Salvage Therapy for Childhood Medulloblastoma: A Single Center Experience

Radiotherapy for Recurrent Medulloblastoma in Children and Adolescents: Survival after Re-Irradiation and First-Time Irradiation

BACKGROUND

Radiotherapy (RT) involving craniospinal irradiation (CSI) is important in the initial treatment of medulloblastoma. At recurrence, the re-irradiation options are limited and associated with severe side-effects.

METHODS

For pre-irradiated patients, patients with re-irradiation (RT2) were matched by sex, histology, time to recurrence, disease status and treatment at recurrence to patients without RT2.

RESULTS

A total of 42 pre-irradiated patients with RT2 were matched to 42 pre-irradiated controls without RT2. RT2 improved the median PFS [21.0 (CI: 15.7-28.7) vs. 12.0 (CI: 8.1-21.0) months] and OS [31.5 (CI: 27.6-64.8) vs. 20.0 (CI: 14.0-36.7) months]. Concerning long-term survival after ten years, RT2 only lead to small improvements in OS [8% (CI: 1.4-45.3) vs. 0%]. RT2 improved survival most without (re)-resection [PFS: 17.5 (CI: 9.7-41.5) vs. 8.0 (CI: 6.6-12.2)/OS: 31.5 (CI: 27.6-NA) vs. 13.3 (CI: 8.1-20.1) months]. In the RT-naïve patients, CSI at recurrence improved their median PFS [25.0 (CI: 16.8-60.6) vs. 6.6 (CI: 1.5-NA) months] and OS [40.2 (CI: 18.7-NA) vs. 12.4 (CI: 4.4-NA) months].

CONCLUSIONS

RT2 could improve the median survival in a matched cohort but offered little benefit regarding long-term survival. In RT-naïve patients, CSI greatly improved their median and long-term survival.

Local and Systemic Therapy of Recurrent Medulloblastomas in Children and Adolescents: Results of the P-HIT-REZ 2005 Study

Simple Summary

A medulloblastoma recurrence is usually associated with an unfavorable prognosis. The German P-HIT-REZ 2005 Study gathered data from patients with relapsed medulloblastomas treated in different, non-randomized therapy arms dependent on preconditions of the patients (previous treatment, comorbidities, relapse pattern), the decision of treating physicians, and the patients’/parents’ choice. A total of 93 evaluable patients with refractory or relapsed medulloblastoma were enrolled. The main aim of this study was to analyze the impact of patient and disease characteristics as well as local and systemic therapies on post-relapse progression-free (PFS) and overall survival (OS). In multivariate analysis, a short time until the first recurrence (<18 months) was the strongest predictor for a worse PFS and OS, which was mainly associated with molecular subgroup 3. Metastatic disease, at relapse, only had a significant impact on OS. Re-biopsy, at relapse, is highly recommended to investigate the histopathological and molecular genetic tumor characteristics and to exclude a secondary malignancy.

Abstract

Recurrent medulloblastomas are associated with survival rates <10%. Adequate multimodal therapy is being discussed as having a major impact on survival. In this study, 93 patients with recurrent medulloblastoma treated in the German P-HIT-REZ 2005 Study were analyzed for survival (PFS, OS) dependent on patient, disease, and treatment characteristics. The median age at the first recurrence was 10.1 years (IQR: 6.9–16.1). Median PFS and OS, at first recurrence, were 7.9 months (CI: 5.7–10.0) and 18.5 months (CI: 13.6–23.5), respectively. Early relapses/progressions (<18 months, n = 30/93) found mainly in molecular subgroup 3 were associated with markedly worse median PFS (HR: 2.34) and OS (HR: 3.26) in regression analyses. A significant survival advantage was found for the use of volume-reducing surgery as well as radiotherapy. Intravenous chemotherapy with carboplatin and etoposide (ivCHT, n = 28/93) showed improved PFS and OS data and the best objective response rate (ORR) was 66.7% compared to oral temozolomide (oCHT, n = 47/93) which was 34.8%. Intraventricular (n = 43) as well as high-dose chemotherapy (n = 17) at first relapse was not related to a significant survival benefit. Although the results are limited due to a non-randomized study design, they may serve as a basis for future treatment decisions in order to improve the patients’ survival.

Clinical Outcomes and Patient-Matched Molecular Composition of Relapsed Medulloblastoma

We sought to investigate clinical outcomes of relapsed medulloblastoma and to compare molecular features between patient-matched diagnostic and relapsed tumors.

Pediatric medulloblastoma in the molecular era: what are the surgical implications?

Pediatric brain tumors are the leading cause of childhood cancer mortality with medulloblastoma (MB) representing the most frequent malignant tumor. Although standardization of therapy resulted in a 2-fold reduction in mortality in patients with MB by 2002, it became clear that further improvements in clinical outcome would require a deeper understanding of the biology of MB. Employing the four main molecular MB subgroups (Wnt, Shh, Group 3 and Group 4), a restratification into clinicogenomic risk categories quantified an unacceptable survival for the high-risk group, urging researchers to focus their efforts towards acquiring a greater biological understanding of these children. Advancing in parallel with the molecular characterization and understanding of pediatric MB is the clinicogenomic correlations giving rise to recommendations for neurosurgical care. While unique observations that distinct radiological patterns can be identified to inform the MB molecular subgroup preoperatively, current neurosurgical practice remains maximal safe surgical resection followed by risk-adapted provision of adjuvant therapy in the context of a clinical trial.

Long Noncoding RNA TP73-AS1 Modulates Medulloblastoma Progression In Vitro And In Vivo By Sponging miR-494-3p And Targeting EIF5A2

Background

Previous studies have shown that P73 antisense RNA 1T (non-protein coding), also known as TP73-AS1, is a long non-coding RNA (lncRNA) and involved in the development of medulloblastoma. However, the regulatory mechanism of lncRNA TP73-AS1 in medulloblastoma was still unclear, the present study was aimed to investigate the detailed functions and the mechanism of TP73-AS1 in regulation of medulloblastoma.

Materials and methods

The levels of TP73-AS1, miR-494-3p, and Eukaryotic initiation factor 5A2 (EIF5A2) were determined using quantitative real-time PCR (qRT-PCR), in situ hybridization (ISH), or Immunohistochemistry (IHC). The function of TP73-AS1 in proliferation, apoptosis, migration, and invasion of medulloblastoma cells was evaluated using cell counting Kit-8 (CCK-8), flow cytometry, and transwell assay, respectively. The protein levels were determined by Western blot. Bioinformatics analysis and dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assay were used to search and confirm the target gene of TP73-AS1 and miR-494-3p. The effect of TP73-AS1 knockdown in vivo was detected by animal experiment.

Results

The levels of TP73-AS1 and EIF5A2 were up-regulated, while miR-494-3p expression was down-regulated in medulloblastoma tissues and cells, ELF5A2 was a direct target of miR-494-3p, and miR-494-3p bound to TP73-AS1. The knockdown of TP73-AS1 inhibited cell proliferation, invasion, migration, and promoted apoptosis of medulloblastoma cells, while the miR-494-3p inhibitor abolished the effects of TP73-AS1 knockdown on medulloblastoma cells.

Conclusion

TP73-AS1 positively regulated EIF5A2 expression by sponging miR-494-3p. These findings suggested that TP73-AS1 served as an oncogene and promoted the progression of medulloblastoma.