Prognostic value of pretreatment F-18 fluorodeoxyglucose PET/CT in colorectal cancer with unresectable metastasis

Purpose The aim of the study was to assess the prognostic value of pretreatment PET/computed tomography (CT) scans in colorectal cancer (CRC) patients with unresectable metastasis. Materials and methods We retrospectively reviewed the pretreatment PET/CT images of 82 CRC patients with unresectable metastasis and their medical records. On PET/CT images, maximum standardized uptake value (SUVmax) of primary tumor, highest SUVmax of metastatic tumors and number of metastatic organs were identified. The patients were further divided into single and multiple organ metastases groups according to the extent of disease. Survival analysis was performed with the clinical variables and metabolic parameters from PET/CT. Results In a total of 82 patients, the age of patients, highest SUVmax of metastatic tumors and number of metastatic organs were independent prognostic factors for overall survival (OS) (all P < 0.05), whereas the SUVmax of primary tumor was not. On multivariate analysis, only the SUVmax of metastatic tumor was a significant prognostic factor in the single organ metastasis group (P = 0.047), whereas the age and highest SUVmax of metastatic tumors were independent prognostic factors in the multiple organ metastases group (all P < 0.05). Conclusion The highest SUVmax of metastatic tumors was an independent prognostic factor for OS in CRC patients with unresectable metastasis.