ESPU Congress 2018 - Abstract Book

109 11–14 APRIL, 2018, HELSINKI, FINLAND 08:09–08:12 S13-4 (PP) PULMONARY METASTASES AND WILMS' TUMOR HISTOPATHOLOGY, AN ASSOCIATION? Seppo TASKINEN  1 , Minna KOSKENVUO  2 , Jouko LOHI  3 , Outi LESKINEN  4 and Mervi TASKINEN  2 1) Helsinki University Hospital, Paediatric surgery, Helsinki, FINLAND - 2) Helsinki University Hospital, Pediatric Hematology/Oncology and Stem Cell Transplantation, Helsinki, FINLAND - 3) Helsinki University Hospital, Pathology, Helsinki, FINLAND - 4) Helsinki University Hospital, Radiology, Helsinki, FINLAND PURPOSE To evaluate if Wilms’ tumor histopathology is different in patients with and without pulmonary metastases. MATERIAL AND METHODS Operative database was evaluated for Wilms’ tumors during years 1988–2015. Pathology sam- ples were re-evaluated from all 59 patients who had diagnostic cutting needle biopsy (CNB) and nephrectomy samples after neoadjuvant chemotherapy available. Tumor volumes at diagnosis and preoperatively were measured from all 52 patients, who had CT- or MRI-images available for re- evaluation. Pulmonary metastases were diagnosed by CT scan. RESULTS Fifteen out of the 59 (25 %) patients had pulmonary metastases in CT-scans. Radiological Wilms’ tumor volume and CNB blastemal cell proportion were usually higher in patients with pulmonary metastases (903 ml (IQR 807–1215) vs. non-metastatic 428 ml (IQR 299–765), p<0.001) and 75 % (IQR 50–97) vs. 50 % (IQR 20–80), p=0.025 respectively). The proportions of stromal and epithelial cells were similar between those with and without metastases (p=0.229 and 0.257 re- spectively). Nephrectomy samples belonged to low risk, intermediate risk and high risk in 5 (11 %), 33 (75 %) and 6 (14 %) patients without pulmonary metastases and in 1 (7 %), 13 (87 %) and 1 (7 %) patients with pulmonary metastases respectively. At nephrectomy samples, the proportion of necrosis was bigger in patients with than without metastases (95 % (IQR76–99) vs. 60 % (IQR 20–96), p=0.033 respectively). In 12/15 cases the pulmonary metastases disappeared during preoperative chemotherapy, with no difference in Wilms’ tumor histopathology between the cases with responding or resistant metastases. CONCLUSIONS Large-volume blastemal-rich Wilms’ tumors are most prone to present with pulmonary metastases. 80 % of pulmonary metastases disappear with preoperative chemotherapy. 08:12–08:24 Discussion