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19–22 APRIL, 2017, BARCELONA, SPAIN
S13: ONCOLOGY
Moderators: Haluk Emir (Turkey), Marc-David Leclair (France)
ESPU Meeting on Friday 21, April 2017, 08:00–08:42
08:00–08:05
S13-1 (LO)
CELLULAR COMPOSITION OF WILMS TUMORS, BEFORE
AND AFTER PREOPERATIVE CHEMOTHERAPY
Seppo TASKINEN
1
, Jouko LOHI
2
, Minna KOSKENVUO
3
and Mervi TASKINEN
3
1) Children’s Hospital, Helsinki University Hospital, Paediatric surgery, Helsinki, FINLAND - 2) Helsinki University
Hospital, Pathology, Helsinki, FINLAND - 3) Children’s Hospital, Helsinki University Hospital, Department of Hematology,
Oncology and Stem Cell Transplantation, Helsinki, FINLAND
PURPOSE
To evaluate the change in Wilms tumor histology during preoperative chemotherapy.
MATERIAL AND METHODS
Ninety pediatric patients were operated at our institution for renal tumors in 1988-2015. We included
all 59 patients who were operated for Wilms tumor and who had undergone cutting needle biopsy
(CNB) at diagnosis before preoperative chemotherapy and whose CNB and nephrectomy samples
were available for re-evaluation. Different cellular components in these samples were re-calculated
by a pathologist.
RESULTS
Wilms tumor diagnosis was obvious in all patients in pre-chemotherapy CNB samples. However,
only focal anaplasia could be found in two of the three patients who had diffuse anaplasia in the
nephrectomy samples. In the patients without diffuse anaplasia the median content of the blas-
temal, stromal and epithelial components were 58 (IQR 23-85)%, 27 (IQR 10-55)% and 4 (IQR
0-10%) in CNB samples and 5 (IQR 0-67)%, 17 (IQR 23-97)% and 10 (IQR 0-40)% in the nephrec-
tomy specimens (p-values <0.001, 0.546 and <0.001 respectively). The median degree of tumor
necrosis was 78 (IQR 23-97) % after preoperative chemotherapy. The degree of tumor necrosis
after chemotherapy had positive correlation with the amount of blastemal component and negative
correlation with amount of epithelial component in pre-chemotherapy CNB samples (p=0.008 and
0.001 respectively).
CONCLUSIONS
It is difficult to detect diffuse anaplasia in CNB samples of the Wilms tumor. In non-anaplastic tumors
blastemal component is most sensitive to chemotherapy and is also associated with tumor necrosis
after the chemotherapy. On the other hand, epithelial component is most resistant to chemotherapy,
and its proportion usually increases during the chemotherapy.