Current role of imaging in the management of children with Wilms tumor according to the new umbrella protocol

Abstract

Wilms tumor is the most common primary renal tumor in childhood. Children with Wilms tumor typically present with an asymptomatic abdominal mass, usually detected on a routine medical checkup or discovered coincidentally by parents. The initial differential diagnosis is with extrarenal abdominal masses; once a tumor of renal origin is established, distinguishing between Wilms tumor and other primary renal neoplasms such as congenital mesoblastic nephroma, clear cell sarcoma, malignant rhabdoid tumor and renal cell carcinoma may not be easy. However, in many cases imaging findings in conjunction with the patient's clinical and epidemiological data, allow the diagnosis of Wilms tumor. Wilms tumor care offers one of the most striking examples of success of pediatric oncology. Over the last decades the European SIOP studies have been the key to developing standardized diagnostic procedures, improved risk stratification, and adjusted treatment recommendations for children with Wilms tumor and this has resulted rate of overall survival is currently greater than 90%. As in previous SIOP trials and studies, the new protocol for the diagnosis and treatment of childhood renal tumors, the UMBRELLA SIOP–RTSG 2016, mandates preoperative chemotherapy without preceding mandatory histological assessment. Therefore, imaging studies are essential to obtain a presumptive diagnosis of WT, to provide disease staging information and to measure the tumor volume after neoadjuvant chemotherapy for the purposes of postoperative treatment stratification. This review describes role of imaging in the management of children with Wilms tumor, according to the current recommendations of the UMBRELLA protocol.