Clinicopathological risk factors associated with tumor relapse of upper tract urothelial carcinoma after radical nephroureterectomy: A single institution 20-year experience.

Upper tract urothelial carcinoma (UTUC) is a relatively rare yet aggressive malignancy. While radical nephroureterectomy (RNU) remains the cornerstone treatment, UTUC has high local and metastatic relapse rates, leading to a dismal prognosis. To identify the clinicopathological factors associated with an increased risk of local and metastatic relapse in UTUC, we conducted a retrospective analysis of 133 consecutive UTUC patients who underwent RNU from 1998 to 2018. Patients lost to follow-up or with a history of bladder cancer were excluded from the study. The remaining 87 patients were categorized into two subgroups: those with tumor recurrence/relapse (40 cases) and those without recurrence/relapse (47 cases). Clinical and pathological characteristics were compared across the two groups. Multiple factors are associated with UTUC recurrence/relapse including larger tumor size, histology divergent differentiations/subtypes, high tumor grade, advanced pathologic T stage, positive margin, lymphovascular invasion (LVI), positive lymph node status, and preoperative hydronephrosis. Multivariate Cox regression analysis revealed that squamous differentiation predicted recurrence/relapse (p = 0.012), independent of tumor stage. Moreover, compared to the conventional histology type, UTUC with squamous differentiation had a significantly higher relapse rate (p = 0.0001) and poorer survival (p = 0.0039). This observation was further validated in invasive high-grade UTUC cases. Our findings suggest that many pathological factors contribute to UTUC recurrence/relapse, particularly, squamous differentiation may serve as an independent risk predictor for relapse and a potent prognosticator for adverse cancer-specific survival in UTUC patients. Recognizing and thoroughly assessing the pathological factors is essential for better oncologic management of UTUC.