Prognostic impact of distinct genetic entities in pediatric diffuse glioma WHO-grade II-Report from the German/Swiss SIOP-LGG 2004 cohort.

Reports on pediatric low-grade diffuse glioma WHO-grade II (DG2) suggest an impaired survival rate, but lack conclusive results for genetically defined DG2-entities. We analyzed the natural history, treatment and prognosis of DG2 and investigated which genetically defined sub-entities proved unfavorable for survival. Within the prospectively registered, population-based German/Swiss SIOP-LGG 2004 cohort 100 patients (age 0.8-17.8 years, 4% neurofibromatosis [NF1]) were diagnosed with a DG2. Following biopsy (41%) or variable extent of resection (59%), 65 patients received no adjuvant treatment. Radiologic progression or severe neurologic symptoms prompted chemotherapy (n = 18) or radiotherapy (n = 17). Multiple lines of salvage treatment were necessary for 19/35 patients. Five years event-free survival dropped to 0.44, while 5 years overall survival was 0.90 (median observation time 8.3 years). Extensive genetic profiling of 65/100 DG2 identified Histone3-K27M-mutation in 4, IDH1-mutation in 11, BRAF-V600-mutation in 12, KIAA1549-BRAF-fusions in 6 patients, while the remaining 32 tumor tissues did not show alterations of these genes. Progression to malignant glioma occurred in 12 cases of all genetically defined subgroups within a range of 0.5 to 10.8 years, except for tumors carrying KIAA1549-BRAF-fusions. Histone3-K27M-mutant tumors proved uniformly fatal within 0.6 to 2.4 years. The current LGG treatment strategy seems appropriate for all DG2-entities, with the exemption of Histone3-K27M-mutant tumors that require a HGG-related treatment strategy. Our data confirm the importance to genetically define pediatric low-grade diffuse gliomas for proper treatment decisions and risk assessment.

Immunotherapy in atypical teratoid-rhabdoid tumors: Data from a survey of the HGG-Immuno Group.

BACKGROUND AIMS: Atypical rhabdoid/teratoid tumors (AT/RT) are the most common brain tumors in infants and associated with a dismal prognosis. Although intensification of first-line therapy has resulted in improvement of overall survival, novel treatment strategies are needed. Because immunotherapy has resulted in remarkable results in several adult tumor entities, incorporation of immunotherapy into AT/RT treatment offers a novel alternative. METHODS: We retrospectively analyzed data from 7 AT/RT patients from five countries treated within the HGG-Immuno Consortium. Two patients were ≤1 year and 4 patients were ≤2 years of age at diagnosis. All received immunotherapy with autologous, tumor-lysate-loaded dendritic cells (DCs) on a compassionate use basis using a schedule of three to four weekly DC vaccinations with up to 2 × 10(7) DCs per vaccine, followed by three lysate boosts each 1 month apart. RESULTS: Monocyte collections (median age at apheresis 31.5, range 20-143 months) and vaccinations were uneventful without any severe adverse event related to the vaccine, demonstrating feasibility and safety in this very young age group. Two children received immunotherapy during their primary and the remaining five during second- or third-line therapy. Three of seven patients survived long term with a follow-up of 143, 138 and 46 months, with at least two of them harboring somatic mutations. One long-term survivor was vaccinated during primary treatment and the other two after first or second relapse/progression. Two analyzed patients showed positive CD8(+) T-cell responses after vaccination. DISCUSSION: Our data demonstrate that anti-tumor immunotherapy with autologous DCs is feasible and safe in young children with ATRTs and that this approach warrants further investigation in controlled clinical trials.

Curative treatment for central nervous system medulloepithelioma despite residual disease after resection. Report of two cases treated according to the GPHO Protocol HIT 2000 and review of the literature.

Medulloepithelioma of the central nervous system (CNS) is an uncommon primitive neuroectodermal tumor (PNET) usually occurring in early childhood. It is characterized by highly malignant behavior with a propensity for progression, recurrence, and dissemination despite intensive therapy. Due to its rarity, the optimal management is still unknown. However, gross total resection (GTR) has been considered crucial to achieve cure. In this article, the authors report on 2 cases of CNS medulloepithelioma in which long-term survival (more than 6 years) could be achieved despite evidence of, or suspected postoperative residual disease with an otherwise dismal prognosis.The patients were treated according to different strata of the protocol for primitive neuroectodermal tumors (PNET) of the German-Austrian multicenter trial of the German Society for Pediatric Oncology and Hematology (GPOH) for childhood brain tumors (HIT 2000). Treatment included postoperative hyperfractionated radiotherapy of the craniospinal axis followed by a boost to the tumor site in combination with chemotherapy. A review of the 2 reported and 37 previously published cases confirmed GTR and older age as positive prognostic factors.