Patrick I. Borgen, MD
Neoadjuvant strategies are underutilized in the treatment of HER2-positive breast cancer, says Patrick Borgen, MD.
, Borgen, chair, Department of Surgery, director, Breast Center, Maimonides Medical Center, discussed the importance of neoadjuvant therapy in the treatment of patients with HER2-positive breast cancer.
OncLive: If a patient undergoes testing and it comes back that they have HER2 expression, what are some of the first things that you are thinking about?
: What has been amazing over the last 20 years of my career is how much the view of HER2-positive [disease] has changed. In the pre-HER2 blockade or pre-trastuzumab (Herceptin) era, HER2-postiivty was the worst possible thing that you could get on a biopsy result. One of the first papers that I ever added to my CV was about how bad it was to have HER2-positivity in the absence of treatment. Now…both single- and double-targeting of HER2 have really revolutionized the outcomes.
In the eighth revision of the staging system, going live this January, HER2-positivity is a good factor—not a negative factor. So, as soon as I get a biopsy result back where we have confirmed that HER2 is IHC3+ or FISH-positive, we begin to look at how we are going to capitalize on that.
Can you discuss some of the data in the neoadjuvant space that have come out this year?
When we look at clinical trials for breast cancer, and we look back at some of the earliest NASPB trials, or MILAN trials, or EORTC, we had to wait 5 or 10 years to get an answer. Our patients do not have the time to wait that long. So, one of things that we are looking at is the possibility of pathologic complete response being a reliable intermediate biomarker in clinical trials. There is some data suggesting, “Yes.”
In 2 landmark trials called TRYPHAENA and NeoSphere, we looked at women with a wide range of cancer, all of which was HER2-positive, ranging from stage 2 all the way through inflammatory. These women got a variety of systemic agents, and then either single or double targeting with HER2. The double targeting group got trastuzumab (Herceptin) and pertuzumab (Perjeta).
What we saw in both of those trials was a shockingly high rate of pathologic complete response. In fact, in one of the trials in women with ER-negative, PR-negative, HER2-positive breast cancer, the pCR rate exceeded 70%. So, this is really becoming the new standard, and I think that we should be thinking about neoadjuvant treatment for all HER2-positive tumors.
Are there any interesting trials currently ongoing?
One of the questions that comes up with HER2-positive breast cancers, is at what size in the node-negative setting do we think about HER2 blockade? Would you do it for a 1mm invasive cancer? Probably not. 5 mm? Maybe. 7mm or 8mm? Yes, absolutely.
For small tumors that are otherwise favorable, there is a trial called APT, which was in very small, early-stage breast cancers that were HER2-positive. In APT, women got [paclitaxel] and trastuzumab, that was it. The survival rates from this trial are among the best we have ever seen. These are patients who are probably not going to need multimodal cytotoxic therapy, and they are not going to need double targeting of HER2. That also bears watching.
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