Competing mortality risks among women aged 50-79 years when diagnosed with invasive breast cancer, Queensland, 1997-2012

Background: Understanding the burden of competing (non-breast cancer) mortality is important for the growing number of breast cancer survivors. We quantity these patterns, and the impact of two leading non-cancer causes of death, within ten years of breast cancer diagnosis. Methods: Population based cancer registry study of 23,809 women aged 50-79 diagnosed with first primary breast cancer in Queensland, Australia, 1997 to 2012 with additional data linkage to identify individual non-cancer mortality causes. Flexible parametric competing-risks models were used to estimate the crude and adjusted probabilities of death. Results: While overall mortality increased with age at diagnosis, this effect was strongest for non-cancer (such as cardiovascular and cerebrovascular disease) mortality. Women diagnosed with advanced breast cancer had a higher crude probability of breast cancer death (23.1% versus 4.5% for localised) but similar probability of competing mortality (11.6% versus 11.3%). Within each category of spread of disease, the probability of breast-cancer deaths remained relatively constant with age, while the probability of competing deaths increased. The 10-year probability of dying from breast cancer was 3.7%, 4.2% and 5.6% among women with localised disease aged 50 to 59, 60-69 and 70-79 respectively, but 3.1%, 7.8% and 22.9% for competing mortality. Increasing age, advanced disease and being unpartnered were independently associated with increased risk of breast cancer and competing deaths. Conclusions: Promotion of improved health behaviors after a cancer diagnosis and development of individualized strategies for clinical management should be prioritized as part of optimal care for breast cancer survivors. (C) 2018 Elsevier Ltd. All rights reserved.