Abstract：
In brain metastases, radiation necrosis (RN) is a complication that arises after single or multiple fractionated stereotactic radiosurgery (SRS/FSRS), which is challenging to distinguish from local recurrence (LR). Studies have shown increased RN incidence rates in non-small cell lung cancer (NSCLC) patients with oncogenic driver mutations (ODMs) or receiving tyrosine kinase inhibitors (TKIs). This study investigated enlarging brain lesions following SRS/FSRS, for which additional surgeries were performed to distinguish between RN and LR. We investigated seven NSCLC patients with ODMs undergoing SRS/FSRS for BM and undergoing surgery for suspicion of LR on MRI imaging. Descriptive statistics were performed. Among the seven patients, six were EGFR+, while one was ALK+. The median irradiation dose was 30 Gy (range, 20-35 Gy). The median time to develop RN after SRS/FSRS was 11.1 months (range: 6.3-31.2 months). Moreover, gradually enlarging lesions were found in all patients after 6 months post-SRS/FSR. Brain radiation necrosis was pathologically confirmed in all the patients. RN should be suspected in NSCLC patients when lesions keep enlarging after 6 months post-SRS/FSRS, especially for patients with ODMs and receiving TKIs. Further, this case series indicates that further dose reduction might be necessary to avoid RN for such patients.
摘要：
在脑转移中，放射性坏死（RN）是单级或多级立体定向放射外科（SRS/FSRS）后出现的并发症，这与局部复发(LR)的区分是具有挑战性的。研究表明，患有致癌驱动突变（ODM）或接受酪氨酸激酶抑制剂（TKIs）的非小细胞肺癌（NSCLC）患者的RN发病率增加。这项研究调查了SRS/FSRS后扩大的脑部病变，进行其他手术以区分RN和LR。我们调查了7例接受SRS/FSRS的ODM患者，并在MRI成像上怀疑LR而接受手术。进行描述性统计。在这7名患者中,六个是EGFR+，一个是ALK+。中位照射剂量为30Gy(范围，20-35Gy）。SRS/FSRS后出现RN的中位时间为11.1个月（范围：6.3-31.2个月）。此外，SRS/FSR后6个月，所有患者均发现病变逐渐扩大。所有患者均经病理证实为脑放射性坏死。当非小细胞肺癌患者在SRS/FSRS后6个月病变继续扩大时，应怀疑RN，特别是对于ODM和接受TKIs的患者。Further,本病例系列显示,对于此类患者,可能需要进一步降低剂量以避免RN.
