Figure 3. Kaplan-Meier curves of the distribution of A. surgery (log-rank P = 0.001) and B. radiotherapy (log-rank P = 0.000) in grade I–II OS; Kaplan-Meier curves of the distribution of C. surgery (log-rank P = 0.002) and D. radiotherapy (log-rank P =0.001) in grade III–IV OS.