Radiotherapy: is it time to lower the dose?

For thousands of women with breast cancer, radiotherapy is a necessary evil. As well as killing off cancer cells, it brings myriad side-effects, including fatigue, hair loss, diarrhoea and loss of appetite. Sometimes, when a high dose of radiation is deployed, the effects are severe.

However, a recent study claims that targeted treatments of radiotherapy – or even lower doses – were just as effective. The study, led by Cambridge University and London’s Institute of Cancer Research, claims that irradiating the tumour – rather than the whole breast – was just as good and came with fewer side-effects. Not only that but a second technique – bathing the whole breast with radiation but using a lower dose – was also equally effective and also reduced adverse effects.

Study into radiotherapy dosage and breast cancer

The trial involved over 1,200 women who were being treated at hospitals across the country. Half were given the usual high dose, while the other half underwent a lower dose, and were then monitored them for five years after treatment. Along the way, the subjects were questioned about adverse side-effects (such as a hardening of tissue, pain, over-sensitivity of the treated area and build-up of fluid) at the start of the study, after six months and one, two and five years after radiotherapy. Most of the side-effects reported alluded to changes affecting the breast: the most commonplace side-effect was an overall change in breast appearance.

The researchers discovered no difference in rates of cancer recurrence with the less aggressive approaches, and the patients in the lower-dose group reported significantly lower side-effects. Furthermore, it was discovered that women were more likely to report adverse side-effects if they were younger, had larger breasts, had a larger volume of breast tissue removed at surgery, if the cancer had spread to any of their lymph nodes, and if, at the start of the study, they were feeling anxious or depressed.

A reassuring development

“The findings from this study are reassuring for women who are offered either whole breast or partial breast radiotherapy using this technique of radiotherapy, which is simple to deliver and already available in centres worldwide,” claimed Dr Indrani Bhattacharya, a clinical research fellow at the Institute of Cancer Research. “This new information will help doctors discuss the risks and benefits of this type of radiotherapy with patients and may improve shared decision-making, as well as enabling them to tailor treatment for individual patients.”

As well as an interesting development in terms of how we treat breast cancer with radiotherapy, the study has also shed light on who is more likely to experience adverse side effects and can help practitioners identify these patients and then offer the necessary support.