Purpose: The gold standard treatment for upper tract urothelial carcinoma (UTUC) is radical nephroureterectomy. The combination of ureterorenoscopy and laser ablation has recently become more accepted. This study aims at investigating the risk factors of tumor recurrence associated with the thulium laser ablation of UTUC and reporting its clinical outcomes with subgroup analyses. Materials and Methods: Patients who underwent endoscopic thulium laser ablation of UTUC as the primary treatment from June 2012 to November 2018 were reviewed retrospectively. Sixty-eight patients were enrolled, of whom 34 had complete data for analysis after applying the exclusion criteria. Bivariate analysis was performed to compare patients with and without recurrence. Multivariable Cox regression models were applied. Kaplan–Meier survival estimates were presented, and three tumor characteristics were used for subgroup analyses. Results: Fifteen patients (44%) had local tumor recurrence. Four patients (12%) had cancer-specific death. In bivariate analysis, statistical significance was noted for age, tumor grade, and tumor size (P = 0.018, 0.047, and 0.014, respectively). In multivariate analysis, statistical significance was noted for age and tumor size (P = 0.017 and 0.042, respectively). In the Kaplan–Meier estimates for subgroup analysis, statistical significance was noted only in the tumor size and tumor grade group (P = 0.0275). The study limitations included the retrospective design and small sample size. Conclusion: Tumor size and tumor grade are influential recurrence factors. The tumor stage did not show statistical significance in recurrence analysis. In subgroup analyses, tumor size was more influential than tumor grade with respect to the prognosis of local recurrence.
