|Home | About | Journals | Submit | Contact Us | Français|
PURPOSE: To investigate the patterns of failure in the treatment of glioblastoma (GBM) when using margins according to Radiation Oncology Group Margins (RTOG) or European Organisation for Research and Treatment of Cancer (EORTC) guidelines at consultant discretion. METHODS: Between January 2012 and November 2015, 41 patients with GBM completed a radical course of radiotherapy (54 to 60 Gy) with concurrent temozolomide. Patients were treated with GTV expansions that ranged from 2–3cm with or without shrinking field technique. The pattern of recurrence was determined by relationships between locations of recurrent tumors and irradiated doses. RESULTS: The median progression-free survival from the time of diagnosis to documented failure was 8 months (range 2–31). 11 patients received doses below 60 Gy in order to meet dose constraints of organs at risk. Of the 38 documented recurrences, 28 patients (73 %) had central recurrence, 3 (8 %) had in-field recurrence, 4 (10 %) had a marginal component, and 3 (8 %) had both in field and distant component with 2 cases of meningeal metastases and 1 case of pathologically confirmed pleural and liver metastasis. CONCLUSIONS: Recurrence patterns of glioblastoma after radical radiotherapy were mainly central. The low rate of marginal or distant recurrence suggests that wide margins would have little impact on the pattern of failure. Further investigation should be carried on to reduce volumes safely and avoid toxicities such as radionecrosis and cognitive decline.