Aims
Embryonal tumours with PLAGL1 or PLAGL2 amplification (ET, PLAGL) show substantial heterogeneity regarding their clinical characteristics and have been treated inconsistently, resulting in diverse outcomes. In this study, we aimed to evaluate the clinical behaviour of ET, PLAGL and elucidate their response pattern across the different applied treatment regimens.
Methods
We conducted an in-depth retrospective analysis of clinical and serial imaging data of 18 patients with ET, PLAGL (nine each of PLAGL1 and PLAGL2 amplified).
Results
Patients with PLAGL1-amplified tumours (ET, PLAGL1) had fewer relapses (3/9), while PLAGL2-amplified tumours (ET, PLAGL2) were prone to early relapse or progression (8/9) and to distant, leptomeningeal and intraventricular relapses. Progression-free survival differed significantly between the subtypes (log-rank test, p = 0.0055). Postoperative treatment included chemotherapy (n = 17, various protocols), alone (n = 8) or combined with radiotherapy (n = 9). Responses to chemotherapy were observed in both subtypes, and incomplete resection was not associated with inferior survival. All three survivors with ET, PLAGL2 were treated with induction and high-dose chemotherapy with (n = 1—low-dose CSI and boost) or without (n = 2) radiotherapy, whereas five patients with less intensive chemotherapy relapsed. All six survivors with ET, PLAGL1 were treated with conventional chemotherapy regimens, with (n = 4—local radiotherapy n = 3; CSI and boost n = 1) or without (n = 2) radiotherapy. Two patients with ET, PLAGL1 relapsed after 8 years.
Conclusions
Adjuvant therapy should be considered for all ET, PLAGL patients: Patients with ET, PLAGL2 might benefit from intensified chemotherapy regimens. In contrast, patients with ET, PLAGL1 showed superior outcomes without high-dose chemotherapy or craniospinal irradiation.
Paediatric high-grade gliomas (pedHGGs) are highly invasive brain tumours accounting for approximately 15 % of all central nervous system (CNS) tumours in children and adolescents. The outcome for these tumours is generally poor with 5-year survival rates of less than 20 %. Despite improved biological insights into pedHGGs and the promise of more effective therapies, little progress has been made in the effective treatment and the outcome of these tumours over the last four decades. Much of the evidence for the use of chemotherapy in pedHGGs is extrapolated from adult data, and the evidence for its use in the paediatric population is still weak. This guideline was written by members of the SIOPE HGG Working Group as part of the European Standard Clinical Practice (ESCP) Project. The guideline aims to integrate available evidence-based and expert opinion-based information to assist healthcare professionals in the management of pedHGGs and in an attempt to provide equity in healthcare reflecting the varying resources of each European country.
