The impact of the time to start radiation therapy on overall survival in newly diagnosed glioblastoma.

ABSTRACT

PURPOSE: The standard treatment for newly diagnosed glioblastoma includes maximal safe surgical resection followed by concurrent radiation therapy and temozolomide (TMZ) and maintenance TMZ. The impact of time to start radiation therapy (TRT) on overall survival (OS) in glioblastoma patients is controversial. The study aimed to evaluate the impact of TRT on OS in patients diagnosed with glioblastoma who received standard treatment. METHODS: In this retrospective study, we included patients with confirmed diagnosis of glioblastoma treated from 2011 to 2016. TRT was defined as the time between surgery (biopsy or resection) and the first day of radiation therapy. The endpoint was OS. The patients were divided according to the TRT in three categories < 30 days, 30-60 days and ≥ 60 days. RESULTS: A total of 134 patients were included with a mean age of 51.82 years (range 19-78 years). Median TRT was 80 days. On univariate and multivariable analysis, we identified age as the only significant independent predictor for OS. There was no statistically significant negative impact of TRT on OS (p = 0.47). CONCLUSIONS: There was no clear evidence that delaying post-operative combined chemoradiotherapy negatively impacts OS, not even for TRT longer than 60 days.