Premature mortality due to breast cancer among Canadian women: An analysis of a 30-year period from 1980 through 2010

Abstract

Background: Breast cancer is the most commonly diagnosed cancer and the second most common cause of cancer deaths for women. In the present study, we examined the trend of premature mortality due to breast cancer among Canadian women from 1980 through 2010 and proposed a new measure of lifespan shortening. Methods: Mortality data for female breast cancer was obtained from the World Health Organization mortality database. Years of life lost (YLL) was estimated using Canadian life tables. Average lifespan shortened (ALSS) that is calculated and expressed by a ratio of YLL relative to expected lifespan. Results: Over this study period, agestandardized rates of breast cancer mortality adjusted to World Standard Population decreased by 40% from 23.2 to 14.2 per 100 000 women. The adjusted YLL rates fell from 5.3 years per 1000 women to 3.3 years. On average women with breast cancer died 20.8 years prior to expected death in 1980 and 18.3 years early in 2010. A novel measure of lifespan shortening, the ALSS decreased from one-fourth of the lifespan in 1980 to one-fifth in 2010. Conclusions: Our study reports that among Canadian women with breast cancer, a smaller proportion of life was lost on average at the end of the study period. The 'life lost' measures presented in this study would be useful tools to monitor the pattern of premature mortality for chronic conditions. These measures gauge the effectiveness of the health system with respect to early detection and treatment.