Retrospective Study of Diagnostic Accuracy of Computed Tomography-Based Staging of Wilms’ Tumor in the Era of Multidetector Computed Tomography

Abstract

Objectives To evaluate the diagnostic accuracy of multidetector computed tomography (MDCT)–based staging of Wilms’ tumor (WT) in comparison with surgical-pathological staging (reference standard) and to assess the interobserver agreement in predicting CT stage for WT. Method Retrospective audit of 50 consecutive cases of WT meeting our eligibility criteria was performed, and an electronic database of CT scan findings, intraoperative findings, and final histopathology staging were created. Two radiologists blinded to surgical and histologic findings reviewed the CT scans, using multiplanar reformations to assess various parameters pertaining to tumor extent and assign a possible stage, which was then compared with the final surgical-pathological stage. Interobserver agreement was assessed using κ-coefficient. Results CT scan correctly staged 31 (62%) of 50 WT cases (both observers’ consensus data, all stages combined). CT accuracy was 37.5% in stage I disease, 66% in stage II disease, and 75% in stage III. There was substantial interobserver agreement (in 80% of the cases) in assigning the stage. Subset analysis showed a 100% positive predictive value (PPV) in detecting renal vein thrombosis. The negative predictive value (NPV) for ureteric involvement was 91 to 93%, and that for retroperitoneal adenopathy, it was 93 to 97%. Conclusion The accuracy of CT in staging WT is dependent on the disease stage. While it overestimates the extent of the disease in early stage, it predicts the advanced stage with very good accuracy and can be used to avoid upfront surgeries in locally advanced WT.

Keywords

• ct staging of wilms’ tumor
• diagnostic accuracy of wilms’ ct
• interobserver agreement