Mj. Coppes et al., Factors affecting the risk of contralateral Wilms tumor development - A report from the National Wilms Tumor Study Group, CANCER, 85(7), 1999, pp. 1616-1625
BACKGROUND. Approximately 1% of children with unilateral Wilms tumor develo
p contralateral disease. The authors assessed the demographic and histologi
c features associated with metachronous bilateral Wilms turner (BWT).
METHODS. Characteristics of all children registered on the first four Natio
nal Wilms Tumor Studies (NWTS) were recorded. The primary endpoint for eval
uation was the first appearance of Wilms tumor in the remaining kidney. The
cumulative risk of contralateral disease as a function of time since initi
al presentation was calculated as 1 minus the Kaplan-Meier estimate of rema
ining free of contralateral disease. A matched case control study was condu
cted to determine whether the presence and type of nephrogenic rests (NRs)
were associated with metachronous BWT.
RESULTS. Fifty-eight of 4669 registered children developed metachronous BWT
; 38 of 2445 females (expected, 30.2) versus 20 of 2224 males (expected, 27
.8) (P = 0.04) developed BWT. The cumulative incidence of contralateral dis
ease 6 years after initial diagnosis decreased from greater than 3% in the
first NWTS to approximately 1.5% in the three subsequent studies (P = 0.08)
. Patients with NRs had a significantly increased risk of metachronous BWT.
This was particularly true for young children (20 of 206 age < 12 months c
ompared with 0 of 304 age > 12 months). Data from the matched case control
study confirmed the increased relative risk associated with young age and t
he presence of NRs.
CONCLUSIONS. Children younger than 12 months diagnosed with Wilms tumor who
also have NRs, in particular perilobar NRs, have a markedly increased risk
of developing contralateral disease and require frequent and regular surve
illance for several years. Surveillance is also recommended for those with
NRs who are diagnosed after the age of 12 months. (C) 1999 American Cancer
Society.