Results of robotic radiotherapy in intracranialschwannomas
iARTIST-International Advanced Radiotherapy Techniques Symposium, İstanbul, Türkiye, 11 - 14 Haziran 2026, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: İstanbul
- Basıldığı Ülke: Türkiye
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
Background: Schwannomas are the most common benign tumors of cranial nerves. Vestibular schwannomas (8th cranial pair) are the most common, with an incidence of approximately two cases per 100,000 population per year. The median age of onset is 55, and 90% of cases are unilateral. For tumors smaller than 3 cm, stereotactic radiotherapy (SRT) offers long-term local control compared to surgery, with a lower risk of functional deficits and preserved hearing. In this study, we aimed to evaluate the outcomes of patients with intracranial schwannoma treated with robotic RT. Materials-Methods: Twenty-six patients with 27 lesions underwent SRT with the CyberKnife-M6 (CK-M6) device between 2019 and 2025, and were evaluated in January 2026 after a 31-month (7-75) follow-up. Results: The median age was 53 (18-70), and the male/female ratio was 8/18 (Table 1). The symptom duration was 12 months (1-120), and 10 cases underwent surgery (macroscopic total excision= 5, subtotal excision= 5). Two patients underwent surgery twice. Two patients had a prior history of GK-based SRS (12 and 12,5 Gy), and one of them had also undergone surgery before SRS. The median interval between radiological diagnosis and SRT was 10 months (1- 142). For 24 lesions with vestibular schwannomas, the Koos grade was 1 (n = 1), 2 (n = 2), 3 (n = 4), and 4 (n = 17), respectively. A median of 12,5 Gy (12- 12,5) was applied to 7 lesions receiving stereotactic radiosurgery (SRS), and a median of 25 Gy (20- 36) in 5 fractions (3- 12) was applied to 20 lesions receiving hypofractionated SRT (hSRT) (Fig 1). The median BED3 and EQD2 values were 66,67 Gy (53,33- 72) and 43,75 Gy (35- 47,25), respectively (Table 2). Two lesions were irradiated simultaneously in one patient. The median treatment duration was 17 minutes (12- 24). In 24 lesions evaluated at a median of 3 months (3- 4) after SRT, 18 stable responses, 2 partial responses, and 4 pseudoprogressions were observed. Pseudoprogression was observed in another patient at 24 months. At the last follow-up, 24 patients were alive, and all of 25 lesions had local control. The 3-year OS, LRPFS, and PFS were 90,8,%, 96,2%, and 91,1%, respectively. Doses delivered to organs at risk (OAR) were within tolerance (Table 3). Of the 24 patients with neurological symptoms before SRT, symptoms regressed in 3 cases after SRT, tinnitus worsened in one case, and ear pain developed in 2 cases. Facial nerve complications developed in 4 cases at a median of 7 months (7- 24). In all but one of the 20 patients with pre-RT hearing loss, hearing function remained stable. In 5 patients who had no pre-RT hearing loss, hearing was preserved after SRT. One patient with bilateral vestibular schwannoma developed hearing loss on one side, but hearing was preserved on the other side. In total, hearing was preserved in 25 out of 27 lesions. Conclusion: Modern RT techniques aim to provide maximum protection to OAR and minimize side effects. In our study, CK-M6-based SRT was found to be effective, comfortable, and safe in the treatment of intracranial schwannomas.