Prognosis, prognostic factors, and risk categories for recurrent Wilms tumor

Approximately 15% of patients with FH Wilms tumor and 50% of patients with anaplastic histology Wilms tumor experience recurrence.[180] The most common site of relapse is lung, followed by abdomen/flank and liver. Recurrence in the brain (0.5%) or bone is rare in children with Wilms tumor.[299,300] Historically, the salvage rate for patients with recurrent FH Wilms tumor was 25% to 40%. As a result of modern treatment combinations, the outcome after recurrence has improved to up to 60%.[301-303]

About 95% of first Wilms tumor recurrences occur within 2 years of initial diagnosis. Relapse more than 5 years after diagnosis is considered a late recurrence and is rare. In the largest retrospective study of more than 1,300 children enrolled in various Wilms tumor trials, the median time to late recurrence after first recurrence was 13 years (range, 5–17 years).[304,305]

A number of potential prognostic features influencing postrecurrence outcomes have been analyzed, but it is difficult to determine whether these factors are independent of each other. Also, the following prognostic factors appear to be changing as therapy for primary and recurrent Wilms tumor evolves:

The NWTS-5 trial showed that time to recurrence and site of recurrence are no longer prognostically significant.[301,307] However, in a SIOP study, patients who experienced a pulmonary relapse within 12 months of diagnosis had a poorer prognosis (5-year OS rate, 47%) than did patients who experienced a pulmonary relapse 12 months or more after diagnosis (5-year OS rate, 75%).[308]

Based on these results, the following three risk categories have been identified: