TABLE 4.

Univariable and Multivariable Cox Regression for Radiographic Progression-Free Survival Following Definitive GKRS for Vestibular Schwannomas

Covariate	Univariable regression		Multivariable regression
	HR (95% CI)	P value	HR (95% CI)	P value
Age	1.010 (0.970-1.052)	.634	N/A
Gender
Male	Reference	—	N/A
Female	1.478 (0.593-3.682)	.401	N/A
Laterality
Left	Reference	—	N/A
Right	1.036 (0.415-2.583)	.940	N/A
Year of diagnosis	1.009 (0.885-1.150)	.896	N/A
Pretreatment serviceable hearing
Yes (Gardner-Robertson I or II)	Reference	—	N/A
No (Gardner-Robertson III, IV, or V)	1.003 (0.311-3.234)	.997	N/A
Pretreatment hearing loss
Yes	1.026 (0.231-4.563)	.973	N/A
No	Reference
Pretreatment CN VII dysfunction
Yes	0.044 (0.000-97.313)	.426	N/A
No	Reference
Pretreatment CN V dysfunction
Yes	1.266 (0.289-5.548)	.754	N/A
No	Reference
Tumor size, max. diameter	0.623 (0.253-1.533)	.303	N/A
Tumor size, volume	0.790 (0.381-1.635)	.525	N/A
Tumor grade (Samii classification)	1.069 (0.801-1.427)	.651	N/A
Dose rate, median
< 2.675 Gy/min	Reference
≥ 2.675 Gy/min	1.300 (0.518-3.265)	.576	N/A
Dose rate, continuous	1.424 (0.716-2.834)	.314	N/A
Prescription isodose	0.998 (0.953-1.045)	.926	N/A
Mean target dose (Gy)	1.001 (0.912-1.097)	.991	N/A
Minimum target dose (Gy)	0.950 (0.762-1.184)	.646	N/A
Maximum target dose (Gy)	0.991 (0.913-1.076)	.838	N/A
RTOG conformity index	0.908 (0.277-2.983)	.874	N/A
Paddick conformity index	3.279 (0.023-469.685)	.639	N/A
Selectivity index	3.416 (0.031-377.991)	.609	N/A
Energy index	9.072 (0.317-259.60)	.198	N/A
RTOG homogeneity index	0.748 (0.036-15.373)	.850	N/A