Background: To evaluate the risk of developing breast cancer among Catalan women and to estimate the number of new cases of this tumor that appear annually in Catalonia (north-east of Spain).
Material and methods: The incidence rates of breast cancer were used in the period 1985-1989 proceeding from the population-based cancer registries of Tarragona and Girona. The age-specific rates (ASR) in Catalonia were estimated by an ASR average of Girona and Tarragona, that were adjusted by the standardized mortality ratio (SMR) of these health regions in relation to Catalonia. The cumulative rate and the risk of developing breast cancer were calculated, considering the probability of death by other causes. The temporal trend of breast cancer incidence was analysed by the Poisson's regression model.
Results: The cumulative risk (0-74 years) for breast cancer among Catalan women was 5.17% (1 out of 19 women). The highest risk of developing breast cancer is in the group of age between 60 and 79 years old. Tarragona and Girona had both a moderate increase that was not statistically significant. About 2,550 new cases of breast cancer have been estimated in 1994 and 2,600 in 1996.
Conclusion: The risk of developing breast cancer in Catalonia after adjusting for the probability of dying by other causes, is lower than in other countries of Northern Europe and the United States.