The significant value of predicting prognosis in patients with colorectal cancer using 18F-FDG PET metabolic parameters of primary tumors and hematological parameters.

OBJECTS: The purpose was to evaluate the correlation of the pre-treatment hematological parameters with metabolic parameters of primary tumor in baseline 18F-FDG PET/CT in patients with colorectal cancer (CRC) and estimate the prognostic value of both. METHODS: We retrospectively investigated 231 patients with CRC who underwent baseline 18F-FDG PET/CT. Routine blood sampling was tested in the same term. PET parameters in term of hematological parameters and pathological characteristics of primary tumor were compared. Kaplan-Meier survival analysis was performed in the patients without distant metastasis. The differences of disease-free survival between groups were compared by log-rank tests. RESULTS: Neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) were significantly correlated with all the metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and tumor lesion glycolysis (TLG). The patients with NLR > 3 had higher MTV (24.82 ± 18.16 vs 19.06 ± 13.30, P = 0.039) and TLG (219.04 ± 186.94 vs 166.45 ± 146.39, P = 0.047) than those whose NLR ≤ 3. NLR in those patients with distant metastasis was significantly higher than those without distant metastasis (P = 0.018) while LMR in those patients with distant metastasis was significantly lower than those without distant metastasis (P = 0.032). Survival analysis showed that those patients with low MTV (P = 0.015), low NLR (P = 0.008) and high LMR (P = 0.027) revealed significant survival benefit. CONCLUSIONS: There was a significant association between the pre-treatment hematological parameters and metabolic parameters of baseline 18F-FDG PET/CT in the patients with CRC. It might be helpful in those patients with high NLR and low LMR to undergo 18F-FDG PET/CT to detect distant metastasis and predict prognosis.