Radiation Oncology/Sarcoma/Hemangiopericytoma

Hemangiopericytoma

Overview

 * Malignant vascular tumor
 * Tumor cells appear like smooth muscle cells, but don't arise from endothelial cells
 * Cell of origin not clear, possibly derived from pericytes
 * Most commonly in pelvic, proximal femur, humerus, and vertebral bodies
 * Median age in 4th and 5th decade
 * Typically slow growing
 * Radiography not definitive
 * Easily confused with meningioma. No calcifications or hyperostosis on CT (where as meningiomas have these features)
 * larger lesions will show flow voids on MRI.
 * Treatment frequently surgical, role of chemo and RT not clear, although small series show lower rates of recurrence with addition of radiotherapy.


 * Heidelberg, 2005 (Germany) (1984-2004) PMID 16222690 — "Precision radiotherapy for hemangiopericytomas of the central nervous system." (Combs SE et al. Cancer. 2005 Dec 1;104(11):2457-65.)
 * Retrospective. 25 patients. 23 surgical resection. Treated with fractionated stereotactic RT or IMRT for tumors of the CNS and spine. Median dose 54 (in 1.8-2 Gy/fx)
 * OS: 5-years 100%, 10-years 64%. 5-year PFS 61%
 * Conclusion: "High precision" RT effective and safe


 * SEER Analysis, 2013 (1990-2008) PMID 22867893 - The Role of Postoperative Radiation Therapy in the Treatment of Meningeal Hemangiopericytoma—Experience From the SEER Database (Stessin AM et al. Int J Radiat Oncol Biol Phys. 2013 Mar 1;85(3):784-90.)
 * SEER analysis from 1990-2008 of 76 patients in, of these 38 (50%) underwent gross total resection (GTR), whereas the other half underwent subtotal resection (STR), with a mean follow-up time is 7.9 years (95 months). There were Postoperative RT was administered to 42% (16/38) of the patients in the GTR group and 50% (19/38) in the STR group. The 1-year, 10-year, and 20-year cause-specific survival rates were 99%, 75%, and 43%, respectively. On multivariate analysis, postoperative RT was associated with significantly better survival (HR = 0.269, 95% CI 0.084-0.862; P=.027), in particular for patients who underwent STR (HR = 0.088, 95% CI: 0.015-0.528; P<.008).
 * Conclusion: Based on the current literature, the practical approach is to deliver limited field RT to doses of 50-60 Gy while respecting the normal tissue tolerance, especially for cases of STR.