Translational Molecular Imaging of Prostate Cancer

Abstract

Prostate cancer is a heterogeneous disease, and its management is now evolving to become more personalized and to incorporate new targeted therapies. With these new changes comes a demand for molecular imaging techniques that can not only detect disease but also assess biology and treatment response. This review article summarizes current molecular imaging approaches in prostate cancer (e.g. ^99mTc bone scintigraphy and ¹⁸F-fluorodeoxyglucose positron emission tomography) and highlights emerging clinical and preclinical imaging agents, with an emphasis on mechanism and clinical application. Emerging agents at various stages of clinical translation include radiolabeled analogs of lipid, amino acid, and nucleoside metabolism, as well as agents more specifically targeting prostate cancer biomarkers including androgen receptor, prostate-specific membrane antigen and others. We also highlight new techniques and targeted contrast agents for magnetic resonance imaging and spectroscopy. For all these imaging techniques, a growing and important unmet need is for well-designed prospective clinical trials to establish clear indications with clinical benefit in prostate cancer.

Keywords: Molecular imaging; androgen receptor; magnetic resonance imaging; positron emission tomography; prostate cancer; prostate-specific membrane antigen; single photon emission computed tomography.

Figure 1

Axial anti-¹⁸F-FACBC PET (A) and PET/CT (B) images in a 67-y-old patient with PSA relapse show intense activity in the left external iliac nodes (black arrow). In the same patient, axial ¹¹¹In-capromab pendetide SPECT (C) and SPECT/CT (D) images demonstrate no significant activity in this region (white arrow). Reproduced with permission from Schuster et al [52].

Figure 2

¹⁸F-FDHT PET images at baseline (A) and after 4 weeks of treatment with enzalutamide (B). The sagittal and coronal images were taken 1 h after administration of ¹⁸F-FDHT. After four weeks, they show a reduction in ¹⁸F-FDHT accumulation in tumor within the vertebrae, compared with the cardiac and aortic blood pool. Reproduced with permission from Scher et al [61].

Figure 3

Temporal PET images of ⁸⁹Zr-DFO-J591 in mice bearing LNCaP xenografts (PSMA-positive, A) or PC-3 xenografts (PSMA-negative, B). Axial and coronal planar images at the center of the tumors show PSMA-specific uptake and retention of ⁸⁹Zr-DFO-J591. Mean tumor-to-muscle ratios and upper thresholds of scale are shown. Reproduced with permission from Holland et al [69].

Figure 4

¹⁸F-DCFBC PET images in a patient with progressive metastatic prostate cancer. An area of focal ¹⁸F-DCFBC uptake in the L4 vertebral body on PET and fused PET/CT (thick arrows, A) showed no correlative abnormality on CT (thin arrow, A) or bone scan (arrow, B). Reproduced with permission from Cho et al [75].