P11.14.B PROGNOSTIC ASSOCIATIONS OF STEROID USE IN GLIOBLASTOMA: A POPULATION-BASED STUDY

Abstract

Abstract BACKGROUND Steroids are widely used in brain tumor patients to control symptoms related to tumor and cerebral edema. A possible detrimental effect of steroid treatment on prognosis in glioblastoma patients has been proposed. Whether this represents only a negative patient selection due to the potential confounding factor of steroid treatment or whether glucocorticoid use per se causes a worse prognosis remains a matter of debate. MATERIAL AND METHODS We reviewed retrospective data of 225 patients diagnosed with isocitrate dehydrogenase (IDH)-wildtype glioblastoma from 2010 to 2014 in the Canton of Zurich, Switzerland. We assessed clinical data and the use of steroids at different time points. Survival data were analyzed with the Kaplan-Meier method, and corrections for known prognostic or predictive factors were performed with Cox regression analyses. Correlations were determined with Spearman’s correlation coefficient. RESULTS Most patients (N=203, 95%) received steroids at least once in the first year after diagnosis, the majority (N=153, 69%) in the perioperative setting (defined at the time of hospitalisation for the surgery plus/minus seven days), and 94 patients (62%) in the first three months. Steroid use at three months after surgery was associated with with steroid treatment at six months, too (p<0.01). The latter was associated with inferior overall survival after correction for known prognostic factors (p=0.006). CONCLUSION Use of steroids at six months after diagnosis was associated with inferior survival in glioblastoma even when controlling for confounding factors. The precise mode of action of steroids in this setting remains to be identified, but cytoprotective effects of tumor cells versus radiotherapy and chemotherapy as well as decreased immune function of the host are potential mechanisms.