2011 SABCS, San Antonio Breast Cancer Symposium, 6-10 December, San Antonio, USA

Axillary dissection may be overtreatment in some breast cancer patients

Dr Viviana Galimberti – European Institute of Oncology, Milan, Italy


Tell us about the results of the international breast cancer trial 2301.

These are very, very preliminary results and this is an international trial from the IBCSG group and is an important trial because it compares axillary dissections versus no axillary dissection in patients with clinically negative nodes and a micrometastatic sentinel node. The background of this study was that we were concerned that axillary dissection may be an overtreatment when the sentinel node is only minimally involved. So we decided to start this trial with the International Breast Cancer Study Group to answer this question.

The design of the study is very simple: if the patient registered for eligibility criteria, presents a micrometastatic sentinel node and a tumour up to 5cm were randomised to axillary dissection or no further axillary treatment. The eligibility criteria could be any age and with a clinical or ultrasonographic or pathological diagnosis of breast cancer. We made some changes during the trial because the eligibility criteria varied also for the sentinel node biopsy. At the beginning we decided to randomise only patients with tumour sizes up to 3cm but later we decided to admit also patients with tumours up to 5cm and also with a multicentric tumour and one or more micrometastatic sentinel nodes. We declared non-inferiority power of the disease free survival for no axillary dissection with five years disease free survival of 88.4% and the axillary section arm with 87.3%. This is very interesting. Also the overall survival is very important because we had 88% of overall survival. But, as I said before, these are very, very preliminary results and we have to wait for the first analysis.

I think that with a sentinel node minimally involved, the finding that micrometastatic sentinel nodes less than 2mm I think is an overtreatment with this data because we have robust data that confirms that this is an overtreatment. So we can conclude that from now on we may not do axillary section in those patients.