Medical Oncology Department, University Hospital of Liège, Liège, Belgium;
Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, University Hospital of Liège, Liège, Belgium.
J Nucl Med. 2022 Dec;63(12):1815-1821. doi: 10.2967/jnumed.121.263611. Epub 2022 Apr 21.
For patients with metastatic castration-resistant prostate cancer (mCRPC), no reliable biomarkers for predicting therapeutic response or assisting in treatment selection and sequencing are currently available. Using the recent European Association of Urology and European Association of Nuclear Medicine recommendations, we aimed to compare response assessment between prostate-specific membrane antigen (PSMA) PET/CT and conventional imaging in mCRPC patients starting first-line treatment with a novel hormonal agent (NHA) and to perform a sequential comparative analysis of PSMA PET/CT-derived parameters after 4 and 12 wk of therapy. Data from 18 mCRPC patients who started NHA treatment and underwent Ga-PSMA-11 PET/CT before therapy initiation (baseline), at week 4 (W4), and at week 12 (W12) in addition to conventional imaging (bone scintigraphy, CT) at baseline and W12 were retrospectively included. PET/CT images were quantitatively analyzed for maximum and mean SUV and total PSMA ligand-positive lesions. Comparative analysis of PET/CT-derived parameters was performed, and patients were classified as having nonprogressive disease or progressive disease (PD) according to Ga-PSMA-11 PET/CT, prostate-specific antigen, and conventional imaging criteria. Treatment response was evaluable by Ga-PSMA-11 PET/CT in 16 of 18 patients (89%) and by conventional imaging in 11 of 18 patients (61%). Five of 16 patients classified as having PD by Ga-PSMA-11 PET/CT at W12 had already met progression criteria at W4, and substantial agreement was observed between W4 and W12 (κ, 0.74) Ga-PSMA-11 PET/CT results. Nonetheless, 2 of 16 patients (13%) were incorrectly classified as having PD because of a flare phenomenon on PSMA PET/CT that disappeared at W12. Volumetric assessments of Ga-PSMA-11 PET/CT imaging can improve response evaluation in NHA-treated patients with mCRPC. Although early response assessments at W4 need to be approached with caution because of flare, Ga-PSMA-11 PET/CT imaging at W4 and W12 revealed substantial agreement in therapy response assessments; these findings warrant further investigation to distinguish PD from flare at W4 and help improve the understanding of resistance to therapy.
对于转移性去势抵抗性前列腺癌（mCRPC）患者，目前尚无可靠的生物标志物可用于预测治疗反应或协助治疗选择和排序。根据最近的欧洲泌尿外科学会和欧洲核医学协会的建议，我们旨在比较使用新型激素药物（NHA）治疗的 mCRPC 患者中前列腺特异性膜抗原（PSMA）PET/CT 与常规影像学之间的反应评估，并对治疗 4 周和 12 周后 PSMA PET/CT 衍生参数进行序贯比较分析。回顾性纳入了 18 例开始 NHA 治疗并在治疗前（基线）、第 4 周（W4）和第 12 周（W12）进行 Ga-PSMA-11 PET/CT 检查以及在基线和 W12 进行常规影像学（骨闪烁扫描、CT）检查的 mCRPC 患者的数据。对 PET/CT 图像进行了最大和平均 SUV 以及总 PSMA 配体阳性病变的定量分析。对 PET/CT 衍生参数进行了比较分析，并根据 Ga-PSMA-11 PET/CT、前列腺特异性抗原和常规影像学标准将患者分为无进展疾病或进展性疾病（PD）。18 例患者中有 16 例（89%）可通过 Ga-PSMA-11 PET/CT 评估治疗反应，11 例（61%）可通过常规影像学评估。在 W12 时，根据 Ga-PSMA-11 PET/CT 标准，16 例患者中有 5 例（31%）被归类为 PD，但在 W4 时已有 5 例患者已达到进展标准，并且在 W4 和 W12 之间观察到了实质性一致性（κ，0.74）。尽管如此，由于 PSMA PET/CT 上的flare 现象，在 W12 时消失，仍有 2 例（13%）患者被错误归类为 PD。Ga-PSMA-11 PET/CT 成像的容积评估可改善 NHA 治疗的 mCRPC 患者的反应评估。尽管由于 flare，在 W4 时进行早期反应评估需要谨慎，但 W4 和 W12 的 Ga-PSMA-11 PET/CT 成像在治疗反应评估中显示出实质性一致性；这些发现值得进一步研究，以区分 W4 时的 PD 和 flare，并有助于更好地了解治疗耐药性。
