Dual-phase images with 18F-FDG PET/CT can exhibit new lesions of colo-rectal cancer.

Objective: Dual-phase 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has demonstrated superiority over conventional imaging methods in various clinical conditions. However, its efficacy in detecting metastases from colorectal cancer is uncertain. We aim to reveal whether dual-phase FDG-PET/CT can be superior in detecting metastases compared to the standard PET-CT study in patients with an established diagnosis of colorectal cancer.

Methods: This is a single-center, retrospective case-control study involving 35 patients with colorectal cancer who underwent whole-body FDG PET-CT imaging. Late-phase FDG-PET-CT images were obtained 1-2 hours after the standard technique, emphasizing the identification of new lesions or clarified lesions.

Results: Among the 35 patients evaluated, 5 (14.3%) exhibited new cancer lesions, while 6 (17.1%) demonstrated more evident cancer regions at late-phase FDG-PET-CT. New lesions or more evident cancer regions with the dual-phase technique were described within the liver, in regional lymph nodes, and in peritumoral regions.

Conclusion: The study findings suggest that dual-phase FDG-PET-CT can reveal new and more evident metastatic lesions in a subset of colorectal cancer patients. This technique, precious in identifying liver metastases and lymph nodes, enhances the accuracy of colorectal cancer diagnosis and staging.