Department of Radiation Oncology, University of Florida, Gainesville, FL, USA.
ENT Clinic, University of Udine, Udine, Italy.
Oral Oncol. 2012 Oct;48(10):918-922. doi: 10.1016/j.oraloncology.2012.02.015. Epub 2012 Mar 15.
Perineural invasion (PNI) occurs in 2% to 6% of cutaneous head and neck basal and squamous cell carcinomas (SCCs) and is associated with mid-face location, recurrent tumors, high histologic grade, and increasing tumor size. Patients may be asymptomatic with PNI appreciated on pathologic examination of the surgical specimen (microscopic), or may present with cranial nerve (CN) deficits (clinical). The V and VII CNs are most commonly involved. Magnetic resonance imaging (MRI) may be obtained to detect and define the extent of PNI; computed tomography (CT) or ultrasound-guided fine needle aspiration cytology (UGFNAC) may assist with detecting or excluding regional lymph node metastases. Patients with apparently resectable cancers undergo surgery, usually followed by postoperative radiotherapy (RT). Patients with unresectable cancers are treated with definitive RT. Moreover, RT may be considered if significant functional or cosmetic impairment is expected after surgical treatment. The 5-year outcomes after treatment for clinically unsuspected microscopic compared with clinical PNI are: local control, 80% and 55%; cause-specific survival, 75% and 65%; and overall survival, 55% and 50%, respectively. The incidence of grade ≥ 3 complications is higher after treatment for clinical PNI versus microscopic PNI; approximately 35% compared with 15%, respectively. Proton beam RT may be used to reduce the risk of late complications by reducing RT dose to the visual apparatus and central nervous system (CNS).
神经周围侵犯（PNI）发生于 2%至 6%的头颈部皮肤基底细胞癌和鳞状细胞癌（SCC），与中面部位置、复发性肿瘤、高组织学分级和肿瘤增大相关。患者可能无症状，PNI 在手术标本的病理检查（显微镜下）时被发现，或可能出现颅神经（CN）缺陷（临床）。V 和 VII CN 最常受累。磁共振成像（MRI）可用于检测和定义 PNI 的范围；计算机断层扫描（CT）或超声引导下细针抽吸细胞学（UGFNAC）可辅助检测或排除区域淋巴结转移。对于明显可切除的癌症患者，进行手术，通常随后进行术后放疗（RT）。对于不可切除的癌症患者，采用根治性 RT 治疗。此外，如果手术后预期会出现明显的功能或美容损伤，也可考虑 RT。治疗临床未发现的显微镜下 PNI 与临床 PNI 的 5 年结果如下：局部控制率分别为 80%和 55%；特定原因生存率分别为 75%和 65%；总生存率分别为 55%和 50%。与治疗显微镜下 PNI 相比，治疗临床 PNI 后发生≥3 级并发症的发生率更高；分别为 35%和 15%左右。质子束 RT 可通过降低视觉器官和中枢神经系统（CNS）的 RT 剂量，降低迟发性并发症的风险。
