Preoperative urography in large bowel cancer: a useless investigation?

The utility of intravenous urography (IVU) in the preoperative assessment of patients with adenocarcinoma of the large bowel has been investigated in 4226 patients derived from a prospective multicentre study entitled the Large Bowel Cancer Project. An IVU was carried out in 956 of these patients (22.6 per cent), subsequent surgery revealed unsuspected direct urinary tract involvement in 75. However, 42 (56 per cent) had shown no IVU abnormality. Twenty patients having a clinical colovesical fistula had had a preoperative IVU. Only half showed an abnormality. In the entire study group, 10 nephrectomies and 40 other concomitant urinary tract resections were performed. Four of these nephrectomies were associated with right-sided tumours. A significantly higher number of patients with a rectal primary had a preoperative IVU. The value of routine preoperative urography before large bowel cancer surgery is questioned, and other methods of determining function in the other kidney before nephrectomy should be sought.