大剂量多次分割立体定向放疗对听神经瘤的疗效分析

摘要

目的：评价大剂量分割立体定向放疗（hypo-FSRT）治疗听神经瘤患者在肿瘤局部控制及有效听力保存等方面的临床价值。方法回顾性分析47例单侧听神经瘤患者，中位年龄61岁，放疗前19例患者持有有效听力，肿瘤最大径中位值20 mm，处方剂量：等中心总剂量25 Gy，5次分割，每日1次，80％剂量曲线包绕计划靶区（ PTV）边缘。采用实体瘤消退评价标准（ RECIST）改良版1．1评估肿瘤消退情况。采用Gardner-Robertson Class 评估听力保存情况。 SPSS 18．0软件进行统计分析。结果中位随访及听力随访时间分别为61及52个月，30例（63．8％）、13例（27．67％）及4例（8．5％）患者分别出现肿瘤部分缩退（PR）、稳定（SD）、进展（PD），根据Kaplan-Meier生存分析，5年肿瘤局部控制率为90．4％，放疗前肿瘤是否合并囊变成分在肿瘤控制方面存在显著性差异（P＝0．015），合并囊变的肿瘤预示放疗后出现肿瘤进展的可能性大。放疗后14例（29．8％）患者出现肿瘤暂时性增大。1、3、5年患者有效听力保存率分别为68．4％，62．1％及35．5％。有效听力保存与未保存患者在肿瘤消退情况方面存在明显差异（P＝0．017）。1例（2．1％）患者行挽救性手术，2例（4．3％）患者行VP-脑室分流术，2例（4．3％）患者新出现三叉神经轻度麻痹。结论 Hypo-FSRT （25 Gy／5次）治疗单侧听神经瘤可有效控制肿瘤，放疗后并发症发生率低。影像定期随访中观察到肿瘤暂时性增大及逐渐缩退过程。放疗前肿瘤合并囊变预示患者放疗后出现肿瘤进展的机率更高。%Objective To study the clinical outcomes of hypofractionated stereotactic radiotherapy ( hypo-FSRT) for a-coustic neuromas (ANs).Methods 47 patients with unilateral acoustic neuroma were treated consecutively with hypo -FSRT. The median age was 61 years old.19 patients kept serviceable hearing status prior to hypo-FSRT.The median value of the maxi-mum diameter was 20 mm.25 Gy in 5 fractions in a week was prescribed at the isocenter and the planning target volume ( PTV) was covered by the 80%isodose line.Statistical analyses were performed with IBM SPSS statistics version 18 (sig.P<0.05). Results The median follow-up and audiometric follow-up were 61 and 52 months,respectively.Estimated local progression-free probability at 5 years were 90.4%.Existence of cystic component before hypo-FSRT had a significantly worse impact on local control (P=0.015).Temporary expansion of tumors was observed in 14 patients (29.8%).Estimated hearing preservation prob-ability at 1,3 and 5 years was 68.4%,62.1% and 35.5%,respectively.Hearing preservation was significantly related to tumor response (better in PR cases,P=0.017).Salvage surgery and VP-shunt surgery was required in one and two cases ,respectively. 2(4.3%) patients experienced newly mild symptom in trigeminal nerve function .Conclusion Hypo-FSRT in 5 fractions for uni-lateral acoustic neuroma can achieve excellent tumor local control with no severe facial and trigeminal complications .Tumor ex-pansion during the imaging follow-up is observed while majority is temporary .Cystic ANs has higher risk of tumor progression .