Treatment Monitoring of Advanced Colorectal Cancer With 18F-FDG PET/CT

Measuring tumor response to treatment based on computed tomography (CT) and/or magnetic resonance imaging (MRI) has been a widely debated issue (response criteria in solid tumors [RECIST] and World Health Organization criteria). Furthermore, early identification of nonresponding patients is of great importance because the rates of response of common malignant solid tumors to chemotherapy are in the range of only 20-30%. Therefore, quantitative imaging of tumor metabolism with 18F-FDG PET/CT may provide important advantages and thus reduce side effects and costs of ineffective therapy. However, the evidence to date for the use of 18F-FDG-PET/CT with this indication is limited.

The purpose of the present trial is to determine the impact of 18F-FDG PET/CT in the management of advanced colorectal cancer. The aim is also to confirm whether a metabolic response can be used as a surrogate end point in monitoring treatment response in this cancer type.

The study consists of 40 patients with advanced colorectal cancer patients. All patients will be studied with 18F-FDG PET/CT combined with diagnostic contrast enhanced abdominal CT before the start of chemotherapy and re-evaluated 4-5 weeks after the initiation of therapy. Effect of this metabolic and anatomic change in therapy are evaluated and correlated to survival, morbidity, and treatment -related costs. Histopathologic confirmation of response is evaluated whenever possible. The data will be collected between 2008 and 2012.