Technical Report No. 10-91
Study of skin cancer incidence in Nagasaki atomic bomb survivors, 1958-85
Sadamori N, Otake M, Honda TSummary
The effects of exposure to ionizing radiation on skin cancer incidence in a cohort of atomic-bomb (A-bomb) survivors in the Nagasaki Extended Life Span Study (LSS-E85) sample have been investigated. Among 25,942 exposed survivors at risk whose DS86 dose estimates were available, 47 cases of skin cancer including malignant melanoma were confirmed in the Nagasaki Tumor Registry during the period from 1 April 1958 to 31 December 1985. The dose-response relationship of skin cancer based on an additive relative risk model showed linearity without threshold, not a linear-quadratic curve. The excess relative risk (ERR) of 2.2 per gray in the LSS-E85 sample was highly significant (95% confidence limits: 0.5 to 5.0). In addition, the ERR of 3.1 per gray in the Adult Health Study (AHS) sample was also significant (95% confidence limits: 0.6 to 20.3). When dose equivalents based on a relative biological effectiveness of neutrons of 10 were used, the ERR in the former sample decreased to 2.0 per sievert (95% confidence limits: 0.7-4.5), and the risk in the latter group also declined, to 2.7 per sievert (95% confidence limits: 0.6-17.8). The ERRs did not differ significantly between males and females in the LSS-E85 and AHS samples, but a highly significant increase was observed for the ERR of age at exposure and time trend since exposure. The ERR of skin cancer cases including and excluding 4 malignant melanoma cases for the LSS-E85 sample (there were no malignant melanoma cases in the AHS sample) showed almost the same linear dose response. This is the first report to demonstrate a highly significant dose-response relationship between A-bomb exposure and skin cancer incidence.
The effects of exposure to ionizing radiation on skin cancer incidence in a cohort of atomic-bomb (A-bomb) survivors in the Nagasaki Extended Life Span Study (LSS-E85) sample have been investigated. Among 25,942 exposed survivors at risk whose DS86 dose estimates were available, 47 cases of skin cancer including malignant melanoma were confirmed in the Nagasaki Tumor Registry during the period from 1 April 1958 to 31 December 1985. The dose-response relationship of skin cancer based on an additive relative risk model showed linearity without threshold, not a linear-quadratic curve. The excess relative risk (ERR) of 2.2 per gray in the LSS-E85 sample was highly significant (95% confidence limits: 0.5 to 5.0). In addition, the ERR of 3.1 per gray in the Adult Health Study (AHS) sample was also significant (95% confidence limits: 0.6 to 20.3). When dose equivalents based on a relative biological effectiveness of neutrons of 10 were used, the ERR in the former sample decreased to 2.0 per sievert (95% confidence limits: 0.7-4.5), and the risk in the latter group also declined, to 2.7 per sievert (95% confidence limits: 0.6-17.8). The ERRs did not differ significantly between males and females in the LSS-E85 and AHS samples, but a highly significant increase was observed for the ERR of age at exposure and time trend since exposure. The ERR of skin cancer cases including and excluding 4 malignant melanoma cases for the LSS-E85 sample (there were no malignant melanoma cases in the AHS sample) showed almost the same linear dose response. This is the first report to demonstrate a highly significant dose-response relationship between A-bomb exposure and skin cancer incidence.