Predictors of long-term tumor control after stereotactic radiosurgery for Koos grade 4 vestibular schwannomas

• DOI: 10.1007/s11060-020-03622-5
• Publication Date: 2021-01-07T22:03:01Z
• Authors: Toshinori Hasegawa; Takenori Kato; Takehiro Naito; Takafumi Tanei; Kazuki Ishii; Eisuke Tsukamoto; Kou Okada; Risa Ito; Yuuta Kouketsu
• Keywords: Adult; Aged, 80 and over; Male; Adolescent; Neuroma, Acoustic; Middle Aged; Prognosis; Radiosurgery; Tumor Burden; 3. Good health; Survival Rate; Young Adult; 03 medical and health sciences; 0302 clinical medicine; Humans; Female; Aged; Follow-Up Studies

To evaluate the predictors of long-term tumor control following stereotactic radiosurgery (SRS) for Koos grade 4 vestibular schwannomas (VSs).Overall, 203 sporadic VS patients with compression of the brainstem were treated with SRS. The median tumor volume was 6.7 cm3 (range, 2.0-28.9 cm3) and the median marginal dose was 12 Gy (range, 9-13.5 Gy).The median follow-up period was 152 months (range, 12-277 months). Tumor control (TC) rates at 3, 5, and 10 years were 89%, 85%, and 82%, respectively. Operation-free survival (OFS) rates at 3, 5, and 10 years were 92%, 85%, and 83%, respectively. Middle cerebellar peduncle (MCP) compression on pre-SRS magnetic resonance imaging scans was significant for both TC (p < 0.001, hazard ratio 1.332) and OFS (p < 0.001, hazard ratio 1.306). The 3-, 5-, and 10-year OFS rates were 98%, 94%, and 92% in the low-risk group (MCP compression < 9.8 mm and > 48 years old), and 58%, 25%, and 17% in high-risk group (MCP compression ≥ 9.8 mm and ≤ 48 years old), respectively. Ten patients (4.9%) developed delayed cyst-related complications. Eleven patients (5.4%) developed newly developed or worsened trigeminal neuralgia. No patient developed persistent facial palsy as an adverse radiation effect. A ventricular peritoneal shunt was required in six patients (3%) who developed hydrocephalus after SRS.SRS is an acceptable treatment option in selected patients with Koos grade 4 VSs. Risk group classification based on patient age and MCP compression is useful in decision-making of Koos grade 4 VSs.