Department of Radiation Oncology, University of Heidelberg, Heidelberg, Germany.
Cancer. 2010 Aug 15;116(16):3961-8. doi: 10.1002/cncr.25187.
The purpose of this study was to present planning, feasibility, toxicity, and outcome of helical tomotherapy for spinal cord-sparing reirradiation of spinal metastases and tumors.
Thirty-six patients with spinal metastases and tumors who had undergone previous radiotherapy were reirradiated with helical tomotherapy because of tumor progression, pain, or compromised stability. Mean spinal cord dose of previous radiotherapy was 36.3 grays (Gy) after a median time interval of 17.5 months. Mean prescribed dose of reirradiation was 34.8 Gy. Daily megavoltage computed tomography (CT) image guidance was performed to assure precise dose application.
Mean beam time was 8.4 minutes; the dose maximum to the spinal cord at reirradiation could be limited to a 9.8-Gy median dose (minimum, 5.2 Gy; maximum, 21.8 Gy). Significant pain relief from a median value of 7 on the visual analogue scale before therapy to a median value of 3 at 6 weeks after radiotherapy was achieved. One- and 2-year local control was 76% and 63%; overall survival was 67% after 1 year and 58% after 2 years. One grade 2 skin toxicity and no grade 3 or higher toxicities were observed.
Helical tomotherapy makes reirradiation of spinal metastases and excellent avoidance of the spinal cord possible and achieves good pain relief and local control. With a minimal distance of several millimeters between target volume and spinal cord, tailor-made dose distributions with steep dose gradients around previously irradiated tissue are obtained and precisely applied with daily megavoltage CT-based image guidance.
本研究旨在介绍螺旋断层放疗（tomotherapy）在脊柱转移瘤和肿瘤的脊髓保护再放疗中的计划、可行性、毒性和结果。
36 例因肿瘤进展、疼痛或稳定性受损而接受过先前放疗的脊柱转移瘤和肿瘤患者，因肿瘤进展、疼痛或稳定性受损而接受螺旋断层放疗再放疗。先前放疗的脊髓平均剂量为 36.3 戈瑞（Gy），中位时间间隔为 17.5 个月。再放疗的平均处方剂量为 34.8Gy。每天进行兆伏 CT（megavoltage CT，MVCT）图像引导，以确保精确的剂量应用。
平均束流时间为 8.4 分钟；再放疗时脊髓的最大剂量可限制在 9.8Gy 的中位数剂量（最小值 5.2Gy；最大值 21.8Gy）。治疗前疼痛的中位数视觉模拟评分（visual analogue scale，VAS）从 7 分降至治疗后 6 周的 3 分，疼痛明显缓解。1 年和 2 年局部控制率分别为 76%和 63%；1 年总生存率为 67%，2 年总生存率为 58%。观察到 1 级皮肤毒性 1 例，无 3 级或更高级别毒性。
螺旋断层放疗使脊柱转移瘤和肿瘤的再放疗成为可能，并能很好地避免脊髓照射，同时能很好地缓解疼痛和控制局部病情。在靶体积与脊髓之间有几毫米的最小距离，可获得围绕先前照射组织的陡峭剂量梯度的定制剂量分布，并通过每日基于 MVCT 的图像引导进行精确应用。
