# Prophylactic heminephrectomy for an asymptomatic, non-functioning moiety in pediatric duplex systems: is cancer prevention justified?

## TL;DR

This paper questions whether removing non-functioning kidney parts in children with a duplicated urinary system is justified for cancer prevention, given the lack of strong evidence.

## Contribution

The paper provides a critical review of the evidence for prophylactic heminephrectomy in pediatric duplex systems for cancer prevention.

## Key findings

- Pediatric renal tumors are rare, and the link between duplicated collecting systems and malignancy is based on only six case reports.
- No cohort data show an increased cancer risk in non-functioning moieties above baseline.
- Prophylactic heminephrectomy carries clinically relevant risks without clear benefit for cancer prevention.

## Abstract

Duplication of the collecting system (DCS) is common. The management of asymptomatic, non-functioning moieties remains controversial because of a theoretical risk of malignancy, and prophylactic heminephrectomy is occasionally proposed despite the standard practice of reserving surgery for symptomatic complications.

To critically appraise whether current evidence supports prophylactic heminephrectomy solely for cancer prevention in asymptomatic pediatric duplex systems.

We conducted a focused narrative mini-review of PubMed (updated May 2025) and population-based cancer registries, concentrating on absolute malignancy risk and DCS-specific oncologic evidence.

Pediatric renal tumors are rare (Wilms tumor ≈7–10 per million children annually; pediatric renal cell carcinoma is even less frequent). The purported association between DCS and malignancy is based on six pediatric case reports (four Wilms tumors and two renal cell carcinomas). No denominator-based cohort data demonstrate an incidence above baseline. Mechanistic plausibility for carcinogenesis in a quiescent, uninfected, non-functioning moiety remains unproven. Although minimally invasive heminephrectomy is generally safe in experienced centers, complications such as bleeding, urinary leak, ureteral stump problems, and potential compromise of the preserved moiety are clinically relevant.

Current evidence does not support routine prophylactic heminephrectomy for asymptomatic, non-functioning moieties in children. A conservative strategy with structured ultrasound surveillance at 6–12-month intervals and predefined surgical triggers is prudent and consistent with the available evidence.