Abdominal recurrences in Wilms' tumours: a report from the SIOP Wilms' tumour trials and studies.

The Wilms' tumour trials and studies conducted from 1971 to 1980 registered 1042 patients. Of these, 82 patients developed an abdominal recurrence. Particulars of these were studied. Half of the recurrences occurred in stage III patients. Often several untoward prognostic factors could be identified, such as large tumour size, difficult operation, incomplete excision, peritoneal adhesions or metastases, tumour extending to renal vein or vena cava. A tumour rupture increases the chance for an abdominal recurrence, especially if appropriate radiotherapy is not given. In many of these cases, postoperative radiotherapy seems to have been insufficiently tailored to the operative findings. For stage III cases, a careful discussion between surgeon, radiotherapist, and pathologist should lead to the optimal radiotherapy field size and dose for each individual patient, so that the risk of abdominal recurrence can be reduced.