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Background and Purpose: To estimate target and cardiac doses from breast cancer radiotherapy in Denmark and in the Stockholm and Umeå areas of Sweden during 1977-2001., Methods: Representative samples of irradiated women were identified from the databases of the Danish Breast Cancer Cooperative Group and the Swedish Nationwide Cancer Registry. Virtual simulation, computed tomography planning and manual planning were used to reconstruct radiotherapy regimens on a typical woman. Estimates of target dose and various measures of cardiac dose were derived from individual radiotherapy charts., Results: Doses were estimated in 681 Danish and 130 Swedish women. Mean heart dose for individual women varied from 1.6 to 14.9 Gray in Denmark and from 1.2 to 22.1 Gray in Sweden. In Denmark, mean target doses averaged across women increased from 40.6 to 53.8 Gray during 1977-2001 but, despite this, mean heart dose averaged across women remained around 6 Gy for left-sided and 2-3 Gray for right-sided radiotherapy. In Sweden mean target dose averaged across women increased from 38.7 to 46.6 Gray during 1977-2001, while mean heart dose averaged across women decreased from 12.0 to 7.3 Gray for left-sided and from 3.6 to 3.2 Gray for right-sided radiotherapy. Temporal trends for mean biologically effective dose [BED] to the heart, mean dose to the left anterior descending coronary artery, the right coronary artery and the circumflex coronary artery were broadly similar., Conclusions: Cardiac doses in Denmark were low relative to those in Sweden. In both countries, target dose increased during 1977-2001. Despite this, cardiac doses remained constant in Denmark and decreased in Sweden., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To study incidence of radiation-related heart disease in a large population of breast cancer patients followed for up to 30 years., Material and Methods: 72,134 women diagnosed with breast cancer in Denmark or Sweden during 1976-2006 and followed prospectively. Radiation-related risk was studied by comparing women with left-sided and right-sided tumours., Results: 34,825 women (48%) received radiotherapy. Among unirradiated women tumour laterality had little relevance to heart disease. Among irradiated women mean dose to the whole heart was 6.3 Gy for left-sided tumours and 2.7 Gy for right-sided tumours. Mortality was similar in irradiated women with left-sided and right-sided tumours, but incidence ratios, left-sided versus right-sided, were raised: acute myocardial infarction 1.22 (95% CI 1.06-1.42), angina 1.25 (1.05-1.49), pericarditis 1.61 (1.06-2.43), valvular heart disease 1.54 (1.11-2.13). Incidence ratios for all heart disease were as high for women irradiated since 1990 (1.09 [1.00-1.19]) as for women irradiated during 1976-1989 (1.08 [0.99-1.17]), and were higher for women diagnosed with ischaemic heart disease prior to breast cancer than for other women (1.58 [1.19-2.10] versus 1.08 [1.01-1.15], p for difference=0.01)., Conclusions: Breast cancer radiotherapy has, at least until recently, increased the risk of developing ischaemic heart disease, pericarditis and valvular disease. Women with ischaemic heart disease before breast cancer diagnosis may have incurred higher risks than others., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To estimate cardiac doses from breast cancer radiotherapy in Sweden from the 1950s to the 1990s. These doses will contribute to deriving dose-response relationships for the risk of radiation-induced heart disease., Materials and Methods: The Swedish nationwide cancer register was used to identify women irradiated for breast cancer in the Stockholm area. Virtual simulation, computed tomography planning, and manual planning were used to reconstruct radiotherapy regimens. Estimates of heart and coronary artery dose were derived for each woman., Results: Cardiac doses were assessed in 358 women. Mean heart dose varied from <0.1 to 23.6 Gy and mean left anterior descending coronary artery dose varied from 0.1 to 46.3 Gy. Mean heart doses averaged across women irradiated in each decade for left-sided and right-sided breast cancers, respectively, were 5.1 and 1.8 Gy in the 1950s, 10.5 and 4.7 Gy in the 1970s and 3.0 and 1.9 Gy in the 1990s., Conclusions: Cardiac doses from Swedish breast cancer radiotherapy increased from the 1950s to the 1970s, and then reduced substantially in the 1980s and 1990s. The wide range of doses observed should provide substantial statistical power for the estimation of dose-response relationships for radiation-induced heart disease.

Data are presented on the risks of cancers other than lung cancer in a cohort of iron miners from northern Sweden occupationally exposed to elevated levels of the radioactive gas radon. Compared with rates for the four northernmost counties of Sweden, mortality was increased for all cancers other than lung cancer (ratio of observed to expected deaths 1.21, 95% confidence interval 1.03-1.41), stomach cancer (ratio of observed to expected deaths 1.45, 95% confidence interval 1.04-1.98), and rectal cancer (ratio of observed to expected deaths 1.94, 95% confidence interval 1.03-3.31). Despite these overall increases, mortality was not significantly associated with cumulative exposure to radon, either for all cancers other than lung cancer or for any site of cancer other than lung cancer individually. However, the data from this cohort on its own have limited power; and for several sites of cancer the data in this study would be consistent with a radon-related increase. Further study of cancers other than lung cancer in populations exposed to radon is required.