March 9, 2016, The European Cancer Organization -- Radiotherapy to the whole breast is standard treatment after breast-conserving surgery for women with early breast cancer, even those who have a low risk of the disease returning in the breast (local relapse). However, whole breast radiotherapy can cause changes in the appearance of the breast, which may also be firmer and tender to the touch, resulting in psychological distress.
"So we considered it important to set up a trial to answer the question: is full dose radiotherapy to whole breast needed in patients with low risk early breast cancer?" Dr Charlotte Coles, MD, Consultant Clinical Oncologist at Cambridge University Hospitals NHS Trust, Cambridge, UK, told the 10th European Breast Cancer Conference (EBCC-10) today (Wednesday). "One group of women received standard full dose radiotherapy to the whole breast. A second group received standard full dose to breast tissue closest to where the lump appears and a slightly lower dose further away. A third group received standard full dose radiotherapy to breast tissue closest to where the lump appears but no radiotherapy dose apart from this.
"We found after five years that rates of local relapse (the reappearance of a cancer after treatment in the breast where it was originally detected) were very low in all treatment groups, including those receiving less radiotherapy. Moderate and marked changes in normal breast tissue were also low across all groups. Follow-up is ongoing and ten-year local recurrence rates will be reported at a later stage," she said.
Dr Coles and colleagues from 30 radiotherapy centres across the UK, led by researchers at The Institute of Cancer Research, London, recruited 2018 patients aged over 50 who had had breast conservation surgery for invasive early breast cancer tumours measuring less than 3cm at their largest point. They were randomised into three groups: 675 had whole breast radiotherapy at the standard dose of 40 Gy* to the whole breast (the control group), 674 had 40 Gy to the tumour bed and 36 Gy to the rest of the breast, and 669 had 40 Gy to the tumour bed only; the latter two "test" groups being two ways of focusing radiotherapy to the tumour bed and giving lower or no dose to the rest of the breast.
All patients were treated with intensity modulated radiotherapy (IMRT), a technique that can deliver an even dose of radiation, thus minimising the chances of hotspots of unwanted high doses and reducing the cosmetic problems that can occur after breast radiotherapy. The characteristics of the three groups were very similar and the average age was 63 years.
