BackgroundIntravesical recurrence (IVR) after surgery for upper tract urothelial carcinoma (UTUC) is a clinical problem. We investigated if preoperative invasive diagnostic modalities (IDM) such as antegrade/retrograde uretero-pyelography and/or selective urine cytology/barbotage, and URS with or without concomitant biopsy are associated with IVR after radical surgery for UTUC. Risk of death from urothelial cancer and all causes was investigated as secondary outcomes. MethodsWe investigated a population-based cohort of 1038 consecutive patients subjected to radical surgery for UTUC 2015-2019 in Sweden, using the Bladder Cancer Data Base Sweden (BladderBaSe 2.0), comprising all patients in the Swedish National Registry of Urinary Bladder Cancer. Risk estimates of IVR, death from urothelial cancer, and all causes was assessed using multivariable Cox regression models. ResultsThe study included 536 cases with and 502 without preoperative IDM. IDM was associated with increased risk of IVR (HR 1.24, 95% CI 1.03-1.52) and risk of urothelial cancer death (HR 1.56, CI 1.12-2.18), compared to no IDM after a median follow-up of 1.3 yrs. Stratified analysis for tumor location showed that IDM was associated with risk of IVR in ureteric cancer (HR 1.66, 95% CI 1.21-2.28) but not in renal pelvic cancer (HR 1.07, 95% CI 0.81-1.41). Limitations included the observational setting and the lack of variables such as tumour grade, multifocality and preoperative hydronephrosis. ConclusionsWorse outcomes for patients subjected to preoperative IDM highlight the need for carefully considering diagnostic decisions for UTUC patients, specifically in tumours located in the ureter.