Wilms' tumour: pre- and post-chemotherapy CT appearances.

Pre-operative chemotherapy is used in our institution for patients with Wilms' Tumours (WT) when surgical 'operability' is in doubt. To date, the computed tomographic (CT) appearances of chemotherapy-induced changes in WT have not been described. We have analysed CT examinations of 18 children undergoing pre-operative chemotherapy to assess the effects of treatment on size, extent and qualitative changes of the tumour. Clinical response to chemotherapy was associated with a reduction in tumour size of at least 50%. Cystic changes were commonly seen within tumours following chemotherapy. CT did not reliably differentiate lymph nodes involved by tumour from those showing only reactive change. Pre-chemotherapy CT scans were incorrect in predicting liver invasion in 4/18 (22%) cases: of these, two were right-sided tumours, and two were bilateral.