LESSONS FROM CHINA 71CHART 4.2. RANGE OF CANCER RATES IN CHINESE COUNTIES
Cancer Site Males Females
All Cancers 35-721 35-491
Nasopharynx 0-75 0-26
Esophagus 1-435 0-286
Stomach 6-386 2-141
liver 7-248 3-67
Colorectal 2-67 2-61
Lung 3-59 0-26
Breast - 0-20
*Age-adjusted death rates, representing # cases/l 00,000 people/yearWhy was there such a massive variation in cancer rates among dif-
ferent counties when genetic backgrounds were similar from place to
place? Might it be possible that cancer is largely due to environmentalJ
lifestyle factors, and not genetics? A few prominent scientists had al-
ready reached that conclusion. The authors of a major review on diet
and cancer, prepared for the u.s. Congress in 1981, estimated that ge-
netics only determines about 2-3% oj the total cancer risk.^4
The data behind the China cancer atlas were profound. The coun-
ties with the highest rates of some cancers were more than 100 times
greater than counties with the lowest rates of these cancers. These
are truly remarkable figures. By way of comparison, we in the U.S.
see, at most, two to three times the cancer rates from one part of the
country to another.
In fact, very small and relatively unimportant differences in cancer
rates make big news, big money and big politics. There has been a long-
standing story in my state of New York about the increased rates of
breast cancer in Long Island. Large amounts of money (about $30 mil-
lion^5 ) and years and years of work have been spent examining the issue.
What sorts of rates were causing such a furor? Two counties in Long Is-
land had rates of breast cancer only 10-20% higher than the state aver-
age. This difference was enough to make front-page news, scare people
and move politicians to action. Contrast this with the findings in China
where some parts of the country had cancer rates 100 times (10,000%)
higher than others.