Effect of Wilms tumor histology on response to neoadjuvant chemotherapy

Abstract

PurposeTo evaluate the association between Wilms tumor histology at diagnosis and the change in Wilms' tumor volume during preoperative chemotherapy. MethodsWe included all the 52 patients operated for Wilms tumor at 1988–2015, who had both pathology samples and either CT or MRI-images before and after preoperative chemotherapy, available for reevaluation. ResultsThe median tumor volume was 586 ml (IQR 323–903) at diagnosis. The median change in tumor volume was −68% (IQR −85 to −40, p < 0.001) and the proportion of tumor necrosis 85% (IQR 24–97), after preoperative chemotherapy. There was a correlation between blastemal cell content in prechemotherapy cutting needle biopsy (CNB) sample and the reduction in tumor volume (Rho = −0.452, p = 0.002). High stromal and epithelial cell contents in CNB samples were associated with the lesser change in tumor volume (Rho = 0.279, p =0.053 and Rho = 0.300, p = 0.038 respectively). Reduction of tumor volume and the proportion of tumor necrosis after chemotherapy were associated (Rho = −0.502, p < 0.001). The actual viable tumor volume decreased in median by 97% (IQR 65–100), and the decrease could be seen in all cellular components. In three patients, the tumor volume increased more than 10% during the preoperative chemotherapy. Two of them had anaplastic tumor in the nephrectomy specimen. ConclusionWilms tumor total and viable tumor volumes were reduced by 68% and 97% with preoperative chemotherapy, respectively. High proportion of blastemal cells in CNB was associated with greatest decrease in Wilms tumor volume. Increase in tumor volume during preoperative chemotherapy may indicate anaplastic tumor and prolonging of preoperative therapy should be avoided. Type of studyRetrospective review. Level of evidenceLevel III.