Alexander E, Moriarty T M, Davis R B, Wen P Y, Fine H A, Black P M, Kooy H M, Loeffler J S
Brain Tumor Center, Brigham and Women's Hospital, Boston, MA 02115, USA.
J Natl Cancer Inst. 1995 Jan 4;87(1):34-40. doi: 10.1093/jnci/87.1.34.
The spread of systemic cancer to the brain is a common complication for cancer patients. Conventional radiotherapy offers modest palliation, and surgery is helpful only for the patient with a single metastasis in an accessible location. Stereotactic radiosurgery, a technique that permits the precise delivery of a high dose of radiation to a small intracranial target while sparing the surrounding normal brain, has been used as an alternative treatment for brain metastases.
Our medical center's 7-year experience with radiosurgery for metastases was reviewed to establish the effectiveness of the treatment and to understand the prognoses in patients so treated.
Retrospective analysis of hospital records, from 248 consecutive patients (421 lesions) that were treated with radiosurgery between May 1986 and May 1993, was performed. Patients were only excluded for a Karnofsky performance score of less than 70, evidence of acute neurologic deterioration, or tumor diameter more than 4 cm. Median follow-up was 26.2 months. Seventy-six percent of patients had recurrent disease, 69% had evidence of systemic disease, 69% had a single metastasis. Treatment was performed using a 6-MeV linear accelerator. The median tumor volume was 3 cm3. The median treatment dose was 1500 cGy. Whole brain radiotherapy was given to all newly diagnosed patients. Patients were followed by neurological examination and neuroimaging at regular intervals. Local control of disease was defined as a lack of progression of solid-contrast enhancement on computed tomography scan or magnetic resonance imaging.
Median overall survival from radiosurgery was 9.4 months. The absence of active systemic disease, younger than 60 years of age, two or fewer lesions, and female sex were significantly associated with increased survival (two-sided P < .05). Actuarial local control rates were approximately 85% at 1 year and 65% at 2 years. Factors associated with a significantly decreased local control rate were location below the tentorium, recurrent tumor, and larger tumor volume (two-sided P < .05). Radioresponsive and radioresistant tumor types had similar control rates. The median drop in Karnofsky performance score at 1 year was 10%.
The results of this retrospective analysis show that radiosurgery is an effective, minimally invasive outpatient treatment option for small intracranial metastases. Results of this study also indicate that radiosurgery not only provides local control rates equivalent to those from surgical series but is also effective in treating patients with surgically inaccessible lesions, with multiple lesions, or with tumor types that are resistant to conventional treatment.
系统性癌症扩散至脑部是癌症患者常见的并发症。传统放疗仅能提供适度的姑息治疗，而手术仅对颅内单一可及转移灶的患者有帮助。立体定向放射外科是一种能够在保护周围正常脑组织的同时，将高剂量辐射精确地作用于小的颅内靶点的技术，已被用作脑转移瘤的替代治疗方法。
回顾我们医疗中心7年的放射外科治疗转移瘤的经验，以确定该治疗方法的有效性，并了解接受该治疗患者的预后情况。
对1986年5月至1993年5月间连续接受放射外科治疗的248例患者（421个病灶）的医院记录进行回顾性分析。仅将卡氏评分低于70、有急性神经功能恶化证据或肿瘤直径超过4 cm的患者排除。中位随访时间为26.2个月。76%的患者有复发性疾病，69%有系统性疾病证据，69%有单一转移灶。使用6 MeV直线加速器进行治疗。中位肿瘤体积为3 cm³。中位治疗剂量为1500 cGy。所有新诊断患者均接受全脑放疗。定期对患者进行神经学检查和神经影像学检查。疾病的局部控制定义为计算机断层扫描或磁共振成像上实性对比增强无进展。
放射外科治疗后的中位总生存期为9.4个月。无活动性系统性疾病、年龄小于60岁、病灶数为两个或更少以及女性与生存期延长显著相关（双侧P < 0.05）。1年和2年的精算局部控制率分别约为85%和65%。与局部控制率显著降低相关的因素是天幕下位置、复发性肿瘤和较大的肿瘤体积（双侧P < 0.05）。放射敏感和放射抵抗的肿瘤类型具有相似的控制率。1年时卡氏评分的中位下降值为10%。
这项回顾性分析的结果表明，放射外科是治疗小的颅内转移瘤的一种有效的、微创的门诊治疗选择。本研究结果还表明，放射外科不仅能提供与手术系列相当的局部控制率，而且对手术无法触及的病灶、多发病灶或对传统治疗耐药的肿瘤类型的患者也有效。
