Figure 6.

Risk classification according to the number of independent risk factors for overall survival. Patients were categorized into 3 groups according to the number of independent risk factors for overall survival: the low-risk group (patients with no risk factors), the intermediate-risk group (1 or 2 risk factors), and the high-risk group (3 or 4 risk factors). Risk classification revealed significantly poor prognosis by increasing the number of risk factors (*P < 0.001). The patients with high-risk group showed significantly poor prognosis compared with those in the other groups.