Estimation of changes in bladder cancer mortality and prevalence of diagnosed cases

Abstract

Introduction Progress in cancer research is usually measured by reporting decreases in cases diagnosed (disease incidence), improvements in survival time, or decreases in cancer mortality. Incidence rates are sensitive to the efficacy of preventive interventions, while survival time characterizes the effectiveness of therapeutic intervention. Both of these variables, either singly or in combination, exert an influence on mortality. As attractive as these measures are, it is recognized that they can be influenced by factors other than those related to research progress. For example , screening and earlier diagnosis may be followed by an increase in observed survival time, which is without merit if not subsequently corroborated by a decline in cancer mortality. On the other hand, a change in incidence or cancer mortality may arise from a modification of the age distribution of the susceptible population and not be attributable to a research-related change in the age-specific incidence rates or survival time. The analyses presented here focus on the U.S. white male population because of the availability of historical data and the relatively high risk of bladder cancer among this population subgroup. Projections are initially made as to what might be expected within this population if the status quo in incidence rates (age-specific) and survival time were to prevail. In this way, incidence and mortality changes due solely to changes in the age distribution of the population can be determined. Projections are then considered where age-specific incidence rates, survival of bladder cancer patients from death due to bladder cancer (reflective of cancer treatment effi-