Evaluation of pre-treatment F-18 FDG PET/CT according to Mandard classification in locally advanced rectal cancer patients undergoing neoadjuvant chemoradiotherapy

Baseline F-18 FDG PET/CT parameters, including SUVmax, MTV, and TLG, were not predictive of TRG or survival in patients with LARC undergoing neoadjuvant chemoradiotherapy. However, clinical and pathological variables such as family history, post-treatment CEA levels, perforation, lymphovascular invasion, and perineural invasion were significantly associated with TRG1. TRG1, histopathological subtype, perforation, and CC were also found to be independent predictors of survival. These findings suggest that while FDG-PET/CT may have limited utility in predicting treatment response, certain clinical and pathological features remain critical for outcome assessment.