Metabolic parameters in F-fluorodeoxyglucose positron emission tomography/computed tomography for treatment response in colorectal carcinoma

SUMMARY OBJECTIVE: In daily practice, 18F-fluorodeoxyglucose positron emission tomography/computed tomography plays a crucial role in the clinical follow-up to evaluate treatment response and detect recurrence in patients with elevated serum tumor markers. In this research, we aimed to elucidate whether there was a correlation between markers and semiquantitative-metabolic parameters. METHODS: In this study, 66 patients who applied to our institution with a histopathological diagnosis of colorectal carcinoma and had two consecutive 18F-fluorodeoxyglucose positron emission tomography/computed tomography scans for diagnosis or response to treatment were enrolled. The obtained images were evaluated based on response evaluation criteria in solid tumors and positron emission tomography response criteria in solid tumors criteria. The patients were divided into two groups: regression patient group (n=45) and progression patient group (n=21). RESULTS: There was a high positive correlation between whole body-total lesion glycolysis and serum tumor marker (r=0.618, p=0.000), a moderate positive correlation between SUVmax (standardized uptake value) and primary tumor-total lesion glycolysis and serum tumor marker (r=0.497, p=0.001; r=0.511, p=0.000), and a weak positive correlation between SUVmean and whole body-metabolic tumor volume and serum tumor marker (r=0.435, p=0.003) in patients achieving regression. There was a moderate positive correlation between whole body-total lesion glycolysis and tumor marker in the progression group (r=0.596, p=0.004) and a weak positive correlation between SUVmax, SUVmean, total lesion glycolysis, whole body-metabolic tumor volume, and tumor marker in the progression group (r=0.343, p=0.128; r=0.299, p=0.188; r=0.279, p=0.220; r=0.374, p=0.095). CONCLUSION: We concluded that 18F-fluorodeoxyglucose positron emission tomography/computed tomography will provide beneficial outcomes in evaluating treatment response and detecting recurrent disease in patients with colorectal carcinoma. In this context, the whole body-total lesion glycolysis value is the most sensitive parameter that can be an alternative to SUVmax in predicting treatment response.