DR MAMOUNAS: So the way I think about that is, if the tumor presents, again, with the single predominant or lobulated mass, one that, if you concentrically shrink it — and most of those that grow in a single-mass fashion, pushing margins, tend to shrink the opposite way, shrink uniformly, so to speak. For those patients, clearly, particularly if the tumor-size to breast-size ratio is the one that dictates the need for a mastectomy, but — or the location of the tumor, by downstaging the disease, you can potentially convert them to lumpectomy candidates. So these are the good candidates where I would apply this principle.

The poor candidates are those who have multicentric disease and particularly disease that there’s fairly no response to neoadjuvant chemotherapy, like lobular histology, low-grade tumor. Obviously, to have extensive microcalcifications in the breast indicate an “excessive” intraductal component. They are not good candidates, because it’s unlikely that these will be downstaged, particularly for patients with either triple-negative or ER-positive, HER2-negative disease. So for those patients, I would tell them that it’s unlikely that I’m going to do a different procedure, even given neoadjuvant chemotherapy, and only if they had a pathologic response, that would be the case. And even in that case, I would feel somewhat uncomfortable if I haven’t sampled extensively, most of the areas where the disease was located before.

DR LOVE: Could you comment on your slide here in terms of how tumors shrink?

DR MAMOUNAS: Yes. This is a slide that I kind of took from the old days with Bernie Fisher where we were looking to how tumors shrink in response to neoadjuvant chemotherapy and whether you can do less surgery depending on the pattern of shrinkage. And the bottom line behind this is that tumors shrink actually both ways. Some tumors shrink concentrically. And those are usually the ones, again, that grow fast and are pushing margins, the high-grade tumors, triple-negatives.

And some tumors shrink in this honeycomb pattern. And this is more of the ER-positive, HER2-negative, low-grade tumors, where they shrink. There is some killing of cells, but you can’t kill the last cell. So the disease remains pretty much in the same area where the tumor resided initially. So if you do a lesser procedure, it’s more likely you’re going to have positive margins. So for those patients, I’m not that enthusiastic about offering neoadjuvant chemotherapy. In fact, for invasive lobular carcinoma, I almost never do neoadjuvant chemotherapy because chances are they may not need chemotherapy to begin with, because they’re not responsive to it.

DR LOVE: How do you approach doing a lumpectomy in terms of the location? Do you use the original location of the tumor or the current location?

DR MAMOUNAS: I mean, the original extends where you’re actually going to —

DR LOVE: Right, the usual extent. And what do you do if there’s a clinical CR?

DR MAMOUNAS: Right. So I use the extent of disease after neoadjuvant chemotherapy. That’s the whole point, because obviously, if you use the original extent, then you don’t downstage the patient. You take exactly the same amount of tumor. So I go by what’s there now, by looking at the mammogram, ultrasound and MRI. And I tailor my lumpectomy to that, meaning I take a lot less. So my idea in somebody who has a clinical complete/radiological complete response is to go after the clip, which is localizedby wire localization, and remove a small area around it, a cosmetic lumpectomy, just to prove that the patient has no residual disease. And if, for some reason, that comes back with the margins involved, then you have to rethink the process or go back and do a re-excision or a mastectomy if there’s a lot of involvement.

DR LOVE: But how much tissue do you take out, though, if there’s no tumor there?

DR MAMOUNAS: I usually take like the size of, I don't know, maybe 3-, 4-cm diameter of a lumpectomy.

But you still have to have a good excisional biopsy, so to speak, but without deforming the breast at all.

DR LOVE: You mentioned, also, clip placement. Maybe you can talk about the images here and how you approach that question.

DR MAMOUNAS: Right. Clip placement is very important. And, at least when I was in Ohio, most patients are getting clipped, but not all the patients are getting clipped. Since I moved to Florida, I realized everybody gets clipped, any biopsy that takes place. And as Kim mentioned before, occasionally you run into the problem that somebody doesn’t have a clip and you don’t expect the clip, so you don’t even think about it. And then you find yourself, you don’t know where the tumor was. So we make sure everybody has a clip at the site of biopsy.

And then what we do is, we’ll put the wild localization or radio-opaque clip and drop a wild right at the edge of where the tumor used to be located and then go around the clip like a lollipop, taking the lesion.

And in this case here, it was a patient with a very ill-defined tumor in the lower part of the breast, it was triple-negative breast cancer, underwent neoadjuvant chemotherapy, with clinical and radiological complete response. And as you can see from the image on the right, the only thing you really have to go by to find where the tumor used to be is the clip. Otherwise, you absolutely cannot be sure that you took the tumor bed out. And this patient, again, had a pathologic complete response with a residual treatment effect when you take the tumor out.

Local disease control and neoadjuvant treatment

Neoadjuvant treatment of HER2-positive tumors

Neoadjuvant treatment of triple-negative tumors

Neoadjuvant treatment of ER-positive, HER2-negative tumors

Other issues in neoadjuvant treatment