Breast Radiotherapy – Protecting the patient’s heart
Breast Health Outcomes for cancer treatments have been improving all the time but this does mean that more patients are living with the long term consequences of their treatment.
It is well known that many of the therapies used to treat cancer patients can have negative effects upon the heart. There is now considerable international interest in this field as evidenced by the fact that London has just hosted the Global Cardio-Oncology Summit at the Royal College of Physicians. The summit was organised by the International CardiOncology Society whose mission is to optimise patient outcomes for cancer patients receiving potentially cardio-toxic therapies.
The Breath-Hold Technique
Therapies that can have a negative effect upon the heart include chemotherapy, immunotherapy and radiotherapy. Radiotherapy in the treatment of breast cancer is of particular interest as it has been shown that these patients have a significant excess risk of ischemic cardiac disease1.
"One of the simplest solutions is where the patient inhales deeply, as the heart moves down."
When patients are receiving radiotherapy to their left breast it is possible for the radiation beams to irradiate part of the heart including the left anterior descending coronary artery. There are a number of possible strategies that can be used to minimise the exposure of the heart in this situation.
One of the simplest but most effective of these relies upon the fact that when the patient inhales deeply the heart moves down in the thorax and away from the anterior chest wall. This effect can be exploited in a technique known as Deep Inspiration Breath Hold or DIBH. Here the patient is encouraged to breathe in deeply and hold their breath for 20 to 30 seconds whilst the radiation beam is being delivered. This allows the whole of the breast target to be treated whilst minimising expose to the heart. The images below are taken from the treatment planning scan of a patient having radiotherapy and illustrate the beneficial effect.
In figure 1 the high dose area is shown by the red colour wash and can be seen to intersect the left anterior part of the patient’s heart.
In figure 2 the patient is in DIBH and it can be seen that the red high dose area is no longer in contact with the heart.
The DIBH technique is relatively simple to implement and does not require any special equipment beyond that available in any radiotherapy department.
1: Darby, S.C., Ewertz, M., McGale, P. et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med. 2013; 368: 987–998