Worldwide trends in breast cancer incidence from 1993 to 2012: Age‑period‑cohort analysis and joinpoint regression

Background: Breast cancer is the most common cancer accounting for about one‑fourth of total cancer cases and 15% of all cancer deaths among women worldwide. It is important to determine its trend across the regions in the world to find the high‑focus regions. Hence, the current study was done to assess the global trends and deviations in the incidence of breast cancer. Materials and Methods: A descriptive trend analysis was done using the data on breast cancer incidence from the WHO Cancer Incidence Data of Five Continents plus database. Joinpoint regression was performed to determine the average annual percent change (AAPC), and age‑period‑cohort analysis was done to obtain age‑, period‑, and cohort‑specific deviations and rate ratio. Results: All the regions showed an increasing trend in breast cancer incidence, with an exception of America. Maximum increase was observed in Asia (AAPC = 2.6%; 95% confidence interval [CI]: 2.4%–2.9%) followed by Europe (AAPC = 0.7%; 95% CI: 0.5%–1%). There was consistent rise in the breast cancer incidence across the age groups in all the four continents with maximum burden in elderly (P < 0.001). Except in America, all other regions showed consistent rise in the incidence of breast cancer through the periods 1998–2002 to 2007–2012 (P < 0.001). There was consistent increase across the cohorts from 1923–1927 to 1978–1982 in continents such as Asia and Oceania (P < 0.001). Conclusion: To summarize, the incidence of breast cancer shows an increasing trend globally with a maximum increase in the Asian region. This makes a strong need for newer strategies irrespective of current prevention and control interventions.