Clinical features, treatment, and outcomes of bilateral Wilms' tumor: A systematic review and meta-analysis.

Background: Wilms' tumor(WT) is the most common malignant renal tumor of childhood. Despite the good prognosis of WT, bilateral Wilms' tumor (BWT) still has a poor outcome. We systematically reviewed the literature on BWT, aiming to define its clinical features, treatment, and outcomes.
Methods: PubMed, OVID EMbase, Web of Science, and Cochrane Library were systematically searched for studies published from 1980 to 2017. Case series and comparative studies reported clinical data of BWT patients were included.
Results: A total of 32 studies comprising 1457 patients were retained for primary outcome. Hemihypertrophy, cryptorchidism, and Beckwith-Wiedemann syndrome(BWS) are the most common congenital anomalies and syndrome. 86% of patients had favorable histology (FH). Patients with local stage I or II accounted for 64%, and 12.6% had metastasis at diagnosis. Bilateral nephron-sparing surgery (NSS) was achieved in 33.8%. Recurrence and renal failure occurred in 20% and 8%. The overall survival (OS) was 73%. In comparative studies, OS of patients undergoing bilateral NSS was similar to that of other operation types.
Conclusion: Prognosis of BWT has been improved but is significantly poorer than WT. Bilateral NSS was recommended by most centers to preserve more renal volume. However, finding a balance between retaining renal function and avoiding recurrence remains a question.
Type of Study: Systematic review.
Level of Evidence: Level IV.
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