Progression of Hearing Loss in Observed Non-Growing Vestibular Schwannoma.

OBJECTIVE

To assess hearing outcomes in observed vestibular schwannoma (VS) with focus on non-growing tumors.

STUDY DESIGN

Retrospective review.

SETTING

Two tertiary neurotology centers.

PATIENTS AND INTERVENTIONS

Patients with sporadic VS undergoing at least 3 years' observation.

MAIN OUTCOME MEASURES

Changes in pure tone averages (PTA) and word recognition scores (WRS) normalized to the contralateral ear.

RESULTS

During the study period, 39 of 105 included patients (37.1%) had tumor growth. Patients with tumor growth had a mean normalized increase in PTA of 8.0 dB HL ( p = 0.008) corresponding to a normalized average worsening of their PTA of 1.8 dB per year. Patients with non-growing tumors less than 5 mm in maximal dimension did not have significant ongoing normalized hearing loss ( p > 0.05). Patients with non-growing tumors more than or equal to 5 mm had a mean normalized increase in PTA of 7.4 dB HL ( p = 0.001) corresponding to an average of 2.0 dB HL per year, which was similar to the loss observed in growing tumors regardless of size ( p > 0.05). Normalized decline in PTA of at least 5 dB HL was seen in 72% of patients with growing tumors, 53% of patients with nongrowing tumors more than or equal to 5 mm, and 38% of patients with non-growing tumors less than 5 mm.

CONCLUSIONS

A long-term analysis of hearing outcomes in observed vestibular schwannoma is presented. With observation, VS more than or equal to 5 mm is associated with continued hearing loss even without tumor growth, while non-growing tumors less than 5 mm are not associated with continuing hearing loss. These data inform expectations for observed VS for providers and patients.