2595 - Stereotactic Radiotherapy for Intracranial and Intramedullary Hemangioblastomas

Purpose/Objective(s): To evaluate the safety and efficacy of stereotactic irradiation for intracranial and intramedullary hemangioblastomas in patients with sporadic tumors and those associated with von Hippel-Lindau (VHL) disease.

Materials/Methods: Between 2005 and 2023, 135 patients with hemangioblastomas (104 with VHL syndrome, 31 sporadic) underwent stereotactic irradiation. A total of 798 tumors were treated, including 588 (73.7%) intracranial and 210 (26.3%) spinal cord lesions. The mean patient age was 30 years (range: 7–76 years). Treatment modalities included single-fraction radiosurgery (SRS; 78% of targets, 14–22 Gy), hypofractionated radiosurgery (HfSRT; 20% of targets, 3–5 fractions, 21–27 Gy), and standard fractionation (2% of targets, 45–54 Gy in 25–30 fractions). 618 tumors were treated in single fraction mode with mean target volume 0,33 cc [0,0002-10,60], median 0,06 [0,025; 0,2]. 164 in hypofractionation mode, mean target volume 2,32 cc (0,006-42,9) median 0,41 [0,1; 2,33]), and 14 tumors- by standard fractionation (with mean target volume 14,78 cc [0,5-79,62]; median 11,4 [1,62; 16,72]. The mean follow-up period was 38.2 months (range: 15–212 months).

Results: The 5- and 10-year recurrence-free survival (RFS) rates were 98% and 92%, respectively. Tumor volume and treatment modality (SRS vs. HfSRT/standard fractionation) were significant predictors of RFS (p < 0.023). SRS demonstrated superior tumor control and RFS compared to HfSRT (p = 0.008) and standard fractionation (p = 0.012). Adverse radiation effects, including perifocal edema, occurred in 12.1% of cases and were associated with larger tumor volumes and pre-existing edema. Event-free survival (EFS) at 5 and 10 years was 95% and 89%, respectively, and was significantly influenced by tumor volume (p < 0.012) and patient age (p < 0.017). With a larger volume of the solid component of the tumor, the probability of the appearance of new or growth of old cysts is higher. The presence of a cyst before irradiation is a prognostically unfavorable factor for the increase in previously identified cysts or the appearance of new ones. The presence of a cyst before irradiation increases the probability of its growth after irradiation or the appearance of new cysts after irradiation (p<0.001). No significant difference in the effectiveness of stereotactic irradiation of sporadic and Von Hippel-Lindau disease-associated hemangioblastomas was found (p<0.001).

Conclusion: Stereotactic irradiation is an effective and safe treatment for hemangioblastomas, both sporadic and VHL-associated. SRS is the preferred modality for small tumors (< 5 cc) and multiple lesions in VHL disease. Tumor volume, treatment modality, and patient age are key predictors of outcomes, with larger tumors and pre-existing cysts or edema associated with higher risks of complications and recurrence.