Preoperative assessment of retrorectal tumours. BJS 2014; 101: 573-577.

Results

In total, 76 patients were identified, all of whom had undergone preoperative cross‐sectional imaging whereas only 22 had preoperative biopsy. Imaging correctly discriminated benign from malignant tumours in 72 of the 76 patients (specificity 97 per cent, sensitivity 88 per cent, positive predictive value 88 per cent and negative predictive value 97 per cent). The corresponding values for preoperative biopsy (benign versus malignant) were 100, 83, 100 and 93 per cent. None of the four patients who were assessed incorrectly as having benign or malignant disease on imaging would have undergone an alternative procedure had this been known before surgery. Preoperative biopsy did not significantly influence patient management, and the absence of preoperative biopsy had no detrimental effect; a definitive preoperative histological diagnosis would not have influenced subsequent management.