Letter to the Editor: Staging Designation for Bilateral Wilms' Tumours
Wilms' tumour is bilateral in between 4 and 6% of patients [ 1,2]. The proportion of patients with unifocal disease and with bilateral disease presenting with lung metastases is similar, indicating that, in the bilaterally affected patients, the multifocal tumours are probably separate primary tumours rather than secondary deposits. Other observations also suggest that bilateral disease is no more "aggressive" than unifocal disease: first, a similar proportion of unilaterally and bilaterally affected patients have "favourable histology" and, second, the outcome for bilaterally affected patients is at least as good as that for stage IV disease. In the first United Kingdom Children's Study Group Wilms' tumour trial (UKWl), for instance, survival of "stage V" patients was 79% at 5 years, compared with 64% for stage IV children 121. Other published reports give survival rates for bilaterally affected patients of between 60 and 87% [1,3]. These figures are all the more impressive when one considers that these patients usually received less intensive chemotherapy that stage IV children.
Given these facts, it is not illogical to designate bilateral disease as "stage V" [4]? Both paediatricians and parents find the term confusing, as it implies a worse prognosis than for children with metastatic disease. A more appropriate description would be ''stage IIIb" , implying "gross residual disease unresectable only because of bilateral involvement. " The designation "group 111"
[S] or "stage IIIb" [6] is already used to describe multifocal childhood hepatocellular tumours involving both lobes of the liver. Alignment of the staging systems for these diseases makes sense to us but other opinions would be appreciated.