New research published in Nature Medicine today highlights the disparities in breast cancer survival and estimates future global burden of the disease.
Dr Miranda Fidler-Benaoudia (Alberta Health Services, University of Calgary) and an international team of researchers analysed breast cancer incidence and mortality rate data from 185 countries and found that women in countries with a lower Human Development Index (HDI)* score were much more likely to be diagnosed at a later stage and die from breast cancer than those in countries with a high-HDI score.
Co-author of the study and stream lead of Breast Cancer Clinical and Population Health research at the Daffodil Centre, Professor Nehmat Houssami says that the study “highlights the growing global burden of breast cancer and that outcomes are worse in less affluent regions”.
Although we have known that disparities in breast cancer outcomes exist, it is concerning that these are expected to widen in the future – meaning we will see worse breast cancer outcomes in countries that are not adequately prepared to tackle this burden.
The study found that there were 2.3 million new cases of and 670,000 deaths from breast cancer in 2022. This translates to 1 in 20 women diagnosed and projects 1 in 70 will die from the disease globally. If the current trends continue, by 2050, there will be 3.2 million new cases and 1.1 million deaths, representing increases of 38% and 68% from 2022.
For younger women, new cases and deaths are expected to decrease by 4-10% in higher-HDI countries due to slower population growth but could more than double in low-HDI countries by 2050. For women aged 50 and older, the burden will increase at all HDI levels, with low-HDI countries seeing a 165% increase in new cases and a 161% increase in deaths, compared to 27% and 42% in very-high-HDI countries.
While higher-HDI countries have the highest incidence rates, lower-HDI countries face greater mortality due to inequities in early detection, diagnosis, and access to treatment. Delays in diagnosis and low treatment rates are due to systemic, economic, and social factors. Lack of health coverage and financial barriers prevent many women from seeking timely diagnosis and treatment, leading to advanced-stage diagnoses. Additionally, some low-HDI countries face shortages of medical personnel, radiotherapy facilities, and chemotherapy medicines, contributing to poor survival rates.
Australia has one of the highest rates of diagnoses, with about 1 in 7 women diagnosed with breast cancer in their lifetime. Professor Houssami says that the high rate of diagnoses can be related to the population structure, screening, and modifiable risk factors. “Breast cancer risk factors that women may be less aware of include alcohol consumption, low physical activity, and post-menopausal obesity — so we need to improve support for women to reduce these potentially modifiable risk factors,” says Professor Houssami.
Despite the high incidence, robust healthcare systems in countries like Australia lead to good prognosis and 5-year survival can reach greater than 90%.
The authors argue that urgent action, particularly in countries with lower-HDI scores, as well as sustained investment and improvements in early diagnosis and treatment are needed to reduce growing inequities in breast cancer survival worldwide.
* Human Development Index (HDI) is a metric used to measure a country’s overall quality of life by considering factors like life expectancy, education levels, and standard of living.
