Bladder cancer in rubber workers. Do screening and doctors' awareness distort the statistics?
The use of recognised carcinogens in the rubber industry before 1950 led to the introduction of screening progammes offering urinary cytology to workers who had been exposed. Publicity given to the introduction of these programmes and to individual claims for compensation have increased medical practitioners' awareness of a relationship between work and the industry and the subsequent development of bladder cancer. In this study 27 rubber workers and 88 controls registered in 1966 and 1967 with bladder cancer have been followed. A comparison of their death-rates and of the relative frequency of bladder cancer recorded on the death certificates should indicate whether cytological screening or doctors' awareness might explain a recent rise in the bladder-cancer death-rate in this industry. Since the proportions of rubber workers and controls who died before 1976 were similar (74% and 73% respectively) and bladder cancer was mentioned with similar frequence on their death certificates (80% and 83% respectively) neither screening nor doctor's awareness would appear to have an important influence.