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Introduction
Cancer burden is expected to show a rapid growth with the aging population and increasing cancer incidence [1-6]. The share of elders (or those aged 65 years or older) in the United States increased from 10.0% in 1972 to 12.7% in 2008, whereas the share for South Korea (Korea hereafter) registered a similar but steeper trend, i.e., 7.3% in 2000 to 11.1% in 2010 [1]. America’s age-standardized incidence rate per 100,000 for all cancers rose from 400 in 1975 to 472 in 2004 [2], while the statistic for Korea went up from 205 in 2000 to 286 in 2010 [3]. As a result, the share of direct cost for cancer care in the United States economy doubled from 0.32% in 1972 to 0.66% in 2008 [1,4,5]. Likewise, the population-health burden of cancer in Korea (disability-adjusted life years per 100,000) showed a rapid growth from 1,109 person-years in 2000 to 1,681 person-years in 2010 [6]. As cancer burden increases rapidly, a burden-of-cancer study designed to improve the quality of patient life and to set up national priorities for resource allocation in health services becomes more essential.
Based on previous studies, a large part of cancer burden in an advanced nation comes from breast, colon, lung, and prostate cancers [7-9]. In terms of direct cost (national dollars, million), these cancers ranked in the top four in the United States for 1996 (5,980, 5,710, 4,680, and 4,610) [7], Canada for 1998 (120, 216, 228, and 103) [8] and New South Wales in Australia for 2004 (77, 132, 77, and 121) [9]. Other research has shown that as medical technology advanced and cancer survival increased, the share of income loss from premature death in cancer burden gradually fell in the developed world [4-5,7,10-13]. The share in the United States, which was 73% in 1972 [4], decreased to 61% in 1990 [7], dipping further to 51% in 2008 [5]. Likewise, the number in Sweden went down from 45% in 2000 to 39% in 2004 [10]. However, based on recent reviews, most existing literature on national economic burden has been limited to direct medical cost and comprehensive examination on national economic burden by cancer site, gender, age group, and cost component over a long time span has been limited [10,11].
Some researchers have estimated economic burden for major cancers in Korea for 2002 and 2005 [12,13]. According to their findings, liver, stomach, and lung cancers led the nation’s cancer burden, with the costs of 1,749, 1,784, and 1,289 million US$ in 2002 and 2,387, 2,321, and 1,614 million US$ in 2005, respectively (or the shares of 18.6%, 18.9%, and 13.7% in all cancers for 2002 and 17.4%, 16.9%, and 11.7% for 2005, respectively) [12,13]. However, cancers that are prevalent in other developed nations, including breast, colon, and prostate cancers, are becoming more common in Korea, a nation characterized by rapid westernization in health behavior in the past two decades [3]. In addition, Korea is becoming an aging society populated by one of the greatest proportions of elderly by 2020 [14]. With such significant transitions, updating the estimation of economic burden for major cancers in Korea during the period 2000-2010 will not only provide invaluable opportunities for designing the nation’s healthcare policies for the future, but will also be helpful in establishing the direction of future study for other nations with similar transformations. In this vein, this research involves a comprehensive examination of cancer burden in Korea during 2000-2010, i.e., by cancer site, gender, age group, and cost component.
Materials and Methods
This study uses the cost of illness (COI) method [7-9,12,13] to estimate the economic burden of cancer in Korea during 2000-2010 by cancer site, gender, and age group. Based on the COI classification, the economic burden of disease consists of three components, i.e., direct, morbidity, and mortality cost. Direct cost is “expenditure for medical services associated with the treatment and care of the disease entity” whereas (indirect) morbidity/mortality cost is “productivity loss due to disability/premature death associated with the disease entity” [7].
Table 1 shows components, formulas, and data sources for the economic burden of cancer in Korea during 2000-2010. Direct cost includes medical cost covered by health insurance, medical cost uncovered, transportation cost, caregiver cost and cost for alternative medicine. Data on medical cost (covered for hospitalization, outpatient visit, and drug prescription) came from national health insurance claims data [15] (the most representative health data in Korea given that the Korean government launched a compulsory national health insurance program for the entire population in Y1989 [12]). Medical cost uncovered was derived from national surveys on out-of-pocket expenditure of patients enrolled in health insurance [16]. For calculation of transportation cost, the number of outpatient visit days [15] was multiplied by transportation cost per outpatient visit day (4.9 US$ [or $4.9 hereafter] in 2002 [12] before being adjusted for inflation [17]). This value was multiplied by 2 (with an assumption that a family member would be present for each outpatient visit [12]). For the estimation of caregiver cost, its “inpatient” and “outpatient” parts were calculated and then combined. Regarding the former part, the number of inpatient days [15] was multiplied by caregiver cost per inpatient day ($50 in 2002 [12] before being adjusted for inflation [17]). Regarding the latter part, the number of outpatient visit days [15] was multiplied by 4 (the number of hours per outpatient visit) [12] and caregiver cost per outpatient visit hour ($9.3 in 2002 [12] before being adjusted for inflation [17]). For calculation of cost for alternative medicine, the number of patients [15] was multiplied by cost for alternative medicine per patient ($1,150 in 2002 [12] before being adjusted for inflation [17]) (Table 1).
