Early treatment of complex located pediatric low-grade gliomas using iodine-125 brachytherapy alone or in combination with microsurgery

Tolerance limit of external beam radiotherapy combined with low-dose rate brachytherapy in normal rabbit tissue

BACKGROUND

Dosage-optimized multimodal radiotherapies that are safe for head and neck cancer patients are desirable. In this study, we investigated tissue tolerance to varying doses of external beam radiotherapy (EBRT) combined with low-dose rate brachytherapy in the neck of a rabbit model.

METHODS

Twenty rabbits were used in the four test groups (five each) with iodine-125 seeds implanted in the neck treated with EBRT in four doses at 50, 40, 30 and 20 Gy each. Twelve rabbits for three control groups (four each). Three months after implantation, all rabbits were euthanized, and target tissues were collected. Analyses included seed implantation assessment, histopathological evaluation, immunohistochemistry staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, electron microscopy and statistics with the SPSS software.

RESULTS

Five rabbits died in the four test groups, and three rabbits died in the three control groups (one per group), which showed no significant difference by survival analysis. The calculated minimum peripheral dose was 17.6 Gy, the maximum dose near the seed was 1812.5 Gy, the D90 was 34.5 Gy and the mean dose was 124.5 Gy. In all groups that received radiation, apoptosis occurred primarily in the esophageal mucosa and corresponded to the dose of radiation; a higher dose caused a greater apoptosis, with significant difference between groups (P < 0.05). Electron microscopy of carotid arteries revealed that endothelial cells were swollen and some were shed from basement membrane, but no other noticeable tissue damages.

CONCLUSIONS

Limited EBRT at maximal dose (50 Gy) combined with the brachytherapy interstitially applied to the neck was tolerated well in the rabbit model.

Radiation necrosis after a combination of external beam radiotherapy and iodine-125 brachytherapy in gliomas

Purpose

Frequency and risk profile of radiation necrosis (RN) in patients with glioma undergoing either upfront stereotactic brachytherapy (SBT) and additional salvage external beam radiotherapy (EBRT) after tumor recurrence or vice versa remains unknown.

Methods

Patients with glioma treated with low-activity temporary iodine-125 SBT at the University of Munich between 1999 and 2016 who had either additional upfront or salvage EBRT were included. Biologically effective doses (BED) were calculated. RN was diagnosed using stereotactic biopsy and/or metabolic imaging. The rate of RN was estimated with the Kaplan Meier method. Risk factors were obtained from logistic regression models.

Results

Eighty-six patients (49 male, 37 female, median age 47 years) were included. 38 patients suffered from low-grade and 48 from high-grade glioma. Median follow-up was 15 months after second treatment. Fifty-eight patients received upfront EBRT (median total dose: 60 Gy), and 28 upfront SBT (median reference dose: 54 Gy, median dose rate: 10.0 cGy/h). Median time interval between treatments was 19 months. RN was diagnosed in 8/75 patients. The 1- and 2-year risk of RN was 5.1% and 11.7%, respectively. Tumor volume and irradiation time of SBT, number of implanted seeds, and salvage EBRT were risk factors for RN. Neither of the BED values nor the time interval between both treatments gained prognostic influence.

Conclusion

The combination of upfront EBRT and salvage SBT or vice versa is feasible for glioma patients. The risk of RN is mainly determined by the treatment volume but not by the interval between therapies.

Radiotherapy in the Management of Paediatric Low-Grade Gliomas

Paediatric low-grade (World Health Organization grade I-II) gliomas (LGGs) represent a spectrum of primary central nervous system tumours. Local tumour control is the cornerstone in the general management of childhood gliomas. Surgery is the primary treatment of choice in the majority. Non-surgical treatments are recommended for progressive or symptomatic inoperable disease. Although chemotherapy is increasingly used as first non-surgical treatment, radiotherapy remains standard as salvage treatment or as primary treatment in selected cases in which surrounding normal tissue can be optimally preserved. The role of targeted therapies is currently under investigation in clinical trials. Modern high-precision radiotherapy techniques, including proton therapy, have the potential to improve long-term toxicities. There is therefore an urgent need for prospective studies to compare the efficacy and safety of modern radiotherapy with systemic treatment in children with LGGs. New information on molecular genetic patterns in LGGs may also have an impact on the selection and sequencing of radiotherapy.

Predictive factors of benefit from iodine-125 brachytherapy for hepatocellular carcinoma with portal vein tumor thrombosis

PURPOSE

The aims of this study were to evaluate treatment responses and predictive factors for overall survival (OS) in hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT) treated with iodine-125 (¹²⁵I) brachytherapy.

METHODS AND MATERIALS

Seventy-seven HCC patients with PVTT underwent ¹²⁵I brachytherapy after transcatheter arterial chemoembolization. Clinical, laboratory, and radiological evaluation were performed before and after treatment, as well as at 4-6 weeks intervals for 7 years to assess the efficacy and toxicity of therapy. Treatment response was assessed using modified response evaluation criteria in solid tumors. OS and predictive factors for each subgroup were evaluated after treatment.

