The global and regional disease burden of breast cancer from 1980 to 2021: An analysis of GBD study 2021.
Authors: Ahmad Shahzaib , Shaukat Muhammad Talha , Rehman Wania Ur , Mohsin Aleenah , Rehman Aqeeb Ur , Graff Stephanie L. 
Published: September 2024

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Background:
Breast cancer (BC) is the most common malignancy in women and presents a huge disease burden worldwide. Early detection, via mammographic screening, improves outcomes significantly. We present estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, delineating the trajectory of BC from 1980 - 2021. This analysis considers the impact of screening practices on the incidence and mortality of patients worldwide, offering comprehensive examination of trends over the past 4 decades.
Methods:
Data were methodically retrieved from GBD study, which included age-standardized death rates and Disability-Adjusted Life Years (DALY). Dataset was stratified globally and by continent, with further regional analysis of the African continent into Northern, Southern, Eastern, Western, and Central, and by World Bank income classifications of countries. We examined global age-standardized mortality rates (ASMR), followed by an analysis of global disability-adjusted life years (DALY). Finally, we identified which countries, stratified by income levels, demonstrate the highest rates. Analytical processing was conducted using Joinpoint regression to determine average annual percentage changes (AAPC).
Results:
Globally, Age Adjusted Death Rates (ASDR) continuously declined from 1980-2021. In 1980, the ASDR was 16.33 (95% UI: 15.39-17.22) and it declined continuously to 14.54 (AAPC: -0.28; 95% CI: -0.3, -0.27) in 2021. Globally, DALYs rate was 503.8 (95% UI: 475.9-532.2) per 100,000 people in 1990 and it decreased to 455.5 (AAPC: 3.22; 95% CI: -0.33, -0.30) in 2021. In geographical analysis, America and Europe had uniformly declining ASDRs while Africa and Asia had a steady rise in ASDR. From 1980 to 2021, America had decreasing death rates with an AAPC of -0.78 (95% CI: -0.80, -0.76). Europe also had a declining trend, albeit nonsignificant, with an AAPC of -0.53 (95% CI: -0.55, -0.49). Conversely, the AAPC for Asia was 0.42 (95% CI: 0.41-0.43) showing a continuous incline in deaths related to BC from 1980 to 2021. The highest increase in ASDRs was observed in Africa with an AAPC of 0.90 (95% CI: 0.89-0.91). Upon sub-analysis of Africa, we observed Western and Southern Africa had highest ASDRs compared to other parts of Africa. According to World Bank income levels, high income countries had declining death rates while upper-middle, lower-middle, and low-income countries all had increasing deaths rates with the highest rise in lower middle income countries.
Conclusions:
Asia and Africa have limited implementation of BC screening protocols and correspondingly exhibit higher BC associated mortality. Enhanced screening programs are imperative for the timely diagnosis and management of BC, ultimately improving survival rate. The enormous discrepancy in mortality rates underscores the critical importance of accessible and comprehensive BC screening initiatives globally.