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.