Imaging of C-X-C Motif Chemokine Receptor 4 Expression in 690 Patients with Solid or Hematologic Neoplasms Using 68Ga-Pentixafor PET

In recent years, molecular imaging addressing the C-X-C motif chemokine receptor 4 (CXCR4) has increasingly been used in various clinical settings. Here, we aimed to assess radiopharmaceutical uptake and image contrast to determine the most relevant clinical applications for CXCR4-directed imaging. We also investigated the impact of specific activity on scan contrast. Methods: Patients (n = 690) with a variety of neoplasms underwent a total of 777 PET/CT scans with Ga-68-Pentixafor, serving as the CXCR4-specific radioligand. A semiquantitative target lesion analysis was conducted (providing SUVmax and targetto-blood pool ratio [TBR], defined as SUVmax [from target lesion] divided by SUVmean [from blood pool]). The applied specific activity (in MBq/mg) was compared with semiquantitative assessments. Results: Of the 777 scans, 242 did not show discernible uptake in disease sites, leaving 535 PET scans (68.9%) for further analysis. Very high tracer uptake (SUVmax > 12) was found in multiple myeloma (n = 113), followed by adrenocortical carcinoma (n = 30), mantle cell lymphoma (n = 20), adrenocortical adenoma (n = 6), and small cell lung cancer (n = 12). Providing information on image contrast, comparable results for TBR were recorded, with TBR (>8) in multiple myeloma, mantle cell lymphoma, and acute lymphoblastoid leukemia (n = 6). When comparing specific activity with semiquantitative parameters, no significant correlation was found for SUVmax or TBR (P >= 0.612). Conclusion: In this large cohort, Ga-68-Pentixafor demonstrated high image contrast in a variety of neoplasms, particularly for hematologic malignancies, small cell lung cancer, and adrenocortical neoplasms. The present analysis may provide a roadmap for detecting patients who may benefit from CXCR4-targeted therapies.

Automated summary

In recent years, molecular imaging targeting CXCR4 has been increasingly used in various clinical settings. This study aimed to assess radiopharmaceutical uptake and image contrast to determine the clinical applications for CXCR4-directed imaging and investigate the impact of specific activity on scan contrast.