Morbidity and mortality costs were derived based on a human capital approach, which assumes that the monetary value of productivity loss equals the current wage [7-9,12,13,18]. It was assumed that those younger than 15 or older than 69 did not work [12,13]. For calculation of morbidity cost, productivity loss due to cancer-specific disability “inside” and “outside” the labor market were estimated and then combined. Regarding the former loss, the yearly wage (or productivity loss) [17] was multiplied by the number of patients [15], the participation rate for economic activity [17], the employment rate [17], and the rate of job loss for the cancer patient (0.51) [13] (the participation rate for economic activity and the employment rate vary by gender, age group, and year). Regarding the latter loss, women’s yearly wage (or productivity loss) [17] was multiplied by the number of female patients [15], women’s non-participation rate for economic activity [17], women’s participation rate for housework (0.67) [13], and the rate of housework loss for the female cancer patient (86.5 days/365.0 days) [13] (The women’s non-participation rate for economic activity varies by age group and year). Likewise, for calculation of mortality cost, productivity loss due to cancer-specific premature death “inside” and “ outside” the labor market were estimated and then combined. Regarding the former loss, the number of mortalities [17] was multiplied by the expected value of the future income during potential years of life lost [17] with a discount rate (0.03) [13]. Regarding the latter loss, the number of women’s mortalities [17] was multiplied by the expected value of women’s opportunity cost (for housework) during potential years of life lost [13,17] with a discount rate (0.03) [13]. For calculation of the expected value of the future income or women’s opportunity cost for housework during potential years of life lost from a base year (e.g., 2010), it was assumed that (1) the participation rate for economic activity and the employment rate (varying by gender and age group in a given year) stay the same in the future as in the base year and (2) the women’s non-participation rate for economic activity (varying by age group in a given year) remains the same in the future as in the base year.
Results
Tables 2 and 3 shows the number of patients (or mortalities) in Korea by cancer site and gender in 2000 and 2010, listed based on the rank in 2010. The total number of cancer patients increased by 66.67%, from 544,402 to 907,347 during 2000-2010. The increase in cancer prevalence during the period was more pronounced for women than for men, with the growth rate of 79.1% versus 54.5% (from 270,208 to 483,813 vs. from 274,194 to 423,534). Thyroid, breast, and prostate cancers led this rapid growth of prevalence during the period. For example, the rank/number of prevalence increased from the 5th/45,619 to the 1st/196,490 for thyroid cancer, from the 6th/42,605 to the 4th/97,507 for breast cancer, and from the 14th/9,881 to the 7th/36,105 for prostate cancer. It is also noteworthy that kidney and bladder cancers entered the top ten during the period, i.e., the 15th/9,855 and the 12th/11,674 in 2000 to the 8th/28,582 and the 10th/21,086 in 2010, respectively. On the contrary, the ranks/numbers of prevalence for liver cancer, non-Hodgkin lymphoma, and ovary cancer declined during the period, i.e., the 3rd/57,161, the 8th/17,261, and the 9th/16,403 in 2000 to the 6th/53,808, the 11th/16,571, and the 12th/14,542 in 2010, respectively. Table 4 and Fig. 1 describe economic burden in Korea by cancer site and gender during 2000-2010 (with the shares of mortality cost in parentheses for the table). In terms of the total burden for the total population (million $), liver, stomach, and lung cancers ranked 1st (3,114), 2nd (3,046), and 4th (1,988) in 2010 after holding the same positions in 2000 (2,065, 2,036, and 1,202). Colorectal cancer, a top five (837) in 2000, replaced leukemia as a top three in 2010 (2,210). Thyroid cancer, out of the top ten in 2000 (11th, 257), made the top five in 2010 (1,724). Likewise, breast cancer, a top seven (529) in 2000, became a top six (1,659) in 2010. A similar trend was observed for men. In terms of the total burden, liver, stomach, and lung cancers constituted the top three both in 2000 (1,744, 1,332, and 881) and in 2010 (2,638, 2,090, and 1,476). Colorectal cancer and leukemia, which ranked 5th (525) and 4th (790) in 2000, switched their positions in 2010 (4th, 1,420 vs. 5th, 965). Thyroid cancer, out of the top ten in 2000 (13th, 110), joined the top six in 2010 (707) (Tables 2-4) (Fig. 1).
