(18)F-FDG uptake by rectal cancer is similar in mucinous and nonmucinous histological subtypes.

ABSTRACT

PURPOSE: PET/CT has been considered limited for the evaluation of mucinous colorectal tumors due to low (18)F-FDG uptake. The aim of our study was to compare PET/CT variables in mucinous (MC) and nonmucinous (NMC) rectal adenocarcinomas. METHODS: Consecutive patients with cT2-4N0-2M0 rectal cancer included in a prospective clinical trial were reviewed. PET/CT was performed for primary baseline staging. Visual and quantitative analysis included SUVmax and SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG). PET/CT parameters were compared according to histological subtypes. RESULTS: Overall, 73 patients were included (18 mucinous and 55 nonmucinous). SUVmax values were similar between MC and NMC (19.7 vs. 16.6; p = 0.5). MTV and TLG values were greater in the MC group (103.9 vs. 54.1; p = 0.007 and 892.5 vs. 358.8; p = 0.020) due to larger tumor volumes of MC. CONCLUSIONS: Metabolic parameters at baseline PET/CT for patients with rectal cancer are similar in mucinous and nonmucinous histological subtypes.