Gallium-68 Labeled Pentixafor PET/CT in Adrenal Masses

Overview

The CXC chemokine receptor type 4 (CXCR4), which is a G protein-coupled receptor expressed on the surface of the cell membrane, contributes to the development and progression of malignancies and functional endocrine disorders. CXCR4 expression has been reported to be upregulated in aldosterone-producing adenomas and cortisol-producing adenomas; however, its expression is almost negligible in non-functioning adrenal adenomas. Besides, CXCR4 is also hardly expressed by the tumor cells in paragangliomas. 68Ga-pentixafor, a CXCR4-specific PET tracer, may therefore be effective for the evaluation of the functional lateralization of adrenal lesion and identification of functional adrenocortical adenomas. In this pilot study, we aimed to develop 68Ga-pentixafor PET/CT as a noninvasive test for the recognition of functional adrenocortical lesions and to help guide the management of patients with suspicious adrenal masses.

Identifying the functional distinctions between adrenal nodules remains challenging. It is imperative to employ the least invasive approach for the functional evaluation of adrenal masses (e.g., adrenal venous sampling) without compromising efficacy. The conventional functional diagnosis protocol of adrenal masses is based on a combination of clinical symptoms, the presence of adrenal hormonal disorders, and radiographic features. However, the clinical manifestations of endocrine diseases are diverse, and a lack of uniformity in diagnostic protocols and assay methods for determining hormonal activation in adrenal disorders results in a significant variability in measurements. Besides, conventional imaging provides information of the morphology of a lesion, but not its functional status. Thus, an effective and non-invasive workup is needed for the characterization of adrenal masses and their therapeutic management.