Detection of Preoperative Wilms Tumor Rupture with CT: A Report from the Children’s Oncology Group

Abstract

Purpose:To retrospectively determine the diagnostic performance of computed tomography (CT) in identifying the presence or absence of preoperative Wilms tumor rupture. Materials and Methods:The cohort was derived from the AREN03B2 study of the Children's Oncology Group. The study was approved by the institutional review board and was compliant with HIPAA. Written informed consent was obtained before enrollment. The diagnosis of Wilms tumor rupture was established by central review of notes from surgery and/or pathologic examination. Seventy Wilms tumor cases with rupture were matched to 70 Wilms tumor controls without rupture according to age and tumor weight (within 6 months and 50 g, respectively). CT scans were independently reviewed by two radiologists, and the following CT findings were assessed: poorly circumscribed mass, perinephric fat stranding, peritumoral fat planes obscured, retroperitoneal fluid (subcapsular vs extracapsular), ascites beyond the cul-de-sac, peritoneal implants, ipsilateral pleural effusion, and intratumoral hemorrhage. All fluids were classified as hemorrhagic or nonhemorrhagic by using a cutoff of 30 HU. The relationship between CT findings and rupture was assessed with logistic regression models. Results:The sensitivity and specificity for detecting Wilms tumor rupture were 54% (36 of 67 cases) and 88% (61 of 69 cases), respectively, for reviewer 1 and 70% (47 of 67 cases) and 88% (61 of 69 cases), respectively, for reviewer 2. Interobserver agreement was substantial (ĸ = 0.76). All imaging signs tested, except peritoneal implants, intratumoral hemorrhage, and subcapsular fluid, showed a significant association with rupture (P  .02). The attenuation of ascitic fluid did not have a significant correlation with rupture (P = .9990). Ascites beyond the cul-de-sac was the single best indicator of rupture for both reviewers, followed by perinephric fat stranding and retroperitoneal fluid for reviewers 1 and 2, respectively (P , .01). Conclusion:CT has moderate specificity but relatively low sensitivity in the detection of preoperative Wilms tumor rupture. Ascites beyond the cul-de-sac, irrespective of attenuation, is most predictive of rupture.q RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup /suppl

Spontaneous rupture of adult Wilms’ tumor: A case report and review of the literature

“…The use of CT scans significantly increased the number of patients who could be classified with tumour rupture, but macroscopic (surgical or pathologic) definition of 'rupture' currently remains the gold standard. Khanna and colleauges 13 reported CT has moderate specificity (88%, 61/69 cases), but relatively low sensitivity (54% and70%, 36 and 47 of 67 cases, respectively) in the detection of preoperative Wilms' tumour rupture. In a study, among those who had ruptures classified as retroperitoneal-only on CT, only 22 of 48 patients were staged as stage III, Consequently, 26 patients who presented radiologic signs of retroperitonealonly rupture at diagnosis were treated postoperatively for stage I disease (17 patients) or stage II disease (9 patients).…”

Feasibility of using CT volume as a predictor of specimen weight in a subgroup of patients with low risk Wilms tumors registered on COG Study AREN03B2: Implications for central venous catheter placement

“…Although a tumor may be small, the accuracy of determining lymph node status, and thus stage, based on CT scan is limited [11,12] and parental decision-making with the oncology team may opt for chemotherapy. Therefore, it is likely that the opportunity to limit CVC placement is less than our data would suggest.…”

Comparison of diagnostic performance of CT and MRI for abdominal staging of pediatric renal tumors: a report from the Children’s Oncology Group

“…If the vessel could not be delineated because of compression by a surrounding mass, venous thrombus was considered to be absent for the purpose of this study [4]. Tumor rupture was considered to be present if there was ascites beyond the culde-sac, extra-capsular retroperitoneal fluid, or fat stranding around the kidney, with ascites being most predictive of rupture [5]. Contralateral synchronous lesions were defined as non-cystic lesions of any size in the contralateral kidney [6] (Fig.…”