The relationship between metabolic parameters, 18F-fluorodeoxyglucose/positron emission tomography, and ras mutation in patients with metastatic colorectal cancer: A descriptive cross-sectional study

Abstract

Objectives: This study aimed to predict the RAS mutation by using imaging techniques and routine clinical or laboratory findings without tissue samples. Methods: The study was conducted in a retrospective cross-sectional plan in a tertiary-care health center between January 2010 and December 2016. Data collection was done from the patient files using the hospital’s electronic patient registry. The primary outcome variable was the presence of RAS mutations as evaluated from the primary surgical specimens. Besides, data was collected on blood count parameters, serum CEA, and CA 19-9 levels. Neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) were calculated. Forty-five patients who underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) with pathologically confirmed metastatic colorectal adenocarcinoma were included in the study. Results: In our study the presence of RAS mutation was 40%(n=18). When the findings were compared according to the presence of RAS mutation, a statistically significant difference was found only in age at diagnosis (p=0.038). TLG (Total Lesion Glycolysis) significantly correlated with all other variables and age at diagnosis (p<0.05). A logistic regression model with age at diagnosis and TLG as explanatory variables had a sensitivity of 70.6% and a specificity of 81.5% in detecting RAS mutation. Conclusion: Although data on TLG and RAS mutations are valuable,they should be supported by studies with a larger cohort.