SHORT REPORT INCREASING COLORECTAL CANCER INCIDENCE RATES IN JAPAN

Transcription

1 Int. J. Cancer: 109, (2004) 2004 Wiley-Liss, Inc. Publication of the International Union Against Cancer SHORT REPORT INCREASING COLORECTAL CANCER INCIDENCE RATES IN JAPAN Hoi-Yan YIU, Alice S. WHITTEMORE and Atsuko SHIBATA* Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA We examined trends of colorectal cancer incidence rates among Japanese (Miyagi Prefecture) and United States (US) whites (State of Connecticut) between 1959 and Agestandardized rates in Japan have increased dramatically and are now similar to US white rates. For both colon and rectum, age-specific rates in Japanese men born after 1930 exceed those in US whites, and the Japanese excess increases with year of birth. Similar patterns are evident for women. The current trends suggest that colorectal cancer will become a major source of morbidity and mortality in Japan, as these young Japanese age and their risks increase Wiley-Liss, Inc. Key words: animal fat; colon neoplasms; descriptive epidemiology; meat; rectal neoplasms; time trends In the mid-twentieth century, colorectal cancer incidence was substantially lower in Japan than in the United States (US). However, Japanese rates have been increasing rapidly. 1 3 The increases may reflect lifestyle changes occurring in Japan since World War II, such as increased consumption of animal fat and meat, and decreased energy expenditure. These characteristics have been associated with increased colorectal cancer risk. 4,5 Here we plot colon and rectal cancer incidence rates in Japanese (Miyagi Prefecture) and US whites (state of Connecticut) for men and women during the period , obtained from volumes I VII of Cancer Incidence in Five Continents (CI5) We chose the Miyagi Prefecture Cancer Registry for the Japanese and the Connecticut Tumor Registry for US whites because they covered the longest time period, with incidence data reported in all of the 7 volumes of CI5. Figure 1a shows age-standardized incidence rates per 100,000 person-years in the 2 populations by 5-year calendar periods defined by the CI5 series. We computed age-standardized rates, truncated to years of age, using the world standard population. Rates among Japanese have increased over the entire period for both sexes. In contrast, rates among US white men increased gradually from 1960 until the mid-1980s and then declined thereafter. Rates among US white women remained constant until the mid-1980s and then declined. Rectal cancer rates present similar patterns (Fig. 1b). Figure 1c shows trends in per capita consumption of meat and animal fat in Japan and the US during the period that was obtained from the Food and Agricultural Organization (FAO) database. 13 Consumption of meat has been substantially higher in the US than in Japan throughout the period examined, and it has increased in both countries, with higher rates of increase observed in Japan. Animal fat consumption has decreased dramatically in the US and increased moderately in Japan. A comparison of Figures 1a,b with Figure 1c indicates that the age-adjusted incidence trends for both colon and rectal cancers are similar to the trends in animal fat consumption. National data on trends in cancer incidence and food disappearance data are inappropriate for causal inferences. Nevertheless, a comparison of trends may motivate hypotheses that could be tested in analytic studies. 14 The low rates of meat consumption in Japan compared with the US suggest that changes in meat consumption do not explain the observed incidence trends in Figure 1. The trends in animal fat consumption appear to parallel the incidence trends more closely, and yet animal fat consumption in recent years in Japan is only about half that in the US. A more formal analysis would model incidence as a lagged function of food consumption to allow for a cancer induction period, but such detailed analysis seems inappropriate given the limitations of these ecological data. The Japanese may be more susceptible to the effects of dietary risk factors than are US whites. Such variation in susceptibility could reflect genetic modulation of colon cancer risk due to dietary risk factors. For instance, the Japanese and US whites may have different allele frequencies of polymorphisms that control detoxification of food-derived carcinogens. 15 The increasing colon cancer risk in native Japanese may also be explained by changes in exposure to other risk factors, such as sedentary lifestyle, body size and alcohol intake. 4,5 Figures 2 and 3 show age-specific incidence rates of colon and rectal cancers, respectively, by birth cohort. For both cancers, age-specific rates in Japanese men born after 1930 have exceeded those of US whites, and the Japanese excess increases with year of birth. Similar patterns are evident for women. The data in Figures 2 and 3 show that colorectal cancer rates in younger generations of Japanese now equal or exceed those in their US white counterparts. Lifestyle changes related to economic development and Westernization in Japan probably were greatest in the 1960s and 1970s. 16,17 The full impact of increased exposure to risk factors may not become evident for several decades, when Japanese exposed to these factors since young age reach their sixth and seventh decades of life. The current trends suggest that colorectal cancer will become a major source of morbidity and mortality in Japan, as these young people age and their risks increase. Grant Sponsor: The Donald E. and Delia B. Baxter Foundation There is no conflict of interest to this article. *Correspondence to: Amgen, Inc. Global Safety, One Amgen Center Drive, MS 17-2-C, Thousand Oaks, CA , U.S.A. Fax: ; ashibata@amgen.com Received 19 May 2003; Revised 24 September 2003, 3 November 2003; Accepted 19 November 2003 DOI /ijc.20030

