Cutaneous squamous cell carcinoma (CSCC) has a propensity for perineural spread (PNS) which is associated with poorer treatment outcomes. Immunotherapy is the new standard of care treatment for advanced CSCC resulting in durable responses. PNS is not captured by traditional response assessment criteria used in clinical trials, e.g. RECIST 1.1, and there is limited literature documenting radiological PNS responses to immunotherapy. In this study we assess PNS responses to immunotherapy using a modified grading system. This is an Australian single-center retrospective review of patients with advanced CSCC who were treated with immunotherapy between April 2018 and February 2022 who had evidence of PNS on pre-treatment magnetic-resonance imaging (MRI). The primary outcome was blinded overall radiological response in PNS using graded radiological criteria, post-commencement of immunotherapy. Three defined timepoints (< 5 months, 5–10 months, > 10 months) were reviewed. Secondary outcomes included a correlation between RECIST 1.1 and PNS assessments and the assessment of PNS on fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT). Twenty CSCC patients treated with immunotherapy were identified. Median age was 75.7 years and 75% (n = 15) were male. All patients had locoregionally advanced disease and no distant metastases. Median follow-up was 18.5 months (range: 2–59). 70% (n = 14) demonstrated a PNS response by 5 months. Three patients experienced pseudoprogression. One patient had PNS progression by the end of study follow up. RECIST 1.1 and PNS responses were largely concordant at > 10 months (Cohen’s Kappa 0.62). 5/14 cases had features suspicious for PNS on FDG-PET/CT. PNS response to immunotherapy can be documented on MRI using graded radiological criteria. High response rates were seen in PNS with the use of immunotherapy in this cohort and these responses were largely concordant with RECIST 1.1 assessments. FDG-PET/CT demonstrated limited sensitivity in the detection of PNS.

中文翻译：

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免疫治疗晚期皮肤鳞状细胞癌神经周围扩散的评估

皮肤鳞状细胞癌 (CSCC) 有神经周围扩散 (PNS) 的倾向，这与较差的治疗结果相关。免疫疗法是晚期 CSCC 护理治疗的新标准，可产生持久的反应。临床试验中使用的传统反应评估标准（例如 RECIST 1.1）并未捕获 PNS，并且记录放射学 PNS 对免疫治疗反应的文献有限。在这项研究中，我们使用改进的分级系统评估三七总皂苷对免疫治疗的反应。这是一项澳大利亚单中心回顾性研究，对象是 2018 年 4 月至 2022 年 2 月期间接受免疫治疗的晚期 CSCC 患者，这些患者在治疗前磁共振成像 (MRI) 上有 PNS 证据。主要结果是在免疫治疗开始后，使用分级放射学标准对 PNS 进行盲法总体放射学反应。审查了三个定义的时间点（< 5 个月、5-10 个月、> 10 个月）。次要结局包括 RECIST 1.1 和 PNS 评估之间的相关性以及氟脱氧葡萄糖 (FDG)-正电子发射断层扫描 (PET)/计算机断层扫描 (CT) 上的 PNS 评估。确定了 20 名接受免疫疗法治疗的 CSCC 患者。中位年龄为 75.7 岁，75% (n = 15) 为男性。所有患者均患有局部晚期疾病且无远处转移。中位随访时间为 18.5 个月（范围：2-59）。70% (n = 14) 在 5 个月内表现出 PNS 反应。三名患者出现假性进展。在研究随访结束时，一名患者出现 PNS 进展。RECIST 1.1 和 PNS 反应在 > 10 个月时基本一致（Cohen 的 Kappa 0.62）。5/14 例在 FDG-PET/CT 上有可疑 PNS 特征。PNS 对免疫治疗的反应可以使用分级放射学标准在 MRI 上记录。在该队列中使用免疫疗法后，PNS 出现了高反应率，并且这些反应在很大程度上与 RECIST 1.1 评估一致。FDG-PET/CT 在检测 PNS 方面表现出有限的敏感性。