Journal of Clinical Oncology, Vol 15, 2631-2635, Copyright © 1997 by American Society of Clinical Oncology
Use of chest computed tomography in the staging of pediatric Wilms' tumor: interobserver variability and prognostic significance
JA Wilimas, SC Kaste, WM Kauffman, H Winer-Muram, R Morris, X Luo and JM Boyett
Department of Hematology-Oncology, St Jude Childrens Research Hospital, Memphis, TN 38105-2794, USA. judith.wilimas@st.jude.org
PURPOSE: To determine the specificity and prognostic significance of
computed tomography (CT) of the chest in pediatric Wilms' tumor. PATIENTS
AND METHODS: Patients treated for newly diagnosed Wilms' tumor at St Jude
Children's Research Hospital between December 1978 and July 1995 were
included in the study if an initial chest radiograph and CT were available
and if pulmonary involvement (determined by chest radiographs) was absent.
For the 202 patients studied, radiographs and CT scans were reviewed
blindly and independently by three experienced radiologists for the
presence of pulmonary nodules. Outcome variables consisted of intraobserver
variability (in a subsample of 40 cases) and concordance between ratings on
radiographs and CT scans (both by McNemar's test), interrater variability
(by logistic regression), and the cumulative incidence of pulmonary relapse
for patients with and without positive CT scans, by reviewer. RESULTS: As
expected, ratings of pulmonary involvement on radiographs were discordant
with CT ratings. There was marked variability among reviewers in CT ratings
(P = .0001). Of 202 CT scans, 78 were read as positive by at least one
reviewer, 41 were rated positive by only one reviewer, 18 by two reviewers,
and 19 by all three. Intrarater variability on repeat reviews was not
significant. Patients with nodules identified on CT had a significantly
higher pulmonary relapse rate when analyzed separately by reviewer.
However, for the 14 patients who had pulmonary relapse, CT scans were rated
positive by all three reviewers in only five cases and as negative by all
three in another five cases. CONCLUSION: The variability in interpretation
of chest CT scans in patients with Wilms' tumor limits the predictive
utility of these studies. Optimal, standardized techniques and central
review are essential if chest CT is to be used for staging in cooperative
studies.