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Objective: Intracranial hemangiopericytomas are rare CNS tumors. Adjuvant radiotherapy(RT) is frequently performed after surgery, depending on tumor size, location and type of resection. Moreover RT is preferred as an effective treatment for local recurrence and metastasis. It was aimed to evaluate the clinical outcomes of intracranial hemangiopericytoma.

Materials-Methods: Patients aged 16 years and older who underwent RT with the histologically confirmed intracranial hemangiopericytoma were evaluated retrospectively. 36 patients from 13 institutions were included. RT was performed in 28 patients after surgery, in 5 patients for local recurrence and in 3 patients after biopsy. Demographic characteristics of the patients, pathological findings and prognostic factors were estimated. Interval of recurrence or metastasis were calculated from begining of RT. Kaplan Meier method was used for local control(LC) and distant metastasis-free survival(DMFS), progression-free survival(PFS) and overall survival(OS). Cox regression test was used for multivariate analyzes.

Results: The median age was 41 years and 70% of the patients were male. Supratentorial location was observed in the 80,6% of patients. The most common initial symptoms were pain(42%) and vision problems(14%). The median maximum tumor size was 4.8(1.6-14)cm. Gross total resection(GTR)  was performed in 39%, subtotal resection was performed in 50% of the patients. Adjuvant RT was started after a median of 5(2-16)weeks after surgery. Postoperative locally RT was performed in median 60(12-64)Gy and median 30(1-33)fractions. Concurrent temozolamide was administered to 4 patients, sunitinib was administered to one patient and interferon was administered to one patient. Local recurrence in 7 patients and locoregional recurrence in 2 patients were observed in median 58(34-143) months after RT. Reoperation and irradiation was applied to 3 patients, reirradiation to 3 patients and reoperation to 3 patients. Reirradation was administered at a median dose of 40(13.5-54)Gy in 5(1-30)fractions. Systemic treatment due to metastasis was applied in 3 patients in a median 24(22-58) months after RT. Palliative RT was applied to 2 patients. At a median follow-up of 62(6-262)months, the 5-year LC rate was 69.9%, DMFS 86.9%, PFS 63.8% and OS 100%. The precense of residual macroscopic tumor before RT was associated lower LC(p=0.01) and shorter PFS(p=0.04). In the presence of residual tumor before RT, 5-year LC decreases from 100% to 50%, while 5-year PFS decreases from 90% to 46%. However, the effect of residual disease before RT on OS wasn’t statistically significant.

Conclusion: Adjuvant RT increases LC, especially in patients who cannot undergo GTR. In our study, although macroscopic residual tumor before RT was a factor affecting LC and PFS, but its effect on OS wasn’t demonstrated. The reason for this was considered to be the effectiveness of reoperation and/or reirradation in the presence of recurrence after RT.