Lymphatic drainage of the rectum, preoperative assessment and its relevance to malignant polyp and rectal cancer management

摘要

The importance of lymph node metastasis in rectal cancer is well recognized with regards to prognosis, staging and treatment. Accurate staging is particularly important where neoadjuvant treatment has been shown to downsize and downstage locally advanced tumors. Vascular invasion, poor differentiation and increasing depth of invasion are related to a higher risk of lymph node metastasis in early cancers while advanced, poorly differentiated and low rectal cancers are more likely to have lateral pelvic sidewall nodal involvement. Nodal staging is crucial in the management of malignant rectal polyps, as is the deferral of surgery in patients who have a complete clinical and radiological response to chemoradiotherapy. In all of these situations nodal staging is vital and warrants ongoing evaluation to improve its accuracy.