Abstract
Only little difference was observed between age specific incidence rate and death rate for ca. esophagus in Japan. This tendency was more striking in males than in females. Far lower sex ratio was noted for cancer of upper 1/3 of esophagus than that for middle 1/3 and lower 1/3 of esophagus in mortality statistics (1958-67), in mortality statistics (1958) and in autopsy statistics (1966-67) for all Japan. Sex ratio was also found to be lower in ca. esophagus of younger age groups. Two endemic areas were noted in Japan; (1) Souther Tohoku to Nouther Kanto and (2) Nara, Wakayama Districts. Sex ratio was noted to be much lower and almost stable for more than 7 years in latter case.
Stimulated by this fact, a world map was made according to the endemicity and sex ratio of cancer of the esophagus. A Type <high mortality (over 9.5 per 100, 000) low sex ratio (less than 2.0): Nara, Wakayama, Areas along Caspian Sea, Transki, China main land, Chile, Colombia, etc.> B Type <high mortality, higher sex ratio (2.0-6.9): Most of Japan, Okinawa, Taiwan, Hongkong, Singapole US Non-White> C Type <high mortality, highest sex ratio (over 7.0): France, Switzerland, South Africa, South America>
It is of interest that the extent of geographical aggeregation by county unit is much higher in Type A than in Type B or C.
A combined effect of daily drinking and smoking was clearly noted on the risk of ca. esophagus. by both retrospective studies and prospective studies. A among non daily drinkers annual death rate was 4.2-7.6 per 100, 000 compared to 27.9 among daily drinkers who also smoke over 20 cigarettes daily (Prospective study for 265, 118). Drinking habit of hot tea and deficiency of citrus fruits, milk, green yeallow vegetables were also noted as possible risk factors. These must be more important in Typpe A endemic areas.
