Adjuvant stereotactic radiosurgery after resection of intracranial hemangiopericytomas

To evaluate adjuvant stereotactic radiosurgery (SRS) in the management of recurrent or residual intracranial hemangiopericytomas (HPCs), we assessed tumor control, survival, and complications in patients who had undergone gamma knife SRS as part of multimodal therapy.

We retrospectively reviewed the records of consecutive 20 HPC patients who had undergone SRS for 29 tumors. The median patient age was 51.5 years (range, 8.9-80.2). All patients had undergone previous surgical resection of their tumors. In addition, 12 patients underwent fractionated radiotherapy before SRS. Of the 20 patients, 16 patients had low-grade HPCs (20 tumors) and 4 had high-grade anaplastic HPCs (9 tumors). The median radiosurgery target volume was 4.5 cm(3) (range, 0.07-34.3), and the median marginal dose was 15.0 Gy (range, 10-20).

At an average of 48.2 months (range, 7.2-124.1), 5 patients had died of metastases and 3 patients had died of disease progression. The overall survival after radiosurgery was 100%, 85.9%, and 13.8% at 1, 5, and 10 years, respectively. The follow-up imaging studies demonstrated tumor control in 21 (72.4%) of 29 tumors. The progression-free survival rate after SRS at 1, 3, and 5 years was 89.1% for low-grade HPCs and 88.9%, 66.7%, and 0%, respectively, for high-grade HPCs. The factors associated with improved progression-free survival included lower grade and higher marginal dose. Eight patients had intracranial or extracranial metastasis after the initial diagnosis, which correlated with the shorter survival.

The results of our study have shown that adjuvant SRS after tumor resection is an important management option for patients with residual or recurrent HPCs and is particularly effective for less-aggressive tumors.