“…The data that were used to develop glioblastoma survival prediction models were retrieved from clinical trials (n = 2) [26,30], institutional data (n = 13) [13-15, 19, 20, 22, 25, 28, 29, 32-34, 36], registry data (n = 9) [12,16,18,21,23,24,27,31,38], combined institutional and database data (n = 1) [35], and unspecified data sources (n = 2) [17,37]. Twelve models used data from consecutive patients [12, 13, 15, 23-29, 35, 38].…”