Gamma knife surgery for hemangioblastomas.

OBJECT: The authors reviewed their 14-year experience using stereotactic radiosurgery for the treatment of hemangioblastomas and define the role and the proper strategy for radiosurgery of this condition.
METHODS: This is a retrospective study of 38 hemangioblastomas in 13 patients. Seven patients had von Hippel-Lindau disease. All patients have undergone at least one follow-up visit. The median and mean tumor volumes were 0.23 cm3 and 0.72 cm3 respectively (range 0.004::4.84 cm3). Twenty-eight tumors received 20 Gy to the margin, and the remainder received 18 Gy. The median clinical follow-up period was 36 months (range 3-159 months). No patient died. The survival rate was 84.6% (11 of 13 patients). The actuarial 5- and 10-year survival rates were both 80.8%. The median radiological follow-up period was 35 months (range 7-147 months). Only one tumor increased in volume 24 months after treatment in association with an intratumoral hemorrhage. The tumor control rate was 97.4% (37 of 38 tumors). Actuarial 5- and 10-year control rates were both 96.2%. New lesions and/or those increasing in size outside the irradiated area were discovered in five patients (38.5%). Nine tumors revealed peritumoral contrast enhancement which was seen more frequently in larger tumors with a volume greater than 0.5 cm3 (p = 0.0034).
CONCLUSIONS: Gamma knife surgery is a safe and effective method to control hemangioblastomas for as many as 10 years. Higher doses and smaller tumors probably contribute to good outcomes. Recurrence outside the original irradiated area is common. Peritumoral contrast enhancement may be seen in larger tumors. The authors recommend regular imaging follow up and early repeated treatment in the face of new or growing tumors.