Association of Tumour Location and Recurrence in Patients with Non-Muscle Invasive Bladder Cancer

Introduction: Accurate prediction of recurrence is important for patients with non-muscle invasive bladder cancer (NMIBC). Objective: To study the association of tumour location with recurrence-free survival (RFS) of patients with primary solitary tumours. Methods: Patients (N=184) with primary, solitary NMIBC (2000–2018). In cases of overlapping areas, the most involved area was selected. Subsequently, the areas were dichotomised into dorsal versus non-dorsal tumours. The dorsal area was defined as the diamond-shaped area bordered by bladder neck, trigone, posterior wall, and orifices. The non-dorsal areas are the lateral walls, dome, and anterior wall. The association of location with RFS was assessed using Cox regression. Median RFS was estimated using the Kaplan–Meier method. Results: Altogether, 25 (14%) and 69 (38%) patients had a recurrence at 1 year and 5 years, respectively. Median RFS was 103 months. Primary tumours located at the anterior wall were associated with the lowest RFS (median: 74 months) and at the posterior wall with highest RFS (median: 133 months). After dichotomisation, 54% of the patients had a tumour in the dorsal area with a median 1-year recurrence rate of 9% versus 19% in the non-dorsal area. Median RFS in the dorsal area was 133 months versus 48 months in the non-dorsal area (p=0.02). Cox analysis showed worse 1- and 5-year RFS on adjusted analysis (hazard ratio [HR]: 2.41; 95% confidence interval [CI]: 1.07–5.46; p=0.04; and HR: 1.77; 95% CI: 1.10–2.85; p=0.02, respectively) for tumours in the non-dorsal area. Conclusion: The tumours in the dorsal area appear to have a lower recurrence rate. There was no association with specific tumour location and RFS.