Background: Radiation necrosis (RN) is a possible late complication of stereotactic radiosurgery (SRS), but only a few risk factors are known. The aim of this study was to assess tumor location in correlation to the development of radiation necrosis for skull base (SB) and non-skull base tumors. Methods: All patients treated with radiosurgery for benign neoplasms (2004–2020) were retrospectively evaluated. The clinical, imaging and medication data were obtained and the largest axial tumor diameter was determined using MRI scans in T1-weighted imaging with gadolinium. The diagnosis of RN was established using imaging parameters. Patients with tumors located at the skull base were compared to patients with tumors in non-skull base locations. Results: 205 patients could be included. Overall, 157 tumors (76.6%) were located at the SB and compared to 48 (23.4%) non-SB tumors. Among SB tumors, the most common were vestibular schwannomas (125 cases) and meningiomas (21 cases). In total, 32 (15.6%) patients developed RN after a median of 10 (IqR 5–12) months. Moreover, 62 patients (30.2%) had already undergone at least one surgical resection. In multivariate Cox regression, SB tumors showed a significantly lower risk of radiation necrosis with a Hazard Ratio (HR) of 0.252,p< 0.001, independently of the applied radiation dose. Furthermore, higher radiation doses had a significant impact on the occurrence of RN (HR 1.372,p= 0.002). Conclusions: The risk for the development of RN for SB tumors appears to be low but should not be underestimated. No difference was found between recurrent tumors and newly diagnosed tumors, which may support the value of radiosurgical treatment for patients with recurrent SB tumors.
背景：放射性坏死是立体定向放射外科治疗后可能出现的晚期并发症，但目前已知的风险因素有限。本研究旨在评估颅底与非颅底肿瘤位置与放射性坏死发生风险的相关性。方法：回顾性分析2004年至2020年间接受放射外科治疗的良性肿瘤患者。收集临床、影像及用药数据，并通过钆增强T1加权磁共振成像测定肿瘤最大轴向直径。放射性坏死的诊断依据影像学参数确立。比较颅底肿瘤患者与非颅底肿瘤患者的临床特征。结果：共纳入205例患者，其中颅底肿瘤157例（76.6%），非颅底肿瘤48例（23.4%）。颅底肿瘤中最常见的是前庭神经鞘瘤（125例）和脑膜瘤（21例）。中位随访10个月（四分位距5-12个月）后，共有32例（15.6%）患者发生放射性坏死。62例（30.2%）患者既往至少接受过一次手术切除。多变量Cox回归分析显示，在排除放射剂量影响后，颅底肿瘤发生放射性坏死的风险显著降低（风险比0.252，p<0.001）。较高放射剂量与放射性坏死发生率显著相关（风险比1.372，p=0.002）。结论：颅底肿瘤发生放射性坏死的风险较低但不容忽视。复发肿瘤与新发肿瘤在放射性坏死发生率上无显著差异，这为复发颅底肿瘤患者接受放射外科治疗提供了依据。
Tumor Location Impacts the Development of Radiation Necrosis in Benign Intracranial Tumors
肿瘤(癌症)患者之家