Associations between PET/CT parameters and nutritional status in patients with colon and lung cancer.

BACKGROUND: Recent investigations have explored the association of positron emission tomography combined with computed tomography (PET/CT)-derived parameters with nutritional status markers, although findings have been inconsistent. The rationale linking PET/CT markers to nutritional status is based on the premise that malnourished individuals exhibit altered hepatic metabolism, characterized by reduced hepatic glucose uptake. OBJECTIVE: We hypothesize that malnourished cancer patients, particularly those with low skeletal muscle mass, present reduced hepatic 18F-FDG uptake and, consequently, increased tumor uptake. METHODS: In this cross-sectional study, 196 patients with confirmed diagnoses of colon or lung cancer who underwent PET/CT scans were included. Liver (SUVmean) and tumor (SUVmax) uptake of fluorodeoxyglucose were measured. Nutritional status was assessed using skeletal muscle index, skeletal muscle radiodensity, subjective global assessment, percentage weight loss (%WL), phase angle, calf circumference, and handgrip strength. Most patients were male, with a median age of 64 y. RESULTS: Liver SUVmean and tumor SUVmax did not differ according to sex, age, or tumor location. Patients undergoing oncological treatment had significantly higher liver SUVmean and lower tumor SUVmax than those not under treatment. Early-stage tumors (I-II) showed higher tumor SUVmax than advanced stages (III-IV). No associations were found between SUV values and most nutritional markers, except for %WL. Tumor SUVmax was independently associated with significant weight loss (P = 0.016). CONCLUSIONS: These findings suggest that tumor metabolic activity is related to weight loss but not to body composition or other nutritional indicators. The proposed hypothesis regarding altered hepatic uptake in malnourished patients was not confirmed in this cohort.