Fig. 5

The survival curves for 223 patients under short- and long- interval follow-up with different risks of secondary recurrence. The OS was similar between patients under short- and long-interval follow-up in the whole group (a), the low- risk group(b) and the high-risk group(c). During validation, the OS was also comparable between patients receiving short- and long-interval follow-up in subgroups with 0 (d), 1 (e) and 2 (f) risk factors. The patients with 0 risk factors and those with low risk in the regression model were the same patients