Section of Nuclear Medicine, University Department of Radiological Sciences and Hematology, Università Cattolica del Sacro Cuore, Rome, Italy.
Unit of Nuclear Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
Eur J Nucl Med Mol Imaging. 2022 Oct;49(12):4182-4193. doi: 10.1007/s00259-022-05848-z. Epub 2022 Jun 8.
To correlate somatostatin receptor (SSTR) and proliferative activity profile (SSTR2, SSTR5, Ki-67) at immunohistochemistry (IHC) with SSTR-PET/CT imaging features in a retrospective series of lung neuroendocrine tumors (NET). Proliferative activity by Ki-67 and F-FDG-PET/CT parameters (when available) were also correlated.
Among 551 patients who underwent SSTR-PET/CT with Ga-DOTA-somatostatin analogs (SSA) between July 2011 and March 2020 for lung neuroendocrine neoplasms, 32 patients with a confirmed diagnosis of NET were included. For 14 of them, F-FDG-PET/CT was available. PET/CT images were reviewed by qualitative and semi-quantitative analyses. Immunohistochemistry for SSTR2, SSTR5, and Ki-67 was assessed. Inferential analysis was performed including kappa statistics and Spearman's rank correlation test.
Definitive diagnosis consisted of 26 typical carcinoids-G1 and six atypical carcinoids-G2. Positive SSTR2-IHC was found in 62.5% of samples while SSTR5-IHC positivity was 19.4%. A correlation between SSTR2-IHC and SSTR-PET/CT was found in 24/32 cases (75.0%, p = 0.003): 20 were concordantly positive, 4 concordantly negative. For positive IHC, 100% concordance with SSTR-PET/CT (both positive) was observed, while for negative IHC concordance (both negative) was 33.3%. In 8 cases, IHC was negative while SSTR-PET/CT was positive, even though with low-grade uptake in all but one. A significant correlation between SUV values at SSTR-PET/CT and the SSTR2-IHC scores was found, with low SUV values corresponding to negative IHC and higher SUV values to positive IHC (p = 0.002).
This retrospective study showed an overall good agreement between SSTR2-IHC and tumor uptake at SSTR-PET/CT in lung NETs. SSTR-PET/CT SUV values can be used as a parameter of SSTR2 density. Within the limits imposed by the relatively small cohort, our data suggest that SSTR2-IHC may surrogate SSTR-PET/CT in selected lung NET patients for clinical decision making when SSTR-PET/CT is not available.
在回顾性肺神经内分泌肿瘤（NET）系列中，将免疫组织化学（IHC）中生长抑素受体（SSTR）和增殖活性谱（SSTR2、SSTR5、Ki-67）与 SSTR-PET/CT 成像特征相关联。还对增殖活性 Ki-67 和 F-FDG-PET/CT 参数（如果有）进行了相关性分析。
在 2011 年 7 月至 2020 年 3 月期间，551 名患者接受了 Ga-DOTA-生长抑素类似物（SSA）的 SSTR-PET/CT 检查，用于肺神经内分泌肿瘤，其中 32 名患者被确诊为 NET。其中 14 名患者有 F-FDG-PET/CT 检查。对 PET/CT 图像进行了定性和半定量分析。评估了 SSTR2、SSTR5 和 Ki-67 的免疫组织化学。进行了推断分析，包括卡帕统计和斯皮尔曼等级相关检验。
明确诊断包括 26 例典型类癌-G1 和 6 例非典型类癌-G2。62.5%的样本中发现 SSTR2-IHC 阳性，而 SSTR5-IHC 阳性率为 19.4%。在 32 例中有 24 例（75.0%，p=0.003）发现 SSTR2-IHC 和 SSTR-PET/CT 之间存在相关性：20 例结果一致，4 例结果一致。对于阳性 IHC，观察到 100%与 SSTR-PET/CT （均阳性）一致，而对于阴性 IHC 一致性（均阴性）为 33.3%。在 8 例中，IHC 为阴性，而 SSTR-PET/CT 为阳性，尽管除 1 例外，其余所有病例的摄取程度均较低。在 SSTR-PET/CT 上的 SUV 值与 SSTR2-IHC 评分之间发现了显著相关性，低 SUV 值对应于阴性 IHC，而高 SUV 值对应于阳性 IHC（p=0.002）。
这项回顾性研究表明，在肺 NET 中，SSTR2-IHC 与 SSTR-PET/CT 肿瘤摄取之间总体上具有良好的一致性。SSTR-PET/CT SUV 值可作为 SSTR2 密度的参数。在相对较小的队列所限制的范围内，我们的数据表明，在没有 SSTR-PET/CT 时，SSTR2-IHC 可替代 SSTR-PET/CT 用于选择的肺 NET 患者的临床决策。
