I am going to present the ten-year results of the study that is a multi-centric randomised international trial of the IBCSG 23-01. In the 1990s the treatment of breast cancer included axillary dissection as a staging procedure and also a regional treatment, but thanks to the sentinel node era that showed that sentinel nodes can accurately stage the axilla, axillary node dissection was abandoned, particularly in clinically node negative patients. But, the exhaustive examination of the sentinel node also revealed a very small amount of metastasis that is called micrometastasis, whose prognostic value was very unclear. So, we designed this time a multi-centric, international trial to assess, to respond, to this problem.
This trial randomised 936 patients from 2000-2011 and patients could be scheduled for mastectomy, this is the thing that can change the eligibility criteria according to 23-01 in respect to Z11 and also breast-conserving surgery. Patients eligible and consenting were registered before surgery and if the sentinel node was micrometastatic patients were randomised to receive axillary dissection or no axillary dissection. The tumour could be up to five centimetres, multi-centric tumours were allowed, and more than one micrometastatic sentinel node. The two groups were well-matched for all characteristics and particularly we have a very good, similar distribution according to the adjuvant treatment and this indicates that the detail of the number of nodes removed does not indicate the guide for adjuvant treatment. This is the news.
The ten-year disease free survival very good, there was no difference between the two curves and particularly the test of non-inferiority gave a very p-value very significant, indicating that axillary dissection is non-inferior to non-axillary dissection. The same for overall survival – we don’t find any difference between the two curves, 91% of the non-axillary dissection group was alive and 88% in the no AD arm.
So, our results say that axillary section can be abandoned when the sentinel node is minimally involved, because the non-inferiority is fulfilled of the primary and the secondary endpoint, and particularly because the axillary failures were very low, 0.8% in the breast-conserving surgery, those that didn’t receive any axillary dissection, and 1.2% in the mastectomy group. I think that this trial provides further level 1 evidence that axillary dissection should be abandoned in those cases.