The role of MRI in the pre‐operative staging of rectal cancer

Pre‐operative local staging in patients with rectal cancer can be used to:

• Assign the most appropriate pre‐operative adjuvant therapy;
• Assist in surgical planning;
• Serve as an accurate baseline from which to compare the success of different treatment strategies.

In image interpretation, the following prognostic information should be sought:

• Tumour T stage;
• The depth of extramural spread of tumour (depth beyond outer muscle wall);
• The relationship of the tumour to the peritoneal reflection;
• The relationship of the tumour to the anal sphincter complex;
• The distance from the outermost edge of the tumour to the mesorectal fascia;
• The presence and location of mesorectal deposits;
• The presence of other prognostic factors, such as extramural venous invasion and peritoneal invasion.