Some gender differences can be seen in Table 4, as breast and thyroid cancers made the top two instead of liver and stomach cancers for women’s total burden in 2010 (1,648, 1,017 vs. 477, 956). Economic burden in Korea by cancer site and age group in 2000 and 2010 is described in Table 5. For the age group 0-14 years old, leukemia, brain cancer, and non-Hodgkin lymphoma led the total burden during 2000-2010. For those aged 15 years or older, liver, stomach, colorectal, and lung cancers constituted the top four in both 2000 and in 2010. However, the former two were more dominant for the age group 15-69 years old, while the latter two were more significant for those aged 70 years or older. Indeed, the rise of colorectal cancer was more evident for the older age group and the opposite was true for thyroid cancer. Finally, Table 6 and Fig. 2 show the economic burden of cancer in Korea by cost component during 2000-2010. With an average annual growth rate of 8.9%, the total burden (million $) increased from 11,424 to 20,858 during the period. The share of mortality cost in the total burden dropped from 70.7% to 51.7% during 2000-2010, as the figures for most cancers fell by more than 10.0% during the period (Table 4, Fig. 1). On the contrary, the shares of direct and morbidity cost in the total burden rose during 2000-2010, from 5.6% to 14.7% for medical cost (covered), from 2.9% to 3.8% for medical cost (uncovered), from 0.2% to 0.4% for transportation cost, from 2.5% to 4.4% for caregiver cost, from 5.4% to 6.7% for the cost of alternative medicine, and from 12.8% to 18.3% for morbidity cost. Colorectal, thyroid, breast, and prostate cancers led this rapid growth of direct and morbidity cost during the period (Table 4, Fig. 1). For example, the rank/amount of direct cost (million $) increased from the 4th/211 to the 1st/855 for colorectal cancer, from the 6th/120 to the 3rd/703 for thyroid cancer, from the 5th/131 to the 4th/673 for breast cancer, and from the 18th/26 to the 8th/194 for prostate cancer (data not reported in the tables) (Tables 5 and 6, Fig. 2).
Discussion
1. Main findings of this study
Colorectal, thyroid, and breast cancers became more significant in terms of economic burden for Korea during 2000-2010. The rise of colorectal cancer was more evident for the older age group and the opposite was true for thyroid cancer. In addition, liver and stomach cancers were prominent in the nation during the period. Finally, the share of mortality cost in the total burden dropped from 71% to 51% in Korea during 2000-2010, and the relative growths of direct and morbidity cost were led by colorectal, thyroid, breast, and prostate cancers during the period. These results show that the economic burden of cancer in Korea is characterized by an increasing importance of chronic components.
2. What is already known on this topic
The economic burden of cancer in an advanced nation centers on breast, colon, lung, and prostate cancers. Indeed, as medical technology advances and cancer survival increases, the share of mortality cost in cancer burden registers a graduate fall in the developed world.
3. What this study adds
This research presents a very rare analysis of economic burden by cancer site, gender, age group, and cost component in Korea during 2000-2010. Most existing literature on national economic burden has been limited to direct medical cost, and comprehensive examination of the national economic burden by cancer site, gender, age group, and cost component over a long time span has been limited.
