Department of Nuclear Medicine, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany;
Department of Nuclear Medicine, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
J Nucl Med. 2022 Sep;63(9):1334-1342. doi: 10.2967/jnumed.121.263440. Epub 2022 Jan 6.
F-rhPSMA-7.3, the lead compound of a new class of radiohybrid prostate-specific membrane antigen (rhPSMA) ligand, is currently in phase III trials for prostate cancer (PCa) imaging. Here, we describe our experience in primary PCa staging. We retrospectively identified 279 patients with primary PCa who underwent F-rhPSMA-7.3 PET/CT (staging cohort). A subset of patients (83/279) subsequently underwent prostatectomy with lymph node (LN) dissection without prior treatment (efficacy cohort). The distribution of tumor lesions was determined for the staging cohort and stratified by National Comprehensive Cancer Network risk score. Involvement of pelvic LNs was assessed retrospectively by 3 masked independent central readers, and a majority rule was used for analysis. Standard surgical fields were rated on a 5-point scale independently for PET and for morphologic imaging. Results were compared with histopathologic findings on a patient, right-vs.-left, and template basis. For the staging cohort, F-rhPSMA-7.3 PET was positive in 275 of 279 (98.6%), 106 of 279 (38.0%), 46 of 279 (16.5%), 65 of 279 (23.3%), and 5 of 279 (1.8%) patients for local, pelvic nodal, extrapelvic nodal, metastatic bone, and visceral metastatic disease, respectively. In the efficacy cohort, LN metastases were present in 24 of 83 patients (29%) and were located in 48 of 420 (11%) resected templates and in 33 of 166 (19.9%) hemipelvic templates in histopathology. The majority vote results showed that patient-level sensitivity, specificity, and accuracy for pelvic nodal metastases were 66.7% (95% CI, 44.7%-83.6%), 96.6% (95% CI, 87.3%-99.4%), and 88.0% (95% CI, 78.5%-93.8%), respectively, for F-rhPSMA-7.3 PET and 37.5% (95% CI, 19.6%-59.2%), 91.5% (95% CI, 80.6%-96.8%), and 75.9% (95% CI, 65.0%-84.3%), respectively, for morphologic imaging. F-rhPSMA-7.3 showed higher interobserver agreement than morphologic imaging (patient-level Fleiss κ = 0.54 [95% CI, 0.47-0.62] vs. 0.24 [95% CI, 0.17-0.31]). A mean SUV ratio of 6.6 (95% CI, 5.2-8.1) documented a high image contrast between local tumors and adjacent low urinary tracer retention. F-rhPSMA-7.3 PET offers diagnostic performance superior to morphologic imaging for primary N-staging of newly diagnosed PCa, shows lower interreader variation, and offers good distinction between primary-tumor activity and bladder background activity. With increasing National Comprehensive Cancer Network risk group, an increasing frequency of extraprostatic tumor lesions was observed.
F-rhPSMA-7.3 是一种新型放射性杂交前列腺特异性膜抗原 (rhPSMA) 配体的先导化合物，目前正在进行前列腺癌 (PCa) 成像的 III 期临床试验。在这里，我们描述了我们在原发性 PCa 分期方面的经验。我们回顾性地确定了 279 名接受 F-rhPSMA-7.3 PET/CT 检查的原发性 PCa 患者（分期队列）。随后，一部分患者（279 例中的 83 例）在没有先前治疗的情况下接受了前列腺切除术和淋巴结 (LN) 解剖（疗效队列）。通过 3 位盲法独立中心读者评估分期队列中肿瘤病变的分布情况，并采用多数规则进行分析。对标准手术野进行独立的 5 分制评分，分别用于 PET 和形态学成像。结果与患者、右侧与左侧以及模板基础上的组织病理学发现进行比较。对于分期队列，F-rhPSMA-7.3 PET 在 279 例患者中的 275 例（98.6%）、106 例（38.0%）、46 例（16.5%）、65 例（23.3%）和 5 例（1.8%）中分别为局部、盆腔淋巴结、盆腔外淋巴结、转移性骨和内脏转移疾病阳性。在疗效队列中，83 例患者中有 24 例（29%）存在 LN 转移，在 420 个切除模板中的 48 个（11%）和 166 个半骨盆模板中的 33 个（19.9%）中存在组织病理学 LN 转移。多数投票结果显示，F-rhPSMA-7.3 PET 对盆腔淋巴结转移的患者水平敏感性、特异性和准确性分别为 66.7%（95%CI，44.7%-83.6%）、96.6%（95%CI，87.3%-99.4%）和 88.0%（95%CI，78.5%-93.8%），形态学成像的分别为 37.5%（95%CI，19.6%-59.2%）、91.5%（95%CI，80.6%-96.8%）和 75.9%（95%CI，65.0%-84.3%）。F-rhPSMA-7.3 比形态学成像显示出更高的观察者间一致性（患者水平的 Fleiss κ=0.54[95%CI，0.47-0.62]比 0.24[95%CI，0.17-0.31]）。平均 SUV 比值为 6.6（95%CI，5.2-8.1），证明了局部肿瘤与相邻低尿 tracer 保留之间的高图像对比度。F-rhPSMA-7.3 PET 提供了优于形态学成像的诊断性能，用于新诊断 PCa 的原发性 N 分期，显示出较低的读者间差异，并提供了原发性肿瘤活性和膀胱背景活性之间的良好区分。随着国家癌症综合网络风险组的增加，观察到前列腺外肿瘤病变的频率增加。
