Objectives: Because bladder cancer (BC) patients often have comorbidities that adversely affect their health, we wanted to determine whether grade and stage of BC at diagnosis are associated with the hazard of death from causes other than BC.
Materials and methods: Cancer records for 93,033 patients diagnosed with urothelial BC during 1988-2002 were obtained from the Surveillance Epidemiology and End Results (SEER) database. The grade-stage categories were defined as follows: (1) low grade, stage 0/I (Ta/T1, N0/Nx), (2) high grade, stage 0/I (Ta/Tis/T1, N0/Nx), (3) any grade, stage II (T2, N0/Nx), (4) any grade, stage III (T3-T4a, N0/Nx), (5) any grade, stage IV (T4b and/or N+). Patients with known distant metastases at presentation were excluded. Other covariates were age, gender, and race. The outcome measures were defined as the hazard of death from all causes, from BC, and from non-BC causes. Cox regression model was used to estimate the effect of grade-stage categories on over-all and cause-specific hazards with adjustment for covariates.
Results: The 5-year mortality proportions by grade-stage category were as follows: low grade, stage 0/I: all-causes 25%, BC 3%, non-BC 22%; high grade stage 0/I: all-causes 38%, BC 13%, non-BC 25%; stage II: all-causes 63%, BC 36%, non-BC 27%; stage III: all-causes 69%, BC 45%, non-BC 24%; stage IV: all-causes 83%, BC 68%, non-BC 15%. Using low grade, stage 0/I as a reference category, the hazard ratios for increasing grade-stage categories (high grade 0/I, II, III, IV) were as follows: all-cause mortality 1.30, 2.37, 3.07, 6.14; BC-related hazard 3.31, 10.02, 14.65, 32.04; non-BC-related hazard: 1.05, 1.37, 1.49, 1.65 (all P < 0.001).
Conclusion: Grade-stage categories were associated with the hazard of death from non-BC causes. However, their influence on BC-related hazard was much greater in magnitude. Because BC (rather than co-morbidities) is the main cause of death in patients with muscle-invasive disease, aggressive BC-directed therapies in these patients, when feasible, are justified.
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