RESUMO
BACKGROUND: Pediatric low-grade gliomas (PLGG) are the most common brain tumors diagnosed during childhood and represent a heterogeneous group associating variable molecular abnormalities. To go further and develop specific statistical patterns between tumor molecular background, imaging features, and patient outcome, a retrospective study was performed in a group of non-neurofibromatosis type 1 (non-NF1) grade 1 PLGGs. PATIENTS AND METHODS: Seventy-eight children, followed from 2004 to 2017, were retrospectively reported. In this population, we analyzed radiological and molecular parameters. Their therapeutic management comprised surgery or surgery plus chemotherapies. RESULTS: Considering all 78 patients, 59 had only a surgical removal and 19 patients were treated with postoperative chemotherapy. Twelve progressions were reported in the partially resected and chemotherapeutic groups, whereas four deaths occurred only in the highly treated patients. As expected, in the global cohort, PLGG with BRAF p.V600E and/or CDKN2A loss exhibited poor outcomes and we evidenced significant associations between those molecular characteristics and their imaging presentation. In the chemo-treated patients, when associating initial and 6-month magnetic resonance imaging (MRI) parameters to the molecular features, the good risk situations were significantly linked to the presence of a large tumor cyst at diagnosis and the appearance during treatment of a higher cystic proportion that we called cystic conversion. CONCLUSION: So, additionally to the presence of BRAF p.V600E or CDKN2A deletion in grade 1 PLGGs, the absence on diagnostic MRI of cystic parts and/or cystic conversion at 6-month chemotherapy were significantly linked to a worst prognosis and response to treatment. These imaging features should be considered as prognostic markers in future PLGG studies.
Assuntos
Neoplasias Encefálicas , Glioma , Linfoma Folicular , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Criança , Glioma/diagnóstico por imagem , Glioma/genética , Glioma/terapia , Humanos , Mutação , Prognóstico , Proteínas Proto-Oncogênicas B-raf/genética , Estudos RetrospectivosRESUMO
Effects that tumor heterogeneity and drug resistance have on the structure of chemotherapy protocols are discussed from a mathematical modeling and optimal control point of view. In the case when two compartments consisting of sensitive and resistant cells are considered, optimal protocols consist of full dose chemotherapy as long as the relative proportion of sensitive cells is high. When resistant cells become more dominant, optimal controls switch to lower dose regimens defined by so-called singular controls. The role that singular controls play in the structure of optimal therapy protocols for cell populations with a large number of traits is explored in mathematical models.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Resistencia a Medicamentos Antineoplásicos , Modelos Teóricos , Neoplasias/tratamento farmacológico , Antineoplásicos/uso terapêutico , HumanosRESUMO
The association of bevacizumab and irinotecan has been shown to display a quick efficacy in low-grade glioma (LGG), but most patients relapse within months after cessation of therapy. From October 2012 to March 2014, four patients have been treated with irinotecan-bevacizumab followed by a metronomic maintenance with weekly vinblastine to try to prevent relapses. After a median follow-up of 23 months after the end of the bevacizumab-irinotecan induction, no patient relapsed. These observations suggest that maintenance chemotherapy with weekly vinblastine after an induction by irinotecan-bevacizumab can improve progression-free survival in children with LGG.
