Indeterminate Liver Lesions in Patients With Early Stage Rectal Cancer: Can They Be Ignored?

Purpose: Small, hypoattenuating, indeterminate liver lesions are often encountered during staging computed tomography (CT) in patients with early-stage rectal cancer. This study aimed to determine the incidence and prognostic significance of these lesions. Methods and Materials: A single institution's colorectal cancer (CRC) database was searched for patients with early-stage rectal cancer, defined as a cT1-2N0 tumor on magnetic resonance imaging (MRI). Abdominal CT scans of these patients were assessed for the presence of liver lesions and categorized according to their morphology. Preoperative MRI scans of the liver and abdominal follow-up imaging were assessed to determine whether the liver lesions found during staging CT appeared to be CRC metastases or not. Results: In a consecutive cohort of 1232 patients with CRC who had undergone surgery, 84 patients with early-stage rectal cancer (cT1-2N0 on MRI) were identified. Of those 84 patients, 45 (54%) had 1 or more liver lesions on staging CT; a total of 122 liver lesions were observed, consisting of 95 indeterminate lesions (78%), 25 cysts (20%), and 2 hemangiomas (2%). Preoperative MRI of the liver and regular follow-up imaging revealed no synchronous or metachronous liver metastases in this cohort. Conclusions: In this study, small, hypoattenuating, indeterminate lesions of the liver were common in patients diagnosed with early rectal cancer and seemed to have no clinical significance. Additional preoperative imaging or follow-up imaging for indeterminate liver lesions in such patients may be unnecessary. (C) 2021 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.