Preoperative staging of rectal carcinoma.

BACKGROUND: The development of treatment modalities for rectal cancer, including local excision, total mesorectal excision and preoperative radiotherapy, has increased the importance of accurate preoperative staging to allow the optimum treatment to be selected.
METHODS: A literature review was undertaken of methods of preoperative staging of rectal carcinoma and the evidence for each was evaluated critically.
RESULTS: Clinical assessment of rectal carcinoma may give an indication of fixity but is not accurate for staging. Endoanal ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), radioimmunoscintigraphy and positron emission tomography have all been used for staging. The extent of tumour spread through the bowel wall (T stage) is most accurately assessed by endoanal ultrasonography, although this technique is poor at assessing tumour extension into adjacent organs for which both CT and MRI are more accurate. No method accurately determines lymph node involvement, but endoanal ultrasonography is the best available. Liver metastases may be assessed by abdominal ultrasonography, CT, MRI and CT portography (with increasing sensitivity and cost in that order).
CONCLUSION: Endoanal ultrasonography is the most effective method of local tumour staging, with the addition of either CT or MRI if adjacent organ involvement is suspected. Abdominal ultrasonography or CT is recommended for routine preoperative assessment of the liver.