STAGING PROBLEMS IN THE PREOPERATIVE CHEMOTHERAPY OF WILMS-TUMOR

Objective To determine the effect of the International Society of Paed iatric Oncology (SIOP) Wilms' tumour protocols (pre-operative chemothe rapy based on clinical and radiological findings, with no prior tumour verification by open or needle biopsy) on subsequent intra-operative tumour diagnosis and staging. Patients and methods The diagnosis and s taging of possible Wilms' tumour by clinical, ultrasonographic and rad iological assessment were compared with the intra-operative findings i n 14 consecutive children (1-12 years of age) treated between 1989 and 1994. Results A diagnosis of Wilms' tumour was histologically verifie d in 11 of 14 children. In two children, verification was not possible due to complete necrosis of the tumour following pre-operative chemot herapy. In a 12-year-old boy with an estimated stage IV disease due to a solitary lung metastasis, a renal cell carcinoma was revealed in th e nephrectomy specimen while subsequent thoracotomy revealed dysmorphi c but not malignant tissue, The estimated tumour stage was correct wit h regard to localized or metastatic disease in nine of 11 children wit h histologically confirmed Wilms' tumour, while in two children with a n estimated stage II tumour, liver metastases were found intra-operati vely and the tumour was upstaged to IV. Conclusion Exact tumour diagno sis and staging was difficult in these patients, Although the accuracy of tumour staging depends on the sensitivity of radiological and ultr asonographic examinations, difficulties in tumour diagnosis may be ove rcome by biopsies of the primary tumour. The justification of upstagin g a low-stage I/II tumour to stage III, provoking a more intense post- operative treatment, should be proven by prospective randomized studie s. The decision to perform a primary tumour biopsy would be facilitate d if possible subsequent deterioration of outcome could be excluded.