Clinical Significance of Preoperative Magnetic Resonance Imaging in Staging of Rectal Cancer

Kim, Joo Hee

Abstract

Rectal cancer carries poor prognosis because of metastasis and local recurrence. Local recurrence has a profound effect on morbidity and quality of life. Randomized trials have proven that neoadjuvant treatment can significantly reduce local recurrence rate in some selected cases of advanced rectal cancer. Therefore, preoperative staging of rectal cancer has an important impact on treatment plan. Two main factors in predicting the local recurrence are known as the circumferential resection margin (CRM) and the nodal status. Recently, high-resolution magnetic resonance imaging (MRI) is regarded as a superior modality in the preoperative assessment of CRM with high accuracy and reproducibility. However, the results of imaging in predicting of nodal involvement are not satisfactory. In order to increase the accuracy of preoperative nodal staging, several efforts were done to evaluate lymph node by MRI or by pelvic MRI using lymph node-specific contrast agent (ultrasmall superparamagnetic iron oxide, USPIO). In this review, the role of MRI in preoperative evaluation of rectal cancer will be discussed.