Breast Cancer in Asia
“Breasts feed us, nurture us and excite us. But the most versatile organ in the female body can also kill us”.1 “For such an enormously popular feature of the human race, it’s remarkable how little we know about their basic biology”.2 Although some of the above comments were made in relation to potential pollutants in breast milk, when you think about the same quotes from the insurance perspective, they are also relevant, as we know very little about the different patterns of breast cancer across the globe. This article will highlight the pattern of breast cancer in Asia.
Over the past few decades, Asia has seen rapid economic growth, resulting in increasing life expectancy, declining mortality from communicable diseases and westernization of lifestyle. While these developments are overall beneficial, they come with a price. Breast cancer incidence is rapidly increasing in Asian populations.
Breast cancer incidence in Asia lower than the West but rising
Currently, the incidence of breast cancer in Asian women is still lower than in their western counterparts across all age groups;3 however, the dramatic increase of incidence rates in Asian populations renders it conceivable that in the near future the majority of breast cancer patients worldwide will be of Asian ethnicity.4
It was estimated that almost 1.7 million cases of female breast cancer were diagnosed worldwide during 2012, corresponding to a rate of 43 per 100,000. Close to a quarter (24%) of all breast cancers were diagnosed within the Asia-Pacific region (approximately 404,000 cases at a rate of 30 per 100,000), with the greatest number of those occurring in China (46%), Japan (14%) and Indonesia (12%). Australia (86 per 100,000) and New Zealand (85 per 100,000) also had much higher incidence rates than any of the other major countries in the region. The highest incidence of breast cancer for East Asia occurred in Japan and South Korea (both 52 per 100,000); for Southeast Asia the highest rate was in Singapore (65 per 100,000).
The age-standardized incidence of breast cancer in Singapore, for instance, had increased from 20.2 per 100,000 per year between 1968 and 1972,5 and to 60.7 per 100,000 per year between 2006 and 2010.6 In China and India, incidence rates have increased by up to 30% over the last 10 years, whereas in Japan, Korea and Singapore the rates have doubled or even tripled in the past few decades.7
Rate of increase in breast cancer incidence higher in Asia than the West
Overall, significant increases in breast cancer incidence in recent years were observed in several Asian countries with incidence rates increasing by 3% to 4% per year in China (Shanghai), Singapore and Thailand. The largest rise was reported in Japan, where significant increases from 1980 onwards culminated in an average increase of 6% per year between 1999 and 2008.8 A different pattern was seen for both Australia and New Zealand (similar to U.S./Europe), where incidence rates increased until the mid to late-1990s, but have since stabilized.
Globally, one in three women (33%) diagnosed with breast cancer were estimated to be aged under 50 at the time of diagnosis during 2008, compared to 42% throughout the Asia-Pacific region and 47% within the sub-region of Southeast Asia. The proportion of female breast cancers that were diagnosed among women less than 50 years of age ranged from 21% in Australia to 55% in South Korea.9
Influence of changes in lifestyle
The same range of hormonal, acquired and intrinsic risk factors for breast cancer have been identified in East Asian and Western women. Although consistent breast cancer risk factors have been identified, the level of exposure to each specific factor may vary according to a woman’s ethnicity, culture and place of residence. For example, the decline in parity, the decline in breastfeeding and its duration, the fall in age at menarche, the increase in fat consumption, the westernization of lifestyle and diet in parallel with a potential decline in the consumption of traditional foods containing soybeans, and an associated increase in obesity — all can be contributing to the rise in breast cancer risk being observed in East Asian women.10
Potential of screening
Screening may improve early detection and outcomes, but it also increases incidence. In most Asian countries, there are no national population-based breast cancer screening programs. However, some countries — such as South Korea, Japan, Singapore, China and Taiwan — have initiated population-based screening programs. In Korea biennial mammographic screening starting at age 50 is being recommended. Chinese recommendations include annual mammographic screening for women aged 40-49 years and every one to two years for those aged 50-69 years.11
There are several cultural and economic obstacles involved in screening for breast cancer in parts of the Asia-Pacific region, including misunderstanding about the disease (such as the incorrect idea that surgery will cause cancer cells to spread more quickly), geographical isolation, lack of education and awareness, inadequate diagnostic equipment and treatment facilities, competing healthcare needs and a reliance on traditional remedies. The effectiveness of mammography screening among Asian women is unproven. Studies show that countries with the most dramatic recent increase in breast cancer screening rates are the ones that have also seen the highest increase in incidence, and this may not be coincidence. Taken together, these factors indicate that mammographic screening needs to be adopted prudently in Asian countries with customization for each region.
Survival rates in Asia
Survival Rates and Mortality to Incidence Ratio (MI Ratio) for countries with developed healthcare systems in Asia are comparable to the West, while emerging markets are lagging behind (see Graph 1).
International comparisons of survival have to be interpreted with some caution due to variation in factors, such as the time period being considered, population coverage, data quality and statistical methodology for cancers detected by population-based screening. It is clear that there are considerable differences between countries in the prognosis for female breast cancer. Five-year relative survival estimates for selected countries are presented.12
Much of the actual variation in breast cancer survival between countries is likely to be caused by disparities in early detection programmes and access to appropriate treatment services. In particular, the extent of breast cancer screening using mammography is instrumental in determining the proportion of early stage tumours, which in turn has an impact on survival. Educational and cultural barriers also exist for women in less developed countries, which often lead to late presentation, such as a lack of awareness of breast cancer, an incorrect belief that the disease is incurable or contagious, the stigma of having a mastectomy, and fear of rejection by their partner or community.
The good news, however, is that significant and continuing improvements have been reported in survival for female breast cancer in Asia despite some of the barriers mentioned above. Survival rates have generally increased over time for all age groups (although by varying amounts), but changes in survival show a mixed result depending on stage of disease.13
Studies from different parts of the world have indicated that the improvements in survival for breast cancer patients have been driven by a combination of earlier diagnosis (due to mammographic screening of asymptomatic women) and advances in treatment, although the extent of the contribution of each of these factors remains unclear.14
- It has been predicted that the international incidence of female breast cancer will reach approximately 3.2 million new cases per year by 2050.
- Aside from population growth, breast cancer incidence rates are expected to further increase within many less developed countries due to longer life expectancy coupled with the adoption of a more “westernized” lifestyle and increased population-based screening. As a consequence, the worldwide breast cancer burden is likely to be heavily influenced by changes to incidence in the Asia region.
- On a more positive note, the gains achieved in the treatment of breast cancer over the previous 20 to 30 years appear set to continue, led by the prospect of better tailoring of therapies to individual patients through molecular profiling and target therapies. This trend will result in improvement of breast cancer survival rates in Asia.
- Increases in screening uptake, coupled with better technology, will thereby increase the diagnosis of early breast cancer and carcinoma-in-situ and this will be reflected at underwriting and claims stage in Critical Illness and Cancer products.
All of the above trends will have a significant impact on product development, pricing, underwriting and claims, particularly around Cancer and Critical Illness products in Asia.