De novo upper tract urothelial carcinoma after renal transplantation: a single-center experience in China.

Background: Long-term prognosis and risk factors of de novo upper tract urothelial carcinoma after renal transplantation were rarely studied. Thus, the aim of this study was to investigate the clinical features, risk factors, and long-term prognosis of de novo upper tract urothelial carcinoma after renal transplantation, especially the impact of aristolochic acid on tumor, using a large sample.

Methods: 106 patients were enrolled in retrospective study. The endpoints included overall survival, cancer-specific survival, bladder or contralateral upper tract recurrence-free survival. Patients were grouped according to aristolochic acid exposure. Survival analysis was performed using Kaplan-Meier curve. Log-rank test was used to compare the difference. Multivariable cox regression was conducted to evaluate the prognostic significance.

Results: Median time from transplantation to development of upper tract urothelial carcinoma was 91.5 months. Cancer-specific survival rate at 1, 5, 10 years was 89.2%, 73.2%, 61.6%. Tumor staging (≥ T2), lymph node status (N +) were independent risk factors for cancer-specific death. Contralateral upper tract recurrence-free survival rate at 1, 3, 5 years was 80.4%, 68.5%, 50.9%. Aristolochic acid exposure was independent risk factor for contralateral upper tract recurrence. The patients exposed to aristolochic acid had more multifocal tumors and higher incidence of contralateral upper tract recurrence.

Conclusion: Both higher tumor staging and positive lymph node status were associated with a worse cancer-specific survival in patients with post-transplant de novo upper tract urothelial carcinoma, which highlighted the importance of early diagnosis. Aristolochic acid was associated with multifocality of tumors and higher incidence of contralateral upper tract recurrence. Thus, prophylactic contralateral resection was suggested for post-transplant upper tract urothelial carcinoma, especially for patients with aristolochic acid exposure.