In patients with unfavorable cardiac anatomy, where the heart is close to the thoracic wall, the cardiac doses increase significantly [ 10, 11].
Use of intensity modulated radiation therapy (IMRT) has been proposed to reduce cardiac dose in these patients.
Cardiac dose-limiting toxicity (DLT) in the form of atrial fibrillation did occur in 1 of 6 patients treated with melphalan 280 mg/m280
Attempts have been made to reduce cardiac dose delivered during breast radiotherapy through positional manoeuvres.
Acetylsalicylic acid in small "cardiac" doses and beta-blockers seem to be safe drugs in pregnancy.
The cardiac dose for right-sided patients is generally from scattered irradiation alone (Taylor et al, 2008).
They had received a mean uniform single cardiac dose of ⩽4 Gy, and within this cohort subsequent studies showed excess mortality from cardiac disease (Preston et al, 2003).
Although the cardiac dose from left-tangential radiotherapy has also decreased considerably over the past few decades, part of the heart still receives >20 Gy for approximately half of those with left-sided tumours.
However, if the effects on reduction in cardiac dose of this study are being compared to the results of other planning studies, this needs to be taken into account.
A contrast between left and right sided breast cancer will tend to produce conservative estimates of risk because radiotherapy to the right breast, especially methods involving internal mammary lymph node (IMN) fields, also entails some cardiac dose.
