profile of bis-chloroethyl-nitrosourea (BCNU) wafer implantation after malignant glioma resection with or without ventricular opening (VO).

METHODS

This single-center retrospective study included 66 consecutive patients with BCNU wafer implantation after malignant glioma resection between March 2013 and August 2021. The patients were categorized into 2 groups based on whether VO occurred during the malignant glioma resection. Fifty-eight patients had glioblastoma, and 8 had anaplastic astrocytoma or oligodendroglioma. Forty-eight patients underwent an initial treatment, and 18 underwent recurrent surgeries. Infection, hydrocephalus, subcutaneous fluid collection, chronic subdural hematoma, early seizure after surgery within 1 month, symptomatic edema surrounding the resected cavity, cyst formation, and postoperative hemorrhage were defined as adverse events (AEs).

RESULTS

Thirty-three patients underwent resection with VO, and 33 without. The median survival time was 28 months in the initial treatment group and 11.5 months in the recurrent treatment group. The with and without VO groups had similar median survival times. Postoperative AEs occurred in 7/33 patients (21.2%) with VO and 10/33 (30.3%) without VO, with no difference between them (P = 0.574).

CONCLUSIONS

This study showed that VO during surgery with BCNU wafer implantation might not influence the occurrence of postoperative AEs. If VO happens, BCNU wafer implantation can be performed safely with accurate closing of the ventricle.

Early Therapeutic Interventions for Newly Diagnosed Glioblastoma: Rationale and Review of the Literature

PURPOSE OF REVIEW

Glioblastoma is the commonest primary brain cancer in adults whose outcomes are amongst the worst of any cancer. The current treatment pathway comprises surgery and postoperative chemoradiotherapy though unresectable diffusely infiltrative tumour cells remain untreated for several weeks post-diagnosis. Intratumoural heterogeneity combined with increased hypoxia in the postoperative tumour microenvironment potentially decreases the efficacy of adjuvant interventions and fails to prevent early postoperative regrowth, called rapid early progression (REP). In this review, we discuss the clinical implications and biological foundations of post-surgery REP. Subsequently, clinical interventions potentially targeting this phenomenon are reviewed systematically.

RECENT FINDINGS

Early interventions include early systemic chemotherapy, neoadjuvant immunotherapy, local therapies delivered during surgery (including Gliadel wafers, nanoparticles and stem cell therapy) and several radiotherapy techniques. We critically appraise and compare these strategies in terms of their efficacy, toxicity, challenges and potential to prolong survival. Finally, we discuss the most promising strategies that could benefit future glioblastoma patients. There is biological rationale to suggest that early interventions could improve the outcome of glioblastoma patients and they should be investigated in future trials.

Long-term follow-up after BCNU wafer implantation in patients with newly diagnosed glioblastoma

1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU, or Carmustine) wafers are intraoperatively implantable wafers used to achieve local tumor control. There is scarce data about the behavior of wafers in the long-term follow-up of implanted cases. We reviewed the data of 64 patients with newly diagnosed glioblastoma treated by surgery, BCNU wafers, radiation therapy, and temozolomide administration. This cohort included 55 patients who presented first recurrence, and 49 of them showed tumor progression to death. The MR imaging of each patient at the terminal stage and an autopsy case were used to elucidate the tumor progression pattern after the wafer implantation. We subdivided the first recurrence pattern into local, distant, and multifocal based on MR imaging or into infield, outfield, and marginal based on the radiation field. The first recurrence pattern was 33 patients (60%) with local, 13 (24%) with distant, and nine (16%) with multifocal recurrence, or 38 patients (69%) with infield, 13 (24%) with outfield, and four (7%) with marginal. The median and mean time intervals between MR imaging at the terminal stage and death were 2.0 and 2.3 months, respectively. Of note, 13 patients with first distant recurrence had no obvious radiological local tumor progression even at the terminal stage. Long-term follow-up after BCNU wafer implantation revealed that patients with first distant recurrence had long-lasting local tumor control until the terminal stage.

Adverse Event with the Use of Carmustine Wafers and Postoperative Radiochemotherapy for the Treatment of High-grade Glioma

Randomized, controlled trials have shown significant improvement of survival after implantation of 1,3-bis(2-Chloroethyl)-1-nitrosourea (BCNU) wafers for patients suffering from high-grade glioma. A combination of local chemotherapy with BCNU and concomitant radiochemotherapy with temozolomide (TMZ) appears to be attractive to enhance the overall survival, even though these treatments may potentially cumulate their toxicity. We report a clinical case of a patient submitted to this combined treatment protocol. Severe brain edema and a cystic formation in the surgical cavity rapidly developed. Data supporting the use of Gliadel® combined with TMZ comes from small retrospective studies, and some series have shown a very high rate of adverse events (AEs) when this multimodality treatment is applied. Combined protocols of local and systemic chemotherapy might provide survival benefits, although AEs seem currently underestimated.

