Predictive Role of FDG PET-CT in Localised Rectal Carcinoma: A Systematic Review and Meta-Analysis

Rectal carcinoma (RC) has high incidence and rate of recurrence. Currently, routine 18- fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT) is not recommend for routine monitoring for post RC treatment. We examined the utility of FDG PET-CT for the prognostication of patients with RC and what FDG PET-CT metrics are of value.

PubMed, Embase, MEDLINE, and Cochrane (Central) were comprehensively searched till 19 May 2024. A modified Newcastle Ottawa scale was used to assess for study bias. We presented our systematic review alongside pooled hazard ratios (HR) for maximum standardised uptake values (SUV) as a predictor of disease-free survival (DFS) and overall survival (OS).

Eleven papers including 771 patients were included in our systematic review. Considering the current evidence, there is potential to consider percentage change in SUV_max, TLG, MTV, and lymph node highest peak SUV as possible predictors of outcome for localised non metastatic rectal carcinoma.

Pooled meta-analysis of three homogenous parameters examines the relationship of SUV_Max and survival, and did not demonstrate correlation with survival outcomes. The overall pooled hazard ratio for pretreatment SUV_Max to DFS was 0.69, CI (0.29-1.63). The overall pooled HR for post treatment SUV_Max to DFS was 0.88, CI (0.43-1.81), and posttreatment SUV_Max to OS was 1.73, CI (0.34-8.66). Post treatment FDG PET-CT may have a role to play in the prognostic evaluation of RC patients; however, further data is required.