Zhang Qichen, Hamilton Daniel, Conway Paul, Xie Sophia Jing, Haghighi Neda, Lasocki Arian
Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
Icon Cancer Centre Gold Coast University Hospital, Queensland, Gold Coast, Australia.
J Med Imaging Radiat Oncol. 2023 Apr;67(3):308-319. doi: 10.1111/1754-9485.13519. Epub 2023 Feb 27.
Balancing disease control and treatment-related toxicities can be challenging when treating higher-risk brain metastases (BMs) that are larger in size or eloquent anatomical locations. Hypofractionated stereotactic radiosurgery (hfSRS) is expected to offer superior or equal efficacy with lower toxicity profile compared with single-fraction SRS (sfSRS). We report the efficacy and toxicity profiles of hfSRS in a consecutive cohort of patients to support this predicted benefit from hfSRS for high-risk BMs.
We retrospectively analysed 185 consecutive individual lesions from 152 patients with intact BMs treated with hfSRS between 1 July 2016 and 31 October 2019 and followed up to 30 April 2022 with serial brain magnetic resonance imaging (MRI). The primary endpoint was the event of radiation necrosis (RN). Local control (LC) rate and distant brain failure (DBF) were reported as secondary outcomes. Kaplan-Meier method was used to report the cumulative incidence of RN and overall survival and the incidence of DBF. Potential risk factors for RN were assessed using univariable Cox regression analysis.
The median follow-up was 38.0 months, and the median survival post-SRS was 9.5 months. The cumulative incidence rate of RN was 13.2% (95% CI: 7.0-24.7%), and 18.1% of patients with confirmed RN were symptomatic. Higher mean dose delivered to planning target volume (PTV) (HR 1.22, 95% CI: 1.05-1.42, P = 0.01), higher mean BED (biological equivalent dose assuming a tissue ratio of 10) (HR 1.12, 95% CI: 1.04-1.2, P < 0.001), and higher mean BED (HR 1.02, 95% CI: 1-1.04, P = 0.04) delivered to the lesion was associated with increased risk of RN. LC rate was 86% and the cumulative incidence of DBF was 36% with a median onset of 28.4 months.
Our results support the predicted radiobiological benefit of the use of hfSRS in high-risk BMs to limit treatment-related toxicity with low risk for symptomatic RN comparable with lower risk population receiving sfSRS while achieving satisfactory local disease control.
在治疗体积较大或位于功能区等高危脑转移瘤（BMs）时，平衡疾病控制与治疗相关毒性可能具有挑战性。与单次分割立体定向放射外科手术（sfSRS）相比，超分割立体定向放射外科手术（hfSRS）有望提供疗效相当或更优且毒性更低的治疗效果。我们报告了连续一组患者接受hfSRS治疗的疗效和毒性情况，以支持hfSRS对高危BMs所预测的益处。
我们回顾性分析了2016年7月1日至2019年10月31日期间接受hfSRS治疗的152例完整BMs患者的185个连续个体病灶，并通过系列脑磁共振成像（MRI）随访至2022年4月30日。主要终点是放射性坏死（RN）事件。局部控制（LC）率和远处脑转移（DBF）作为次要结果进行报告。采用Kaplan-Meier方法报告RN的累积发生率、总生存率和DBF的发生率。使用单变量Cox回归分析评估RN的潜在风险因素。
中位随访时间为38.0个月，SRS术后中位生存期为9.5个月。RN的累积发生率为13.2%（95%CI：7.0 - 24.7%），确诊为RN的患者中有18.1%出现症状。给予计划靶体积（PTV）的平均剂量较高（HR 1.22，95%CI：1.05 - 1.42，P = 0.01）、平均生物等效剂量（假设组织比为10时的生物等效剂量）较高（HR 1.12，95%CI：1.04 - 1.2，P < 0.001）以及给予病灶的平均生物等效剂量较高（HR 1.02，95%CI：1 - 1.04，P = 0.04）与RN风险增加相关。LC率为86%，DBF的累积发生率为36%，中位发病时间为28.4个月。
我们的结果支持在高危BMs中使用hfSRS所预测的放射生物学益处，即限制治疗相关毒性，有症状RN的风险较低，与接受sfSRS的低风险人群相当，同时实现令人满意的局部疾病控制。
