Yan Michael, Zalay Osbert, Kennedy Thomas, Owen Timothy E, Purzner James, Taslimi Shervin, Purzner Teresa, Alkins Ryan, Moideen Nikitha, Fung Andrea S, Moraes Fabio Y
Department of Oncology, Division of Radiation Oncology, Kingston Health Sciences Centre, Queen's University, Kingston, ON, Canada.
Division of Neurosurgery, Department of Surgery, Kingston Health Sciences Centre, Queen's University, Kingston, ON, Canada.
Front Oncol. 2022 Apr 4;12:869572. doi: 10.3389/fonc.2022.869572. eCollection 2022.
Stereotactic radiosurgery (SRS) is the standard treatment for limited intracranial metastases. With the advent of frameless treatment delivery, fractionated stereotactic radiotherapy (FSRT) has become more commonly implemented given superior control and toxicity rates for larger lesions. We reviewed our institutional experience of FSRT to brain metastases without size restriction.
We performed a retrospective review of our institutional database of patients treated with FSRT for brain metastases. Clinical and dosimetric details were abstracted. All patients were treated in 3 or 5 fractions using LINAC-based FSRT, did not receive prior cranial radiotherapy, and had at least 6 months of MRI follow-up. Overall survival was estimated using the Kaplan-Meier method. Local failure and radionecrosis cumulative incidence rates were estimated using a competing risks model with death as the competing risk. Univariable and multivariable analyses using Fine and Gray's proportional subdistribution hazards regression model were performed to determine covariates predictive of local failure and radionecrosis.
We identified 60 patients and 133 brain metastases treated at our institution from 2016 to 2020. The most common histologies were lung (53%) and melanoma (25%). Most lesions were >1 cm in diameter (84.2%) and did not have previous surgical resection (88%). The median duration of imaging follow-up was 9.8 months. The median survival for the whole cohort was 20.5 months. The local failure at 12 months was 17.8% for all lesions, 22.1% for lesions >1 cm, and 13.7% for lesions ≤1 cm (p = 0.36). The risk of radionecrosis at 12 months was 7.1% for all lesions, 13.2% for lesions >1 cm, and 3.2% for lesions ≤1 cm (p = 0.15).
FSRT is safe and effective in the treatment of brain metastases of any size with excellent local control and toxicity outcomes. Prospective evaluation against single-fraction SRS is warranted for all lesion sizes.
立体定向放射外科（SRS）是局限性颅内转移瘤的标准治疗方法。随着无框架治疗技术的出现，鉴于对于较大病灶其在控制率和毒性方面更具优势，分次立体定向放射治疗（FSRT）已得到更广泛应用。我们回顾了本机构对无大小限制的脑转移瘤进行FSRT治疗的经验。
我们对本机构接受FSRT治疗脑转移瘤患者的数据库进行了回顾性分析。提取了临床和剂量学细节。所有患者均采用基于直线加速器的FSRT分3次或5次进行治疗，未接受过先前的颅脑放疗，且有至少6个月的MRI随访。采用Kaplan-Meier法估计总生存期。使用以死亡作为竞争风险的竞争风险模型估计局部失败和放射性坏死的累积发生率。采用Fine和Gray比例子分布风险回归模型进行单变量和多变量分析，以确定预测局部失败和放射性坏死的协变量。
我们确定了2016年至2020年在本机构接受治疗的60例患者及133个脑转移瘤。最常见的组织学类型为肺癌（53%）和黑色素瘤（25%）。大多数病灶直径>1 cm（84.2%），且未接受过手术切除（88%）。影像学随访的中位时长为9.8个月。整个队列的中位生存期为20.5个月。所有病灶12个月时的局部失败率为17.8%，直径>1 cm的病灶为22.1%，直径≤1 cm的病灶为13.7%（p = 0.36）。所有病灶12个月时的放射性坏死风险为7.1%，直径>1 cm的病灶为13.2%，直径≤1 cm的病灶为3.2%（p = 0.15）。
FSRT治疗任何大小的脑转移瘤均安全有效，局部控制良好且毒性结果理想。对于所有大小的病灶，均有必要与单次分割SRS进行前瞻性评估。