2 778 YIU ET AL. FIGURE 1 (a,b). Age-standardized incidence rates (cases per 100,000 person-years) of colon (a) and rectal (b) cancer (standardized to the world standard population, truncated to years of age) for Japanese (Miyagi Prefecture) and US whites (State of Connecticut). C. Per capita daily consumption of meat and animal fat in Japan and the US (Source: Food and Agricultural Organization 13 ).

3 COLORECTAL CANCER INCIDENCE IN JAPAN 779 FIGURE 2 Age-specific incidence rates of colon cancer for Japanese (Miyagi Prefecture) and US whites (State of Connecticut) by birth cohort ( to ).

4 780 YIU ET AL. FIGURE 3 Age-specific incidence rates of rectal cancer for Japanese (Miyagi Prefecture) and US whites (State of Connecticut) by birth cohort ( to ).

5 COLORECTAL CANCER INCIDENCE IN JAPAN 781 REFERENCES 1. Hirayama T. Cancer epidemiology in Japan. Environ Health Perspect 1979;32: Wynder EL, Fujita Y, Harris RE, Hirayama T, Hiyama T. Comparative epidemiology of cancer between the United States and Japan. Cancer 1991;67: Tamura K, Ishiguro S, Munakata A, Yoshida Y, Nakaji S, Sugawara K. Annual changes in colorectal carcinoma incidence in Japan: analysis of survey data on incidence in Aomori Prefecture. Cancer 1996; 78: World Cancer Research Fund/American Institute for Cancer Research. Colon, rectum. In: Food, nutrition and the prevention of cancer: a global perspective. Washington (DC): American Institute for Cancer Research, IARC Working Group on the Evaluation of Cancer-Preventive Strategies. Cancer-preventive effectives. In: Vainio H, Bianchini F, eds. IARC handbooks of cancer prevention: weight control and physical activity. Lyon: IARC Press, Doll R, Payne P, Waterhouse J, eds. Cancer incidence in five continents, vol. I. Lyon: International Agency for Research on Cancer, Doll R, Muir C, Waterhouse J, editors. Cancer incidence in five continents, vol. II. Lyon: International Agency for Research on Cancer, Waterhouse J, Muir C, Correa P, Powell J, eds. Cancer incidence in five continents, vol. III. Lyon: International Agency for Research on Cancer, Waterhouse J, Muir C, Shanmugaratnam K, Powell J, eds. Cancer incidence in five continents, vol. IV. Lyon: International Agency for Research on Cancer, Muir C, Waterhouse J, Mack T, Powell J, Whelan S, eds. Cancer incidence in five continents, vol V. Lyon: International Agency for Research on Cancer, Parkin DM, Muir CS, Whelan SL, Gao YT, Ferlay J, Powell J, eds. Cancer incidence in five continents, vol VI. Lyon: International Agency for Research on Cancer, Parkin DM, Whelan SL, Ferlay J, Raymond L, Young J, eds. Cancer incidence in five continents, vol VII. Lyon: International Agency for Research on Cancer, Food and Agricultural Organization. FAOSTAT database: food supply livestock and fish primary equivalent. (online:). 14. Pruss A, Corvalan CF, Pastides H, De Hollander AE. Methodologic considerations in estimating burden of disease from environmental risk factors at national and glocal levels. Int J Occup Environ Health 2001;7: Le Marchand L, Hankin JH, Pierce LM, Sinha R, Nerurkar PV, Franke AA, Wilkens LR, Kolonel LN, Donlon T, Seifried A, Custer LJ, Lum-Jones A, et al. Well-done red meat, metabolic phenotypes and colorectal cancer in Hawaii. Mutat Res 2002;506 7, Ganmaa D, Li XM, Qin LQ, Wang PY, Takeda M, Sato A. The experience of Japan as a clue to the etiology of testicular and prostatic cancers. Med Hypotheses 2003;60: Kawamori R. Diabetes trends in Japan. Diabetes Metab Res Rev 2002;18:S9 13.