Improved Primary Staging of Marginal-Zone Lymphoma by Addition of CXCR4-Directed PET/CT
Johannes Duell, Franziska Krummenast, Andreas Schirbel, Philipp Klassen, Samuel Samnick, Hilka Rauert‐Wunderlich, Leo Rasche, Andreas K. Buck, Hans‐Jürgen Wester, Andreas Rosenwald, H. Einsele, Max S. Topp, Constantin Lapa, Malte Kircher
Abstract
PET/CT with <sup>18</sup>F-FDG is an integral component in the primary staging of most lymphomas. However, its utility is limited in marginal-zone lymphoma (MZL) because of inconsistent <sup>18</sup>F-FDG avidity. One diagnostic alternative could be the targeting of C-X-C motif chemokine receptor 4 (CXCR4), shown to be expressed by MZL cells. This study investigated the value of adding CXCR4-directed <sup>68</sup>Ga-pentixafor PET/CT to conventional staging. <b>Methods:</b> Twenty-two newly diagnosed MZL patients were staged conventionally and with CXCR4 PET/CT. Lesions identified exclusively by CXCR4 PET/CT were biopsied as the standard of reference and compared with imaging results. The impact of CXCR4-directed imaging on staging results and treatment protocol was assessed. <b>Results:</b> CXCR4 PET/CT correctly identified all patients with viable MZL and was superior to conventional staging (<i>P</i> < 0.001). CXCR4-directed imaging results were validated by confirmation of MZL in 16 of 18 PET-guided biopsy samples. Inclusion of CXCR4 PET/CT in primary staging significantly impacted staging results in almost half of patients and treatment protocols in a third (upstaging, <i>n</i> = 7; downstaging, <i>n</i> = 3; treatment change, <i>n</i> = 8; <i>P</i> < 0.03). <b>Conclusion:</b> CXCR4 PET/CT is a suitable tool in primary staging of MZL and holds the potential to improve existing diagnostic algorithms.