Sneed Penny K, Chan Jason W, Ma Lijun, Braunstein Steve E, Theodosopoulos Philip V, Fogh Shannon E, Nakamura Jean L, Boreta Lauren, Raleigh David R, Ziemer Benjamin P, Morin Olivier, Hervey-Jumper Shawn L, McDermott Michael W
1Department of Radiation Oncology, University of California, San Francisco.
2Department of Radiation Oncology, University of Southern California, Los Angeles.
J Neurosurg. 2022 May 20;138(1):104-112. doi: 10.3171/2022.4.JNS212597. Print 2023 Jan 1.
The authors previously evaluated risk and time course of adverse radiation effects (AREs) following stereotactic radiosurgery (SRS) for brain metastases, excluding lesions treated after prior SRS. In the present analysis they focus specifically on single-fraction salvage SRS to brain metastases previously treated with SRS or hypofractionated SRS (HFSRS), evaluating freedom from progression (FFP) and the risk and time course of AREs.
Brain metastases treated from September 1998 to May 2019 with single-fraction SRS after prior SRS or HFSRS were analyzed. Serial follow-up magnetic resonance imaging (MRI) and surgical pathology reports were reviewed to score local treatment failure and AREs. The Kaplan-Meier method was used to estimate FFP and risk of ARE measured from the date of repeat SRS with censoring at the last brain MRI.
A total of 229 retreated brain metastases in 124 patients were evaluable. The most common primary cancers were breast, lung, and melanoma. The median interval from prior SRS/HFSRS to repeat SRS was 15.4 months, the median prescription dose was 18 Gy, and the median duration of follow-up imaging was 14.5 months. At 1 year after repeat SRS, FFP was 80% and the risk of symptomatic ARE was 11%. The 1-year risk of imaging changes, including asymptomatic RE and symptomatic ARE, was 30%. Among lesions that demonstrated RE, the median time to onset was 6.7 months (IQR 4.7-9.9 months) and the median time to peak imaging changes was 10.1 months (IQR 5.6-13.6 months). Lesion size by quadratic mean diameter (QMD) showed similar results for QMDs ranging from 0.75 to 2.0 cm (1-year FFP 82%, 1-year risk of symptomatic ARE 11%). For QMD < 0.75 cm, the 1-year FFP was 86% and the 1-year risk of symptomatic ARE was only 2%. Outcomes were worse for QMDs 2.01-3.0 cm (1-year FFP 65%, 1-year risk of symptomatic ARE 24%). The risk of symptomatic ARE was not increased with tyrosine kinase inhibitors or immunotherapy before or after repeat SRS.
RE on imaging was common after repeat SRS (30% at 1 year), but the risk of a symptomatic ARE was much less (11% at 1 year). The results of repeat single-fraction SRS were good for brain metastases ≤ 2 cm. The authors recommend an interval ≥ 6 months from prior SRS and a prescription dose ≥ 18 Gy. Alternatives such as HFSRS, laser interstitial thermal therapy, or resection with adjuvant radiation should be considered for recurrent brain metastases > 2 cm.
作者之前评估了立体定向放射外科治疗（SRS）脑转移瘤后不良放射效应（AREs）的风险和时间进程，排除了先前接受过SRS治疗的病变。在本分析中，他们特别关注先前接受过SRS或低分次SRS（HFSRS）治疗的脑转移瘤的单次分割挽救性SRS，评估无进展生存期（FFP）以及AREs的风险和时间进程。
分析了1998年9月至2019年5月期间在先前接受SRS或HFSRS治疗后接受单次分割SRS治疗的脑转移瘤。回顾了系列随访磁共振成像（MRI）和手术病理报告，以对局部治疗失败和AREs进行评分。采用Kaplan-Meier方法估计从重复SRS日期开始测量的FFP和AREs风险，并在最后一次脑部MRI检查时进行删失。
共有124例患者的229个复发性脑转移瘤可进行评估。最常见的原发癌为乳腺癌、肺癌和黑色素瘤。从先前SRS/HFSRS到重复SRS的中位间隔时间为15.4个月，中位处方剂量为18 Gy，随访成像的中位持续时间为14.5个月。重复SRS后1年，FFP为80%，有症状AREs的风险为11%。包括无症状放射性坏死（RE）和有症状AREs在内的成像改变的1年风险为30%。在出现RE的病变中，发病的中位时间为6.7个月（四分位间距4.7 - 9.9个月），成像改变达到峰值的中位时间为10.1个月（四分位间距5.6 - 13.6个月）。按二次平均直径（QMD）计算的病变大小在0.75至2.0 cm范围内显示出相似的结果（1年FFP 82%，有症状AREs的1年风险11%）。对于QMD < 0.75 cm，1年FFP为86%，有症状AREs的1年风险仅为2%。对于QMD为2.01 - 3.0 cm的病变，结果较差（1年FFP 65%，有症状AREs的1年风险24%）。在重复SRS之前或之后使用酪氨酸激酶抑制剂或免疫治疗，有症状AREs的风险并未增加。
重复SRS后成像上的RE很常见（1年时为30%），但有症状AREs的风险要低得多（1年时为11%）。重复单次分割SRS对直径≤2 cm的脑转移瘤效果良好。作者建议与先前SRS的间隔≥6个月，处方剂量≥18 Gy。对于直径>2 cm的复发性脑转移瘤，应考虑其他治疗方法，如HFSRS、激光间质热疗或辅助放疗后的切除术。
