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Historically, it is stated that large intracranial tumors, herein defined as a maximum dimension of ≥3 cm or tumor volume ≥14.2 cm3, are not candidates for stereotactic radiosurgery (SRS). We report outcomes of patients with large benign intracranial tumors treated with SRS. With institutional review board approval, we retrospectively identified 74 patients with large benign intracranial tumors (59 meningiomas, 9 vestibular schwannomas, and 6 glomus jugulare tumors) treated with robotic SRS (2007–2018). Patients received definitive SRS in 47.3% of the cases, adjuvant to surgical resection in 44.6%, and salvage after past radiation treatment in 8.1%. A median tumor volume of 16.0 cm3 (range, 10.1–65.5 cm3) received a median dose of 24.0 Gy (range, 14.0–30.0 Gy) in a median of 3 fractions (range, 1–5), for a median single fraction equivalent dose (with alpha/beta of 3) of 14.8 Gy (range, 11.3–18.0 Gy). The Kaplan-Meier estimate of tumor local control (LC) was calculated from date of SRS. With a median clinical follow-up of 32.8 months (range, 0.6–125.9 months) and median radiologic follow-up of 28.5 months (range, 0.6–121.4 months), LC was 96.5% (95% confidence interval, 92.4%–100%) at 3 years and 91.7% (95% confidence interval, 87.6%–95.7%) at 5 years. Adverse radiation effect (ARE) was seen in 10 patients (13.5%) at a median of 13.5 months (range, 7.8–34.5 months). ARE occurred in 9% of those with prior treatment compared with 5% who were radiation-naïve (P = 0.23). With 236.4 person-years of follow-up, no secondary malignancies were seen. Despite the historical adage, we find that SRS provides high rates of LC for these large tumors, with rates of ARE similar to historical reports of SRS for smaller benign tumors. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration. Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990–2020 and had pre- and post-treatment audiograms. Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12–60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS. Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing. [ABSTRACT FROM AUTHOR]