Stereotactic radiosurgery for vestibular schwannomas: average 10-year follow-up results focusing on long-term hearing preservation
Stereotactic radiosurgery for vestibular schwannomas: average 10-year follow-up results focusing on long-term hearing preservation
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DOI：
10.3171/2016.7.gks161494
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发表时间：
2016-12-01
影响因子：
4.1
通讯作者：
Kasuya, Hidetoshi
中科院分区：
文献类型：
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作者：
Watanabe, Shinya;Yamamoto, Masaaki;Kasuya, Hidetoshi
目的探讨立体定向放射外科治疗前庭神经鞘瘤的远期疗效。作者使用了一个数据库，其中包括采用独特剂量计划技术接受SRS的患者，即，部分肿瘤覆盖，旨在避免面神经和耳蜗神经的过度照射，重点是肿瘤控制和听力保护。与SRS后肿瘤控制和长期听力preservations.METHODS的机构审查委员会批准，回顾性队列研究使用作者的前瞻性积累的数据库的临床因素进行了分析。在1990年至2005年期间接受伽玛刀SRS治疗VS的207例患者中，对183例（SRS后随访至少36个月）进行了研究。中位肿瘤体积为2.0 cm 3（范围0.05-26.2 cm 3）。肿瘤周边的中位处方剂量为12.0戈伊（范围8.8-15.0戈伊; 171例患者[93%]使用了12.0戈伊），而面向面神经和耳蜗神经的肿瘤部分接受了10.0戈伊的照射。结果，每个肿瘤的72%-99%用规定剂量照射。耳蜗平均剂量为2.3 ~ 5.7戈伊（中位剂量为4.1戈伊）。结果影像学和听力随访的中位时间分别为114个月（四分位距73-144个月）和59个月（四分位距33-109个月）。110例（61%）患者的肿瘤缩小，48例（27%）患者无变化，其他22例（12%）患者的肿瘤增大。15例（8%）患者需要进一步手术（FP）。因此，肿瘤生长控制率为88%，临床控制率（即，不需要FP）为92%。SRS后第60、120和180个月的累积无FP率分别为96%、93%和87%。6例（3%）患者出现面部疼痛，2例出现一过性面瘫。可用听力定义为纯音听力图结果优于50 dB。在66例SRS前听力正常的患者中，23例（35%）听力得以保留。在SRS术后第60、120和180个月，精算可用听力保留率分别为49%、24%和12%。单因素分析，只有囊性肿瘤（HR 3.36，95% CI 1.18-9.36; p = 0.02）显示与FR存在显著不利相关性。多变量分析后进行单变量分析显示，年龄> 65岁：HR 2.66，95% CI 1.16-5.92; p = 0.02）、肿瘤体积> 8 cm-1：HR 5.36，95%CI 1.20-17.4; p = 0.03）和较高的耳蜗剂量（平均耳蜗剂量> 4.2戈伊：HR 2.22，95%CI 1.07-4.77; p = 0.03）是听力保护的不利因素。肿瘤控制是可以接受的，在小到中等大小的VS患者中几乎没有严重并发症。不幸的是，听力保护并不令人满意。然而，观察期越长，比较SRS后听力下降与未治疗病例的自然下降就越重要。
OBJECTIVE The aim of this study was to reappraise long-term treatment outcomes of stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs). The authors used a database that included patients who underwent SRS with a unique dose-planning technique, i.e., partial tumor coverage designed to avoid excess irradiation of the facial and cochlear nerves, focusing on tumor control and hearing preservation. Clinical factors associated with post-SRS tumor control and long-term hearing preservation were also analyzed.METHODS This institutional review board approved, retrospective cohort study used the authors' prospectively accumulated database. Among 207 patients who underwent Gamma Knife SRS for VSs between 1990 and 2005, 183 (who were followed up for at least 36 post-SRS months) were studied. The median tumor volume was 2.0 cm3 (range 0.05-26.2 cm3). The median prescribed dose at the tumor periphery was 12.0 Gy (range 8.8-15.0 Gy; 12.0 Gy was used in 171 patients [93%]), whereas tumor portions facing the facial and cochlear nerves were irradiated with 10.0 Gy. As a result, 72%-99% of each tumor was irradiated with the prescribed dose. The mean cochlear doses ranged from 2.3 to 5.7 Gy (median 4.1 Gy).RESULTS The median durations of imaging and audiometric follow-up were 114 months (interquartile range 73-144 months) and 59 months (interquartile range 33-109 months), respectively. Tumor shrinkage was documented in 110 (61%), no change in 48 (27%), and enlargement in the other 22 (12%) patients. A further procedure (FP) was required in 15 (8%) patients. Thus, the tumor growth control rate was 88% and the clinical control rate (i.e., no need for an FP) was 92%. The cumulative FP-free rates were 96%, 93%, and 87% at the 60th, 120th, and 180th post-SRS month, respectively. Six (3%) patients experienced facial pain, and 2 developed transient facial palsy. Serviceable hearing was defined as a pure tone audiogram result better than 50 dB. Among the 66 patients with serviceable hearing before SRS who were followed up, hearing acuity was preserved in 23 (35%). Actuarial serviceable hearing preservation rates were 49%, 24%, and 12% at the 60th, 120th, and 180th post-SRS month, respectively. On univariable analysis, only cystic-type tumor (HR 3.36, 95% CI 1.18-9.36; p = 0.02) was shown to have a significantly unfavorable association with FR Multivariable analysis followed by univariable analysis revealed that higher age 65 years: HR 2.66, 95% CI 1.16-5.92; p = 0.02), larger tumor volume 8 cm': HR 5.36, 95% CI 1.20-17.4; p = 0.03), and higher cochlear dose (mean cochlear dose > 4.2 Gy: HR 2.22, 95% CI 1.07-4.77; p = 0.03) were unfavorable factors for hearing preservation.CONCLUSIONS Stereotactic radiosurgery achieved good long-term results in this series. Tumor control was acceptable, and there were few serious complications in patients with small-to medium-sized VSs. Unfortunately, hearing preservation was not satisfactory. However, the longer the observation period; the more important it becomes to compare post-SRS hearing decreases with the natural decline in untreated cases.