Fig. 3

Age is an independent risk factor for the prognosis of GBM. a Patients treated with surgical intervention were divided into 7 groups based on age (18–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–95 years old, respectively). Kaplan–Meier (KM) curved (left side) showed better prognosis among patients aged with 18–39, compared to that of patients aged from 40–95 years old. Log-rank test was used as statistical method. P < 0.0001. KM curve on the right side showed the patients under 40 years old had significantly better prognosis than those equal and greater than 40 years old. Log-rank test was used as statistical method. P < 0.0001. b Patients in natural progress group (treated with non-resection intervention) were also divided into 7 groups based on age. KM curved (left side) showed better prognosis among patients aged with 18–39, compared to that of patients aged from 40–95 years old. Log-rank test was used as statistical method. P < 0.0001. KM curve on the right side showed the patients under 40 years old had significantly better prognosis than those equal and greater than 40 years old. Log-rank test was used as statistical method. P < 0.0001. c ROC curves showed age as a prognostic predictor and indicator of GBM patients both in the natural progression group. ROC curves of 3, 6, and 12 months were produced in natural progress, the AUC value of these ROC curves were 0.632, 0.702 and 0.770, respectively. ROC curves of 12, 24 and 36 months were produced in resection group, the AUC value of these ROC curves were 0.692, 0.682, and 0.703, respectively