USE OF CHEST COMPUTED-TOMOGRAPHY IN THE STAGING OF PEDIATRIC WILMS-TUMOR - INTEROBSERVER VARIABILITY AND PROGNOSTIC-SIGNIFICANCE

Purpose: To determine the specificity and prognostic significance of c omputed tomography (CT) of the chest in pediatric Wilms' tumor, Patien ts and Methods: Patients treated for newly diagnosed Wilms' tumor at S t Jude Children's Research Hospital between December 1978 and July 199 5 were included in the study if an initial chest radiograph and CT wer e available and if pulmonary involvement (determined by chest radiogra phs) was absent, For the 202 patients studied, radiographs and CT scan s were reviewed blindly and independently by three experienced radiolo gists for the presence of pulmonary nodules. Outcome variables consist ed of intraobserver variability (in a subsample of 40 cases) and conco rdance between ratings on radiographs and CT scans (both by McNemar's test), interrater variability (by logistic regression), and the cumula tive incidence of pulmonary relapse for patients with and without posi tive CT scans, by reviewer. Results: As expected, ratings of pulmonary involvement on radiographs were discordant with CT ratings, There wet s marked variability among reviewers in CT ratings (P=.0001). Of 202 C T scans, 78 were read as positive by at least one reviewer, 41 were ra ted positive by only one reviewer, 18 by two reviewers, and 19 by all three, Intrarater variability on repeat reviews was not significant. P atients with nodules identified on CT held a significantly higher pulm onary relapse rate when analyzed separately by reviewer. However, for the 14 patients who had pulmonary relapse, CT scans were rated positiv e by all three reviewers in only five cases and as negative by all thr ee in another five cases. Conclusion: The variability in interpretatio n of chest CT scans in patients with Wilms' tumor limits the predictiv e utility of these studies, Optimal, standardized techniques and centr al review are essential if chest CT is to be used for staging in coope rative studies. (C) 1997 by American Society of Clinical Oncology.