Long-term follow-up reveals low toxicity of radiosurgery for vestibular schwannoma.
OBJECTIVE
The long-term effects of radiosurgery of vestibular schwannomas were investigated in a group of consecutively treated patients.


METHODS
Between 1995 and 2001, 26 patients (median age: 67, range: 30-82) with a vestibular schwannoma were treated by Linac-based stereotactic radiosurgery (SRS). The median follow-up was 49 months (16-85 months). Only progressive tumours were treated. The median size of tumours was 18 mm (range 9-30 mm). Before SRS, 11 patients had a useful hearing (Gardner-Robertson classes 1 and 2). Single doses of 10-14 Gy were prescribed at the 80% isodose at the tumour margin. The follow-up consisted of regular imaging with MRI the first 3-6 months after the intervention, followed by additional yearly MRIs, a hearing test and a neurological examination.


RESULTS
The 5-year-probability of tumour control (defined as stabilization or decrease in size) was 95%. Five-year-probability of preservation of hearing and facial nerve function was 96% and 100%, respectively. Hearing was preserved in 10 out of 11 patients who had a normal or useful hearing at the time of treatment. Mild and transient trigeminal toxicity occurred in 2 (8%) patients. It appeared to be significantly correlated to the dose used (p=0.044). However, only a tendency to significance could be demonstrated in the relationship between the two factors when using the Cox analysis (hazard ratio=1.7; 95% CI: 0.7-3.9; p=0.23).


CONCLUSIONS
With the doses used, our study demonstrates that SRS provides an equivalent tumour control rate when compared to surgery, as well as on a long-term basis, an excellent preservation of the facial and the acoustic nerves. Although no permanent trigeminal toxicity was observed, our data confirm that doses below 14 Gy can avoid transient dysesthesias.
Rutten
Isabelle
I
Department of Radiotherapy, C.H.U. of Liège, Liège, Belgium. irutten@chu.ulg.ac.be
Baumert
Brigitta G
BG
Seidel
Laurence
L
Kotolenko
Snezana
S
Collignon
Jacques
J
Kaschten
Bruno
B
Albert
Adelin
A
Martin
Didier
D
Deneufbourg
Jean-Marie
JM
Demanez
Jean-Pierre
JP
Stevenaert
Achille
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003391:Cranial Nerves / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D016896:Treatment Outcome