Fractionated Stereotactic Radiotherapy for Bilateral Vestibular Schwannomas Associated with Neurofibromatosis Type 2: Early Experiences in Ramathibodi Hospital
Mantana Dhanachai MD*, Veerasak Theerapancharoen MD**, Jiraporn Laothamatas MD*, Chanchai Jariengprasert MD***, Puangtong Kraiphibul MD*, Pornpan Yongvithisatid MD****
Affiliation : * Department of Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University ** Department of Surgery, Faculty of Medicine, Ramathibodi Hospital, Mahidol University *** Department of Otolaryngology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University **** Radiosurgery Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University
Purpose : To evaluate the rates of tumor control and useful hearing preservation in patients with bilateral
vestibular schwannomas (VSs) associated with neurofibromatosis type 2 (NF-2) treated with fractionated
stereotactic radiotherapy (FSRT).
Materials and Methods : From August 1998-December 2002 there were 5 patients with NF-2 who underwent
FSRT (Linac-based system) for bilateral CP angle tumors. Median age was 28 (18-47) years. Median tumor
volume was 5.4 (2.2-9.4) cc. Eight lesions received a marginal dose of 44.2-59.9 (median = 46.2) Gy in 25-
33 fractions. The other 2 lesions received 4.4 and 4.9 Gy / fraction for 6 fractions in 3 and 2 weeks. Median
follow-up was 19 (14-44) months.
Results : Radiographic and clinical tumor control rate was 90%. One lesion progressed at 7 months after
FSRT and was completely resected. Of the 5 lesions with Gardner-Robertson class I-II hearing before FSRT,
2 (40%) retained useful hearing at the last follow-up. One patient had left facial spasm at 10 months after
FSRT which gradually improved. No patient had facial palsy, facial numbness or pain.
Conclusions : FSRT provided good tumor control and hearing preservation rate in NF-2 patients with
minimal morbidity. However, a longer follow-up is needed to evaluate long term results.
Keywords : Neurofibromatosis type 2, Stereotactic Radiotherapy, Vestibular Schwannoma
