Effect of Wilms tumor histology on response to neoadjuvant chemotherapy

Purpose: To evaluate the association between Wilms tumor histology at diagnosis and the change in Wilms' tumor volume during preoperative chemotherapy. Methods: We 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. Results: The 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