BREAST-CANCER INCIDENCE AND PREVALENCE ESTIMATED FROM SURVIVAL AND MORTALITY

Survival probability for female breast cancer patients was used to estimate incidence rates from breast cancer mortality data in Italy. The female breast cancer survival curve from the Lombardy Cancer Registry (LCR) was used to test the method on data from four local cancer registries, covering areas in different regions of Italy. In spite of the well known geographic variability of female breast cancer incidence and mortality, the results support the idea that survival probability does not change across the country and that the survival probability from the LCR is a good estimate of that in the country as a whole. Female breast cancer incidence and prevalence rates were then estimated for Italy, making use of a mathematical model specifically developed for chronic diseases. In 1985, crude incidence and prevalence rates of female breast cancer, for ages up to 74 years, were estimated as 71 and 701 per 100,000 women, respectively. Estimated incidence rates show a complex trend with age, increasing to a temporary pronounced peak at the age of 52. A marked cohort effect was found to increase significantly the risk of the disease from the 1886 to the 1930 birth cohorts by a factor of 2.9. After the 1930 cohort, risks have continued at a constant high level.