Prediction of KRAS Mutation in Rectal Cancer Using MRI.

AIM: The purpose of the study was to investigate imaging predictors of Kirsten-ras (KRAS) mutations using magnetic resonance imaging (MRI) in patients with rectal cancer.

PATIENTS AND METHODS: A total of 275 patients with rectal cancer were enrolled. They underwent pretreatment rectal MRI, and then KRAS mutation evaluation following surgery. Two reviewers assessed diverse MRI findings associated with rectal cancer.

RESULTS: KRAS mutations were detected in 107 (38.9%). KRAS mutations were associated with N stage, gross tumor pattern, axial length of the tumor, and the ratio of the axial to the longitudinal dimensions of the tumor (p=0.0064, p<0.0001, p=0.0003 and p=0.0090). The frequency of KRAS mutations was higher in N2 stage (53.70%), and polypoid tumors (59.09%). Tumors with KRAS mutations exhibited a longer axial length, as well as a larger ratio of the axial to the longitudinal dimensions.

CONCLUSION: KRAS mutations were associated with N stage, a polypoid pattern, axial tumor length, and the ratio of the axial to the longitudinal dimensions of the tumor.