Dunne Emma Maria, Fraser Ian Mark, Liu Mitchell
Department of Radiation Oncology, British Columbia Cancer Agency (BCCA), Vancouver, Canada.
Ann Transl Med. 2018 Jul;6(14):283. doi: 10.21037/atm.2018.06.40.
Stereotactic body radiation therapy (SBRT) also referred to as stereotactic ablative radiotherapy (SABR), is a technique which has emerged over the past two decades due to improvements in radiation technology. Unlike conventional external beam radiotherapy (cEBRT) which traditionally delivers radiation in small doses [approximately 2 Gray (Gy) per fraction] over several weeks, SBRT, typically delivered in one to eight fractions, is a technique whereby potentially ablative doses of radiotherapy (usually 7.5-20 Gy per fraction) can be delivered with steeper dose gradients and sub millimetre precision, minimising risk to surrounding normal tissues. The potential benefits of excellent tumor control with low toxicity has led to the increasing use of SBRT in a number of clinical situations. Due to compelling evidence, SBRT is now the treatment of choice for medically inoperable patients with peripherally located stage I non-small cell lung cancer (NSCLC). Controversy remains however as to its efficacy and safety for central or ultra-central lung tumors. The evidence base supporting the use of SBRT as a novel treatment for spinal metastases and oligometastases is rapidly expanding but challenges remain in these difficult patient populations. In an era where targeted therapy and improved systemic treatments for stage IV cancer have resulted in increased disease-free survival, and our knowledge of the oligometastatic state is ever expanding, using SBRT to treat metastatic disease and gain durable local control is increasingly desirable. Several randomized trials are currently underway and are sure to provide valuable information on the benefit and utility of SBRT across many tumor sites including early-stage NSCLC, spinal metastases and oligometastatic disease. Recognizing the evolving role of SBRT in clinical practice, this paper provides a critical review of recent developments in each of these areas particularly highlighting the challenges facing clinicians and discusses potential areas for future research.
立体定向体部放射治疗（SBRT），也被称为立体定向消融放疗（SABR），是过去二十年来随着放射技术进步而出现的一种技术。与传统的外照射放疗（cEBRT）不同，传统外照射放疗通常在数周内小剂量（每次约2格雷（Gy））给予放疗，而SBRT通常分1至8次给予，是一种能够以更陡的剂量梯度和亚毫米精度给予潜在消融剂量放疗（通常每次7.5 - 20 Gy）的技术，从而将对周围正常组织的风险降至最低。其具有低毒性且能出色控制肿瘤的潜在益处，使得SBRT在多种临床情况下的应用日益增多。由于有令人信服的证据，SBRT现在是外周型I期非小细胞肺癌（NSCLC）医学上无法手术的患者的首选治疗方法。然而，对于中央型或超中央型肺肿瘤，其疗效和安全性仍存在争议。支持将SBRT用作脊柱转移瘤和寡转移瘤新治疗方法的证据基础正在迅速扩大，但在这些病情复杂的患者群体中仍存在挑战。在一个靶向治疗和针对IV期癌症的改良全身治疗已使无病生存期增加，且我们对寡转移状态的认识不断扩展的时代，使用SBRT治疗转移性疾病并获得持久的局部控制越来越受到关注。目前正在进行多项随机试验，这些试验肯定会提供有关SBRT在包括早期NSCLC、脊柱转移瘤和寡转移疾病在内的许多肿瘤部位的益处和效用的有价值信息。认识到SBRT在临床实践中不断演变的作用，本文对这些领域的最新进展进行了批判性综述，特别强调了临床医生面临的挑战，并讨论了未来研究的潜在领域。
