Global Burden of Female Breast Cancer: Age-Period-Cohort Analysis of Incidence Trends From 1990 to 2019 and Forecasts for 2035

Abstract

Introduction: This study aimed to describe the latest epidemiology of female breast cancer globally, analyze the change pattern of the incidence rates and the disease's association with age, period, and birth cohort, and subsequently present a forecast of breast cancer incidence.

Methods: Data for analysis were obtained from Global Burden of Disease (GBD) Study 2019 and World Population Prospects 2019 revision by the United Nations (UN). We described the age-standardized incidence rates (ASIRs) from 1990 to 2019 and then calculated the relative risks of period and cohort using an age-period-cohort model, and predicted the trends of ASIRs to 2035.

Results: In 2019, the global incidence of breast cancer in women increased to 1,977,212 (95% uncertainty interval = 1 807 615 to 2 145 215), with an ASIR of 45.86 (41.91 to 49.76) per 100 000 person-year. Among the six selected countries facing burdensome ASIRs, only the USA showed a downward trend from 1990 to 2019, whereas the others showed an increasing or stable trend. The overall net drift was similar in Japan (1.78%), India (1.66%), and Russia (1.27%), reflecting increasing morbidity from 1990 to 2019. The increase in morbidity was particularly striking in China (2.60%) and not significant in Germany (0.42%). The ASIRs were predicted to continue to increase globally, from 45.26 in 2010 to 47.36 in 2035. In most countries and regions, the age specific incidence rate is the highest in those aged over 70 years and will increase in all age groups until 2035. In high-income regions, the age specific incidence rates are expected to decline in women aged over 50 years.

Conclusions: The global burden of female breast cancer is becoming more serious, especially in developing countries. Raising awareness of the risk factors and prevention strategies for female breast cancer is necessary to reduce future burden.

Keywords: age-period-cohort model; breast cancer; epidemiology; global burden of disease; prediction.

Figure 1

Age-standardized incidence and death rates of female breast cancer in 204 countries and territories, 2019. (A) age-standardized incidence rates; (B) age-standardized death rates.

Figure 2

Age-specific incidence rates by period and cohort-specific incidence rates by age group of female breast cancer across six most burdensome countries from 1990 to 2019. Note: The six most burdensome countries include China, Germany, India, Japan, Russian Federation, and the United States of America. (A) age-specific incidence rate, survey years were arranged into six consecutive 5-year periods from 1990-1994 (median 1992) to 2015-2019 (median 2017), longitudinal age curves were estimated by age-period-cohort model and indicated the expected age-specific rates of incidence. (B) cohort-specific incidence rate, people aged 20 to 79 were divided into twelve consecutive 5-year age groups from 20-24 (median 22) to 75-79 (median 77), thus we have 17 consecutive birth cohorts, including those born from 1908-1912 (median 1910) to 1988-1992 (median 1990).

Figure 3

Local drift and net drift values for female breast cancer compared in the six most burdensome countries from 1990 to 2019. Note: Net drift indicates the overall annual percentage change over time, and local drift indicates the annual percentage change of each age group. The horizontal and dashed lines with different colors represent the levels of net drift in different countries, and the broken and solid lines represent the levels of local drift in different countries.

Figure 4

Estimates of age, period, and cohort effects on the incidence of female breast cancer in the six burdensome countries from 1990 to 2019. (A) age effects; (B) period effects, with period 2000-2004 (median 2002) as reference period; (C) cohort effects, with cohort born in 1958-1962 (median 1960) as reference birth cohort.

Figure 5

Age-standardized incidence rates of female breast cancer in 1990 and 2010, and predicted incidence rates in 2035 worldwide, in four World Bank income regions, and in 13 countries.

Figure 6

Trends in age-specific incidence rates of female breast cancer in four World Bank income regions by age group from 1990 to 2035. Note: Observed rates are plotted with solid lines and predicted rates are plotted with dashed lines.