super(18)F-FDG PET/CT-based treatment response evaluation in locally advanced rectal cancer: a prospective validation of long-term outcomes

Purpose: To prospectively evaluate the usefulness of super(18)F-FDG PET/CT) imaging for predicting histopathological response and long-term clinical outcomes in locally advanced rectal cancer (LARC). Methods: This prospective study included 38 patients with a confirmed diagnosis of LARC (cT3-4 or cN+) who underwent super(18)F-FDG PET/CT before and after neoadjuvant therapy (NAT). Total mesorectal excision was scheduled 6 weeks after NAT and was followed by an expert histopathological analysis of the surgical specimen. Baseline variables and previously identified maximum FDG standardized uptake value (SUVmax) cut-off values before NAT (SUVmax sub(PRE) greater than or equal to 6) and after NAT (SUVmax sub(POST) greater than or equal to 2), and the absolute and percentage reductions from baseline SUVmax ( Delta SUVmax