Synopsis

Colorectal carcinoma is the third leading cause of new cancer and cancer-related death in the United States. Prognosis is related to depth of invasion and ability to achieve a negative circumferential resection margin at surgery. Total mesolectal excision and neoadjuvant therapy for locally advanced cancer has been shown to improve local oncologic control. MRI allows good differentiation of T2 and T3 tumors and can define the circumferential resection margin for surgical planning. Accuracy for nodal metastatic disease can be improved by using both size and morphology criteria. Following neoadjuvant therapy, MRI can be used to assess treatment response.