LAUSR

593Background: Prognosis of colorectal cancer (CRC) is greatly influenced by stage at diagnosis. Early colorectal cancer can be subtle on CT scans showing only mild wall thickening, small polyps, or subtle lymph nodes. Identifying these lesions on CT performed for nonspecific symptoms can help identify interval CRC and improve patient outcome. The purpose of the present study is to classify missed CRC on abdominal CT by their imaging features and whether early identification can downstage CRC patients. Methods: A retrospective analysis was conducted of patients (pts) diagnosed with CRC. Data collection included age, gender, ECOG, KRAS mutation status, overall survival (OS). CT obtained prior to and at diagnosis were evaluated. Images were reviewed for multiple CT features including appearance of mass, mesenteric infiltration, abnormal draining lymph nodes, contrast enhancement relative to adjacent mucosa, and intralesional calcifications. Staging was evaluated using available CT scan and based on the TNM ...