Purpose: To determine the relative risk (RR) of upper-tract tumors (UTT) after bladder cancer, stratified by bladder tumor characteristics, demographic factors, and follow-up duration, in order to develop an improved risk-based surveillance strategy.
Patients and methods: The 1973 to 1996 Surveillance, Epidemiology, and End Results (SEER) database was used to determine the observed and expected number of UTT after bladder cancer. The RR with 95% confidence intervals (CI) were calculated, stratifying by race, sex, stage, grade, histology, and follow-up duration. The tumor characteristics and clinical outcome were compared in patients with UTT after bladder cancer and those with de novo UTT.
Results: A total of 94,591 patients had a first diagnosis of bladder cancer, of whom 91,245 had follow-up (median, 4.1 years), with no antecedent or synchronous UTT. UTT developed subsequently in 657 of 91,245 (0.7%), with 12.80 expected cases (RR = 51.3; 95% CI, 47.5 to 55.4). The respective RRs for UTT for white men and women were 64.2 (95% CI, 55.1 to 74.3) and 75.4 (95% CI, 57.7 to 96.9) at less than 2 years, 44.3 (95% CI, 36.7 to 53.0) and 40.5 (95% CI, 27.9 to 56.8) at 2 to 5 years, 50.8 (95% CI, 42.2 to 60.7) and 42.1 (95% CI, 28.8 to 59.4) at 5 to 10 years, and 43.2 (95% CI, 32.6 to 56.1) and 22.2 (95% CI, 10.1 to 42.2) at >or= 10 years. Similar RRs were seen among different strata of race, stage, grade, and histology. Patients with UTT after bladder cancer had lower stage and improved disease-specific survival compared with those with de novo UTT.
Conclusion: The incidence of UTT is stable on long-term follow-up, with no significant risk factors identified. These findings suggest that upper-tract surveillance remain rigorous on extended follow-up of bladder cancer patients.