Subventricular zone contacting glioblastoma: tumor size, molecular biological factors and patient survival

Figures & data

Figure 1. Contrast-enhanced axial T1 MR image (A) and matching coronal T1 image (B) illustrating a right frontal glioblastoma with SVZ contact.

Table 1. Overview of demographic, surgical, molecular biological and volumetric characteristics as well as survival according to subventricular zone contact group.

Parameter	SVZ contact	No SVZ contact	p-value
N (%)	145 (68%)	69 (32%)	–
Sex			.223^a
Female	55 (38%)	20 (29%)
Male	90 (62%)	49 (71%)
Mean age at diagnosis (years)	60	62	.162^b
KPS (mean)	70	70	.115^b
Surgery			.552^a
Biopsy only	40 (27.6%)	15 (21.7%)
STR	60 (41.4%)	28 (40.6%)
GTR	45 (31.0%)	26 (37.7%)
MGMT-methylation			.028^c
No	89 (61.4%)	31 (44.9%)
Yes	45 (31%)	32 (46.4%)
unknown	11 (7.6%)	6 (8.7%)
IDH-mutation			.276^c
No	111 (76.6%)	44 (63.8%)
Yes	10 (6.9%)	7 (10.1%)
unknown	24 (16.5%)	18 (26.1%)
Median tumor volume (mL)*	33.8	15.6	<.001^d
Median overall survival (months)	12.2	16.9	.016^e
Median progression-free survival (months)	5.9	10.3	.007^e

^aFisher’s exact test. ^bIndependent samples t-test. ^cFisher’s exact test with exclusion of NA group. ^dLinear regression model of the log transformed volumes. ^eLog-rank test. *Available in 177 patients.

Significant p-values are highlighted in bold. KPS = Karnofsky Performance Score; STR = subtotal resection; GTR = gross total resection; MGMT = 0⁶-methylguanine-DNA-methyltransferase; IDH = isocitrate dehydrogenase.

Figure 2. Kaplan-Meier curves of overall survival (A) and progression-free survival (B) in glioblastoma with (SVZ_pos) and without (SVZ_neg) subventricular zone contact.

Table 2. Univariate survival analysis for several prognostic factors of glioblastoma patient survival.

		Overall survival			Progression-free survival
Parameter	% of patients	Median (months)	Hazard ratio (95% CI)	Wald test p	Median (months)	Hazard ratio (95% CI)	Wald test p
Age at diagnosis (years)
≥65	35,5%	11.7	1.021 (1.009–1.034)*	.001	6.2	1.009 (0.997–1.021)*	.161
<65	64,5%	14.3			6.7
KPS
≥70	70%	15.33	0.981 (0.971–0.991)*	<.001	7.7	0.987 (0.978–0.997)*	.010
<70	30%	9.4			4.6
Preoperative tumor volume*	82.7%	–	0.997 (0.985–1.009	.588	–	1.005 (0.992–1.019)	.469
Surgery
Biopsy only	25,7%	8.7	–	–	4.7
STR	41,1%	13.0	0.673 (0.480–0.944)	.022	6.2	0.589 (0.417–0.832)	.003
GTR	33,2%	17.0	0.503 (0.371–0.682)	<.001	10.7	0.554 (0.403–0.760)	<.001
MGMT-methylation
Yes	39%	20.9	0.361 (0.263–0.497)	<.001	12.0	0.471 (0.343–0.649)	<.001
No	61%	11.5			5.5
IDH-mutation
Yes	10%	23.8	0.612 (0.359–1.044)	.072	11.3	0.548 (0.319–0.939)	.029
No	90%	13.4			6.3
SVZ contact
Yes	68%	12.2	1.439 (1.067–1.941)	.017	5.9	1.523 (1.119–2.072)	.007
No	32%	16.9			10.3

*Numerical variables were not categorized in Cox regression model.

Significant p-values are highlighted in bold. KPS = Karnofsky Performance Score; STR = subtotal resection; GTR = gross total resection; MGMT = 0⁶-methylguanine-DNA-methyltransferase; IDH = isocitrate dehydrogenase; SVZ = subventricular zone.

Table 3. Multivariate Cox regression model of glioblastoma patient survival adjusted for age, KPS, extent of resection, MGMT-methylation and SVZ contact.

Parameter	Overall survival hazard ratio (95% CI)	Wald test p	Progression-free survival hazard ratio (95% CI)	Wald test p
Age	1.029 (1.014–1.045)	<.001	1.013 (0.998–1.028)	.093
KPS	0.982 (0.969–0.995)	.008	0.985 (0.973–0.997)	.018
Biopsy vs resection	0.503 (0.343–0.736)	<.001	0.594 (0.405–0.872)	.008
MGMT-methylated	0.294 (0.203–0.425)	<.001	0.442 (0.308–0.634)	<.001
IDH-mutated	0.685 (0.518–1.541)	.685	0.653 (0.368–1.158)	.145
With SVZ contact	1.464 (1.027–2.088)	.035	1.483 (1.037–2.121)	.031

Significant p-values are highlighted in bold. CI = confidence interval; KPS = Karnofsky Performance Score; MGMT = 0⁶-methylguanine-DNA-methyltransferase; IDH = isocitrate dehydrogenase; SVZ = subventricular zone.