BACKGROUND AND PURPOSE The role of radiotherapy (RT) in the treatment of hemangiopericytoma/solitary fibrous tumor (HPC/SFT) is still under debate. We aimed at investigating whether radiotherapy can improve the results in patients operated for extracranial HPC/SFT. MATERIALS AND METHODS Data from patients with HPC/SFT, treated from 1982 to 2012, were retrospectively reviewed within the Rare Cancer Network framework. Actuarial local control (LC), disease-free survival (DFS), metastasis-free survival (MFS) and overall survival (OS) were calculated with Kaplan-Meyer method. Patient and tumor parameters were analyzed by univariate and multivariate analysis. RESULTS Of 114 HPC/SFT, 58 (50.9%) occurred in the extremities/superficial trunk and 56 (49.1%) in intra-thoracic/retroperitoneum. Seventy-eight patients (68.4%) underwent surgery only (Sx), and 36 (31.6%) Sx and RT (Sx + RT). Median RT dose was 60 Gy (range 45-68.4 Gy) in 1.6-2.2 Gy fractions. In the extremities/superficial trunk group of patients, actuarial 5-year LC rates were 50.4% after Sx and 91.6% after Sx + RT (p < 0.0001) for LC, and 50.4% after Sx and 83.1% after Sx + RT (p = 0.008) for DFS. In the intra-thoracic/retroperitoneum group of patients, actuarial 5-year rates were 89.3% after Sx and 77.8% after Sx + RT (p = 0.99) for LC, and 73.8% after Sx and 77.8% after Sx + RT (p = 0.93) for DFS. At multivariate analysis, the addition of RT resulted in better LC and DFS in the whole series. The advantage was confirmed for LC in the group of patients affected by extremity/superficial trunk tumors. CONCLUSION Addition of RT to Sx could improve the prognosis, in terms of LC and DFS, essentially in patients with extremities/superficial trunk tumor locations.

中文翻译：

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放射治疗颅外血管外皮细胞瘤/孤立性纤维瘤：来自罕见癌症网络的研究

背景和目的 放疗 (RT) 在治疗血管外皮细胞瘤/孤立性纤维瘤 (HPC/SFT) 中的作用仍存在争议。我们旨在调查放疗是否可以改善颅外 HPC/SFT 手术患者的结果。材料和方法 在罕见癌症网络框架内对 1982 年至 2012 年接受治疗的 HPC/SFT 患者的数据进行了回顾性审查。使用Kaplan-Meyer方法计算精算局部控制（LC）、无病生存（DFS）、无转移生存（MFS）和总生存（OS）。通过单变量和多变量分析来分析患者和肿瘤参数。结果 114例HPC/SFT中，58例（50.9%）发生在四肢/浅表干，56例（49.1%）发生在胸腔内/腹膜后。78 名患者 (68.4%) 仅接受手术 (Sx)，和 36 (31.6%) Sx 和 RT (Sx + RT)。中位放疗剂量为 60 Gy（范围 45-68.4 Gy），分 1.6-2.2 Gy。在患者的四肢/浅表躯干组中，精算 5 年 LC 率在 Sx 后为 50.4%，Sx + RT 后为 91.6%（p < 0.0001），Sx 后为 50.4%，Sx + RT 后为 83.1%（p = 0.008) 对于 DFS。在胸腔内/腹膜后组患者中，LC 的精算 5 年率在 Sx 后为 89.3%，在 Sx + RT 后为 77.8%（p = 0.99），在 Sx 后为 73.8%，在 Sx + RT 后为 77.8%（p = 0.93) 对于 DFS。在多变量分析中，加入 RT 可在整个系列中获得更好的 LC 和 DFS。在受四肢/浅表躯干肿瘤影响的患者组中，LC 的优势得到证实。结论 在 Sx 基础上加用 RT 可以改善预后，就 LC 和 DFS 而言，