Incidence and outcomes of patients with late recurrence of Wilms' tumor.

BACKGROUND

Most relapses from Wilms' tumor occur within 2 years from diagnosis. This study aims to describe the incidence and outcome of patients who experienced a late recurrence (LR) more than 5 years after diagnosis across several clinical trials, and to develop evidence-based recommendations for follow-up surveillance.

METHODS

Available records on children with Wilms' tumor enrolled onto 10 national or international cooperative clinical trials were reviewed to identify patients who experienced a LR.

RESULTS

Seventy of 13,330 (0.5%) patients with Wilms' tumor experienced a LR. No gender bias was observed. Median time elapsing between initial Wilms' tumor diagnosis and first recurrence was 13.2 years (range: 5.1-17.3 years). Initial tumor stage was: stage I (15); stage II (19); stage III (14); stage IV (8); bilateral disease stage V (14). The most frequent sites of relapse were--abdomen: 21, lungs: 20, and contralateral kidney: 15. Thirty-five children died of disease progression. Recurrence in the contralateral kidney was associated with a better outcome (13/15 patients alive), while initial tumor stage did not seem to influence the post-recurrence outcome. Therapies administered at recurrence varied between centers, preventing any conclusion about the best salvage treatment.

CONCLUSIONS

LR of Wilms' tumor is rare and associated with similar outcome to those experiencing earlier recurrence. The low rate of LR does not justify prolonged monitoring. Further study of the biology of these tumors may give us some insights in regards to mechanisms on tumor cell dormancy or cancer stem cell maintenance.