Long-term tumor growth and hearing after conservative management of vestibular schwannomas

Background: There has been no report of a detailed long-term study of hearing at defined frequencies. Aims/Objectives: This study aimed to evaluate long-term vestibular shwannoma (VS) growth and long-term changes in hearing thresholds at defined frequencies. Methods: We retrospectively retrieved the medical records of 67 VS patients. Cases that were followed up for more than 5 years were analyzed. Results: Tumor growth was observed in 15 cases (22.4%) and 6 cases underwent gamma knife treatment (9.0%). The longest case of tumor growth and gamma knife treatment was observed 11 years after the initial diagnosis. Hearing thresholds at 500–2000 Hz was significantly different between the no growth and growth group (p <.05). Particularly at 1000 Hz, there was a significant difference between the two groups from an early time-point. Conclusions and Significance: Even a 10-year or longer follow-up of VS may show an increase in tumor growth. Moreover, hearing thresholds, particularly at 1000 kHz, may predict tumor growth when following-up VS patients.