Department of Neurosurgery, Stanford University Medical Center, CA, USA.
Int J Radiat Oncol Biol Phys. 2010 Oct 1;78(2):499-506. doi: 10.1016/j.ijrobp.2009.07.1727. Epub 2010 Feb 3.
As the spinal cord tolerance often precludes reirradiation with conventional techniques, local recurrence within a previously irradiated field presents a treatment challenge.
We retrospectively reviewed 51 lesions in 42 patients treated from 2002 to 2008 whose spinal metastases recurred in a previous radiation field (median previous spinal cord dose of 40 Gy) and were subsequently treated with stereotactic radiosurgery (SRS).
SRS was delivered to a median marginal dose of 20 Gy (range, 10-30 Gy) in 1-5 fractions (median, 2), targeting a median tumor volume of 10.3 cm(3) (range, 0.2-128.6 cm(3)). Converting the SRS regimens with the linear quadratic model (α/β = 3), the median spinal cord maximum single-session equivalent dose (SSED) was 12.1 Gy(3) (range, 4.7-19.3 Gy(3)). With a median follow-up of 7 months (range, 2-47 months), the Kaplan-Meier local control and overall survival rates at 6/12 months were 87%/73% and 81%/68%, respectively. A time to retreatment of ≤12 months and the combination of time to retreatment of ≤12 months with an SSED of <15 Gy(10) were significant predictors of local failure on univariate and multivariate analyses. In patients with a retreatment interval of <12 months, 6/12 month local control rates were 88%/58%, with a SSED of >15 Gy(10), compared to 45%/0% with <15 Gy(10), respectively. One patient (2%) experienced Grade 4 neurotoxicity.
SRS is safe and effective in the treatment of spinal metastases recurring in previously irradiated fields. Tumor recurrence within 12 months may correlate with biologic aggressiveness and require higher SRS doses (SSED >15 Gy(10)). Further research is needed to define the partial volume retreatment tolerance of the spinal cord and the optimal target dose.
由于脊髓耐受通常排除了常规技术的再照射，因此先前照射野内的局部复发是一个治疗挑战。
我们回顾性分析了 2002 年至 2008 年间治疗的 42 名患者的 51 个病变，这些患者的脊柱转移瘤在先前的放射治疗野内复发（中位先前脊髓剂量为 40 Gy），随后采用立体定向放射外科治疗（SRS）。
SRS 以 1-5 个分次（中位 2 次）给予中位边缘剂量 20 Gy（范围 10-30 Gy），中位肿瘤体积为 10.3 cm3（范围 0.2-128.6 cm3）。通过线性二次模型（α/β=3）转换 SRS 方案，中位脊髓最大单次等效剂量（SSED）为 12.1 Gy3（范围 4.7-19.3 Gy3）。中位随访 7 个月（范围 2-47 个月），6/12 个月的 Kaplan-Meier 局部控制和总生存率分别为 87%/73%和 81%/68%。单因素和多因素分析均显示，≤12 个月的再治疗时间和≤12 个月的再治疗时间与 SSED<15 Gy10 的组合是局部失败的显著预测因素。在再治疗间隔<12 个月的患者中，6/12 个月的局部控制率分别为 88%/58%，SSED>15 Gy10，而 SSED<15 Gy10 分别为 45%/0%。1 名患者（2%）发生 4 级神经毒性。
SRS 是治疗先前照射野内复发的脊柱转移瘤的安全有效方法。12 个月内肿瘤复发可能与生物学侵袭性相关，需要更高的 SRS 剂量（SSED>15 Gy10）。需要进一步研究来确定脊髓的部分体积再治疗耐受量和最佳靶剂量。
