Fractionated stereotactic radiosurgery for treatment of acoustic neuromas.

BACKGROUND: Microsurgery and single-fraction radiosurgery for acoustic neuromas are associated with high rates of control, but can result in facial palsy and trigeminal neuropathy. To reduce the morbidity of treatment for acoustic neuromas while maintaining efficacy, we explored fractionated stereotactic radiosurgery (FSR).

METHODS: We reviewed data for 31 acoustic neuromas in 30 patients treated with 25 Gy (linear accelerator) given in 5 consecutive daily fractions. The minimum follow-up was 6 months (6-44 months). The mean tumor volume was 1.1 cm(3) (0.1-8.74 cm(3)).

RESULTS: All tumors remain controlled (9 smaller, 22 unchanged). No patient has experienced post-radiosurgery facial motor dysfunction. Two patients developed new trigeminal neuropathy; 2 patients with preexisting trigeminal nerve symptoms had improvement after FSR. Balance improved in 3 patients, was unchanged in 20 and worsened in 7 patients. Of the 12 patients with useful hearing (PTA < or = 50 dB) prior to treatment, 9 patients retained useful hearing following FSR. Subjectively, of 25 patients with any hearing prior to treatment, 2 had improvement, 10 remained unchanged and 13 had worsening.

CONCLUSIONS: Short course FSR for acoustic neuromas results in acceptable toxicity and may provide high control of tumors. Longer follow-up is needed to assess outcomes.