The prognostic role of metabolic tumor burden in 18F-FDG PET/CT in the primary staging of rectal cancers

Abstract

Introduction

The prognostic value of FDG PET/CT metabolic tumor burden has been established in various solid tumors, but its significance in the staging of rectal cancer remains underexplored. This study aimed to investigate the prognostic role of FDG PET/CT metabolic tumor burden in the primary staging of rectal cancer.

Methods

A retrospective analysis was conducted on 82 consecutive histology-proven rectal cancer patients, including 30 females (37%), with a mean age of 60.8 years. These patients underwent staging FDG PET/CT, and various metabolic tumor burden parameters (tuSUVmax, tuMTV, wbMTV, tuTLG, wbTLG) were calculated. The study assessed the correlation between metabolic tumor burden parameters and overall survival (OS), progression-free survival (PFS), as well as histopathology, clinical staging, performance status, bone-mineral indexes, hematology, and therapy management strategies.

Results

The study revealed that metabolic tumor burden, along with the presence of sarcopenia and absence of surgery, were significantly and independently associated with overall survival. Notably, a wbTLG cutoff value of 354 effectively discriminated survivors from non-survivors (p = 0.0007) with 83% specificity. Furthermore, higher whole-body tumor burden (wbTLG: p = 0.0090) and low body mass index (p = 0.0231) were significantly linked to an increased risk of disease progression.

Conclusion

This research suggests that whole-body tumor burden assessed through staging FDG PET/CT can serve as an independent imaging biomarker for prognostication in rectal cancer patients.