Higher-income countries are seeing their rates of premenopausal breast cancer increase faster, whereas cases of postmenopausal breast cancer are increasing in number faster in lower-income studies.
Higher-income countries are seeing their rates of premenopausal breast cancer increase faster, whereas cases of postmenopausal breast cancer are increasing in number faster in lower-income, but developing, countries, according to study results published recently in The Lancet Global Health.
“To our knowledge, this is the first study to investigate the global rates and trends of pre- and postmenopausal breast cancer,” said Miranda Fidler-Benaoudia, PhD, study principal investigator and member of the O’Brien Institute of Public Health at the Cumming School of Medicine in Calgary, Alberta, Canada, in a statement announcing the study results.
Their population-based analysis study, which investigated both incidence and mortality for pre- and postmenopausal breast cancer, comprised 44 patient populations from 41 countries (22 in Europe, 5 in North America, 10 in Asia, 1 in Africa, 4 in South America, 2 in Oceania), with trends assessed at 3 levels: national, local, and ethnic. Women who were postmenopausal were 50 years and older, while those premenopausal were younger than 50 years.
“We chose the cutoff point of 50 years because, internationally, the average age of natural menopause is 45-55 years, so we selected the mean of 50 years,” the authors noted.
Results show that overall cases of postmenopausal invasive breast cancer were diagnosed 53.9% more often than premenopausal breast cancer (645,000 vs 1,400,000, respectively), with 73.5% more deaths (130,000 vs 490,000).
The authors estimated trends in pre- and postmenopausal breast cancer for 1998 through 2012 with data from the International Agency for Research on Cancer’s (IARC) Cancer in Five Continents plus database and assessed their burden in 2018 with information from the IARC’s GLOBOCAN Cancer Today database.
The authors suggest that the top reasons for the postmenopausal increase in developing countries is their adoption of a more Western lifestyle, including less physical activity, higher alcohol consumption, hormone-replacement therapy, and implementing screening for breast cancer. For the rise in premenopausal breast cancer, the authors note that reproductive decisions play a large part, chiefly having few, or no, children, and delaying childbirth to an older age, as well as earlier screening for breast cancer.
“We provide evidence of a rising burden of both premenopausal and postmenopausal breast cancer worldwide,” they concluded. “Although early diagnosis and access to treatment remain crucial in low-income and middle-income countries, primary prevention efforts seeking to decrease exposure to known breast cancer risk factors are warranted in all world regions to curb the future breast cancer burden.”
Heer E, Harper A, Escandor N, Sung H, McCormack V, Fidler-Benaoudia MM. Global burden and trends in premenopausal and postmenopausal breast cancer: a population-based study. Lancet Glob Health. 2020;8:e1027-e1037. doi:10.1016/S2214-109X(20)30215-1