RESULTS

In total, 11 patients (14.29%) achieved complete response, and 41 patients (53.25%) achieved partial response. The response rate (complete response + partial response) was 67.53% (52/77). The median OS was 9 months. The multivariable Cox regression model indicated that post-treatment tumor size with PVTT (p = 0.016, hazard ratio [HR] = 1.889, 95% confidence interval [CI]: 1.127 to 3.166) and baseline hemoglobin (p = 0.013, HR=0.518, 95% CI: 0.308 to 0.872) and alkaline phosphatase (p = 0.002, HR=2.275, 95% CI: 1.338 to 3.868) levels were significant independent predictors of OS.

CONCLUSIONS

¹²⁵I brachytherapy results in favorable treatment responses in HCC patients with PVTT. Notably, post-treatment tumor size and baseline hemoglobin and alkaline phosphatase levels are significant independent predictive factors for OS and provide the most predictive information regarding OS.

MEG-3-mediated Wnt/β-catenin signaling pathway controls the inhibition of tunicamycin-mediated viability in glioblastoma

Glioblastoma is the most common primary brain carcinoma and leads to a poor survival rate of patients worldwide. Results of previous studies have suggested that tunicamycin may inhibit aggressiveness by promoting apoptosis of glioblastoma cells. In the present study, the effects of tunicamycin and its potential molecular mechanisms underlying the viability and aggressiveness of glioblastoma cells were investigated. Western blot analysis, the reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, apoptosis assays and immunofluorescence were employed to examine the effects of tunicamycin on apoptosis, viability, aggressiveness and cell cycle arrest of glioblastoma cells by downregulation of the expression levels of fibronectin and epithelial cadherin. In vitro experiments demonstrated that tunicamycin significantly inhibited the viability, migration and invasion of glioblastoma cells. Results demonstrated that tunicamycin administration promoted apoptosis of glioblastoma cells through the upregulation of poly(ADP-ribose) polymerase and caspase-9. Cell cycle assays revealed that tunicamycin suppressed the proliferation of, and induced cell cycle arrest at S phase in, glioblastoma cells. Additionally, tunicamycin increased the expression of maternally expressed gene-3 (MEG-3) and wingless/integrated (Wnt)/β-catenin in glioblastoma cells. Results also indicated that tunicamycin administration promoted the Wnt/β-catenin signaling pathway in glioblastoma cells. Knockdown of MEG-3 inhibited tunicamycin-mediated downregulation of the Wnt/β-catenin signaling pathway, which was inhibited further by tunicamycin-mediated inhibition of viability and aggressiveness in glioblastoma. In vivo assays demonstrated that tunicamycin treatment significantly inhibited tumor viability and promoted apoptosis, which further led to an increased survival rate of tumor-bearing mice compared with that of the control group. In conclusion, these results indicate that tunicamycin may inhibit the viability and aggressiveness by regulating MEG-3-mediated Wnt/β-catenin signaling, suggesting that tunicamycin may be a potential anticancer agent for glioblastoma therapy.

Tunicamycin inhibits progression of glioma cells through downregulation of the MEG-3-regulated wnt/β-catenin signaling pathway

Glioma is derived from the oncogenic transformation of brain and spinal cord glial cells, and is one of the most common primary brain tumors. Tunicamycin (TUN) can significantly inhibit glioma growth and aggressiveness by promoting apoptosis in glioma cells. The purpose of the present study was to investigate the effects of TUN on growth of glioma cells and examine the TUN-mediated signaling pathway. The inhibitory effects of TUN on apoptosis, growth, aggressiveness and cell cycle arrest of glioma tumor cells were determined by western blotting, reverse transcription-quantitative polymerase chain reaction, apoptotic assays and immunofluorescence. The results demonstrated that treatment with TUN suppressed growth, migration and invasion of glioma carcinoma cells. In addition, TUN treatment induced apoptosis of glioma cells through downregulation of Bcl-2 and P53 expression levels. Findings also indicated that TUN suppressed proliferation and arrested the glioma cells in the S phase of the cell cycle. Further analysis of the mechanisms of TUN demonstrated that TUN treatment upregulated the expression levels of maternally expressed gene (MEG)-3, wnt and β-catenin in glioma cells. Furthermore, knockdown of MEG-3 expression reversed the TUN-decreased wnt/β-catenin signaling pathway, which subsequently also reversed the TUN-inhibited growth and aggressiveness of glioma cells. In conclusion, the findings in the present study indicated that TUN treatment inhibited growth and aggressiveness through MEG-3-mediated wnt/β-catenin signaling, suggesting that TUN may be an efficient anticancer agent for the treatment of glioma.

Cystic Craniopharyngiomas: Microsurgical or Stereotactic Treatment?

BACKGROUND

Prognosis and treatment of cystic craniopharyngiomas are poorly defined.

