The incidence of breast cancer is growing in Asia and is the most common cancer among women in the region. With medical advancements, the survival rates for breast cancer have improved over time. However, unmet needs remain for breast cancer survivors and it is important that we continue to develop new innovations and enhance patients’ access to innovative cancer drugs.
by Dr Rebecca Dent
The Burden of Cancer in Asia
Breast cancer is the most common cancer among women in Asia1 and its incidence is growing. Since 2012, cases regionally increased from 1.7 million2 to 2.3 million3 in 2020 and are expected to continue growing. With medical advancements, the survival rates for this common cancer have improved significantly across the region. However, there remains a significant unmet need for breast cancer treatment in the region and it is vital that we continue to develop solutions that meet these needs.
Survival rates and mortality-to-incidence ratio for developed countries in Asia are comparable to the West. The mortality-to-incidence ratio (MIR) indicates the efficacy of cancer control programmes.4 The ratio identifies whether a country has a higher or lower mortality for a condition normalised to its incidence.5
Survival rates have generally increased over time across all age groups even though changes in survival are mixed as it depends on the stage of the disease.8 Research conducted in Singapore shows that stage I breast cancer patients have a five-year survival rate of 90 per cent9 whereas patients with locally advanced breast cancer (LABC) have a poorer prognosis of a 15 per cent reduction in five-year survival rates.10 Nevertheless, a combination of different factors including early diagnosis and advances in treatment have led to improved survival rates among breast cancer patients.8 The positive outcomes from breast cancer treatments are likely to continue as patients are presented with more options such as molecular profiling and targeted therapies.
Unmet Needs Remain for Breast Cancer Survivors
However, advances in treatment have been uneven. Breast cancer is a highly complex and heterogeneous disease11 that can manifest differently in individual patients. Over time, breast cancers adapt and evolve dynamically. Some patients face drug resistance and tumour progression.12 Once breast cancer has reached a late stage, recurrence of metastatic breast cancer remains a significant problem because of its systemic nature and inevitable resistance to therapy.13 There remains a significant unmet need for these patients whose conditions have evolved. Fortunately, the life sciences sector has made great strides in advancing life-saving therapies for patients.
Medical Breakthrough for HER2 Breast Cancer Patients
A study found that the incidence of HER2-positive breast cancer diagnosed in Asian women was higher than women from Western countries. The study also found that women in Asian countries presented with breast cancer at an earlier age.14
In Singapore, breast cancer is the leading cause of cancer death among women. Of which, patients with an advanced stage render a poorer prognosis.10 This is because screening rates remain below 40 per cent despite an established breast screening programme (BreastScreen Singapore).10 In 2019, the screening rate for breast cancer was 38.7 per cent.15 There were 11,232 diagnoses over five years (2014-2018)1 and 2,196 deaths or approximately 17 per cent of cancer deaths.2 HER2-positive breast cancer affects between 15 and 20 per cent of breast cancer patients in Singapore.16
Oncology is a dynamic field where standards of care are constantly evolving. New discoveries and technologies are driving major advances in our understanding of cancer and underpinning a new era of treatment options17 such as Enhertu (trastuzumab deruxtecan), which is targeted at adult patients with advanced breast cancer who have received two or more anti-HER2 regimens.
Existing treatment options offer limited benefits with response rates of approximately 9 to 14 per cent and progression-free survival of three to eight months in the third-line setting.18 New drugs such as Enhertu provide advanced breast cancer patients with a clear, established standard of care following progression on second-line treatment.
The Way Forward: Developing New Innovations and Enhancing Access to Innovative Cancer Drugs
Medical innovation is complex, high-risk, time-consuming, and extremely expensive but also key to alleviating diseases and saving more lives. Various stakeholders have a role to play in building an ecosystem that supports the development of new innovations while ensuring that these treatment options remain accessible to patients who need them the most.
Firstly, continued investment is needed to develop new innovations in hard-to-treat cancers. Research and development activities in the Asia Pacific region will need to identify new understandings and this needs to be supported with investments from the public and private sectors.
Secondly, regular medical education for healthcare professionals is necessary to improve the uptake of innovative drugs for patients who are still hoping for a cure.
Lastly, policies need to be in place to ensure that innovation is taken up while ensuring that measures are available to support patients who need to access these treatments. With limited resources and increasing demand for healthcare in the Asia Pacific, it is timely for governments and regulators to have an ongoing dialogue on how we can optimise the cancer research ecosystem and capitalise on our existing research to develop novel treatments and therapies to bring about step-change benefits17 for patients.
- Singapore Cancer Registry Annual Report 2018. (2018). Retrieved 23 March 2022, from https://www.nrdo.gov.sg/docs/librariesprovider3/default-document-library/scr-annual-report-2018.pdf?sfvrsn=bcf56c25_0.%20Published%202021.
