The chronic side-effects of radiotherapy for early breast cancer, as reported by women themselves, are not any worse when treatment is given in a lower overall dose in fewer but larger treatments according to a trial part funded by Cancer Research UK and published today in the Lancet Oncology.
The study was part of the 4,451 patient START1 trials, which were co-ordinated by the Clinical Trials and Statistics Unit at The Institute of Cancer Research and funded by Cancer Research UK, the Medical Research Council and the Department of Health. These trials found that a lower total dose of radiotherapy, delivered in fewer, larger treatments is as effective at treating the disease as the international standard of a higher total dose delivered over a longer time.
The new part of the START trial published today used a questionnaire2 approach to assess the chronic side-effects of different radiotherapy doses for early breast cancer which until now have been uncertain.
About half the women in the trial were asked to fill in questionnaires over a five year period before and after treatment to see if they had noticed changes to the breast such as hardness, swelling and sensitivity or if they had experienced any arm or shoulder problems including pain and stiffness. These 2,208 women also answered questions on perceptions of body image.
The researchers found that long term side-effects were common for all the radiotherapy schedules with about 40 per cent of women overall reporting moderate or marked changes to the breast since treatment. Over time, breast symptoms and body image concerns did decrease.
They also found that skin changes were significantly fewer in the treatments giving lower overall dose in fewer larger doses, with a similar overall pattern for the other side effects, which supports the use of delivering radiotherapy treatment in this manner for women who have had surgery for early breast cancer.
Professor John Yarnold, Chief Investigator of the trial from the ICR, said: “Using women’s personal ratings of the side effects they experienced since treatment for early breast cancer gives us a unique insight into the effects of the lower dose of radiotherapy compared to the international standard. Trials which follow up patients like this are crucial so that improvements in treatment can be made without compromising the side effects.”
Kate Law, director of clinical research at Cancer Research UK, said: “Fewer doses of radiotherapy that are just as effective as the standard treatment and don’t increase the side effects will have a big impact for patients, especially as it means less visits to hospital. And, importantly, women in this study themselves reported the side effects they were experiencing. Cancer Research UK will continue to fund future parts of this trial to ensure that women receive the best possible treatment with the minimum amount of side effects.”
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Comparison of patient-assessed breast, arm and shoulder symptoms and body images after radiotherapy for early breast cancer: 5 year follow-up in the randomised Standardisation of Breast Radiotherapy (START) Trials by Penelope Hopwood, Judith Bliss, John Yarnold et al. Lancet Oncology
START trial – Standardisation of Breast Radiotherapy
The START trials compared the international standard dose of radiotherapy (50 Gy delivered in 25 fractions over 5 weeks) with alternative schedules based on fewer but higher doses. In Trial A, doses of 39 Gy and 41.6 Gy were given in 13 fractions over 5 weeks and in Trial B, 40 Gy was given in 15 fractions over 3 weeks. Results showed that radiotherapy delivered as a lower overall dose in fewer larger doses gives similar tumour control and the potential for fewer adverse side effects than the international standard schedule.
The START trials are currently the largest studies to explore the safety and efficacy of this approach, called hypofractionation, in women with early breast cancer.
The women completed a questionnaire before treatment and were then sent questionnaires to fill in at home 6, 12, 24 and 60 months after their treatment.
Radiotherapy side-effects can include moderate or marked oedema (swelling), breast shrinkage, telangiectasia (visible small blood vessels) and induration (hardening of the tissue).
Breast cancer is the most common cancer in the UK. Each year more than 45,500 women are diagnosed with breast cancer.