In vitro Study of Serial Changes to Carmustine Wafers (Gliadel) with MR Imaging and Computed Tomography

PURPOSE

Implantation of carmustine wafers (Gliadel) in vivo is accompanied by characteristic serial changes on MRI and CT, such as transient hyperintensity of the wafers on T₁-weighted images (T₁WIs) and considerable gas accumulation in surgical resection cavities. The purpose of this study was to evaluate intrinsic imaging changes to carmustine wafers in vitro.

METHODS

Three phantoms simulating a surgical resection cavity were constructed. Each contained either a carmustine wafer fixed with oxidized regenerated cellulose and fibrin sealant, an unfixed carmustine wafer, or a fixed polyethylene control disk, immersed in phosphate-buffered saline. Image acquisition of the phantoms was performed on MRI and CT until 182 days after construction. The radiological appearances of the object in each phantom were assessed by visual evaluation and quantification of the region of interest. The volume of gas around the objects at 24 h after constructing the phantoms was also measured.

RESULTS

The carmustine wafers showed low signal intensities on T₁WIs and T₂-weighted images (T₂WIs), and high densities on CT images at 24 h. The signal intensities and CT densities gradually approximated those of saline over a period of months. However, the carmustine wafers never showed hyperintensity on T₁WIs in vitro. The fixed carmustine wafer showed slower radiological changes, as compared to the unfixed wafer. The gas volume around the fixed carmustine wafer was greater than that around the fixed control disk.

CONCLUSION

Changes to the carmustine wafers probably reflected penetration of fluid inside and degradation of the hydrophobic matrix. Reported transient hyperintensity of wafers on T₁WIs in vivo is regarded as the result of biological reactions, whereas the initial production of gas is considered as an intrinsic characteristic of wafers.

Safety and efficacy of carmustine (BCNU) wafers for metastatic brain tumors

BACKGROUND

Carmustine (BCNU) wafers (Gliadel) prolongs local disease control and progression-free survival (PFS) in patients with malignant gliomas. However, in metastatic brain tumors, there is a paucity of evidence in support of its safety and efficacy. The goal of this study was to assess the safety and efficacy of Gliadel wafers in patients with metastatic brain tumors.

METHODS

We retrospectively reviewed the University of Washington experience with Gliadel wafers for metastatic brain tumors between 2000 and 2015.

RESULTS

Gliadel wafers were used in 14 patients with metastatic brain tumors during the period reviewed. There were no postoperative seizures, strokes, or hemorrhages. There was one postoperative wound infection necessitating return to the operating room. The mean time to tumor progression (n = 7) and death (n = 5) after Gliadel wafer implantation was 2.5 and 2.9 years, respectively. Age was the only variable affecting PFS in patients receiving Gliadel wafers. Patients <53 years old (n = 7) had a PFS of 0.52 years, whereas patients >53 years old (n = 7) had a PFS of 4.29 years (P = 0.02). There was no significant difference in PFS in relation to presenting Karnofsky Performance Status (P = 0.26), number of brain metastasis (P = 0.82), tumor volume (P = 0.54), prior surgery (P = 0.57), or prior radiation (P = 0.41). There were no significant differences in the mean survival in relationship to any variable including age.

CONCLUSIONS

BCNU wafers are a safe and a potentially efficacious adjunct to surgery and radiation for improving local disease control in metastatic brain tumors. Larger studies, however, are needed to examine overall efficacy and tumor specific efficacy.

Novel delivery methods bypassing the blood-brain and blood-tumor barriers

Glioblastoma (GBM) is the most common primary brain tumor and carries a grave prognosis. Despite years of research investigating potentially new therapies for GBM, the median survival rate of individuals with this disease has remained fairly stagnant. Delivery of drugs to the tumor site is hampered by various barriers posed by the GBM pathological process and by the complex physiology of the blood-brain and blood-cerebrospinal fluid barriers. These anatomical and physiological barriers serve as a natural protection for the brain and preserve brain homeostasis, but they also have significantly limited the reach of intraparenchymal treatments in patients with GBM. In this article, the authors review the functional capabilities of the physical and physiological barriers that impede chemotherapy for GBM, with a specific focus on the pathological alterations of the blood-brain barrier (BBB) in this disease. They also provide an overview of current and future methods for circumventing these barriers in therapeutic interventions. Although ongoing research has yielded some potential options for future GBM therapies, delivery of chemotherapy medications across the BBB remains elusive and has limited the efficacy of these medications.

