The geographic pathology of bowel cancer

The most recent international data (for 1966–1967) show that Scotland still has the highest reported death rate from bowel cancer, despite a 20% reduction from the rate of 15 years earlier. The English death rates also dropped, while the rates for Japan, Italy, and West Germany rose appreciably. International data reinforce the recent case‐control observation that bowel cancer and beef consumption are closely associated. Comparison of incidence rates for colon and rectum show a generally close correlation, stronger than previously reported. The mathematical description of the association can be interpreted as saying that, while much rectal cancer is caused by the same factors that cause colon cancer, there is a second set of rectal cancers of different etiology. This hypothesis also is consistent with the differences in location of rectal cancers found in populations of low and high incidence. In particular, rectal cancer in the United States now tends to be upper rectal cancer, and only about 12% of U.S. bowel cancer is palpable on digital examination.