Fig. 4From: Analysis of prognostic factors for survival in patients with primary spinal chordoma using the SEER Registry from 1973 to 2014Kaplan–Meier estimated overall survival which is stratified by primary site (vertebral column vs sacrum/pelvis) in spinal chordoma patients from different ages (a 0- to 20-year-old age group, b 21- to 59-year-old age group, c over 60-year-old age group, and d all age groups)Back to article page