Table 4.

Univariate and Multivariate Analysis of overall survival with Cox proportional hazards model

Characteristics	Hazard ratio (95% CI)	P value
Univariate analysis
Adjuvant treatment	0.075 (0.028–0.204)	3.47e–7
Post-operative complications	4.119 (1.753–9.679)	0.001
Pre-operative KPS (KPS score ≥70 vs. KPS score <70)	0.559 (0.301–1.040)	0.066
EOR (GTR+NTR vs. STR)	0.540 (0.209–1.400)	0.205
MGMT * (methylated and partially methylated vs. unmethylated)	0.694 (0.366–1.317)	0.264
Gender	1.431 (0.762–2.690)	0.265
Image guidance technique (ioUS vs. ioMRI + ioUS)	1.450 (0.712–2.954)	0.306
Pre-operative altered mental status	1.290 (0.677–2.460)	0.439
Involvement of eloquent structures	1.192 (0.621–2.289)	0.598
Pre-operative motor deficit	1.175 (0.606–2.281)	0.633
Tumor volume	0.998 (0.990–1.008)	0.802
Follow-Up KPS (KPS score ≥70 vs. KPS score <70)	1.044 (0.495–2.203)	0.910
Multivariate analysis
EOR (GTR+NTR vs. STR)	0.329 (0.121–0.896)	0.030
Post-operative complications	3.620 (1.433–9.144)	0.006
Adjuvant treatment	0.144 (0.057–0.362)	3.80e–5

Bold values indicate statistical significance at the p < 0.05 level

*An independent univariate analysis was further performed to assess the impact of MGMT status on overall survival in patients who had MGMT status determined as “methylated” or “unmethylated” and received temozolomide treatment (n = 29), (P = 0.172, HR:0.550, 95% CI 0.233 – 1.30)

Abbreviations: KPS, Karnofski Performance Scale; ioUS, intraoperative ultrasonography; ioMRI, intraoperative magnetic resonance imaging; EOR, Extent of resection; GTR, gross total resection; NTR, near total resection; STR, subtotal resection