Yeo Seung-Gu
Department of Radiation Oncology, Soonchunhyang University College of Medicine, Soonchunhyang University Hospital, Cheonan, Republic of Korea.
Onco Targets Ther. 2017 Aug 11;10:4017-4021. doi: 10.2147/OTT.S143719. eCollection 2017.
Prophylactic cranial irradiation (PCI) lowers the risk of brain metastasis (BM) and increases survival in small cell lung cancer (SCLC) patients, but it also entails a risk of neurocognitive dysfunction (NCD). One strategy to mitigate this neurotoxicity is hippocampus-avoiding (HA) whole-brain radiation therapy, as the hippocampus is mainly responsible for radiation-related NCD and hippocampal or perihippocampal metastases are rare. A few prospective clinical trials have demonstrated a reduction in NCD following HA whole-brain radiation therapy. The 59-year-old male patient described in this report had limited-stage SCLC and a complete response to thoracic chemoradiotherapy. Seven months after receiving HA-PCI of 25 Gy in 10 fractions using intensity-modulated radiation therapy, a 36 mm solitary metastasis was detected in the right perihippocampal region. The mass was surgically removed but the patient died 2 months later. The development of a solitary HA region metastasis is uncommon, considering that metastasis in this area usually occurs in patients with high numbers of BMs. Our case demonstrates the need for further validation of HA-PCI for SCLC patients in terms of both neurocognitive protection and the absence of compromise in terms of BM prevention.
预防性颅脑照射（PCI）可降低小细胞肺癌（SCLC）患者发生脑转移（BM）的风险并提高生存率，但它也带来了神经认知功能障碍（NCD）的风险。减轻这种神经毒性的一种策略是避免海马体（HA）的全脑放射治疗，因为海马体是辐射相关NCD的主要原因，且海马体或海马旁转移很少见。一些前瞻性临床试验表明，HA全脑放射治疗后NCD有所减少。本报告中描述的59岁男性患者患有局限期SCLC，对胸部放化疗有完全反应。在使用调强放射治疗分10次给予25 Gy的HA-PCI后7个月，在右侧海马旁区域检测到一个36 mm的孤立转移灶。该肿块通过手术切除，但患者在2个月后死亡。考虑到该区域转移通常发生在BM数量较多的患者中，孤立的HA区域转移的发生并不常见。我们的病例表明，对于SCLC患者，需要在神经认知保护以及在预防BM方面不出现妥协方面对HA-PCI进行进一步验证。
