Giovacchini Giampiero, Giovannini Elisabetta, Riondato Mattia, Ciarmiello Andrea
Nuclear Medicine Department, S. Andrea Hospital, La Spezia, Italy.
Curr Radiopharm. 2018;11(1):4-13. doi: 10.2174/1874471010666171101121803.
In the last twenty years, positron emission tomography / computed tomography (PET/CT) with radiolabeled choline, represented the most powerful imaging modality for prostate cancer (PCa). However, the low positive detection rate of the technique for PSA < 1 ng/ml prompted the development of other tracers for imaging PCa.
We performed a critical review of 68Ga-PSMA, a receptor ligand tracer, which has been identified as the most promising radiopharmaceutical for imaging PCa.
The most promising feature of this radiopharmaceutical is the high positive detection rate for prostate specific antigen (PSA) levels < 1 ng/ml or less (i.e., PSA < 0.5 ng/ml). 68Ga-PSMA detection rate is also sensitive to PSA kinetics, expressed either as PSA doubling time or PSA velocity. There are initial results indicating that 68Ga-PSMA may significantly affect the clinical management of PCa patients, even though the additional advantages in comparison to radiolabeled choline need to be further supported in future perspective studies. Other clinical implications, such as whether 68Ga-PSMA PET/CT predicts PCa-specific survival, have not yet been investigated. Numerous clinical studies have been published, some of them with histopathological verification so that despite the recent introduction in the clinical field reliable estimation of sensitivity and specificity of 68Ga-PSMA PET/CT have been obtained through meta-analyses. Most clinical studies with PET/CT with 68Ga-PSMA are retrospective, single-institutional studies and in many cases include heterogeneous patient cohorts. Thus, multidisciplinary, well-throughout prospective trials are needed to better define the clinical implications of 68Ga- PSMA PET/CT in PCa patients. The increasing availability of positron emission tomography / magnetic resonance (PET/MR) hybrid devices promotes the use of this radiopharmaceutical especially at initial staging when identification of tumor localization and of extra-prostatic disease represent clinically relevant questions. PSMA cold ligands can also be labeled with beta emitters with good chemical stability so that 68Ga-PSMA PET/CT can be used to guide radiometabolic therapy of advanced metastatic PCa patients through 177Lu-labeled PSMA ligands.
PSMA labeled ligands appear very promising for diagnosis and treatment of PCa.
在过去二十年中，用放射性标记胆碱的正电子发射断层扫描/计算机断层扫描（PET/CT）是前列腺癌（PCa）最强大的成像方式。然而，该技术对前列腺特异性抗原（PSA）<1 ng/ml的阳性检测率较低，促使人们开发其他用于PCa成像的示踪剂。
我们对68Ga-PSMA进行了批判性综述，68Ga-PSMA是一种受体配体示踪剂，已被确定为用于PCa成像最有前景的放射性药物。
这种放射性药物最有前景的特点是对前列腺特异性抗原（PSA）水平<1 ng/ml或更低（即PSA<0.5 ng/ml）的阳性检测率高。68Ga-PSMA检测率对PSA动力学也很敏感，PSA动力学可表示为PSA倍增时间或PSA速度。有初步结果表明，68Ga-PSMA可能会显著影响PCa患者的临床管理，尽管与放射性标记胆碱相比的其他优势需要在未来的前瞻性研究中得到进一步支持。其他临床意义，如68Ga-PSMA PET/CT是否能预测PCa特异性生存，尚未得到研究。已经发表了许多临床研究，其中一些有组织病理学验证，因此尽管68Ga-PSMA PET/CT最近才引入临床领域，但通过荟萃分析已经对其敏感性和特异性进行了可靠估计。大多数使用68Ga-PSMA进行PET/CT的临床研究都是回顾性的单机构研究，而且在许多情况下纳入的患者队列 heterogeneous。因此，需要多学科、全面的前瞻性试验来更好地确定68Ga-PSMA PET/CT在PCa患者中的临床意义。正电子发射断层扫描/磁共振（PET/MR）混合设备的可用性不断提高，促进了这种放射性药物的使用，尤其是在初始分期时，确定肿瘤定位和前列腺外疾病是临床相关问题。PSMA冷配体也可以用具有良好化学稳定性的β发射体标记，这样68Ga-PSMA PET/CT就可以通过177Lu标记的PSMA配体用于指导晚期转移性PCa患者的放射代谢治疗。
PSMA标记的配体在PCa的诊断和治疗中似乎非常有前景。
