Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
Jpn J Clin Oncol. 2013 Aug;43(8):805-12. doi: 10.1093/jjco/hyt082. Epub 2013 Jun 17.
To retrospectively examine the outcomes of hypofractionated stereotactic radiation therapy in three to five fractions for vestibular schwannomas.
Twenty-five patients with 26 vestibular schwannomas were treated with hypofractionated stereotactic radiation therapy using a CyberKnife. The vestibular schwannomas of 5 patients were associated with type II neurofibromatosis. The median follow-up time was 80 months (range: 6-167); the median planning target volume was 2.6 cm(3) (0.3-15.4); and the median prescribed dose (≥D90) was 21 Gy in three fractions (18-25 Gy in three to five fractions). Progression was defined as ≥2 mm 3-dimensional post-treatment tumor enlargement excluding transient expansion. Progression or any death was counted as an event in progression-free survival rates, whereas only progression was counted in progression-free rates.
The 7-year progression-free survival and progression-free rates were 78 and 95%, respectively. Late adverse events (≥3 months) with grades based on Common Terminology Criteria for Adverse Events, v4.03 were observed in 6 patients: Grade 3 hydrocephalus in one patient, Grade 2 facial nerve disorders in two and Grade 1-2 tinnitus in three. In total, 12 out of 25 patients maintained pure tone averages ≤50 dB before hypofractionated stereotactic radiation therapy, and 6 of these 12 patients (50%) maintained pure tone averages at this level at the final audiometric follow-up after hypofractionated stereotactic radiation therapy. However, gradient deterioration of pure tone average was observed in 11 of these 12 patients. The mean pure tone averages before hypofractionated stereotactic radiation therapy and at the final follow-up for the aforementioned 12 patients were 29.8 and 57.1 dB, respectively.
Treating vestibular schwannomas with hypofractionated stereotactic radiation therapy in three to five fractions may prevent tumor progression with tolerable toxicity. However, gradient deterioration of pure tone average was observed.
回顾性分析立体定向放射治疗 3-5 次分割治疗前庭神经鞘瘤的结果。
25 例 26 个前庭神经鞘瘤患者采用 CyberKnife 进行立体定向放射治疗。5 例患者的前庭神经鞘瘤伴 II 型神经纤维瘤病。中位随访时间为 80 个月（范围：6-167）；中位计划靶区体积为 2.6cm³（0.3-15.4）；中位处方剂量（≥D90）为 3 次分割 21 Gy（3-5 次分割 18-25 Gy）。进展定义为 3D 治疗后肿瘤体积增大≥2mm，排除短暂扩张。进展或任何死亡均计为无进展生存率的事件，而仅进展计为无进展率的事件。
7 年无进展生存率和无进展率分别为 78%和 95%。根据通用不良事件术语标准，4.03 版，6 例患者出现晚期不良事件（≥3 个月）：1 例患者出现 3 级脑积水，2 例患者出现 2 级面神经障碍，3 例患者出现 1-2 级耳鸣。25 例患者中，共有 12 例患者在接受立体定向放射治疗前纯音平均听阈≤50dB，其中 6 例（50%）在接受立体定向放射治疗后的最终听力随访时保持在这一水平。然而，在这 12 例患者中，有 11 例出现纯音平均听阈的梯度恶化。在接受立体定向放射治疗前和上述 12 例患者的最终随访时，平均纯音平均听阈分别为 29.8dB 和 57.1dB。
采用立体定向放射治疗 3-5 次分割治疗前庭神经鞘瘤可预防肿瘤进展，且毒性可耐受。然而，观察到纯音平均听阈的梯度恶化。
