非小细胞肺癌脑转移单中心影像学特点分析——海马保护的全脑放疗安全范围探索

Radiological features of non-small.cell lung cancer with brain metastases in a single center： an implication for the HA-WBRT approach

目的 通过分析影像学图像了解脑转移在颅内亚结构分布特点,探索行海马保护的全脑放疗（HA-WBRT）时海马区保护的安全边界范围.方法 分析瑞金医院2011-2016年头颅增强MRI诊断为脑转移患者,测量患者颅内距离海马最近的病灶与海马区的距离.结果 患者总数146例（男90例）共630个脑转移病灶.64例患者初诊时即发现肺癌合并脑转移,剩余82例患者从初诊至发现脑转移平均时间为（14.5±14.3）个月.小脑幕上脑转移数目为486个（77.1％）,颅内最大病灶的平均直径为（12.5±10.3）mm（95％CI为10.8～14.2）.630个脑转移颅内分布情况为小脑138个（21.9％）、额叶182个（28.9％）、颞叶114个（18.1％）、顶叶78个（12.4％）、枕叶87个（12.7％）、丘脑28个（4.4％）、脑干10个（1.6％）.海马累及的概率为3.4％（5 mm）、4.8％（10 mm）、8.2％（20 mm）.单因素及多因素发现年龄〉60岁患者海马累及风险显著上升（OR=11.576,P=0.042）.结论 海马区周围10 mm范围内脑转移发生概率低,行HA-WBRT可在降低认知功能损伤情况下达到控制颅内病灶效果,是一种安全可行的治疗方法.

Objective Whole brain radiotherapy （ WBRT） remains the primary treatment for patients with multiple brain metastases （ BM）. Hippocampal avoidance WBRT （ HA-WBRT） offers the feasibility of less cognitive function impairment than conventional WBRT.WBRT yields better control rate of intracranial distant progression than stereotatic body radiotherapy （SBRT）.This study aims to understand the distribution characteristics of BM within the cranial structures by analyzing imaging features and define the safe margin during HA-WBRT. Methods Clinical data of patients diagnosed with BM by enhanced MRI in Ruijin Hospital from July 2011 to July 2016 were retrospectively analyzed. The distance between the intracranial lesion closest to the hippocampus and the hippocampus was measured. Results A total of 146 patients （90 male and 56 female） with 630 BM lesions were reviewed. Sixty-four patients were diagnosed with non-small-cell lung cancer complicated with BM during the initial admission. In the other 82 patients, the average time from the initial diagnosis to the diagnosis of BM was （14.5±14. 3） months. In total,486 （77. 1%） BM lesions were situated beyond the tentorium. The average diameter of the largest intracranial lesion was （12.5± 10. 3） mm （95%CI：10. 8-14. 2）. All 630 BM lesions were distributed as follows：138 （21. 9%） in the cerebellum, 182 （ 28. 9%） in the frontal lobe, 114 （ 18. 1%） in the temporal lobe, 78 （12. 4%） in the parietal lobe,87（12. 7%） in the occipital lobe,28（4. 4%） in the thalamus and 10（1. 6%） in the brainstem. The frequency of hippocampal involvement was 3. 4%（5 mm）,4. 8%（10 mm） and 8. 2%（20 mm）. The univariate and multivariate logistic analyses indicated that with the risk of hippocampal involvement in patients aged〉 60 years was significantly increased （OR= 11. 576 P= 0. 042）. Conclusions The probability of brain metastasis within 10 mm around the hippocampus is low. HA-WBRT can control the intracranial lesions and reduce cognitive impairment,which is a safe and feasible treatment method.