Fig. 2

Survival curves for poorly differentiated chordoma by site. Kaplan-Meier survival statistics were performed on poorly differentiated chordoma comparing survival of patients with tumors arising in the skull base and those with tumors arising in the spine. For the skull base and the spine, respectively, mean overall survival (a) is 62 months (SE = 11 months) and 46 months (SE = 7 months); mean progression free survival (b) is 34 months (SE = 13 months) and 23 months (SE = 7 months); mean local control time (c) is 41 months (SE = 13 months) and 31 months (SE = 8 months); and mean metastasis free survival (d) is 49 months (SE = 13 months) and 30 months (SE = 7 months). A log-rank (Mantel–Cox) test shows that there is no difference in survival between poorly differentiated chordoma of the skull base and the spine for mean overall survival (p = 0.63), mean progression free survival (p = 0.88), mean local control time (p = 0.88), and mean metastasis free survival (p = 0.50)