Controversies in the Management of Colorectal Liver Metastases: Role of PET and PET/CT

Abstract

Positron emission tomography (PET) using [F-18]-2-deoxy-2-fluoro-D-glucose (FDG) has emerged as a promising diagnostic modality in recurrent colorectal cancer. Data in the literature show that the addition of FDG-PET changes patient management in up to 30% of patients with potentially resectable liver metastases, mainly by detecting previously unknown extrahepatic disease. Furthermore, FDG-PET is useful in the follow-up of patients who underwent surgical procedures of the liver, since it is sensitive in detecting residual or relapse malignancy in scarred liver tissue following both resection and local ablative techniques. For follow-up during systemic therapy, early FDG-PET appears predictive for response to therapy. FDG-PET, computerized tomography and magnetic resonance imaging are complementary techniques in staging and restaging patients with advanced colorectal cancer. A combination of FDG-PET and CT scanning characteristics seems promising, and integrated PET/ CT is becoming more widely available, although the exact clinical value and efficacy is not yet fully established. In addition, assessment of these modalities in joint reading sessions with radiologist, nuclear medicine physician, medical and surgical oncologists significantly impacts upon patient management. This review evaluates the potential of FDG-PET and combined PET/CT in patients with colorectal liver metastases and discusses potential future possibilities.

Assessment of Response to Therapy

“…Published data (although heterogeneous with respect to the methods of PET quantification, the evaluation interval, the metabolic response criteria, and the clinical endpoints) indicate that 18F-FDG PET has a high predictive value in the therapeutic management of patients with colorectal cancer. This technique could be an asset for improving patient care by decreasing the side effects, costs, and effort associated with ineffective futile treatments in nonresponders (Wiering et al 2008). …”

“…18F-FDG PET has emerged as a promising diagnostic modality, not only for staging and re-staging of colorectal cancer (Fig. 3), but also as predictive of response to therapy and a promising tool for early monitoring of treatment (Wiering et al 2008). A recent systematic review by de Geus-Oei et al has covered almost all available documents in the field.…”

Designing Liver Resections and Pushing the Envelope with Resections for Hepatic Colorectal Metastases

“…CT and MRI may be equivalent regarding the detection of metastases in the liver; however MRI appears to be inferior to CT when evaluating extrahepatic disease [7]. Positron emission tomography (PET) with radiolabeled fluorodeoxyglucose (FDG) imaging also can improve patient selection by identifying patients with extrahepatic metastatic disease [16][17][18], and PET imaging has been shown to alter treatment plans in up to 24 % of cases due to identification of additional disease [16]. For patients with potentially resectable metastatic disease, PET imaging may be considered.…”

Hybrid PET/CT and SPECT/CT Imaging

“…Size is a limiting factor and the additional value of PET/CT is not yet fully established (Wiering et al, 2008).…”