This research shows that Korea is converging with other advanced nations in the economic burden of cancer. In terms of direct cost, breast, colon, lung and prostate cancers, which ranked in the top four in the United States for 1996, Canada for 1998 and New South Wales in Australia for 2004, constituted the top eight in Korea for 2010, i.e., colorectal cancer (first position, 855 million US$), breast cancer (fourth, 673 million US$), lung cancer (fifth, 651 million US$) and prostate cancer (eighth, 194 million US$). In addition, the share of mortality cost in the total burden, which dropped from 73% to 51% in the United States during 1972-2008, registered a similar trend in Korea, i.e., a fall from 71% to 51%, albeit during a much shorter period, 2000-2010. Korea’s convergence with other advanced nations in cancer burden might reflect their convergence in living standards, the age structure, health behavior and medical technology during the past four decades. The rise of Korea’s Gross Domestic Product per capita relative to the Organisation for Economic Cooperation and Development average (e.g., from 0.26 to 0.77 during 1980-2012 in terms of Purchasing Power Parity current international dollars [1]) has been accompanied by the growing proportion of the elderly population and the rise of meat consumption. Korea’s share of the population aged 60 years or older, which was 15% in 2009, is likely to reach 21% in 2018, the figure for the developed regions in 2009 [14,17]. The average share of energy intake from meat consumption increased from 5.1% to 14.2% in the nation during 1970-1993 [19]. This “modified (or westernized)” dietary pattern became more robust among younger and metropolitan residents with more education and higher income in the nation during 1998-2005 [20]. Korea’s convergence with other developed nations has been apparent in medical technology as well, particularly in selective, customized cancer treatment [21]. With the establishment of the National Cancer Center in 2000 and the legislation of the Cancer Control Act in 2003, the Second 10-Year Plan for Cancer Control in Korea during 2006-2015 has contributed to the rise of 5-year relative cancer survival from 53.7% during 2001-2005 to 64.1% during 2006-2010 [22]. These economic, demographic, behavioral, technological, and sociopolitical changes might have aided in the shift of cancer from acute to chronic in Korea.
Unlike Australia, Canada, and the United States, however, Korea has been characterized by the continued importance of stomach and liver cancers during 2000-2010 according to the results of this work. In terms of the total burden, these two cancers ranked first and second in 2000 (2,065, 2,036 million US$), holding the same positions in 2010 (3,114, 3,046 million US$). Indeed, a change in the pattern of economic burden for major cancers in Korea has been much more dramatic than in other advanced nations. For example, it took 36 years in the United States for the share of mortality cost to hit 51% (in 2008) from 73% (in 1972). However, the length of that period was just 10 years for Korea, given that the statistic for the nation started at 71% in 2000 and arrived at 51% in 2010. These results suggest that the economic burden of cancer in Korea follows the pattern of other advanced nations in general but also registers some unique characteristics affected by its distinctive epidemiological and sociocultural contexts, e.g., higher sodium intake (regarding stomach cancer), higher infection of hepatitis B virus (regarding liver cancer), over-diagnosis of thyroid cancer, and sudden advent of an aging society (regarding direct/morbidity cost) [14,17]. With such a rapidly aging population, Korea’s average annual rate of economic growth, which was 9.5% during 2000-2010 [17], might drop to 4.1% during 2011-2020 and decrease further to 2.8% during 2021-2030 [23]. Given these dramatic transitions, two recommendations can be made for cancer control in Korea. First, greater focus on primary prevention, including sodium-controlled diet and hepatitis B vaccination, is needed in Korea. When economic resources are limited, primary prevention is the most costeffective strategy for reducing cancer burden, and this is particularly true for a nation like Korea, where gastrointestinal cancer is dominant with widespread bacterial infection [24]. Second, a more consistent and integrative system of cost-effective analysis (CEA) on cancer screening and treatment is needed in Korea. At this time, only a quarter of new screening/treatment technologies are covered by health insurance in Korea, largely because its CEA system is neither consistent nor integrative enough for timely and appropriate evaluation. More evidence might be helpful in reducing cancer burden in Korea. The findings of this study might provide good lessons and important policy implications for all nations striving for rapid economic growth and experiencing sudden sociocultural transformations.
4. Limitations of this study
For the calculation of the expected value of the future income or women’s opportunity cost for housework during potential years of life lost from a base year, it was presumed that (1) the participation rate for economic activity and the employment rate (varying by gender and age group in a given year) stay the same in the future as in the base year and (2) the women’s non-participation rate for economic activity (varying by age group in a given year) remains the same in the future as in the base year. Modifying these assumptions might improve the accuracy of estimating mortality cost. Also, projecting Korea’s cancer burden over 2010-2030 might provide additional insight into existing literature on cancer burden. Indeed, comparative analysis of Korea and other nations might contribute to more systematic examination of cancer burden. In addition, the extension of this study into all main diseases in Korea is expected to further the boundary of knowledge on disease burden. Despite these limitations, this research constructs rich data and presents a rare comprehensive examination of cancer burden in Korea, a nation with the most rapid demographic, socioeconomic, behavioral, and technological transformations in the past four decades.
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