Progression of hearing loss after LINAC-based stereotactic radiotherapy for vestibular schwannoma is associated with cochlear dose, not with pre-treatment hearing level

Table 4 Univariate and multivariate linear regression of deterioration of the PTA in 77 patients with audiograms within 21 months after treatment

Cases with first audiometric follow up < = 21mnths n = 77	Univariate				Multivariate
Cases with first audiometric follow up < = 21mnths n = 77	RC	95% CI Lower	95%CI Upper	Univar p-value	RC	95% CI Lower	95% CI Upper	Multivar p-value
Age	0.072	0.005	0.139	0.035	0.078	0.030	0.261	0.012
PTA pre- treatment	0	−0.041	0.041	0.99				n.s.
Tumor diameter CPA (cm)	0.649	−0.482	1.779	0.26				n.s.
Tumor diameter IAC (cm)	2.66	−0.064	5.38	0.06				n.s.
Tumor volume pre- treatment (ml)	0.21	0.003	0.416	0.046				n.s.
Dose scheme (0 = FSRT, 1 = SRS)	−1.31	−3.09	0.461	0.145				n.s.
Max cochlear dose cGy EQD₂^a	0.000	0.000	0.001	0.264				n.s.
Mean cochlear dose cGy EQD₂^a	0.001	0.000	0.001	0.005				n.s.
V90 cochlea EQD₂ ^cb	0.025	0.009	0.041	0.003	0.024	0.009	0.039	0.002
Cochlear volume (ml)	−0.003	− 0.020	0.014	0.74				n.s.
Time-to-first-audiogram (after treatment)	−0.365	− 0.585	− 0.145	0.001	− 0.302	− 0.508	−0.096	0.005

ISSN: 1748-717X