Department of Neurosurgery, Geisinger Health, Danville, PA, United States.
Department of Radiation Oncology, Geisinger Health, Danville, PA, United States.
Radiother Oncol. 2023 Jul;184:109314. doi: 10.1016/j.radonc.2022.07.019. Epub 2022 Jul 26.
Stereotactic radiosurgery (SRS) after maximal safe resection is an accepted treatment strategy for patients with cerebral metastatic disease. Despite its high conformality profile, the incidence of radionecrosis (RN) remains high. SRS delivered pre-operatively could be associated with a reduced incidence of RN. We sought to evaluate whether neoadjuvant SRS could reduce radiotherapy doses in a cohort of patients treated with post-operative SRS.
A cohort of 47 brain metastases (BM) treated at 2 academic institutions was retrospectively analyzed. Subjects underwent surgical extirpation of BMs and subsequent SRS to surgical bed. Post-operative volumetric and dosimetric data was collected from records or recreations of delivered plans; pre-operative data were derived from hypothetical radiotherapy courses and compared using Wilcoxon signed-rank tests.
Higher planned tumor volume post-operatively (median[IQR] 12.28 [6.54, 18.69]cc vs 10.20 [4.53, 21.70]cc respectively, p = 0.4150) was observed. The median prescribed radiotherapy dose (DRx) was 16 Gy pre-operatively and 24 Gy post-operatively (p < 0.0001). Further investigations revealed improved pre-operative conformity index (1.23[1.20, 1.29] vs 1.29[1.23, 1.39], p = 0.0098) and gradient index (2.72[2.59, 2.98] vs 2.94[2.69, 3.47], p = 0.0004). A significant difference was found in normal brain tissue exposed to 10 Gy (12.97[6.78, 25.54]cc vs 32.13[19.42, 48.40]cc, p < 0.0001), 12 Gy (9.31[4.56, 17.43]cc vs 23.80[14.74, 36.56]cc, p < 0.0001), and 14 Gy (5.62[3.23, 11.61]cc vs 17.47[9.00, 28.31]cc, p < 0.0001), favoring pre-operative SRS.
Neoadjuvant SRS is associated reduced DRx, better conformality profile and decreased radiation to normal tissue. These findings could support the use of neoadjuvant SRS for the treatment of BMs.
最大限度安全切除后行立体定向放射外科（SRS）治疗是脑转移瘤患者的一种公认的治疗策略。尽管 SRS 具有很高的适形性，但放射性坏死（RN）的发生率仍然很高。术前 SRS 可能与 RN 发生率降低有关。我们旨在评估新辅助 SRS 是否可以降低接受术后 SRS 治疗的患者的放疗剂量。
对在 2 个学术机构接受治疗的 47 例脑转移瘤（BM）患者进行回顾性分析。患者接受 BM 的手术切除，随后对手术床行 SRS。术后容积和剂量学数据从记录或交付计划的重建中收集；术前数据来自假设的放疗课程，并使用 Wilcoxon 符号秩检验进行比较。
术后计划肿瘤体积较高（中位数[IQR]分别为 12.28[6.54, 18.69]cc 和 10.20[4.53, 21.70]cc，p=0.4150）。术前中位放疗剂量（DRx）为 16 Gy，术后为 24 Gy（p<0.0001）。进一步研究显示，术前的适形性指数（1.23[1.20, 1.29]和 1.29[1.23, 1.39]，p=0.0098）和梯度指数（2.72[2.59, 2.98]和 2.94[2.69, 3.47]，p=0.0004）均得到改善。接受 10 Gy（12.97[6.78, 25.54]cc 和 32.13[19.42, 48.40]cc，p<0.0001）、12 Gy（9.31[4.56, 17.43]cc 和 23.80[14.74, 36.56]cc，p<0.0001）和 14 Gy（5.62[3.23, 11.61]cc 和 17.47[9.00, 28.31]cc，p<0.0001）照射的正常脑组织体积有显著差异，这对术前 SRS 有利。
新辅助 SRS 可降低放疗剂量、改善适形性和减少对正常组织的辐射。这些发现可能支持新辅助 SRS 治疗脑转移瘤。
