cancers Review Prognostic Factors for Wilms Tumor Recurrence: A Review of the Literature Alissa Groenendijk 1, *, Filippo Spreafico 2 , Ronald R. de Krijger 1,3 , Jarno Drost 1,4 , Jesper Brok 5,6 , Daniela Perotti 7 , Harm van Tinteren 1 , Rajkumar Venkatramani 8 , Jan Godzi ´ nski 9,10 , Christian Rübe 11 , James I. Geller 12 , Norbert Graf 13 , Marry M. van den Heuvel-Eibrink 1 and Annelies M. C. Mavinkurve-Groothuis 1   Citation: Groenendijk, A.; Spreafico, F.; de Krijger, R.R.; Drost, J.; Brok, J.; Perotti, D.; van Tinteren, H.; Venkatramani, R.; Godzi´ nski, J.; Rübe, C.; et al. Prognostic Factors for Wilms Tumor Recurrence: A Review of the Literature. Cancers 2021, 13, 3142. https://doi.org/10.3390/ cancers13133142 Academic Editors: Jaume Mora and Kamijo Takehiko Received: 23 April 2021 Accepted: 18 June 2021 Published: 23 June 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands; R.R.deKrijger-2@prinsesmaximacentrum.nl (R.R.d.K.); J.Drost@prinsesmaximacentrum.nl (J.D.); H.vanTinteren@prinsesmaximacentrum.nl (H.v.T.); m.m.vandenheuvel-eibrink@prinsesmaximacentrum.nl (M.M.v.d.H.-E.); A.M.C.Mavinkurve-Groothuis@prinsesmaximacentrum.nl (A.M.C.M.-G.) 2 Department of Medical Oncology and Hematology, Pediatric Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy; Filippo.Spreafico@istitutotumori.mi.it 3 Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands 4 Oncode Institute, 3584 CS Utrecht, The Netherlands 5 Department of Pediatric Oncology and Hematology, Rigshospitalet, 2100 Copenhagen, Denmark; Jesper.Sune.Brok@regionh.dk 6 Developmental Biology and Cancer Research and Teaching Department, University College London Great Ormond Street Institute of Child Health, London WC1N 1EH, UK 7 Molecular Bases of Genetic Risk and Genetic Testing Unit, Department of Research, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 Milan, Italy; Daniela.Perotti@istitutotumori.mi.it 8 Texas Children’s Hospital, Baylor College of Medicine, Houston, TX 77030, USA; Rajkumar.Venkatramani@bcm.edu 9 Department of Pediatric Surgery, Marciniak Hospital, Fieldorfa 2, 54-049 Wroclaw, Poland; jgodzin@wp.pl 10 Department of Pediatric Traumatology and Emergency Medicine, Wroclaw Medical University, Bujwida 44a, 50-345 Wroclaw, Poland 11 Department of Radiation Oncology, Saarland University Medical Center and Saarland University Faculty of Medicine, D-66421 Homburg, Germany; Christian.Ruebe@uks.eu 12 Division of Oncology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA; James.Geller@cchmc.org 13 Department of Pediatric Oncology and Hematology, Saarland University Medical Center and Saarland University Faculty of Medicine, D-66421 Homburg, Germany; Norbert.Graf@uks.eu * Correspondence: A.Groenendijk-15@prinsesmaximacentrum.nl Simple Summary: A Wilms tumor is a childhood kidney tumor. In high-income countries, 90% of patients with this tumor survive. However, the tumor recurs in 15% of patients. It is important to identify the patients at risk of recurrence in order to adjust treatment in such a way that recurrence may potentially be prevented. However, we are currently unable to determine precisely which patients are at risk of recurrence. Therefore, we present an overview of factors that influence the risk of recurrence, also known as prognostic factors. These factors range from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. In addition to these factors, biological markers, such as genetic alterations, should be studied more intensively as these markers may be able to better identify patients at risk of tumor recurrence. Abstract: In high-income countries, the overall survival of children with Wilms tumors (WT) is ~90%. However, overall, 15% of patients experience tumor recurrence. The adverse prognostic factors currently used for risk stratification (advanced stage, high risk histology, and combined loss of heterozygosity at 1p and 16q in chemotherapy-naïve WTs) are present in only one third of these cases, and the significance of these factors is prone to change with advancing knowledge and improved treatment regimens. Therefore, we present a comprehensive, updated overview of the published prognostic variables for WT recurrence, ranging from patient-, tumor- and treatment-related char- acteristics to geographic and socioeconomic factors. Improved first-line treatment regimens based Cancers 2021, 13, 3142. https://doi.org/10.3390/cancers13133142 https://www.mdpi.com/journal/cancers