- Youn, H., & Han, W. (2020). A Review of the Epidemiology of Breast Cancer in Asia: Focus on Risk Factors. Asian Pacific Journal Of Cancer Prevention, 21(4), 867-880. doi: 10.31557/apjcp.2020.21.4.867
- Number of new cases in 2020, both sexes, all ages. (2020). Retrieved 23 March 2022, from https://gco.iarc.fr/today/data/factsheets/populations/935-asia-fact-sheets.pdf
- Asadzadeh Vostakolaei, F., Karim-Kos, H., Janssen-Heijnen, M., Visser, O., Verbeek, A., & Kiemeney, L. (2010). The validity of the mortality to incidence ratio as a proxy for site-specific cancer survival. European Journal Of Public Health, 21(5), 573-577. doi: 10.1093/eurpub/ckq120
- Choi, E., Lee, S., Nhung, B., Suh, M., Park, B., Jun, J., & Choi, K. (2017). Cancer mortality-to-incidence ratio as an indicator of cancer management outcomes in Organization for Economic Cooperation and Development countries. Epidemiology And Health, 39, e2017006. doi: 10.4178/epih.e2017006
- Breast cancer in Asia. (2016). Retrieved 23 March 2022, from https://impact.economist.com/perspectives/healthcare/breast-cancer-asia/white-paper/breast-cancer-asia-challenge-and-response.
- Kim, Y., Yoo, K., & Goodman, M. (2015). Differences in Incidence, Mortality and Survival of Breast Cancer by Regions and Countries in Asia and Contributing Factors. Asian Pacific Journal Of Cancer Prevention, 16(7), 2857-2870. doi: 10.7314/apjcp.2015.16.7.2857
- Girardi, F., Fersht, N., Coleman, M., & Allemani, C. (2019). Global trends in population-based survival for 303,169 adults diagnosed with glioblastoma in 44 countries during 2000-2014 (CONCORD-3). Annals Of Oncology, 30, v150. doi: 10.1093/annonc/mdz243.020
- The importance of Breast Cancer Research. Retrieved 23 March 2022, from https://www.nccs.com.sg/giving/pages/breast-cancer-research.aspx#:~: text=According%20to%20the%20Singapore%20Cancer,year%20survival% 20rate%20of%2080%25
- Ng, D., Tudor Car, L., Ng, M., Lu, J., Leung, J., Goo, T., & Chia, C. (2021). Identifying barriers to early presentation in patients with locally advanced breast cancer (LABC) in Northern Singapore: Qualitative study. PLOS ONE, 16(5), e0252008. doi: 10.1371/journal.pone.0252008
- Lüönd, F., Tiede, S., & Christofori, G. (2021). Breast cancer as an example of tumour heterogeneity and tumour cell plasticity during malignant progression. British Journal Of Cancer, 125(2), 164-175. doi: 10.1038/s41416-021-01328-7
- Turajlic, S., Sottoriva, A., Graham, T., & Swanton, C. (2019). Resolving genetic heterogeneity in cancer. Nature Reviews Genetics, 20(7), 404-416. doi: 10.1038/s41576-019-0114-6
- Riggio, A., Varley, K., & Welm, A. (2020). The lingering mysteries of metastatic recurrence in breast cancer. British Journal Of Cancer, 124(1), 13-26. doi: 10.1038/s41416-020-01161-4
- Pathmanathan, N., Geng, J., Li, W., Nie, X., Veloso, J., & Hill, J. et al. (2016). Human epidermal growth factor receptor 2 status of breast cancer patients in Asia: Results from a large, multicountry study. Asia-Pacific Journal Of Clinical Oncology, 12(4), 369-379. doi: 10.1111/ajco.12514
- SCREENING RATE FOR BREAST CANCER. (2020). Retrieved 23 March 2022, from https://www.moh.gov.sg/news-highlights/details/screening-rate-for-breast-cancer
- Faulty KTPH test: What is the HER2 test and the breast cancer type linked to it?. (2020). Retrieved 23 March 2022, from https://www.straitstimes.com/singapore/health/faulty-ktph-test-what-is-the-her2-test-and-the-breast-cancer-type-linked-to-it
- Hoey, R., Sharpe, E., Kukula, A., & Workman, P. (2021). Enhancing access to innovative cancer drugs: Cross-sector consensus on a way forward to benefit patients. Drug Discovery Today, 27(4), 946-950. doi: 10.1016/j.drudis.2021.12.015
- Modi, S. (2021). Trastuzumab deruxtecan in previously treated HER2-positive metastatic breast cancer: Plain language summary of the DESTINY-Breast01 study. Future Oncology, 17(26), 3415-3423. doi: 10.2217/fon-2021-0427
About the Author
Rebecca Dent, MD FRCP
Head of Medical Oncology and
Senior Consultant, National Cancer Center Singapore
Associate Professor, Duke-NUS