TABLE 6.

Univariable and Multivariable Cox Regression for Post-treatment Freedom from Progressive Symptomatic Hearing Loss and FND following GKRS

	Univariable regression		Multivariable regression
Covariate	HR (95% CI)	P value	HR (95% CI)	P value
Age	0.995 (0.977-1.014)	.613	—
Gender
Male	Reference	—	—
Female	1.085 (0.696-1.691)	.718	—
Laterality
Left	Reference	—	—
Right	0.820 (0.527-1.278)	.381	—
Year of diagnosis	1.027 (0.974-1.084)	.325
Pretreatment serviceable hearing
Yes (Gardner-Robertson I or II)	2.187 (1.098-4.356)	.026*	—
No (Gardner-Robertson III, IV, or V)	Reference	—	—	.247 (NS)
Pretreatment hearing loss
Yes	0.805 (0.402-1.613)	.541	—
No	Reference		—
Pretreatment CN VII dysfunction
Yes	0.228 (0.032-1.641)	.142	—	.412 (NS)
No	Reference		—
Pretreatment CN V dysfunction
Yes	0.893 (0.429-1.857)	.761	—
No	Reference		—
Tumor size, max. diameter	0.407 (0.254-0.651)	.000*	0.324 (0.155-0.677)	.003
Tumor size, volume	0.633 (0.404-0.994)	.047*	—	.889 (NS)
Tumor grade (Samii classification)	0.753 (0.630-0.898)	.002*	—	.242 (NS)
Post-treatment tumor size
Decreased	Reference	—	—	.554 (NS)
Stable	2.126 (1.084-4.169)	.028*	—
Increased	2.619 (1.250-5.487)	.011*	—
Dose rate, median
<2.675 Gy/min	Reference		Reference
≥2.675 Gy/min	1.581 (1.008-2.479)	.046*	2.248 (1.082-4.672)	.030
Dose rate, continuous	1.145 (0.820-1.600)	.427	—
Prescription isodose	0.997 (0.976-1.019)	.800	—
Mean target dose (Gy)	1.003 (0.961-1.047)	.881	—
Minimum target dose (Gy)	0.953 (0.862-1.053)	.341	—
Maximum target dose (Gy)	0.998 (0.966-1.031)	.905	—
RTOG conformity index	1.292 (0.795-2.101)	.302	—
Paddick conformity index	0.310 (0.034-2.866)	.302	—
Selectivity index	0.334 (0.041-2.706)	.304	—
Energy index	1.902 (0.540-6.697)	.317	—
RTOG homogeneity index	1.004 (0.300-3.353)	.995	—