Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA 02115, USA.
Int J Radiat Oncol Biol Phys. 2012 Jan 1;82(1):95-101. doi: 10.1016/j.ijrobp.2010.10.043. Epub 2010 Dec 17.
Whole-brain radiation therapy (WBRT) is the standard of care after resection of a brain metastasis. However, concern regarding possible neurocognitive effects and the lack of survival benefit with this approach has led to the use of stereotactic radiosurgery (SRS) to the resection cavity in place of WBRT. We report our initial experience using an image-guided linear accelerator-based frameless stereotactic system and review the technical issues in applying this technique.
We retrospectively reviewed the setup accuracy, treatment outcome, and patterns of failure of the first 18 consecutive cases treated at Brigham and Women's Hospital. The target volume was the resection cavity without a margin excluding the surgical track.
The median number of brain metastases per patient was 1 (range, 1-3). The median planning target volume was 3.49 mL. The median prescribed dose was 18 Gy (range, 15-18 Gy) with normalization ranging from 68% to 85%. In all cases, 99% of the planning target volume was covered by the prescribed dose. The median conformity index was 1.6 (range, 1.41-1.92). The SRS was delivered with submillimeter accuracy. At a median follow-up of 12.7 months, local control was achieved in 16/18 cavities treated. True local recurrence occurred in 2 patients. No marginal failures occurred. Distant recurrence occurred in 6/17 patients. Median time to any failure was 7.4 months. No Grade 3 or higher toxicity was recorded. A long interval between initial cancer diagnosis and the development of brain metastasis was the only factor that trended toward a significant association with the absence of recurrence (local or distant) (log-rank p = 0.097).
Frameless stereotactic irradiation of the resection cavity after surgery for a brain metastasis is a safe and accurate technique that offers durable local control and defers the use of WBRT in select patients. This technique should be tested in larger prospective studies.
全脑放射治疗（WBRT）是脑转移瘤切除后的标准治疗方法。然而，由于担心可能的神经认知影响以及这种方法缺乏生存获益，导致立体定向放射外科（SRS）用于切除部位的立体定向放射治疗。我们报告了使用图像引导直线加速器无框架立体定向系统的初步经验，并回顾了应用该技术的技术问题。
我们回顾性地审查了在布莱根妇女医院治疗的前 18 例连续病例的设置准确性、治疗结果和失败模式。靶区为无边缘的切除腔，不包括手术轨迹。
每位患者的脑转移中位数为 1 个（范围，1-3 个）。中位计划靶区体积为 3.49 毫升。中位处方剂量为 18 Gy（范围，15-18 Gy），归一化范围为 68%-85%。在所有病例中，99%的计划靶区体积都被处方剂量覆盖。中位适形指数为 1.6（范围，1.41-1.92）。SRS 以亚毫米精度传递。在中位随访 12.7 个月时，18 个治疗腔中有 16 个获得了局部控制。2 例患者发生真正的局部复发。无边缘失败。17 例患者中有 6 例发生远处复发。任何失败的中位时间为 7.4 个月。未记录到 3 级或更高级别的毒性。初次癌症诊断与脑转移发展之间的间隔时间较长是唯一与无复发（局部或远处）显著相关的因素（对数秩检验，p=0.097）。
手术后脑转移瘤切除部位的无框架立体定向照射是一种安全、准确的技术，可提供持久的局部控制，并使选择的患者推迟使用 WBRT。这项技术应该在更大的前瞻性研究中进行测试。
