Technical Report No. 8-86
Malignant and benign ovarian neoplasms among atomic bomb survivors, Hiroshima and Nagasaki, 1950-80
Tokuoka S, Kawai K, Shimizu Y, Inai K, Ohe K, Fujikura T, Kato HEditor’s note: A publication based on this report was published in JNCI 79:47-57, 1987.
Summary
For 1950-80, 194 ovarian cancer cases were ascertained among the 70,030 females of the RERF Life Span Study (LSS-E85) sample, and 106 autopsied cases with benign ovarian neoplasms were ascertained among all 3,046 autopsies performed in the same sample. On the basis of microscopic review, 66% of the cancer and 84% of the benign tumor cases were classified by the histological type.
The age-adjusted ovarian cancer incidence rates showed a statistically significant increase with increased exposure dose, both in the entire exposed group (P < 0.01) and the microscopically reviewed subset (P < 0.01). This dose response was only significant (P < 0.01) in the latter half of the study period, 1965-80. The radiation effect was higher in the younger age-group at the time of the bomb (ATB) for the specific attained age or adjusted for attained age.
In general, relative risk (RR, 100 rad or more vs 0 rad) did not differ by attained age, except for the youngest age-group (under 20 years ATB) where the RR tended to decrease with increase attained age, though cases are few in number and follow-up study is necessary. Estimated minimum latent period for radiation-induced ovarian cancer seems to be 15-20 years.
The proportion of the autopsied cases with benign ovarian tumor increased with increasing exposure dose, in both the entire series of cases (P < 0.05) and the microscopically reviewed subset. Statistical significance, however, was not achieved in the latter group (P > 0.10). The distribution of histological types of both cancer and benign tumor of the ovary did not vary significantly with radiation dose.
The date are consistent with the hypothesis that radiation injury of ovaries with secondary excess of gonadotrophic hormones are important causative factors in the development of ovarian neoplasms.
For 1950-80, 194 ovarian cancer cases were ascertained among the 70,030 females of the RERF Life Span Study (LSS-E85) sample, and 106 autopsied cases with benign ovarian neoplasms were ascertained among all 3,046 autopsies performed in the same sample. On the basis of microscopic review, 66% of the cancer and 84% of the benign tumor cases were classified by the histological type.
The age-adjusted ovarian cancer incidence rates showed a statistically significant increase with increased exposure dose, both in the entire exposed group (P < 0.01) and the microscopically reviewed subset (P < 0.01). This dose response was only significant (P < 0.01) in the latter half of the study period, 1965-80. The radiation effect was higher in the younger age-group at the time of the bomb (ATB) for the specific attained age or adjusted for attained age.
In general, relative risk (RR, 100 rad or more vs 0 rad) did not differ by attained age, except for the youngest age-group (under 20 years ATB) where the RR tended to decrease with increase attained age, though cases are few in number and follow-up study is necessary. Estimated minimum latent period for radiation-induced ovarian cancer seems to be 15-20 years.
The proportion of the autopsied cases with benign ovarian tumor increased with increasing exposure dose, in both the entire series of cases (P < 0.05) and the microscopically reviewed subset. Statistical significance, however, was not achieved in the latter group (P > 0.10). The distribution of histological types of both cancer and benign tumor of the ovary did not vary significantly with radiation dose.
The date are consistent with the hypothesis that radiation injury of ovaries with secondary excess of gonadotrophic hormones are important causative factors in the development of ovarian neoplasms.