Results of the National Wilms' Tumor Study: Treatment response in misclassified patients.

This report evaluates the outcome in patients treated in accord with protocol requirements of the National Wilms' Tumor Study who were assigned incorrectly to any of several clinical groups because of mistaken initial assessments of the extent of disease. A significant difference in response was found between patients correctly staged Group I and those of higher stages incorrectly placed in Group I. This observation emphasizes the need for careful staging, and for "upstaging" in doubtful Group I patients.