Impact of CXCR4-Directed PET/CT on Staging and Proposed Oncologic Management in Patients With Digestive System Tumors.

Purpose: To elucidate the influence of CXC motif chemokine receptor 4 (CXCR4)-directed imaging on staging and proposed oncologic management in patients with digestive system tumors compared with guideline-appropriate imaging (GAI).
Methods: From our PET/CT database, we retrospectively identified 37 patients with advanced digestive system tumors, which had been scheduled for CXCR4-targeted [ 68 Ga]Ga-pentixafor PET/CT for potential theranostic considerations. In all subjects, concurrent GAI was also available. Patients were afflicted with gastroenteropancreatic neuroendocrine neoplasms (21/37 [56.8%]), pancreatic duct adenocarcinoma (6/37 [16.2%]), cholangiocarcinoma (5/37 [13.5%]), hepatocellular carcinoma (4/37 [10.8%]), and colorectal carcinoma (1/37 [2.7%]). Staging results and impact on proposed oncologic management by a board-certified gastroenterologist were compared between GAI and [ 68 Ga]Ga-pentixafor PET/CT.
Results: Relative to GAI, CXCR4-directed PET/CT resulted in staging changes in 14 of 37 patients (37.8%). Upstaging was seen in 1 of 14 patients (7.1%), whereas downstaging was recorded in the remaining 13 of 14 patients (92.9%). Among those, staging changes would not have triggered any changes in oncological management in 4 of 14 (28.6%). For the remaining 10 of 14 patients (71.4%), however, findings on [ 68 Ga]Ga-pentixafor PET/CT would have impacted subsequent clinical algorithm, including the necessity for further diagnostic steps or failure to initiate antitumor therapy.
Conclusion: [ 68 Ga]Ga-pentixafor PET/CT missed tumor lesions in 13 patients with digestive system tumors, which would have led to inappropriate downstaging and clinical treatment of 10 patients. As such, our results do not support a more widespread use of [ 68 Ga]Ga-pentixafor PET/CT for clinical staging in those tumor entities.
Competing Interests: Conflicts of interest and sources of funding: This project was partially supported by the Okayama University “RECTOR” Program, KAKENHI grant (21K19450) from the Japan Society for the Promotion of Science (to T.H.) and the German Research Foundation (507803309, to R.A.W.; 453989101, to R.A.W., T.H.). R.A.W. and A.K.B. have received speaker's honoraria from PentixaPharm. A.K.B. is a member of the advisory board of PentixaPharm. All other authors declare no conflict of interest.
(Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)