Rectal cancer staging: is there an optimal method?

The staging process in a newly diagnosed rectal cancer is divided into three parts. One essential part is the local staging, in which both endorectal ultrasound and MRI are used to disclose the size of the tumor and its correlation to the perirectal fascia, and to identify lymph node deposits and vascular invasion. This local staging process will guide clinicians to decide upon not only the type of surgery (local excision or radical surgery) but also whether or not some type of neoadjuvant treatment, such as radiotherapy and/or chemotherapy, is indicated. The second part is to evaluate whether or not the tumor has already metastasized at diagnosis. The most important organs to evaluate are the liver and lungs, and imaging techniques such as ultrasound. CT-scan, or sometimes PET-CT, and MRI can be used. The third important part is to investigate the rest of the large bowel for synchronous adenomas or cancers. This will preferably be done with colonoscopy or CT-colonography and sometimes barium enema. This article discusses the imaging techniques used for local staging and distant metastases.