In 2020, 2.3 million new breast cancer cases were diagnosed worldwide, overtaking lung cancer as the most common cancer1. Breast cancer accounts for 24.5% of all female cancers. In Asia, breast cancer is the most commonly diagnosed cancer among women as well.
Current studies into the difference between Asian and Non-Hispanic White breast cancer incidence have concluded the following:
- Asian women have a lower overall incidence of the disease compared to non-Hispanic white women in the United States2.
- Breast cancers can present up to two decades earlier in Asian women. The onset for non-Hispanic patients is between 60 and 70 years, compared with between 40 to 50 years for Asian patients2.
- Asian women are less likely to receive recommended breast cancer screening, such as mammography, as shown by a study conducted in the US. Cultural beliefs, language barriers and financial circumstances may contribute to lower screening and detection rates3.
- Asian women are less likely to receive the recommended therapy. They have the highest mastectomy rates among US women, at the expense of not receiving the recommended lumpectomy and radiation therapy4. Asian patients are also less likely to receive breast reconstruction.
- Genetically, multiple Asian ethnicities have an increased risk for HER-2+ breast cancer, which is biologically aggressive and has poorer survival outcomes than other hormone-receptor-positive types of breast cancer5.
As summarised above, most of the current studies have grouped Asian women together as a single entity in breast cancer research, which can obscure differences among different ethnicities. There are very limited studies conducted into the differences between Asian ethnicities when it comes to breast cancer6.
For example, Asian women have dense breasts, a breast cancer risk factor. Having dense breasts is associated with greater incidence, a feature independent of reduced cancer detection on dense mammograms. However, paradoxically, Asian women have lower disease incidence. This seeming paradox highlights that other factors, such as ethnic heterogeneities are not fully adjusted and understood for analysis of breast cancer risk7.
Disaggregated research is necessary to identify and address disparities in the disease incidence, screening, treatment, and outcomes among Asian women. This type of future study could include examining the role of genetic, lifestyle, and environmental factors that may contribute to differences in breast cancer incidence among different Asian ethnic groups6. They could also explore how cultural beliefs and language barriers affect breast cancer screening and treatment.
On the other hand, from a geographical and regional point of view, despite the establishment of screening guidelines globally, Asia has been slow to adopt breast cancer screening8. High-income Asian countries are not benefiting fully from their national screening programs due to an underutilization of the preventive services available, while low- and middle-income countries could not implement similar programmes. Further studies are required to identify the possibility of incorporating stratified screening, with the use of both genetic and non-genetic risk factors9.
In conclusion, it is crucial to conduct disaggregated research to understand and address breast cancer disparities in Asian women. This research can help to improve screening and treatment outcomes for all Asian ethnicities and Asian countries, and ultimately reduce the burden of breast cancer in this population.
Reference:
- Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA: A Cancer Journal for Clinicians [Internet]. 2021 Feb 4;71(3):209–49. Available from: https://acsjournals.onlinelibrary.wiley.com/doi/10.3322/caac.21660
- Leong SPL, Shen Z-Z, Liu T-J, Agarwal G, Tajima T, Paik N-S, et al. Is Breast Cancer the Same Disease in Asian and Western Countries? World Journal of Surgery [Internet]. 2010;34(10):2308–24. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936680/
- Ponce NA, Babey SH, Etzioni D, Spencer BA, Brown ERR, Chawla N. Cancer Screening in California: Findings from the 2001 California Health Interview Survey. escholarshiporg [Internet]. 2003 Dec 1 [cited 2023 Mar 3]; Available from: https://escholarship.org/uc/item/7143p53x
- Prehn AW, Topol B, Stewart S, Glaser SL, O’Connor L, West DW. Differences in treatment patterns for localized breast carcinoma among Asian/Pacific islander women. Cancer. 2002 Nov 15;95(11):2268–75.
- Keating NL, Kouri EM, He Y, Freedman RA, Volya R, Zaslavsky AM. Location Isn’t Everything: Proximity, Hospital Characteristics, Choice of Hospital, and Disparities for Breast Cancer Surgery Patients. Health Services Research [Internet]. 2016 Aug 1 [cited 2021 Dec 10];51(4):1561–83. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4946041/?tool=pmcentrez&report=abstract
- Fane L, Biswas T, Jindal C, Choi YM, Efird JT. Breast Cancer Disparities in Asian Women: The Need for Disaggregated Research. International Journal of Environmental Research and Public Health [Internet]. 2022 Jan 1 [cited 2022 Oct 22];19(16):9790. Available from: https://www.mdpi.com/1660-4601/19/16/9790/htm
- Perry CS, Otero JC, Palmer JL, Gross AS. Risk factors for breast cancer in East Asian women relative to women in the West. Asia-Pacific Journal of Clinical Oncology. 2009 Dec;5(4):219–31.
- Lim YX, Lim ZL, Ho PJ, Li J. Breast Cancer in Asia: Incidence, Mortality, Early Detection, Mammography Programs, and Risk-Based Screening Initiatives. Cancers. 2022 Aug 30;14(17):4218.
- Chong HY, Allotey PA, Chaiyakunapruk N. Current landscape of personalized medicine adoption and implementation in Southeast Asia. BMC Medical Genomics. 2018 Oct 26;11(1).
