Long-term results of LINAC-based stereotactic radiosurgery for acoustic neuroma: The Greek experience

Purpose: To estimate the value of LINAC-based stereotactic radiosurgery (SRS) for the long-term local control of unilateral acoustic neuromas. Materials and Methods: Twenty patients (median age 66; range 57-80 years) with unilateral acoustic neuroma underwent LINAC-based SRS from May 2000 through June 2004 with a dose of 11-12 Gy. The follow-up period ranged from 36 to 84 months (median follow-up period: 55 months). Before SRS none of the patients had useful hearing. The follow-up consisted of repeat imaging studies and clinical examination for assessment of facial and trigeminal nerve function at 6-month intervals for the first year and yearly thereafter. Results: Eleven tumors (58) decreased in size and eight (42) remained stable. One tumor showed a minor increase in size on the MRI done 6 months after SRS in comparison with the pretreatment MRI; however, a subsequent decrease was noticed on the next radiographic assessment and the tumor remained stable from then on. None of the tumors increased in size in the long-term follow-up, thus giving an overall growth control of 100 for the patients in this study. None of the patients had useful hearing before SRS, so hearing level was not assessed during follow-up. No patient developed new, permanent facial or trigeminal neuropathy. Conclusion: LINAC-based SRS with 11-12 Gy provides excellent tumor control in acoustic neuroma and has low toxicity even after long-term follow-up.