MGMT inactivation and clinical response in newly diagnosed GBM patients treated with Gliadel

We examined the relationship between the O(6)-methylguanine-methyltransferase (MGMT) methylation status and clinical outcomes in newly diagnosed glioblastoma multiforme (GBM) patients who were treated with Gliadel wafers (Eisai, Tokyo, Japan). MGMT promoter methylation has been associated with increased survival among patients with GBM who are treated with various alkylating agents. MGMT promoter methylation, in DNA from 122 of 160 newly diagnosed GBM patients treated with Gliadel, was determined by a quantitative methylation-specific polymerase chain reaction, and was correlated with overall survival (OS) and recurrence-free survival (RFS). The MGMT promoter was methylated in 40 (32.7%) of 122 patients. The median OS was 13.5 months (95% confidence interval [CI] 11.0-14.5) and RFS was 9.4 months (95% CI 7.8-10.2). After adjusting for age, Karnofsky performance score, extent of resection, temozolomide (TMZ) and radiation therapy (RT), the newly diagnosed GBM patients with MGMT methylation had a 15% reduced mortality risk, compared to patients with unmethylated MGMT (hazard ratio 0.85; 95% CI 0.56-1.31; p=0.46). The patients aged over 70 years with MGMT methylation had a significantly longer median OS of 13.5 months, compared to 7.6 months in patients with unmethylated MGMT (p=0.027). A significant difference was also found in older patients, with a median RFS of 13.1 versus 7.6 months for methylated and unmethylated MGMT groups, respectively (p=0.01). Methylation of the MGMT promoter in newly diagnosed GBM patients treated with Gliadel, RT and TMZ, was associated with significantly improved OS compared to the unmethylated population. In elderly patients, methylation of the MGMT promoter was associated with significantly better OS and RFS.

Gliadel wafers in the treatment of malignant glioma: a systematic review

Question

What is the safety and efficacy of interstitial chemotherapy with carmustine-loaded polymers (Gliadel wafers: MGI Pharma, Bloomington, MN, U.S.A.) in the treatment of newly diagnosed or recurrent malignant glioma (that is, glioblastoma multiforme, anaplastic astrocytoma, anaplastic oligoastrocytoma, and anaplastic oligodendroglioma)?

Perspectives

Malignant glioma is the most common type of primary brain tumour in adults. In general, efficacy of systemic therapy in this patient population has been disappointing, and novel treatment approaches are needed. Because several randomized controlled trials (rcts) investigating the safety and efficacy of Gliadel are available, the Neuro-oncology Disease Site Group of Cancer Care Ontario’s Program in Evidence-Based Care decided that a systematic review of the evidence was necessary.

Outcomes

The outcomes of interest for this review were overall survival, adverse events, and quality of life.

Methodology

Systematic searches of the medline, embase, and Cochrane Library databases were conducted for relevant evidence. Fully-published reports of rcts comparing treatment with Gliadel wafers to placebo or alternative treatment were selected for inclusion. Prospective cohort studies were also included.

Results

Two rcts that compared Gliadel to placebo in patients with newly diagnosed malignant glioma were obtained. Both rcts reported a significant survival benefit for patients who received Gliadel as compared with patients in the control group. One rct and one prospective cohort study were obtained that examined the role of Gliadel in patients with recurrent malignant glioma. The rct demonstrated a significant survival benefit for Gliadel only after adjustment for prognostic factors, and the prospective cohort study reported no survival benefit for Gliadel as compared with a historical control group. All three rcts reported similar rates of adverse events in the treatment and control groups. The most frequently reported adverse events were convulsions, confusion, brain edema, infection, hemiparesis, aphasia, and visual field defects.

Conclusions

Gliadel is an option for selected patients with newly diagnosed malignant glioma where a near gross total resection is possible. No evidence is available comparing Gliadel with systemic therapy, and a decision to combine Gliadel with systemic therapy should be made for patients individually. The patient population that would benefit from Gliadel (age, histology, and performance status) is unclear; further investigation is needed. Gliadel is also an option for patients with surgically resectable recurrent malignant glioma.