A Case of Relapsed Medulloblastoma Treated with Intensity-Modulated Radiotherapy and Temozolomide

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

Temozolomide in relapsed pediatric brain tumors: 14 cases from a single center

AIM

Temozolomide is an active drug against gliomas in adults. It also has some promising effects in pediatric patients with brain tumors. We have conducted a retrospective study to investigate the effectiveness of temozolomide in patients with relapsed brain tumors.

PATIENTS AND METHODS

The files of 14 children treated at our hospital between 2005 and 2010 with the diagnoses of relapsed brain tumors were reviewed for pathological characteristics, treatment results, and outcomes.

RESULTS

The median age at relapse was 8 years (range, 1.08-23; F/M, 5/9). Diagnoses included medulloblastoma (n = 5), atypical teratoid rhabdoid tumor (n = 2), ependymoma (n = 2), glioneuronal tumor (n = 1), malignant neoplasm (n = 1), pontine glioma (n = 1), astrocytoma grade III (n = 1), and glioblastoma multiforme (n = 1). All patients except the one with pontine glioma had undergone surgical resection, and all had prior adjuvant chemotherapy. Twelve out of 14 patients had received radiotherapy. The median number of temozolomide courses was 5.0 (range, 1-24). Objective response rate in our patients was 35.7% (three complete responses, one partial response, and one minor response). Stable disease achieved in 14.3% of patients and 50% had progressive disease. Median survival time was 8 months (range, 1-55). At the end of the study, three patients were alive. Hematological toxicity was seen in 30.8% of all courses.

CONCLUSIONS

Relapsed brain tumors in childhood have an unfavorable prognosis. These data suggest that temozolomide might be an active agent against recurrent medulloblastoma. Although overall objective response rate was low, further multicentric studies with temozolomide may be warranted in children with recurrent brain tumors.

Gadd45a sensitizes medulloblastoma cells to irradiation and suppresses MMP-9-mediated EMT

Medulloblastomas are the most common malignant tumors of the central nervous system during childhood. Radiation-induced medulloblastoma tumor recurrences are aggressive and metastatic in nature. In the present study, we demonstrate that Gadd45a expression can sensitize medulloblastoma cells to radiotherapy. We have elucidated the role of Gadd45a in ionizing radiation (IR)-induced G2-M arrest and invasion and metastatic potential of the medulloblastoma cancer cell lines DAOY and D283. We demonstrate that Gadd45a is induced by IR and results in p53 phosphorylation. The role of IR-induced Gadd45a in G2-M arrest is demonstrated by fluorescence-activated cell sorting analysis in the cells treated with siRNA Gadd45a and Ov-exp Gadd45a. We show that Ov-exp Gadd45a aggravates G2-M blockage and also increases binding of Gadd45a to Cdc2 by immunocytochemistry analysis. Furthermore, we show the anti-tumorigenic role of Gadd45a to be mediated by the negative regulation of IR-induced cancer cell invasion and migration-associated proteins, such as matrix metallopeptidase (MMP)-9 and β-catenin. When compared with IR treatment alone, Ov-exp Gadd45a plus IR treatment resulted in decreased nuclear localization and increased membrane localization of β-catenin, and this was further confirmed by membrane distribution. We also show that Ov-exp Gadd45a resulted in downregulation of MMP-9 and suppression of epithelial-mesenchymal transition (EMT). Alternatively, inhibition of MMP-9 (pM) resulted in upregulation of Gadd45a and suppression of EMT. The anti-tumor effect of pM was correlated with increased expression of Gadd45a protein in nude mice intracranial tumors. Taken together, our studies demonstrate that upregulation of Gadd45a or suppression of MMP-9 (pM) with IR retards medulloblastoma tumor metastatic potential.

The role of radiotherapy in adult medulloblastoma: long-term single-institution experience and a review of the literature

Medulloblastoma (MB) occurs infrequently in adult patients and standard treatment is still controversial. We report our long-term, single-institution experience of adult MB and a review of the literature. We analysed adult patients with histologically proved MB treated by postoperative radiotherapy. Primary endpoints were local control (LC), disease-free survival (DFS), and overall survival (OS). Acute toxicity was reported according to CTC-NCI score vers. 3.0 and specific neuropsychological assessment analysis was performed to define late brain toxicity. From 1990-2008, 13 patients were treated by craniospinal (CSI, 12/13) or cranial irradiation (1/13, because of bad clinical conditions). Median follow up was 101 months (64-218). Complete radiological response was observed in 12/13 patients and a partial response in 1/13. Ten-year LC, OS, and DFS were 91, 76, and 84%, respectively. Two patients died because of local and spinal progression after 13 and 62 months. Acute G3 haematological toxicity (RTOG score) was observed for one patient only. The neuropsychological analysis did not reveal late toxicity related to brain radiotherapy. This experience confirms the efficacy and safety of radiotherapy in adult MB patients, resulting in very interesting 10-year LC and OS.