Selch Michael T, Pedroso Alessandro, Lee Steve P, Solberg Timothy D, Agazaryan Nzhde, Cabatan-Awang Cynthia, DeSalles Antonio A F
Department of Radiation Oncology and Division of Neurosurgery, David Geffen School of Medicine, University of California, 90045-6951, USA.
J Neurosurg. 2004 Nov;101 Suppl 3:362-72.
The authors sought to assess the safety and efficacy of stereotactic radiotherapy when using a linear accelerator equipped with a micromultileaf collimator for the treatment of patients with acoustic neuromas.
Fifty patients harboring acoustic neuromas were treated with stereotactic radiotherapy between September 1997 and June 2003. Two patients were lost to follow-up review. Patient age ranged from 20 to 76 years (median 59 years), and none had neurofibromatosis. Forty-two patients had useful hearing prior to stereotactic radiotherapy. The fifth and seventh cranial nerve functions were normal in 44 and 46 patients, respectively. Tumor volume ranged from 0.3 to 19.25 ml (median 2.51 ml). The largest tumor dimension varied from 0.6 to 4 cm (median 2.2 cm). Treatment planning in all patients included computerized tomography and magnetic resonance image fusion and beam shaping by using a micromultileaf collimator. The planning target volume included the contrast-enhancing tumor mass and a margin of normal tissue varying from 1 to 3 mm (median 2 mm). All tumors were treated with 6-MV photons and received 54 Gy prescribed at the 90% isodose line encompassing the planning target volume. A sustained increase greater than 2 mm in any tumor dimension was defined as local relapse. The follow-up duration varied from 6 to 74 months (median 36 months). The local tumor control rate in the 48 patients available for follow up was 100%. Central tumor hypodensity occurred in 32 patients (67%) at a median of 6 months following stereotactic radiotherapy. In 12 patients (25%), tumor size increased 1 to 2 mm at a median of 6 months following stereotactic radiotherapy. Increased tumor size in six of these patients was transient. In 13 patients (27%), tumor size decreased 1 to 14 mm at a median of 6 months after treatment. Useful hearing was preserved in 39 patients (93%). New facial numbness occurred in one patient (2.2%) with normal fifth cranial nerve function prior to stereotactic radiotherapy. New facial palsy occurred in one patient (2.1 %) with normal seventh cranial nerve function prior to treatment. No patient's pretreatment dysfunction of the fifth or seventh cranial nerve worsened after stereotactic radiotherapy. Tinnitus improved in six patients and worsened in two.
Stereotactic radiotherapy using field shaping for the treatment of acoustic neuromas achieves high rates of tumor control and preservation of useful hearing. The technique produces low rates of damage to the fifth and seventh cranial nerves. Long-term follow-up studies are necessary to confirm these findings.
作者旨在评估使用配备微型多叶准直器的直线加速器进行立体定向放射治疗听神经瘤患者的安全性和有效性。
1997年9月至2003年6月期间，50例听神经瘤患者接受了立体定向放射治疗。2例患者失访。患者年龄在20至76岁之间（中位年龄59岁），均无神经纤维瘤病。42例患者在立体定向放射治疗前听力正常。44例和46例患者的第五和第七颅神经功能分别正常。肿瘤体积为0.3至19.25毫升（中位体积2.51毫升）。肿瘤最大直径为0.6至4厘米（中位直径2.2厘米）。所有患者的治疗计划包括计算机断层扫描和磁共振图像融合，并使用微型多叶准直器进行射束整形。计划靶体积包括增强造影的肿瘤块和1至3毫米（中位值2毫米）的正常组织边缘。所有肿瘤均采用6兆伏光子治疗，在90%等剂量线处给予54 Gy，该等剂量线涵盖计划靶体积。任何肿瘤直径持续增加超过2毫米被定义为局部复发。随访时间为6至74个月（中位时间36个月）。48例可进行随访的患者局部肿瘤控制率为100%。32例患者（67%）在立体定向放射治疗后中位6个月出现肿瘤中心低密度。12例患者（25%）在立体定向放射治疗后中位6个月肿瘤大小增加1至2毫米。其中6例患者肿瘤大小增加是短暂的。13例患者（27%）在治疗后中位6个月肿瘤大小减小1至14毫米。39例患者（93%）保留了有用听力。1例在立体定向放射治疗前第五颅神经功能正常的患者出现新的面部麻木（2.2%）。1例在治疗前第七颅神经功能正常的患者出现新的面瘫（2.1%）。立体定向放射治疗后，没有患者的第五或第七颅神经预处理功能障碍恶化。6例患者耳鸣改善，2例患者耳鸣恶化。
使用射野整形的立体定向放射治疗听神经瘤可实现高肿瘤控制率和保留有用听力。该技术对第五和第七颅神经的损伤率较低。需要长期随访研究来证实这些发现。
