Comparison of Survival and Recurrence Pattern With an External Control Arm
infiltrating non-enhancing disease
DISEASE
An external control arm was generated by collecting available data for recurrent GBM patients treated with re-irradiation at our institution (92 courses of re-irradiation). We tested the associations between our novel administration schedule and both progression-free and overall survival (The pattern of progression was defined as the location of the earliest progression following re-irradiation. For the study cohort, all follow-up imaging studies were fused volumetrically with baseline and subsequent imaging studies. Local progression was defined by progressive enhancing within or abutting the PTV or by progressive infiltrating non-enhancing disease; distant progression was defined by non-continuous disease which did not abut the treated PTV; marginal progression was defined by distant progressive disease occurring within 1 cm of the PTV