Logistic Model for Lymph Node Metastasis Can Improve the Accuracy of MRI Diagnosis of Rectal Cancer

Lymph node metastasis of rectal cancer in different stages had incidences of T1 11.9%, T2 25.7%, T3 55.9%, and T4 62.4% in a study of 6,442 patients in multiple centers in Japan (Watanabe et al., 2012). Thus, the incidence of lymph node metastasis of rectal cancer was very high in stage T3 and higher. Lymph node metastasis is a risk factor for local recurrence and a poor prognosis in rectal cancer (Quadros et al., 2012; Nadoshan et al., 2013) and the treatment strategy must account for lymph node metastasis (Colombo et al., 2011). Preoperative radiotherapy or chemoradiotherapy may reduce the risk of local recurrence (Sauer et al., 2004; Dou et al., 2013) and NCCN Guidelines recommend these therapies for rectal cancer with suspected lymph node metastasis (National Comprehensive Cancer Network., 2014). Establishment of an indication for neoadjuvant therapy requires evaluation of nodal staging and T stage and mesorectal fascia (MRF) involvement. If the symptoms are underestimated due to inaccurate nodal staging, the patient