Table 3.
Cardiac dose estimates for Swedish women identified using the Swedish nationwide cancer register and irradiated for breast cancer since 1977, based on individual radiotherapy charts.
| Year of radiotherapya | Number of women evaluated | Average mean dose (standard deviation) |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Target dose (Gy) | Heart dose (Gy) |
Heart BEDb (Gy2) |
LADc dose (Gy) |
RCAd dose (Gy) |
Circe dose |
|||||||
| Left | Right | Left | Right | Left | Right | Left | Right | Left | Right | |||
| 1977–1981 | 36 | 38.7 | 12.0 | 3.6 | 20.8 | 4.5 | 23.6 | 1.5 | 8.7 | 9.5 | 7.7 | 0.8 |
| (10.2) | (5.2) | (3.0) | (10.0) | (4.0) | (7.6) | (0.8) | (5.4) | (9.1) | (3.4) | (0.3) | ||
| 1982–1988 | 51 | 44.6 | 8.0 | 3.7 | 11.6 | 5.1 | 21.1 | 1.9 | 6.9 | 11.1 | 4.2 | 0.9 |
| (8.8) | (5.8) | (2.4) | (10.2) | (3.9) | (9.0) | (1.0) | (7.1) | (9.9) | (2.9) | (0.4) | ||
| 1989–2001 | 43 | 46.6 | 7.3 | 3.2 | 10.5 | 4.2 | 18.8 | 2.1 | 5.7 | 8.4 | 3.9 | 1.3 |
| (8.5) | (7.2) | (2.2) | (11.2) | (3.2) | (11.7) | (0.7) | (6.2) | (9.5) | (3.3) | (0.3) | ||
Regimens were reconstructed on a representative patient with typical anatomy.
Women were grouped according to the years that breast cancer protocols changed in Denmark to enable comparison with Danish women in Table 2.
The biologically effective dose (BED) takes into account the fraction size as well as dose and is given by BED = [nd(1 + d/(α/β)] where n is number of fractions and d is dose per fraction in Gy. α/β was assumed to be 2 Gray. It was possible to calculate BEDs for women who received computer planned technique combinations or a single manually planned technique (91% of the women studied). It was not possible to calculate BED for the other women who received two techniques, one of which was manually planned (9% of the women studied).
Left anterior descending coronary artery.
Right coronary artery.
Circumflex coronary artery.