The increase in working years due to elimination of cancer as a cause of death

The relative significance of various forms of cancer in terms of causing death is analysed by estimation of the increase in person‐years of working age (20‐64 years) following elimination of the disease. Methods based upon the theory of competing risks are applied to the statistics on causes of death in Finland during the years 1966‐70. It is estimated that if there were no lung cancer (the commonest type of cancer in both morbidity and mortality statistics in males in Finland) the annual deaths saved would yield 5,900 working years (both sexes combined). Leukaemia and cancer of the stomach would be next in rank order, with figures of respectively 4,000 and 3,900 working years more. Female cancer with the highest incidence, that of the breast, would be characterized by 2,900 additional working years. The significance of types of cancer that affect young people is stressed in these calculations: leukaemia, brain tumours and lymphomas (both sexes combined) are 6th, 12th and 11th respectively in the statistics of cancer causes of death, but 2nd, 4th and 6th respectively in the list of additional working years to be gained by elimination of the disease. On the other hand, cancer of the prostate, 3rd in males according to the annual numbers of cancer deaths, would take the 15th position for the increase in working years in males. If no risk of cancer existed, the annual deaths saved would produce 36,000 working years, a figure exceeded only by those for cardiovascular diseases (55,000 working years) and accidents (51,000 working years). The results indicate that no practical differences exist between the results derived under the assumptions of various models for competing risks, but that the exclusion of competing risks may result in considerable degrees of bias in estimation if the population has a high general mortality.