Variant histology is associated with more non-urothelial tract recurrence but less intravesical recurrence for upper tract urothelial carcinoma after radical nephroureterectomy

Purpose: To investigate the prognostic impact of variant histology (VH) on oncological outcomes in patients with upper urinary tract urothelial carcinoma (UTUC) who had undergone radical nephroureterectomy (RNU).Patients and methods: A total of 1239 patients with clinically localized UTUC who underwent RNU at a single institution between January 2005 and June 2020 were included. The VH was reviewed by a uro-pathologist at our institution. The Cox regression model was used to perform multivariate analysis, including VH and other established prognostic factors for post-RNU oncological outcomes (intravesical recurrence [IVR], non-urothelial recurrence, and cancer-specific death).Results: Of the 1239 patients with UTUC, 384 patients (31%) were found to have VH. Advanced tumor stage, lymph node metastasis, high tumor grade, lymphovascular invasion, open surgery, and renal pelvis had a significantly larger proportion of UTUC with VH compared to pure UTUC (all p < 0.05). VH was an independent prognostic factor associated with less IVR identified by multivariate analysis, more non-urothelial recurrence, and more cancer-specific mortality.Conclusion: Patients with VH account for 31% with UTUC treated with RNU in this cohort. VH was an independent prognostic factor associated with more non-urothelial recurrence and cancer-specific mortality but less IVR.