'Very-low-risk' bladder tumours - a new entity?

To evaluate the homogeneity of the 'low-risk' bladder cancer group in an attempt to optimise follow-up protocols.

Between June 1998 and December 2008, 211 patients (mean [sd] age of 66.7 [12.8] years) underwent transurethral resection of low-risk bladder cancer. Postoperative follow-up included cystoscopy at 3 and 12 months after surgery, then annually for a total of 5 years, and then annual ultrasonography indefinitely.

After a median follow-up of 10 years, 65 patients (30.7%) developed tumour recurrence and three (1.4%) stage progressions. In all, 84 patients (40%) had tumours of ≤1 cm; these patients were significantly younger than patients with 1.1-3 cm tumours (64.6 vs 68.3 years, P = 0.03). Their 5-year recurrence-free survival rate was significantly higher (92% vs 70% in patients with larger tumours, P < 0.001). The median time to recurrence was 5.7 years in patients with smaller tumours and 3.6 years in patients with larger tumours (P = 0.03). Only 43.7% of the recurrences in patients with small tumours occurred within 5 years, compared to 75.5% in patients with larger tumours.

Patients with low-risk bladder cancer make an inhomogeneous group. They can be stratified according to tumour size. Patients with tumours of ≤1 cm are younger, have lower risk of tumour recurrence, and most of their recurrences arise beyond the recommended 5-year surveillance period. It seems that these patients can be classified separately to a 'very-low-risk' group. Follow-up in these cases can be based on prolonged non-invasive evaluations.