Outcome of two cohorts with nephroblastoma treated with consecutive International Society of Paediatric Oncology protocols in a South African paediatric oncology unit

Background. Nephroblastoma is a common childhood solid tumour in South Africa.Objective. The aim was to determine outcomes of patients diagnosed with nephroblastoma between 1990 and 2018 and compare outcomes of two cohorts treated with consecutive International Society of Paediatric Oncology (SIOP) nephroblastoma protocols.Methods. This was a retrospective, descriptive study of two cohorts in Tygerberg Hospital. Cohort 1 (1990 - 2007) was treated with theSIOP 9 and SIOP 93-01 protocols, and Cohort 2 (2008 - 2018) with the SIOP 2001 protocol. Data included demographic data (age atdiagnosis, sex), HIV status, pre- and postoperative staging, surgical complications, histological types, lymph node sampling, overallsurvival (OS) and event-free survival (EFS) with the end point two years after diagnosis.Results. There were 60 children (M:F ratio 1:1.14) in Cohort 1 with an older mean age of 42 months (interquartile range (IQR)16.25 - 56.5 months) v. 45 children (M:F ratio 1:0.8) in Cohort 2 with a mean age of 37 months (IQR 22 - 45.5 months). Cohort 2 hadmore patients with localised disease (76%) than Cohort 1 (55%) (trend towards significance p=0.076). Both cohorts had a good OS(respectively 88% and 93%) and EFS (respectively 82% and 80%). Half of Cohort 1 (50%; n=30/60) did not have lymph nodes sampledwith four subsequent relapses, significantly associated with OS (p<0.001) and EFS (p=0.006). There was a significant associationbetween OS and EFS and underlying histology (respectively p=0.006 and p=0.015) for Cohort 1, but only for EFS and histology (p=0.02)for Cohort 2.Conclusion. There was good OS for children with nephroblastoma treated with consecutive SIOP protocols in a single institution inSouth Africa.