Anaplastic Wilms' tumor: clinical and pathologic studies.

A review of almost 1,200 children participating in the first and second National Wilms' Tumor Study (NWTS-1 and -2) has demonstrated a number of significant differences in the clinical presentation and response to therapy of anaplastic and nonanaplastic Wilms' tumor. Compared to their counterparts, children with anaplastic Wilms' tumor were generally one to two years older at diagnosis, more were non-white, and more had lymph node metastases at diagnosis. Consistent with previous studies, children with anaplastic Wilms' tumor survived for a significantly shorter time than those with non-anaplastic Wilms' tumor. A hopeful outlook, however, was suggested by the NWTS-2 experience since the more aggressive chemotherapies used in this study appear to have substantially improved the survival of patients with diffusely anaplastic tumors. Also, the survival of NWTS-2 patients with anaplastic Wilms' tumor was determined in part by clinicopathologic stage. It may be possible therefore to refine therapy according to stage so as to provide children with localized disease a chance for cure with fewer untoward treatment-related sequelae.