Staging Pathways in Recurrent Colorectal Carcinoma: Is Contrast-Enhanced ¹⁸F-FDG PET/CT the Diagnostic Tool of Choice?

Abstract

18 F-FDG PET/CT has gained wide acceptance for evaluation of recurrent colorectal carcinoma. However in clinical practice, contrast-enhanced CT (ceCT) is still the first-line restaging tool. The aim of this study was to investigate the value of contrastenhanced PET/CT (cePET/CT) as a first-line restaging tool with a special focus on the importance of the use of intravenous contrast. Methods: Fifty-four patients (17 women, 37 men; mean age, 60.3 y), referred for restaging of colorectal carcinoma, were examined with cePET/CT. Retrospective analysis was performed by 2 experienced readers by consensus: first, ceCT alone; second, non-cePET/CT; and third, cePET/CT. The number, localization, and diagnostic certainty of lesions were evaluated. Additionally, the therapeutic impact of the findings was determined. In 29 patients, histology, clinical imaging, and clinical follow-up served as the reference standard. In 25 patients, clinical follow-up and imaging served as the reference standard. Results: Overall, non-cePET/CT delivered correct additional information to the ceCT findings in 27 of 54 patients (50%). This occurred in (a) 20 of 30 patients, where ceCT was found to be inconclusive, and in (b) 7 of 24 patients with conclusive ceCT findings, where non-cePET/CT found additional lesions, leading to a therapy modification in 5 patients. Compared with non-cePET/ CT, cePET/CT revealed additional information in 39 of 54 patients (72%), with therapeutic relevance in 23 patients. This large number was primarily due to correct segmental localization of liver metastases, which is crucial for surgical therapy planning. Conclusion: On the basis of its higher accuracy and therapeutic impact compared with ceCT, our data suggest that cePET/CT might be considered as the first-line diagnostic tool for restaging in patients with colorectal cancer.

Role of F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Staging of Colorectal Carcinoma

“…Authors suggested that CE PET/CT might be considered as the first-line diagnostic tool for restaging of patients with colorectal cancer. 9 We totally agree with the study conducted by Soyka JD et al that corroborates with an added benefit of CE PET/CT over non CE PET/CT seen in our study. In our study, CECT (Chest, Abdomen, and Pelvis) correctly identified overall (TNM) stage in 57.4% (31/54) of patients and PET/CT correctly identified overall (TNM) stage in 72.2% (39/54) of patients.…”

The value of FDG positron emission tomography/computerised tomography (PET/CT) in pre-operative staging of colorectal cancer: a systematic review and economic evaluation.

“…Four therapeutic impact studies reported the findings from retrospective case series; 49,90,92,93 in one report the design was unclear;…”

“…The search identified seven therapeutic impact studies 49,[89][90][91][92][93][94] that sought to assess the value of FDG PET/CT in management. A further study published online as a pre-publication report was identified by one of our review team clinicians, and permission to include the study was obtained from the authors.…”

“…45,46 Other methodological considerations in reviewing studies of diagnostic test accuracy and therapeutic impact relate to the intended role of FDG PET/CT; in all included diagnostic test accuracy studies, and in six of the seven included therapeutic impact studies, FDG PET/CT is treated as a replacement test; 49,[90][91][92][93][94] however, in one of the therapeutic impact studies its role as an add-on test is evaluated. 89 Because some of the diagnostic test accuracy studies also presented data for the therapeutic impact of FDG PET/CT, we present these data while recognising the important differences in study designs between diagnostic test accuracy and therapeutic impact studies, and recognising the two different roles for FDG PET/CT.…”

Hybrid versus fusion imaging: are we moving forward judiciously?

“…Compared with nonenhanced PET/CT, PET/ceCT provided additional information in 39 of the 54 patients (72%); this information had therapeutic relevance in 23 patients. This large number was primarily due to correct segmental localization of liver metastases, which is crucial for surgical therapy planning [7].…”