Slide 25
Population-Based Studies
One way of identifying the various causes of cancer is by studying populations and behaviors. This approach compares cancer rates among various groups of people exposed to different factors or exhibiting different behaviors. A striking finding to emerge from population studies is that cancers arise with different frequencies in different areas of the world. For example, stomach cancer is especially frequent in Japan, colon cancer is prominent in the United States, and skin cancer is common in Australia. What is the reason for the high rates of specific kinds of cancer in certain countries?
Table 23-1Variation Between Countries in the Incidence of Some Common Cancers
SITE OF ORIGIN OF CANCER | HIGH-INCIDENCE POPULATION | LOW-INCIDENCE POPULATION | ||
---|---|---|---|---|
LOCATION | INCIDENCE* | LOCATION | INCIDENCE* | |
Lung | USA (New Orleans, blacks) | 110 | India (Madras) | 5.8 |
Breast | Hawaii (Hawaiians) | 94 | Israel (non-Jews) | 14.0 |
Prostate | USA (Atlanta, blacks) | 91 | China (Tianjin) | 1.3 |
Uterine cervix | Brazil (Recife) | 83 | Israel (non-Jews) | 3.0 |
Stomach | Japan (Nagasaki) | 82 | Kuwait (Kuwaitis) | 3.7 |
Liver | China (Shanghai) | 34 | Canada (Nova Scotia) | 0.7 |
Colon | USA (Connecticut, whites) | 34 | India (Madras) | 1.8 |
Melanoma | Australia (Queensland) | 31 | Japan (Osaka) | 0.2 |
Nasopharynx | Hong Kong | 30 | UK (Southwestern) | 0.3 |
Esophagus | France (Calvados) | 30 | Romania (urban Cluj) | 1.1 |
Bladder | Switzerland (Basal) | 28 | India (Nagpur) | 1.7 |
Uterus | USA (San Francisco Bay Area, whites) | 26 | India (Nagpur) | 1.2 |
Ovary | New Zealand (Polynesian Islanders) | 26 | Kuwait (Kuwaitis) | 3.3 |
Rectum | Israel (European and USA born) | 23 | Kuwait (Kuwaitis) | 3.0 |
Larynx | Brazil (São Paulo) | 18 | Japan (rural Miyagi) | 2.1 |
Pancreas | USA (Los Angeles, Koreans) | 16 | India (Poona) | 1.5 |
Lip | Canada (Newfoundland) | 15 | Japan (Osaka) | 0.1 |
Kidney | Canada (NWT and Yukon) | 15 | India (Poona) | 0.7 |
Oral cavity | France (Bas-Rhin) | 14 | India (Poona) | 0.4 |
Leukemia | Canada (Ontario) | 12 | India (Nagpur) | 2.2 |
Testis | Switzerland (urban Vaud) | 10 | China (Tianjin) | 0.6 |
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Incidence = number of new cases per year per 100,000 population, adjusted for standardized population age distribution (so as to eliminate effects due merely to differences of population age distribution). Figures for cancers of breast, uterine cervix, uterus, and ovary are for women; other figures are for men. (Adapted from V.T. DeVita, S. Hellman, and S.A. Rosenberg (eds.), Cancer: Principles and Practice of Oncology, 4th edn. Philadelphia: Lippincott, 1993; based on data from C. Muir et al., Cancer Incidence in Five Continents, Vol. 5. Lyon: International Agency for Research on Cancer, 1987.)
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