Clinicopathological Observation of Gastric Cancer in Atomic Bomb Survivors, Relationship with the Distance from the Hypocenter

Hisashi Oshiro, Kazuo Inagaki, Hideki Odan, Takao Hinoi, Masafumi Kikkawa, Tamaki Nakatani, Naoki Haruta, Issei Tanaka, Yasuji Yamamoto

First Department of Surgery, Hiroshima Prefectural Hiroshima Hospital

On the basis of the distance from the hypocenter, 569 cases of gastric cancer in atomic bomb survivors operated on during the last 23 years were divided into three groups: a closely exposed group consisting of 137 cases at sites within 2.0 km from the hypocenter, a distantly exposed group comprising 165 cases at sites more than 2.1 km from the hypocenter, and a secondarily exposed group composed of 264 cases. Poorly differentiated carcinomas occurred at a rate of 42.7% in the closely exposed group, 40.3% in the distantly exposed group, and 29.6% in the secondarily exposed group. In other words, each of these three groups contains more cases of well differentiated than poorly differentiated carcinomas, but it is also true that the number of cases of poorly differentiated types increased as the distans from the hypocenter decreased. Furthermore, the difference between the directly, i.e. the closely and distantly exposed groups, and the secondarily exposed groups is significant. In our analysis based on the subjects ages, in the directly exposed group poorly differentiated carcinomas accounted for 67.9% of the carcinomas in patients under 50 years of age, 52.6% in their 50s, 36.0% in their 60s, and 31.7% in those 70 years of age or older. Thus, poorly differentiated types are more frequent under age 50, whereas, the well differentiated ones are prevalent in patients 60 years of age of older. In the secondarily exposed group, the incidence of poorly and well differentiated types is similar in patients under 50 years of age, but in other age groups well differentiated carcinomas are found more often. On the basis of distance from the hypocenter there are no significant differences in resectability ratios for gastric cancers, extension to the stomach wall, lymph node metastasis, vascular invasion, staging or survival rate.

Key words
gastric cancer in atomic bomb survivors, distance from the hypocenter, directly exposed to atomic bomb explosion, indirectly exposed to atomic bomb explosion, secondary exposure

Reprint requests
Hisashi Oshiro First Department of Surgery, Hiroshima Prefectural Hiroshima Hospital
1-5-54 Ujina-kanda, Minami-ku, Hiroshima, 734 JAPAN

Accepted
April 1, 1992

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