Prognostic outcomes of multifocal bilateral Wilms tumor: A Chinese multicenter cohort study.

BACKGROUND

Synchronous multifocal bilateral Wilms tumor (mBWT) is rare. This study aimed to evaluate long-term outcomes in children with mBWT and to identify treatment-related risk factors for renal impairment.

METHODS

Patients with synchronous mBWT were identified from a multicenter retrospective cohort. Multifocal disease was defined radiologically as the presence of more than two discrete nodules, each measuring >1 cm in diameter, in one or both kidneys before neoadjuvant chemotherapy (NAC). Survival outcomes and long-term renal function were assessed. Renal impairment was defined as an estimated glomerular filtration rate <90 mL/min/1.73 m2.

RESULTS

Fifty-six patients with mBWT were included. Ten patients (17.8%) underwent one-step bilateral surgery and (82.2%) underwent staged procedures. Overall, nephron-sparing surgery (NSS) was performed on 100 of 112 renal units (89.2%). After a median follow-up of 6 years, the 5-year overall survival (OS) and event-free survival (EFS) rates were 86.8% and 77.1%, respectively. No significant differences in OS or EFS were observed between patients treated with bilateral NSS and those treated with NSS + total nephrectomy (TN). Renal impairment occurred in 18 patients (32.1%), with 17 developing new-onset or progressive dysfunction during follow-up. Multivariable analysis identified one-step bilateral surgery and collecting system involvement requiring reconstruction as independent risk factors for renal impairment.

CONCLUSION

In patients with synchronous mBWT, multifocality alone should not be considered an indication for TN. Staged bilateral NSS appears to be associated with less renal impairment than one-step bilateral surgery or TN + NSS.