PET Avidity in Cachexia-Inducing Lung and Gastrointestinal Tumors

PET has an established role in the initial staging of patients with newly diagnosed lung and gastrointestinal tumors.PET avidity is described with both maximum and mean standardized uptake values.Malignant cells have increased activity on PET, defined as the standardized uptake value (SUV), with increased uptake of FDG in tumor due to elevated levels of GLUT receptors, elevated intracellular levels of hexokinase and increased rates of glycolysis. However, there is a subset of patients with lung and gastrointestinal tumors that are not PET avid.These patients may present with clinically and systemically aggressive disease with a declining performance status and/or weight loss.