Background: The AHOPCA (Asociación de Hemato-Oncología Pediátrica de Centro América) Wilms tumor (WT) treatment guidelines, adapted from NWTS-4 and -5 and recommending upfront nephrectomy (UN), were modified to include 4 to 6 weeks of preoperative chemotherapy (POC) in frail patients with advanced disease. We aim to describe the outcomes of this implemented approach. Procedure: A retrospective analysis of prospectively collected data from newly diagnosed patients with unilateral WT between 2012 and 2018. Results: Of 353 eligible patients, 247 (70%) received POC. POC group had higher initial tumor volume (median 590 ml vs. 308 ml, p<0.0001) and more stage IV disease (30% vs. 3%, p<0.0001) compared to UN group. During POC, there were 4 deaths, 14 abandonments and 11 progressive diseases. After response assessment, 62% showed partial tumor response with median tumor volume reduction to 257 ml. Two-hundred eighteen (88.2%) underwent nephrectomy. Tumor rupture/spillage occurred in 17.9% of UN and 18.8% of POC group; Local stage III was found in 55% of UN and 68.3% of POC group. Anaplasia (focal and diffuse) was present in 13.6% (17% UN and 11.9% POC). The 5-year abandonment-sensitive event-free survival (asEFS) and abandonment-sensitive overall survival (asOS) rates were 69%±2.5% and 75%±2.4%, respectively. The asEFS rates were 75%±4.3% for UN and 66%±3.0% for POC (p=0.07). Conclusions: Many AHOPCA patients presented with unresectable advanced disease, necessitating the use of POC. POC effectively reduced tumor volume and facilitated safe surgery in fragile patients. Adopting the standard SIOP WT neoadjuvant approach could enhance staging and risk stratification in AHOPCA.

Since 2000, centers across Central America have shared treatment guidelines for Wilms tumor, using histology (anaplasia present or absent) and tumor stage to stratify patients into low, intermediate, and high-risk groups. Weekly virtual tumor board meetings involving local and international experts were held to ensure consistent treatment assignments. We analyzed data from 367 children with unilateral tumor treated per these guidelines. Five-year abandonment-sensitive event-free and overall survival estimates were: low-risk 82% ±3.8% and 86% ±3.6%, intermediate-risk 50% ±3.4% and 60% ±3.4%, and high-risk 36% ±7.6% and 45% ±7.9%. Survival outcomes were suboptimal, primarily due to advanced disease in fragile children at presentation and abandonment of treatment.

Survival of Wilms tumor (WT) is >90% in high-resource settings but <30% in low-resource settings. Adapting a standardized surgical approach to WT is challenging in low-resource settings, but a local control strategy is crucial to improving outcomes. Objective: Provide resource-sensitive recommendations for the surgical management of WT. Methods: We performed a systematic review of PubMed and EMBASE through July 7, 2020, and used the GRADE approach to assess evidence and recommendations. Recommendations: Initiation of treatment should be expedited, and surgery should be done in a high-volume setting. Cross-sectional imaging should be done to optimize preoperative planning. For patients with typical clinical features of WT, biopsy should not be done before chemotherapy, and neoadjuvant chemotherapy should precede surgical resection. Also, resection should include a large transperitoneal laparotomy, adequate lymph node sampling, and documentation of staging findings. For WT with tumor thrombus in the inferior vena cava, neoadjuvant chemotherapy should be given before en bloc resection of the tumor and thrombus and evaluation for viable tumor thrombus. For those with bilateral WT, neoadjuvant chemotherapy should be given for 6–12 weeks. Neither routine use of complex hilar control techniques during nephron-sparing surgery, nor nephron-sparing resection for unilateral WT with a normal contralateral kidney is recommended. When indicated, postoperative radiotherapy should be administered within 14 days of surgery. Post-chemotherapy pulmonary oligometastasis should be resected when feasible, if local protocols allow omission of whole-lung irradiation in patients with non-anaplastic histology stage IV WT with pulmonary metastasis without evidence of extrapulmonary metastasis. Conclusion: We provide evidence-based recommendations for the surgical management of WT, considering the benefits/risks associated with limited-resource settings.