Chang Eric L, Hassenbusch Samuel J, Shiu Almon S, Lang Frederick F, Allen Pamela K, Sawaya Raymond, Maor Moshe H
Division of Radiation Oncology, Brain Tumor Center, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
Neurosurgery. 2003 Aug;53(2):272-80; discussion 280-1. doi: 10.1227/01.neu.0000073546.61154.9a.
To identify a size cutoff below which it is safe to observe obscure brain lesions suspected of being metastases so that treatment of nonmetastases can be avoided.
Medical records from patients who underwent linear accelerator-based radiosurgery from August 1991 to October 2001 were reviewed. Inclusion criteria were defined as brain metastasis tumor volume less than 5 cm(3) (diameter, thick similar 2.1 cm) treated with a dose of 20 Gy or more. One hundred thirty-five patients had 153 evaluable brain metastases with follow-up imaging that met inclusion criteria. Median age was 54 years (range, 18-79 yr). Lesion primaries were non-small-cell lung (n = 39), melanoma (n = 44), renal (n = 37), breast (n = 18), colon (n = 3), sarcoma (n = 5), other (n = 5), and unknown primary (n = 2). Median tumor volume was 0.67 cm(3) (range, 0.06-4.58 cm(3)). The minimum peripheral dose was 20 Gy (n = 132) or 21 to 24 Gy (n = 21). At the time of analysis, the median follow-up for all patients was 10 months (range, 0.2-99 mo).
The 1- and 2-year actuarial local control rates for all of the lesions were 69 and 46%, respectively. For lesions of 1 cm (0.5 cm(3)) or less, the corresponding local control rates were 86 and 78%, respectively, which was significantly higher than the corresponding rates of 56 and 24%, respectively, for lesions larger than 1 cm (0.5 cm(3)) (P = 0.0016).
A convincing brain metastasis measuring less than 1 cm should be pursued aggressively. If the suspected brain metastasis is ambiguous, observation is proposed up to a diameter of 1 cm. This is the first study in the literature to identify a 1-cm cutoff for radiosurgical control of small brain metastases, and validation by additional studies is required.
确定一个大小阈值，低于该阈值时，对怀疑为转移瘤的隐匿性脑病变进行观察是安全的，从而避免对非转移瘤进行治疗。
回顾了1991年8月至2001年10月接受直线加速器放射外科治疗的患者的病历。纳入标准定义为脑转移瘤体积小于5 cm³（直径，厚约2.1 cm），接受20 Gy或更高剂量治疗。135例患者有153个符合纳入标准且有随访影像学检查的可评估脑转移瘤。中位年龄为54岁（范围，18 - 79岁）。原发病变为非小细胞肺癌（n = 39）、黑色素瘤（n = 44）、肾癌（n = 37）、乳腺癌（n = 18）、结肠癌（n = 3）、肉瘤（n = 5）、其他（n = 5）和原发灶不明（n = 2）。中位肿瘤体积为0.67 cm³（范围，0.06 - 4.58 cm³）。最小周边剂量为20 Gy（n = 132）或21至24 Gy（n = 21）。在分析时，所有患者的中位随访时间为10个月（范围，0.2 - 99个月）。
所有病变的1年和2年精算局部控制率分别为69%和46%。对于直径1 cm（0.5 cm³）或更小的病变，相应的局部控制率分别为86%和78%，显著高于直径大于1 cm（0.5 cm³）病变的相应局部控制率，分别为56%和24%（P = 0.0016）。
对于直径小于1 cm的明确脑转移瘤应积极治疗。如果怀疑的脑转移瘤不明确，建议观察至直径1 cm。这是文献中首次确定小脑转移瘤放射外科治疗控制的1 cm阈值，需要更多研究进行验证。
