Repeat Stereotactic Radiosurgery for Acoustic Neuromas.

Purpose <br/>To evaluate the outcome of repeat stereotactic radiosurgery (SRS) for acoustic neuromas, we assessed tumor control, clinical outcomes, and the risk of adverse radiation effects in patients whose tumors progressed after initial management. <br/> <br/>Methods and Materials <br/>During a 21-year experience at our center, 1,352 patients underwent SRS as management for their acoustic neuromas. We retrospectively identified 6 patients who underwent SRS twice for the same tumor. The median patient age was 47 years (range, 35–71 years). All patients had imaging evidence of tumor progression despite initial SRS. One patient also had incomplete surgical resection after initial SRS. All patients were deaf at the time of the second SRS. The median radiosurgery target volume at the time of the initial SRS was 0.5 cc and was 2.1 cc at the time of the second SRS. The median margin dose at the time of the initial SRS was 13 Gy and was 11 Gy at the time of the second SRS. The median interval between initial SRS and repeat SRS was 63 months (range, 25–169 months). <br/> <br/>Results <br/>At a median follow-up of 29 months after the second SRS (range, 13–71 months), tumor control or regression was achieved in all 6 patients. No patient developed symptomatic adverse radiation effects or new neurological symptoms after the second SRS. <br/> <br/>Conclusions <br/>With this limited experience, we found that repeat SRS for a persistently enlarging acoustic neuroma can be performed safely and effectively. <br/> <br/>