Cancer epidemiology in Japan.

Patterns, change in occurrence, causative risk factors, and control strategy for cancer of each site in Japanese populations were studied by applying standard methods and techniques of biostatistics and epidemiology. As the results, cancers in Japan were classified into two groups: one on the decrease (stomach, cervix) and the other on the increase (lung, colon, pancreas, breast, prostate, urinary organs, leukemia). Analysis of vital statistics, national nutrition survey data, and on-going prospective study data revealed change in selective dietary intake and increase in cigarette consumption are the major factors responsible for such trend. Epidemiological characteristics and major risk factors of cancers of stomach, colon, pancreas, lung, breast, uterine cervix, ovary, endometrium, prostate, urinary bladder, and leukemia in Japan were summarized. A limited effect of mass screening was observed in the case of stomach cancer in addition to the strong effect of diet and nutrition. Cigarette smoking was confirmed to be the major causative factor of lung cancer in Japan. A close association of increased intake of animal fat and breast cancer risk in Japanese women was also observed.