Usher etxearen hondamendia

Jan 15, 20131 like236 views

Usher etxearen hondamendia lana komiki eran. Literatura unibertsala. Lauro Ikastola

Ependymoma accounts for 8–10% of all pediatric brain tumors and constitutes the third most common brain tumor in children. No robust molecular markers are yet in routine clinical use. Surgical resection and adjuvant radiotherapy cure approximately 40-70% of pediatric patients with ependymoma. In our centre, we have been using prophylactic valproic acid treatment for brain tumor patients. Initial observations indicated that valproate could have a beneficial effect in the survival of patients. Recent observations by other authors have shown that patients with glioblastoma benefited from the treatment with valproic acid, a histone deacetylase inhibitor.[1] Random survival forests (RSF) modeling is a new statistical method that grows numerous mature trees with many branches, reducing variance and bias by using all variables collected and by automatically assessing for nonlinear effects and complex interactions. [2] These results are part of a retrospective study approved by the institutional review board of our institution (CAAE 26609514.4.0000.5042). We reviewed the charts of patients referred to our institution and diagnosed between January 2000 and De- cember 2010 with ependymoma, aged 0-17 years. Since January 2007, valproate sodium at doses 10-15mg/kg/day every 8-12h was routinely prescribed for all pediatric brain tumor patients in our institution as prophylactic anticonvulsant. The primary study endpoint was time to death from any cause, measured from the diagnosis, from which overall survival (OS) percentage was computed. The primary objective of the statistical analysis was to determine the predictors of OS. The following variables were assessed for prognostic value: age, sex, metastasis at diagnosis (metastasis), anaplasia, tumor site, treatment with chemotherapy, treatment with radiotherapy, extent of surgery, prophylatic treatment with valproate. Random survival analysis used all-cause mortality for the outcome. A survival forest of 1000 survival trees was constructed. Between 2000 and 2010, 27 patients were diagnosed with ependymoma. There were seventeen males and 10 fema- les. Mean and median ages were 7.6 and 8.3 years. Seventeen had posterior fossa tumors, 6 had supratento- rial lesions. Eighteen were submitted to complete surgical resection, whereas 9 had partial resection or biopsy. Nine- teen received radiotherapy. Seventeen received adjuvant chemotherapy. Simple Kaplan-Meier estimates were cal- culated. Univariate analysis with log-rank test indicated that surgical extent (p<0.01),><0.01) and valproic acid therapy (p=0.01) modified survival, but not tumor site (p=0.5). RSF model indicated 6 variables as predictors of OS: surgery extent, valproic acid treatment, radiotherapy treatment, anaplasia, topography and chemotherapy. After variable selection, 3 variables were left, in order of importance: valproic acid, surgery, and radiotherapy. Mean concordance error rate for the final RSF model was 0.25. (truncated)