Major EORTC trial presented at San Antonio Breast Cancer Symposium: 10-year follow-up of AMAROS shows benefits for post-operative radiotherapy to the axilla in patients with a tumour-positive sentinel node

Results from a 10-year follow of patients in the EORTC AMAROS trial were presented at the San Antonio Breast Cancer Symposium (USA) on Thursday 6 December. The international trial, enrolling 4806 eligible patients from 34 centres situated in nine European countries, (between February 2001 and April 2010), compared the practice of the surgical removal of all armpit lymph nodes (the axillary nodes) with radiotherapy to the same area in breast cancer patients who had cancer cells in the sentinel node – the first lymph node to which a tumour drains.

Patients in the trial had early breast cancer, where pre-operative chemotherapy was not indicated, and with no enlargement of the lymph nodes that could be detected by either palpation or ultrasound. Before their sentinel nodes were biopsied for the presence of tumour cells, they were randomised into the two groups. Cancer was found in the sentinel nodes of 1425 patients and were randomized:  744 had complete axillary surgery and 681 had radiotherapy to the axillary lymph nodes.

The ten-year analysis in 1425 sentinel node positive patients showed that there was a very low incidence of cancer recurrence in the breast and the armpit in both groups. An update of the five-year results for quality of life and arm morbidity were also presented and showed that the risk of lymphedema, one of the most serious side effects of breast cancer treatment, was reduced by more than half in those patients who had radiotherapy rather than surgery to the axilla. Lymphedema is swelling caused by removal of lymph nodes, which can lead to a blockage that prevents lymphatic fluid from draining. There is currently no cure, and it can have a major effect on quality of life.

«This outcome confirms the findings of our five-year analysis:  that radiotherapy to the axilla is an excellent alternative to full surgery in women with a positive sentinel node. Regional control of the tumour is comparable with surgery, and there are far fewer side effects  – hence a better quality of life, » says Professor Emiel Rutgers, of The Netherlands Cancer Institute, Amsterdam, The Netherlands, who presented the results.

Most of the patients in this trial had breast conservation surgery, and thus would have been likely to have radiotherapy in any event. « But patients who have a mastectomy are not always recommended for radiotherapy, so we cannot say if the results of this trial would always be applicable to them. This a question that still needs to be answered, » he said.

Decreasing the severity of side effects is an important part of cancer treatment, and the identification of the role of the sentinel node has played an important part in this. « Its importance is now widely recognised, but in 1999, when we started to design the trial, the contribution of sentinel node biopsy was accepted only to a limited degree, » said Prof Rutgers.

The trialists say that, as well as the question of mastectomy, another question still to be answered concerns the outcome of a reduced radiotherapy dose – the patients in the trial received 25 doses of 2Gy – or, indeed, omitting radiotherapy altogether in some patients. « Given the strength of the results, we see no need to follow up these patients further. The outcome for those who had breast conservation exceeded our expectations and is so impressive that we believe that our work will be practice-changing for this group, » said Prof Rutgers.

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