PracticeUpdate: Haematology & Oncology

SABCS 2016 25

Axillary nodes after neoadjuvant treatment: an update from SABCS 2016

Dr Haffizulla: About sentinel node detection as it relates to neoadjuvant chemotherapy in patients who have not had any previous axillary node involvement – can you summarise some of the data that’s come to the forefront and describe where we are now? Dr Anderson: We’ve been increasingly using neoadjuvant chemotherapy as we’ve been learning that it’s really about the biology of the disease that tailors what we do. That doesn’t make surgery unimportant, but the questions that we’re asking is when is it that we can do less in the way of surgery. This is true both in the breast and in the nodes. When we give people chemotherapy upfront, if they have never had evidence of cancer in the nodes, then sentinel node biopsy is an extremely useful technique because the likelihood of getting arm swelling, lymphedema, is markedly reduced when we can limit that node dissection. Risk is 15–20% with a complete node dissection versus 3–5% with a sentinel node. There was a study suggesting that if we do chemotherapy prior to surgery that it might adversely influence the findings of sentinel node biopsy – we actually published that in Cancer several years ago – but we’re learning that it actually isn’t the case. If someone was a sentinel node biopsy can- didate, meaning no evidence of cancer in the nodes before chemo, that’s still true after. At the SABCS meeting, we saw a confirmatory study of this; the GANEA 2 trial that verified those findings. The really hard question is what happens when the nodes were involved before chemotherapy and can we downstage the disease to a point where we can limit ourselves to the sentinel node biopsy. And increasing evidence is suggesting that when the nodes do respond to chemotherapy, that we may well be able to do this. The complete node dissection has been our standard of care and I think it will continue to maintain a role for the very advanced stage disease. But with earlier stage disease and better treatment based upon the biology of the cancer, we may be able to do less and less and limit ourselves to these less aggressive axillary node procedures. Dr Haffizulla: On imaging modalities that may be able to pick up on nodal involvement in the neoadjuvant setting, can you highlight some of the newer technologies that are available? Dr Anderson: There are multiple imaging tools and they do different things. Ultrasound, for example, is very important and valuable

prior to the initiation of chemotherapy. It’s a good way of seeing gross nodal disease that’s present and it’s also a good tool for sampling the nodes. We generally will look in the axilla before starting chemotherapy and prove that someone is node positive, if we can, prior to that. As we follow patients during neoadjuvant chemotherapy, MRI has been a very valuable tool, especially looking at the breast, but it also has a role in the lymph nodes as well. There was a study that was presented at this meeting suggesting that PET imaging may be a good predictor of response to chemotherapy in the nodal bed. In our centre, we will follow patients with MRI and, in particular, if we see good evidence of response to nodal disease, particularly if it looks like it resolves, those are the settings where we think about using sentinel node biopsy in place of complete node dissection, even when they had very significant involvement. Dr Haffizulla: Can you highlight some of the therapeutic options that might be at the forefront at this stage in nodal involvement disease in the neoadjuvant setting? Dr Anderson: There are patients who would absolutely require a complete axillary node dissection if they have clinically positive disease, meaning a palpable mass in the axilla that’s proven to be cancer. If you operate on them before chemotherapy, they do warrant a complete axially node dissection. We do know that radiation treatment is very effective in the management of nodes, but how much nodal disease can be present and still be treated with radiation is one of our areas of current active investigation. However, after neoadjuvant chemotherapy with this imaging, if we see evidence of com- plete resolution, the current debate is can you just stop with a sentinel node biopsy. In our centre, there are two trials that are ongoing that we really need the answers to. One is the NSABP B-51 trial, and then there is a mirroring Alliance trial; one for when the sentinel node is positive after neoadjuvant chemotherapy and the other when it’s negative. And without getting into too much detail about the trials, in both settings we’re learning how to do less. That is really the mainstay. Dr Haffizulla: We’re looking forward to hearing more from those particular studies, see what the mature data shows us, and how practice changing this can be.

Benjamin Anderson MD, FACS, Director of the Breast Health Clinic and Professor of Surgery at the University of Washington, speaks with Dr Farzanna Haffizulla about sentinel node detection and neoadjuvant chemotherapy.

Go to practiceupdate.com to watch the full video interview with Dr Benjamin Anderson.

VOL. 2 • NO. 1 • 2017