Over the past decades, a focus on collaboration, rather than on differences in approach, has opened the door for SIOP-RTSG and COG-RTC to make translational steps on a global level towards better care. An article of Giulio D’Angio, one of the pioneers in Pediatric Oncology, addressed the question of pre- or postoperative therapy for Wilms’ tumor in 2008, when he wrote: “SIOP participants, their North American colleagues, and other investigators have conducted this debate in a thoroughly collegial manner. Members of any study are welcome to attend meetings of other groups, where advice and data are willingly interchanged. The children have been the beneficiaries, as they should be.” (5) . It was again Giulio D’Angio, who stated that ‘’the investigators have achieved what political and religious leaders have not accomplished so far”, (6) after the very first joint publication, in which data sets of children with renal tumors up to the age of 6 months were merged illustrating the benefits of such a collaborative endeavor. (7) These early efforts led to a global ‘’surgery first”” consensus for such young infants. A collaborative consensus guideline for the management of adult Wilms tumors was developed as well, (8) as was a meta-analysis on the potential role of high dose chemotherapy with stem cell rescue for relapse Wilms tumor. (9) Targeting the IGF pathways was summarized as a collaborate effort resulting from the SIOP/COG ENCCA conference. (10) Intergroup mentoring of young investigators in the field of molecular genetics of WT and CCSK revealed the molecular landscape of DAWT, FHWT and CCSK through the TARGET initiative. (11-14)

More recently, during the HARMONICA era, coordinated parallel manuscript/research efforts from COG/SIOP have focused on imaging surveillance, (15, 16) stage 1 DAWT (17, 18) and WAGR and WT. (19, 20) Collaborative reviews on unmet needs in WT, (21) addressing international progress in WT, (3) WT phase 1 and 2 studies, (22) congenital mesoblastic nephroma, (23) renal cell carcinoma (24) Wilms tumor broadly, (25)) and more recently a comprehensive position paper on oncofertility issues pertinent to pediatric renal cancer (26) have been finalized.

Since the onset of HARMONICA, clinical outputs from such international collaboration have produced practice changes in both cooperative groups. The COG has adopted post-chemotherapy histology in patients with bilateral Wilms tumor who undergo delayed nephrectomy, using post-chemotherapy histologic risk criteria defined by SIOP. The SIOP has adopted the COG approach to defining lung metastases and select abdominal radiotherapy dosing guidelines for CCSK. Both groups have adopted a harmonized definition to relapse Wilms risk classification, based on upfront treatment intensity and histologic risk criteria. Such advances only touch the surface of what is possible through data sharing and meaningful open communication and dialogue.