Kabasakal Levent, Demirci Emre, Nematyazar Jamal, Akyel Reşit, Razavi Baresh, Ocak Meltem, Aygun Aslan, Obek Can, Kural Ali R
aDepartment of Nuclear Medicine, Cerrahpasa Medical Faculty bDepartment of Pharmaceutical Technology, Pharmacy Faculty cDepartment of Urology, Cerrahpasa Medical Faculty, Istanbul University dDepartment of Nuclear Medicine, Sisli Etfal Training and Research Hospital eDepartment of Urology, Acibadem University Medical Faculty, Istanbul, Turkey.
Nucl Med Commun. 2017 Feb;38(2):149-155. doi: 10.1097/MNM.0000000000000617.
Prostate-specific membrane antigen (PSMA) is increasingly being recognized as a novel target for the PET imaging of prostate cancer (PCa) and Ga-DKFZ-11 (Ga-PSMA) has been suggested as a novel tracer for detection of PCa relapses and metastases. The aim of this study was to evaluate the diagnostic value of PSMA PET/CT in the diagnosis of recurrent PCa with low prostate-specific antigen (PSA) levels.
We carried out a retrospective analysis of patients who underwent PSMA PET/CT from November 2013 to December 2014 in our department. Among these patients, 50 out of 178 who had increasing PSA levels (<5 ng/ml) and did not have known metastasis were included in this study.
Patients had an average PSA of 1.41 ng/ml. A total of 29 patients (58%) showed at least one positive lesion. PET positivity rates of 31% (n=4), 54% (n=13), and 88% (n=14) were observed in patients with a PSA level of less than 0.2, 0.2-2, and 2-5 ng/ml, respectively. A positive correlation was observed between positivity rate and Gleason scores and blood PSA levels. Verification was performed in 46 patients, with biopsy (n=3) and follow-up, and conventional imaging studies at the time of the PET/CT or during follow-up with a mean period of 10.6±3.3 months and ranged from 3.8 to 16.4 months. According to patient-based analysis of 46 cases, 57% of patients had true positive, 24% of patients had true negative, 2% of patients had false positive, an 18% of patients had false-negative findings. A sensitivity of 76.47% (95% confidence interval: 58.83-89.25%) and a specificity of 91.67% (95% confidence interval: 61.52-99.79%) were found.
PET/CT with Ga-PSMA is a valuable tool for assessing recurrence of PCa with a high sensitivity in patients who have PSA levels between 0.2 and 5 ng/ml. In addition, this study suggests that PSMA PET/CT can be used in patients with very low (<0.2 ng/ml) but increasing PSA levels, which, in many cases, may influence further clinical management.
前列腺特异性膜抗原（PSMA）日益被视为前列腺癌（PCa）正电子发射断层显像（PET）成像的新靶点，且已有人提出Ga-DKFZ-11（Ga-PSMA）作为检测PCa复发和转移的新型示踪剂。本研究旨在评估PSMA PET/CT在诊断前列腺特异性抗原（PSA）水平较低的复发性PCa中的诊断价值。
我们对2013年11月至2014年12月在我科接受PSMA PET/CT检查的患者进行了回顾性分析。在这些患者中，178例PSA水平升高（<5 ng/ml）且无已知转移的患者中有50例纳入本研究。
患者的平均PSA为1.41 ng/ml。共有29例患者（58%）显示至少有一个阳性病灶。PSA水平低于0.2、0.2 - 2和2 - 5 ng/ml的患者中，PET阳性率分别为31%（n = 4）、54%（n = 13）和88%（n = 14）。阳性率与Gleason评分和血PSA水平之间存在正相关。对46例患者进行了验证，包括活检（n = 3）和随访，以及在PET/CT检查时或随访期间进行的传统影像学检查，平均随访期为10.6±3.3个月，范围为3.8至16.4个月。根据对46例患者的基于个体的分析，57%的患者为真阳性，24%的患者为真阴性，2%的患者为假阳性，18%的患者为假阴性。敏感性为76.47 %（95%置信区间：58.83 - 89.25%），特异性为91.67 %（95%置信区间：61.52 - 99.79%）。
对于PSA水平在0.2至5 ng/ml之间的患者，Ga-PSMA PET/CT是评估PCa复发的有价值工具，具有高敏感性。此外，本研究表明PSMA PET/CT可用于PSA水平极低（<0.2 ng/ml）但呈上升趋势的患者，在许多情况下，这可能会影响进一步的临床管理。
