Department of Nuclear Medicine, University Hospital Zürich, Zürich, Switzerland
Department of Nuclear Medicine, University Hospital Zürich, Zürich, Switzerland.
J Nucl Med. 2019 Aug;60(8):1118-1123. doi: 10.2967/jnumed.118.221564. Epub 2019 Jan 25.
High-intensity focused ultrasound (HIFU) is a promising new modality for the treatment of localized prostate cancer (PCa). Follow-up of patients is recommended with biopsies and multiparametric MRI (mpMRI). However, mpMRI in the postinterventional setting is often false-negative. It was our aim to investigate if the new tracer targeting the prostate-specific membrane antigen (Ga-PSMA-11) could be used to localize recurrent disease with PET/MR in patients with discrepant findings between mpMRI and template biopsies. Interim analysis was performed of the first 10 patients scanned between September 2016 and May 2018 with positive template biopsy and negative mpMRI after HIFU from an ongoing clinical trial (NCT02265159). All patients underwent Ga-PSMA-11 PET/MRI within 3 mo. Four prostatic quadrants were defined, and for every quadrant suspicion for recurrence was rated on a 5-point Likert scale from definitely no recurrence (1) to highly suspected of recurrence (5), with 4 used as a cutoff for suspected disease based on PET/MRI by a masked reader. Ga-PSMA-11 uptake of suspected lesions and background areas was measured with the SUV The apparent diffusion coefficient values of lesions and background were given for each segment. PET/MRI scans were compared with the template biopsy results, including corresponding Gleason scores (GS), number of positive cores, and tumor length. The quadrant-based sensitivity, specificity, and positive and negative predictive values for PET/MRI were 55%, 100%, 100%, and 85%, respectively. Patient-based PET/MRI was negative in 4 cases with GS 3 + 4 and a tumor length between 0.1 and 3 mm. All tumor lesions with GS 4 + 3 or higher were detected on PET/MRI. Our preliminary results indicate that Ga-PSMA-11-PET/MR has the potential to localize PCa recurrence after HIFU occult on mpMRI.
高强度聚焦超声（HIFU）是治疗局限性前列腺癌（PCa）的一种很有前途的新方法。建议对患者进行随访，包括活检和多参数 MRI（mpMRI）。然而，介入后 mpMRI 常常呈假阴性。我们的目的是研究新的前列腺特异性膜抗原（Ga-PSMA-11）示踪剂是否可用于定位 HIFU 后 mpMRI 结果阴性而模板活检阳性的患者中存在的疾病复发。对 2016 年 9 月至 2018 年 5 月间接受 HIFU 治疗的 10 例连续临床研究（NCT02265159）患者进行了初步分析。所有患者均在 HIFU 治疗后 3 个月内行 Ga-PSMA-11 PET/MRI 检查。定义了 4 个前列腺象限，每一个象限的可疑复发程度用 5 分制 Likert 量表进行评分（1 分表示肯定没有复发，5 分表示高度怀疑复发），采用 4 分作为基于 PET/MRI 由一位盲法读片者判断的可疑疾病的截断值。可疑病变和背景区域的 Ga-PSMA-11 摄取量用 SUV 表示，每个节段均给出病变和背景的表观扩散系数值。PET/MRI 扫描与模板活检结果进行比较，包括相应的 Gleason 评分（GS）、阳性核心数和肿瘤长度。基于象限的 PET/MRI 诊断的敏感性、特异性、阳性预测值和阴性预测值分别为 55%、100%、100%和 85%。4 例 GS 为 3+4 且肿瘤长度在 0.1-3mm 之间的患者基于患者的 PET/MRI 为阴性。所有 GS 为 4+3 或更高的肿瘤病变均在 PET/MRI 上被检测到。我们的初步结果表明，Ga-PSMA-11-PET/MR 有可能定位 HIFU 后 mpMRI 隐匿性的 PCa 复发。
