Department of Radiation Oncology, Royal Adelaide Hospital, University of Adelaide, Australia.
Radiother Oncol. 2011 Dec;101(3):420-4. doi: 10.1016/j.radonc.2011.06.035. Epub 2011 Jul 7.
To assess long term outcomes and factors determining hearing preservation after low dose linac stereotactic radiosurgery (SRS) for acoustic neuroma (AN) at the Royal Adelaide Hospital using prospectively collected data.
Between 1994 and 2010, 102 patients had SRS for AN. Five patients had neurofibromatosis type 2, six sporadic cases had relapsed after surgery, and the remaining 91 sporadic cases had primary SRS. Dose was 12 or 14 Gy. Sustained changes ≥ 2 mm in any diameter were deemed significant, and useful hearing was defined as inter-aural pure tone average (PTA) ≤ 50 dB. Possible prognostic factors for hearing retention were tested by dividing the patients at pre-specified cutpoints: age (60 years), maximum tumour diameter (20mm), initial PTA (20 dB) and dose (12 vs 14 Gy).
Eighty-four of the 91 sporadic primary SRS cases were evaluable for tumour control with at least one post-treatment MRI. Their median follow-up was 65 mo (range 10-184 mo). Eighty-two (97.6%) were controlled, the remaining two requiring salvage surgery for progression at 5.75 and 9.75 years. Also, one of the post-operative cases required surgery at 2.1 years after SRS. For the 50 sporadic primary SRS patients with initially useful hearing, median age was 56 (range 21-76), median initial PTA 16 dB (range -11 to +45 dB) and median tumour diameter 21 mm (range 10-33 mm). Four received 14 Gy, the rest 12 Gy. After SRS, 19 patients (38%) retained useful hearing. The Kaplan-Meier estimated preservation rate at 5 years was 50% (95% CI 36-64%) but by 10 years, this had fallen to 23% (95% CI 12-41%). On univariate analysis, the only significant factor was initial PTA (P < 0.0001). The estimated risk of hearing loss after SRS for patients with initial PTA ≥ 20 dB was 5.0 (95% CI 2.2-11.2) times that with PTA < 20 dB.
Tumour control was excellent (99/102=97% freedom from surgical salvage). Hearing preservation was strongly dependent on initial PTA, but there was a steady fall-off in hearing out to at least 10 years.
使用前瞻性收集的数据，评估皇家阿德莱德医院低剂量直线加速器立体定向放射外科（SRS）治疗听神经瘤（AN）后长期疗效和决定听力保留的因素。
1994 年至 2010 年间，102 例患者接受 SRS 治疗 AN。5 例患者为神经纤维瘤病 2 型，6 例散发性病例在手术后复发，其余 91 例为原发性 SRS。剂量为 12 或 14 Gy。任何直径持续变化≥2mm 被认为是显著的，有用听力定义为双耳纯音平均听阈（PTA）≤50dB。通过将患者分为预定切点的组，测试听力保留的可能预测因素：年龄（60 岁）、最大肿瘤直径（20mm）、初始 PTA（20dB）和剂量（12 与 14Gy）。
91 例原发性 SRS 中 84 例可评估肿瘤控制，至少有一次治疗后 MRI。中位随访时间为 65 个月（范围 10-184 个月）。82 例（97.6%）得到控制，其余 2 例因进展而需要挽救性手术，分别在 5.75 年和 9.75 年。另外，2 例术后患者在 SRS 后 2.1 年需要手术。对于 50 例原发性 SRS 且初始听力有用的患者，中位年龄为 56 岁（范围 21-76 岁），中位初始 PTA 为 16dB（范围-11 至+45dB），肿瘤直径中位数为 21mm（范围 10-33mm）。4 例患者接受 14Gy，其余 91 例接受 12Gy。SRS 后，19 例（38%）保留了有用的听力。Kaplan-Meier 估计 5 年保留率为 50%（95%CI36-64%），但 10 年后，这一比例降至 23%（95%CI12-41%）。单因素分析，唯一显著的因素是初始 PTA（P<0.0001）。初始 PTA≥20dB 的患者 SRS 后听力损失的风险估计为 PTA<20dB 的患者的 5.0（95%CI2.2-11.2）倍。
肿瘤控制非常好（102 例中有 97%免于手术挽救）。听力保留与初始 PTA 密切相关，但至少在 10 年内听力持续下降。
