Relapsed rhabdoid tumours and other non-nephroblastoma childhood and adolescent kidney tumours: perspectives from the HARMONICA collaboration

Paediatric kidney tumours are generally associated with a favourable survival rate. Most children are diagnosed with Wilms tumour, which has a 90% long-term survival rate with conventional front-line and salvage therapies. However, treatments and outcomes of children with relapsed non-Wilms tumours, such as malignant rhabdoid tumour of the kidney, renal-cell carcinoma (including renal medullary carcinoma), clear-cell sarcoma of the kidney, anaplastic sarcoma of the kidney and congenital mesoblastic nephroma are not well defined. Several of these non-Wilms tumours include unfavourable prognostic subtypes. Currently available data on non-Wilms tumours support advancing studies that pivot from conventional strategies towards disease-specific, biologically driven novel treatments to improve outcomes for each of these rare childhood kidney tumours.