Small-field fractionated radiotherapy with or without stereotactic boost for vestibular schwannoma

Purpose: To assess the efficacy and toxicity of small-field fractionated ra diotherapy with or without stereotactic boost (SB) for vestibular schwannom as. Methods and materials: Thirty-nine patients with vestibular schwannoma were treated with irradiation between March 1991 and February 1996. Extra-meata l tumor diameters were under 30 mm. Thirty-three patients received small-fi eld fractionated radiotherapy followed by SE. Basic dose schedule was 44 Gy in 22 fractions over 5 1/2 weeks plus 4 Gy in one session. Six patients re ceived small-field fractionated radiotherapy only (40-44 Gy in 20-22 fracti ons over 5-5 1/2 weeks or 36 Gy in 20 fractions over 5 weeks).dash;p > Resu lts: Follow-up ranged from 6 to 69 months (median, 24 months). Tumors decre ased in size in 13 cases (33%), were unchanged in 25 (64%), and increased i n one (3%). The actuarial 2-year tumor control rate was 97%. Fifteen patien ts had useful hearing (Gardner-Robertson class 1-2) and 25 patients had tes table hearing (class 1-4) before irradiation. The 2-year actuarial rates of useful hearing preservation (free of deterioration from class 1-2 to class 3-5) were 78%. The 2-year actuarial rates of any testable hearing preserva tion (free of deterioration from class 1-4 to class 5) were 96%. No permane nt facial and trigeminal neuropathy developed after irradiation. The 2-year actuarial incidences of facial and trigeminal neuropathies were 8% and 16% , respectively. Conclusions: Small-field fractionated radiotherapy with or without SE provi des, excellent short-term local control and a relatively low incidence of c omplications for vestibular schwannoma, although further follow-up is neces sary to evaluate the long-term results. (C) 1999 Elsevier Science Ireland L td. All rights reserved.