Purpose: Previously published data on the 25-year outcome of G1Ta and G2Ta bladder tumors demonstrated that both tumors have a similarly low risk of recurrence in cases in which no tumor was detected in the first 5 years after presentation. A further 4 prospectively maintained cohorts were available for comparison between institutions or across time periods.
Materials and methods: Review of a prospectively kept, computerized record of patients with bladder cancer allowed analysis of the long-term outcome of 4 further cohorts of bladder cancer presenting in 1978 to 1986 or 1991 to 1996.
Results: A total of 325 patients with G1Ta and 190 with G2Ta bladder tumors had up to 25 years of followup. The risk of recurrence in the first 5 years was identical in all cohorts from the 1980s. However, in those patients without recurrence in the initial 5 years, the subsequent risk of recurrence (in G1 and G2Ta tumors) was 3.2% in the earlier cohorts but increased 3-fold to 10.8% in the cohorts from the early 1990s (RR 3.3, 95% CI 1.2-9.5, p=0.016).
Conclusions: A difference was observed in the pattern of late biopsy proven recurrence in the more contemporary cases. Increased use of prophylactic intravesical chemotherapy does not seem to be a strong factor. Changes in the ability to detect lesions and the readiness to biopsy suspicious lesions may be responsible for this difference.