OBJECTIVE

To analyze progression-free survival (PFS) and safety profile of cystic craniopharyngiomas undergoing resection or minimally invasive drainage procedures. We compared further outcome measurements for cystic and solid tumors undergoing resection to elucidate the impact of the initial tumor composition on both PFS and the toxicity profile.

METHODS

All patients with craniopharyngiomas consecutively treated between 1999 and 2014 were included. A treatment decision in favor of microsurgery or stereotactic treatment was made interdisciplinarily. For stereotactic drainage, a catheter was implanted, allowing both permanent upstream (into ventricular spaces) and downstream (into prepontine cistern) drainage. Study endpoints were tumor progression, functional outcome, and treatment toxicity. Functional endocrinological and visual outcome analyses referred to data obtained preoperatively and 6 weeks after treatment. The Kaplan-Meier method was used for survival analysis. Prognostic factors were obtained from proportional hazard models.

RESULTS

Seventy-nine patients were included. The distribution of clinical and tumor-related data was well balanced among patients with solid (n = 35) and cystic (n = 44) tumors and those undergoing microsurgical or stereotactic treatment. Cystic tumors had shorter PFS (5-year PFS: 53.6% vs 66.8%, P = .10) and needed significantly more therapeutic interventions, which was independent of the initial treatment mode. The endocrinological deterioration rate was high for both solid and cystic tumors after microsurgery (59.4% and 85.7%, respectively), whereas it was significantly lower for cystic tumors undergoing stereotactic treatment (23.1%, P < .001).

CONCLUSION

Stereotactic bidirectional drainage of cystic craniopharyngiomas is effective and provides a better endocrinological outcome than conventional microsurgery.

Long-term outcomes of primarily metastatic juvenile pilocytic astrocytoma in children

OBJECTIVE Primarily metastatic juvenile pilocytic astrocytoma (JPA) is rare, likely representing 2%-3% of all cases of JPA. Due to the rarity of primarily metastatic JPA, there is currently no standard treatment paradigm and the long-term outcomes are not fully known. The goal of this case series was to add to the current understanding of this disease process. METHODS The authors searched a comprehensive database of pediatric patients with brain and spinal cord tumors treated at Lucile Packard Children's Hospital from 1997 to 2016 and identified 5 patients with primarily metastatic JPA. A retrospective chart review was performed and details of the patients' treatment and clinical course were recorded for further analysis. RESULTS For the 5 patients with primarily metastatic JPA, the mean follow-up period was 12.3 years. All patients in our series had biopsies or subtotal resections and upfront treatment. Three patients were treated with chemotherapy alone, one was treated with chemotherapy and radiotherapy, and one was treated with radiotherapy alone. Four patients had stable disease after initial treatment, and one patient had multiple episodes of progressive disease but underwent successful salvage therapy and has had stable disease for 19 years. One patient died of an intracerebral hemorrhage 10 years following initial radiation treatment believed to be secondary to radiation vasculopathy. CONCLUSIONS Evaluation of the entire neuraxis should be performed in all instances of initial JPA diagnosis to properly assess for primarily metastatic disease. Many patients with primarily metastatic JPA will have stable disease after upfront treatment, although the higher rate of stable disease found in this series relative to other reports is likely secondary to the small sample size.

Early treatment of complex located pediatric low-grade gliomas using iodine-125 brachytherapy alone or in combination with microsurgery

To analyze efficacy, functional outcome, and treatment toxicity of low-dose rate I-125 brachytherapy (SBT) alone or in combination with best safe resection (in case of larger tumor volumes) as first-line treatment for pediatric low-grade gliomas (PLGGs) not suitable for complete resection. Consecutively treated (2000-2014) complex located circumscribed WHO grade I/II PLGGs were included. For small tumors (≤4 cm in diameter) SBT alone was performed; for larger tumors best safe resection and subsequent SBT was chosen. Temporary Iodine-125 seeds were used (median reference dose: 54 Gy). Treatment response was estimated with the modified MacDonald criteria. Analysis of functional outcome included ophthalmological, endocrinological and neurological evaluation. Survival was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from proportional hazards models. Toxicity was categorized according to the Common Terminology Criteria for Adverse Events. Fifty-eight patients were included treated either with SBT alone (n = 39) or with SBT plus microsurgery (n = 19). Five-year progression-free survival was 87%. Two patients had died due to tumor progression. Among survivors, improvement/stabilization/deterioration of functional deficits was seen in 20/14/5 patients, respectively. Complete/partial response had beneficial impact on functional scores (P = 0.02). The 5-year estimated risk to receive adjuvant radiotherapy/chemotherapy was 5.2%. The overall early (delayed) toxicity rate was 8.6% (10.3%), respectively. No permanent morbidity occurred. In complex located PLGGs, early SBT alone or combined with best safe resection preserves/improves functional scores and results in tumor control rates usually achieved with complete resection. Long-term analysis is necessary for confirmation of these results.