[Preoperative x-ray computed tomography in cancer of the kidney]

The authors emphasise the importance of computed tomography in the detection, diagnosis and pre-treatment staging of cancer of the kidney. In a series of 82 cases, the diagnosis was made on the basis of ultrasonography combined with computed tomography in 55% of their last 44 cases. They stress the decreasing value of intravenous urography, which was used to detect the lesion in 68% of their first 38 patients and which was used in only 41% of the last 44 cases. Computed tomography is an essential step in the pre-treatment staging of cancer of the kidney. The real local extension of the tumour was correctly diagnosed by the CT scan in 79% of cases. Under-estimation of the degree of invasion of adjacent organs was observed in 3 cases and multiple tumours in the one kidney were misdiagnosed in one case (4 errors: 5%). Over-estimation was more common, affecting 13 out of 82 cases (16%). The CT scan was found to be reliable in the detection of lymph node invasion in 62 cases (76%) and inaccurate in 24% of cases (14 over-estimations (17% of cases) and 6 under-estimations (7%]. There is therefore an excessively high false positive rate in the detection of lymph node involvement. The CT scan is not reliable in this area. Staging of venous involvement was correct in 68% of cases. Three of the 17 cases of venous invasion were recognised by the CT scan. Overall, a large lymph node on the CT scan does not signify a neoplastic node and a normal-sized node does not signify a disease-free node.(ABSTRACT TRUNCATED AT 250 WORDS)