GEOGRAPHICAL DIFFERENCES IN CANCER OCCURRENCE RATES AND FATALITY RATES

As mentioned in another WHO report, carcinogenic substances are strongly associated with the occurrence of cancer. This is obvious from the substantial variations in the cancer incidence and death rates in various locations.

Table 15. Geographical variations and incidence of different forms of cancer

For example, the results of a survey in 1992 conducted in Japan on the comparative death rate are as follows:

Provinces with higher death rates for carcinoma of the stomach:

Male Yamagata, Toyama, Akita
Female Toyama, Niigata

Provinces with lower death rates for carcinoma of the stomach:

Male Okinawa, Kagoshima
Female Okinawa Kagoshima

Provinces with higher death rates for cancer of the lung:

Male Osaka, Nara, Fukuoka, Nagasaki
Female Osaka, Kyoto, Hyogo, Fukuoka

Provinces with higher death rates of liver cancer:

Male Saga, Nagasaki, Fukuoka, Osaka
Female Saga, Miyazaki

Notwithstanding the variations in the occurrence rates of cancer among different races throughout the world, the significant variations in incidence rates in such a small country as Japan demonstrates the relationship between the occurrence of different forms of cancer and environmental differences. These include differences in ecological systems, living conditions, food, and other lifestyle variations. The carcinogenic substances have a particularly important relationship to the type of cancer found in a given area.