Prognostic Value of Metabolic Tumor Volume and Total Lesion Glycolysis Measured by Positron Emission Tomography for liver metastases in Colorectal Cancer

Introduction: The liver is considered the most common site for hematogenous spreading in colorectal cancer (CRC) . PET/CT has a great value for the detection, staging, restaging and follow up treatment response of colorectal cancer patients. Aim of the current study is to determine prognostic value of measuring PET parameters, Standard Uptake Value (SUV) total lesion glycolysis (TLG) and metabolic tumor volume (MTV) of liver metastatic lesions in colorectal patient s. Methods: Two consecutive PET/CT scans belong to 50 patients with pathologically proven colon cancer and liver metastasis are reviewed for SUV max, MTV, TLG of the liver metastatic lesions, MTV difference and TLG difference were calculated. Patients are classified into 4 groups according to the results of 2nd PET/CT: Group 1: complete remission, Group 2: partial remission, Group 3: stable disease& Group 4: progressed disease, One way ANOVA, ROC curve analysis and Cox regression model were done. Results: there is significant difference between the 4 groups for both SUV max and MTV with P value< 0.05 while for TLG, P value was 0.08, the best Cut off point for SUV max 7.9 with sensitivity 61% and specificity 59%, for MTV 16.21 with sensitivity 52% and specificity 63%& for TLG 77.5 with sensitivity 55% and specificity 62%. TLG difference has significant prognostic value. Conclusion: quantitative PET parameters as MTV, TLG, percent MTV and TLG difference can provide additional diagnostic and prognostic value in patients with colorectal patients with liver metastases .