Walker Ronald, Deppen Stephen, Smith Gary, Shi Chanjuan, Lehman Jonathan, Clanton Jeff, Moore Brandon, Burns Rena, Grogan Eric L, Massion Pierre P
Medical Imaging Service, Tennessee Valley VA Healthcare System, Nashville, Tennessee, United States of America.
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.
PLoS One. 2017 Feb 9;12(2):e0171301. doi: 10.1371/journal.pone.0171301. eCollection 2017.
18F-FDG PET/CT is widely used to evaluate indeterminate pulmonary nodules (IPNs). False positive results occur, especially from active granulomatous nodules. A PET-based imaging agent with superior specificity to 18F-FDG for IPNs, is badly needed, especially in areas of endemic granulomatous nodules. Somatostatin receptors (SSTR) are expressed in many malignant cells including small cell and non-small cell lung cancers (NSCLCs). 68Ga-DOTATATE, a positron emitter labeled somatostatin analog, combined with PET/CT imaging, may improve the diagnosis of IPNs over 18F-FDG by reducing false positives. Our study purpose was to test this hypothesis in our region with high endemic granulomatous IPNs.
We prospectively performed 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT scans in the same 30 patients with newly diagnosed, treatment-naïve lung cancer (N = 14) or IPNs (N = 15) and one metastatic nodule. 68Ga-DOTATATE SUVmax levels at or above 1.5 were considered likely malignant. We analyzed the scan results, correlating with ultimate diagnosis via biopsy or 2-year chest CT follow-up. We also correlated 68Ga-DOTATATE uptake with immunohistochemical (IHC) staining for SSTR subtype 2A (SSTR2A) in pathological specimens.
We analyzed 31 lesions in 30 individuals, with 14 (45%) being non-neuroendocrine lung cancers and 1 (3%) being metastatic disease. McNemar's result comparing the two radiopharmaceuticals (p = 0.65) indicates that their accuracy of diagnosis in this indication are equivalent. 68Ga-DOTATATE was more specific (94% compared to 81%) and less sensitive 73% compared to 93%) than 18F-FDG. 68Ga-DOTATATE uptake correlated with SSTR2A expression in tumor stroma determined by immunohistochemical (IHC) staining in 5 of 9 (55%) NSCLCs.
68Ga-DOTATATE and 18F-FDG PET/CT had equivalent accuracy in the diagnosis of non-neuroendocrine lung cancer and 68Ga-DOTATATE was more specific than 18F-FDG for the diagnosis of IPNs. IHC staining for SSTR2A receptor expression correlated with tumor stroma but not tumor cells.
18F-FDG PET/CT被广泛用于评估不明原因的肺结节（IPN）。会出现假阳性结果，尤其是来自活动性肉芽肿结节。迫切需要一种对IPN具有比18F-FDG更高特异性的基于PET的成像剂，特别是在地方性肉芽肿结节流行地区。生长抑素受体（SSTR）在包括小细胞肺癌和非小细胞肺癌（NSCLC）在内的许多恶性细胞中表达。68Ga-DOTATATE，一种正电子发射体标记的生长抑素类似物，结合PET/CT成像，可能通过减少假阳性来改善IPN的诊断。我们的研究目的是在我们这个地方性肉芽肿性IPN高发地区验证这一假设。
我们对30例新诊断的、未经治疗的肺癌患者（n = 14）或IPN患者（n = 15）以及1例转移瘤患者进行了前瞻性的68Ga-DOTATATE PET/CT和18F-FDG PET/CT扫描。68Ga-DOTATATE的SUVmax水平在1.5及以上被认为可能是恶性的。我们分析了扫描结果，并通过活检或2年的胸部CT随访与最终诊断进行关联。我们还将68Ga-DOTATATE摄取与病理标本中SSTR 2A亚型（SSTR2A）的免疫组化（IHC）染色进行关联。
我们分析了30例个体中的31个病变，其中14个（45%）为非神经内分泌性肺癌，1个（3%）为转移性疾病。比较两种放射性药物的McNemar结果（p = 0.65）表明，它们在该适应症中的诊断准确性相当。68Ga-DOTATATE比18F-FDG更具特异性（分别为94%和81%），但敏感性更低（分别为73%和93%）。在9例（55%）NSCLC中，有5例通过免疫组化（IHC）染色确定68Ga-DOTATATE摄取与肿瘤基质中SSTR2A表达相关。
68Ga-DOTATATE和18F-FDG PET/CT在非神经内分泌性肺癌的诊断中具有同等准确性，并且68Ga-DOTATATE在IPN的诊断中比18F-FDG更具特异性。SSTR2A受体表达的免疫组化染色与肿瘤基质相关，但与肿瘤细胞无关。
