Contributions of incidence and case fatality to mortality from bladder cancer in the south Thames Regions.

STUDY OBJECTIVE

The aim was to assess the individual contributions of incidence and case fatality to variations in bladder cancer mortality between districts in the South Thames Regions.

DESIGN

The standardised mortality ratios for bladder cancer were calculated for the health districts in the South Thames Regions using data from the Thames Cancer Registry. The results were compared with the standardised registration ratios, used as a measurement of incidence, and survival hazard function, used as a measurement of case fatality. As one determinant of case fatality is the severity at presentation, mortality was also compared with the standardised proportion of cases with advanced disease at diagnosis.

SETTING

The study took place in the 28 health districts in South East and South West Thames regional health authorities.

SUBJECTS

Subjects were 3271 cases of bladder cancer aged 15-74 years resident in one of the two South Thames regional health authorities at diagnosis and registered between 1982 and 1985.

MAIN RESULTS

The standardised mortality ratios for the different districts varied from 62 to 139. The standardised registration ratios, the survival hazard functions adjusted for age and stage of disease at diagnosis, and the proportion of cases with severe disease at diagnosis were all independently and significantly related to the standardised mortality ratios in each district.

CONCLUSIONS

Mortality from bladder cancer was significantly related to measurements of incidence, case fatality, and severity at presentation. These relations have implications for the health services. The incidence of disease may be modified through preventative measures, the case fatality through improved quality of care, and severity at presentation possibly through prompt management of patients with haematuria. Further studies are needed to investigate why these factors have high values in some districts.