From the Departments of Nuclear Medicine.
Gastroenterology, Istanbul University Medical Faculty, Istanbul, Turkey.
Clin Nucl Med. 2019 Sep;44(9):702-706. doi: 10.1097/RLU.0000000000002701.
Prostate specific membrane antigen (PSMA) expression has been demonstrated in tumor neovasculature of many solid tumors, including hepatocellular carcinoma (HCC). The purpose of this study is to evaluate PSMA expression in patients with HCC.
Nineteen HCC patients who underwent F-fluorodeoxyglucose (F-FDG) positron emission tomography (PET) as part of restaging procedure also underwent Ga-PSMA PET. F-FDG PET and Ga-PSMA findings were compared visually as well as quantitatively using maximized standardized uptake values (SUVmax).
FDG was positive in 15 patients while 16 patients demonstrated PSMA expression. The only extrahepatic finding was one metastatic lymph node detected by both tracers. Mean SUVmax of liver lesions on FDG PET/CT was 8.3 ± 2.3 and mean tumor to background ratio was 2.3 ± 1.5. Respective values for Ga-PSMA PET/CT were 17.4 ± 9 and 3.3 ± 2.2. On visual and quantitative evaluation uptake was higher with PSMA in nine patients and higher with FDG in four patients. PSMA and FDG activity were similar in three patients. One of the FDG positive patients was PSMA negative whereas two patients were PSMA positive but FDG negative. Heterogeneous uptake pattern was observed in three patients. Comparison of mean SUVmax and T/B values between PET studies revealed no statistically significant difference (P > 0.1). The mean survival was 25 months (range: 18-32 months) and SUVmax of PSMA (P = 0.05) and FDG (P = 0.012) showed medium strength of correlation with overall survival.
PSMA expression in advanced HCC can be demonstrated by Ga-PSMA PET but is not superior to FDG PET however it could be useful for identifying patients with limited therapeutic options.
评估前列腺特异膜抗原（PSMA）在肝癌（HCC）患者中的表达。
19 例 HCC 患者在进行氟代脱氧葡萄糖（F-FDG）正电子发射断层扫描（PET）作为重新分期程序的一部分时，还进行了 Ga-PSMA PET。通过最大标准化摄取值（SUVmax）对 F-FDG PET 和 Ga-PSMA 的发现进行了视觉和定量比较。
15 例患者 FDG 阳性，16 例患者 PSMA 表达阳性。唯一的肝外发现是两种示踪剂均检测到的一个转移性淋巴结。FDG PET/CT 上肝病变的平均 SUVmax 为 8.3 ± 2.3，肿瘤与背景的平均比值为 2.3 ± 1.5。Ga-PSMA PET/CT 的相应值分别为 17.4 ± 9 和 3.3 ± 2.2。在视觉和定量评估中，9 例患者 PSMA 摄取较高，4 例患者 FDG 摄取较高。PSMA 和 FDG 活性在 3 例患者中相似。1 例 FDG 阳性患者 PSMA 阴性，2 例患者 PSMA 阳性但 FDG 阴性。3 例患者观察到摄取不均匀。PET 研究中 SUVmax 和 T/B 值的比较无统计学差异（P > 0.1）。平均生存时间为 25 个月（范围：18-32 个月），PSMA 的 SUVmax（P = 0.05）和 FDG（P = 0.012）与总生存期呈中等强度相关。
Ga-PSMA PET 可显示晚期 HCC 中的 PSMA 表达，但并不优于 FDG PET，但对于确定治疗选择有限的患者可能有用。
