The relationship between F-FDG-PETCT-derived markers of tumour metabolism and systemic inflammation in patients with recurrent disease following surgery for colorectal cancer.

Aim: F-fluorodeoxyglucose positron emission tomography-computed tomography ( F-FDG-PETCT)-derived markers of tumour metabolism have been reported to have prognostic significance in a variety of tumours. Host inflammation is also recognized to have prognostic significance. The aim of the present study was to investigate the relationship between these markers and host systemic inflammation in patients undergoing elective surgery for colorectal cancer.

Method: Patients with histologically confirmed colorectal cancer who underwent elective surgery between 2008 and 2015 and also underwent F-FDG-PETCT at a single centre were included (n = 103). The neutrophil-lymphocyte ratio (NLR) and modified Glasgow Prognostic Score (mGPS) were derived from routine blood tests. The maximum standardized uptake (SUVmax), peak standardized uptake (SUVpeak), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were measured.

Results: There was no association between F-FDG-PETCT measures of tumour metabolism and systemic inflammation in the 33 patients who underwent preoperative imaging. Of the 70 patients with recurrent disease who underwent F-FDG-PETCT during follow-up, patients with NLR ≥ 5 had a significantly higher SUVmax (20 vs 7, P = 0.002), SUVpeak (14 vs 5, P < 0.001), MTV (29 g vs 2 g, P = 0.001) and TLG (338 g vs 9 g, P < 0.001). Similarly, patients with a mGPS of 1-2 at the time of F-FDG-PETCT had a significantly higher median SUVmax (11 vs 6, P = 0.048), SUVpeak (8 vs 4, P = 0.046), MTV (13 ml vs 2 ml, P = 0.005) and TLG (146 g vs 10 g, P = 0.004).

Conclusion: The present study reports a direct association between F-FDG-PETCT-derived measures of tumour metabolism and systemic inflammation in patients with recurrent colorectal cancer.