Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer Guideline

An interview from Dr. Larissa A. Korde from the National Cancer Institute and Dr. Dawn L. Hershman from Columbia University on "Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer: ASCO Guideline." This guideline covers the optimal use of neoadjuvant therapy for women with invasive, non-metastatic breast cancer. Read the full guideline at www.asco.org/breast-cancer-guidelines.

Transcript

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BRITTANY HARVEY: Hello, and welcome to the ASCO Guidelines podcast series brought to you by the ASCO Podcast Network, a collection of nine programs covering a range of educational and scientific content and offering enriching insight into the world of cancer care. You can find all the shows, including this one podcast.asco.org.

My name is Brittany Harvey, and today I am joined by Dr. Larissa Korde from the clinical investigations Branch of the Cancer Therapy Evaluation Program in the Division of Cancer Treatment and Diagnosis of the National Cancer Institute in Bethesda, Maryland, and Dr. Dawn Hershman from the Herbert Irving Comprehensive Cancer Center at Columbia University in New York, New York, co-chairs on Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer: ASCO Guideline. Thank you for being here Dr. Korde and Dr. Hershman.

DR. LARISSA KORDE: Thank you for having us.

DR. DAWN HERSHMAN: Yes, thank you.

BRITTANY HARVEY: First, I'd like to note that ASCO takes great care in the development of its guidelines in ensuring that the ASCO conflict of interest policy is followed for each guideline. The full conflict of interest information for this guideline panel is available on-line with the publication of the guideline in the Journal of Clinical Oncology. Dr. Korde, do you have any relevant disclosures that are related to this guideline topic?

DR. LARISSA KORDE: I do not.

BRITTANY HARVEY: And Dr. Hershman, do you have any relevant disclosures that are related to this guideline topic?

DR. DAWN HERSHMAN: No, I do not.

BRITTANY HARVEY: Great, thank you both. Then, Dr. Hershman, to kick off the content of the guideline, first, can you give us a general overview of the scope and the purpose of this guideline?

DR. DAWN HERSHMAN: Yeah, sure. In breast cancer, we have seen a plethora of studies looking at neoadjuvant therapy for breast cancer. And as we've learned over time, that neoadjuvant therapy has focused on the role of, really, response as a predictive marker and whether or not the improvement in a pathologic complete response rate translates into benefit in terms of long-term outcome. And the fact that several studies have shown that has really increased our interest in looking at pathologic complete response rate and its predictive value.

So part of the guideline is really to help us really elucidate as the understanding of biology of breast cancer has evolved over time, what scenarios where neoadjuvant therapy is the best choice for patients, and what the real purpose of neoadjuvant therapy is. So the guidelines' purpose is really to help us develop recommendations concerning the optimal use of neoadjuvant therapy, whether it be chemotherapy, endocrine therapy, or targeted therapy for a variety of different biologic subtypes. And I think the overarching principle is that the expert panel strongly advocated for a multidisciplinary team in the management of these patients. Specific guidelines really go into details about each of the scenarios where we would use this therapy.

BRITTANY HARVEY: Great. Then I'd like to review some of those key recommendations that you just mentioned for our listeners. So Dr. Korde, which patients with breast cancer are appropriate candidates for neoadjuvant systemic therapy?

DR. LARISSA KORDE: So when we sat down to write this guideline, we thought through this question in many different ways. But we basically ended up sort of dividing patients by breast cancer subtype and then coming up with recommendations separately for each subtype. So broadly speaking for triple negative breast cancer patients and for HER2-positive breast cancer patients, we felt that the kind of most important triage point is that in both those diseases, there are effective treatments that can be used in the adjuvant setting in patients who do not have a pathologic complete response to neoadjuvant therapy. And so broadly speaking, it's those patients where there would be an adjuvant therapy decision point, or recommendation in whom the neoadjuvant response is important. Those would be the patients in whom we would most strongly recommend neoadjuvant chemotherapy.

In ER-positive disease, we looked at both chemotherapy and endocrine therapy in the neoadjuvant setting. And we know that both of these can improve response. Pathologic complete response is less common in patients with ER-positive disease. But there are also benefits to neoadjuvant treatment in those patients in terms of being able to reduce the size of the surgery, reduce potentially morbidity from surgery, and then also in terms of being able to convert patients who were not lumpectomy candidates from mastectomy to lumpectomy. And so in the guideline we outline the scenarios for ER-positive patients in which neoadjuvant therapy would be recommended as well.

BRITTANY HARVEY: Great, got it. Then Dr. Hershman, what do the guidelines say about how clinicians should measure response in patients receiving neoadjuvant chemotherapy?

DR. DAWN HERSHMAN: Yes, so patients undergoing neoadjuvant therapy should really be monitored by their provider at each visit with a clinical examination at regular intervals. And we really felt that the role of breast imaging was really for patients where there was some clinical suspicion of progression during that therapy to ensure that patients were not progressing during treatment. And ultimately, the best modality for imaging was the modality that was most effective at the point of diagnosis, whether it be mammogram, ultrasound, or MRI, that should be the imaging modality used at follow up.

We did not feel that there were any specific blood markers or tissue based markers at this time that should be used for monitoring patients undergoing neoadjuvant therapy. Much of that is done for clinical trial purposes, but not so much in the clinic. And that when patients had completed their treatment, pathologic complete response rate is the most important outcome and would be really assessed at the time of surgery as the absence of any invasive disease in either the breast or the lymph nodes.

But in order for that to be good for clinical decision making, it's really imperative that the clinician and the surgeons make sure that the tissue is removed that is suspect to begin with, so to make sure that the clips that defined where the tumor was evaluated and that the tumor bed is clear of any evidence of disease.

BRITTANY HARVEY: Great, that's helpful information. So then, Dr. Korde, you mentioned that the recommendations are divided up by biologic subtypes. So what are those neoadjuvant systemic therapy regimens recommended for the following patient population-- so first, those with triple negative breast cancer, second, those with HER2-negative hormone receptor positive breast cancer, and then finally, for those with HER2-positive disease?

DR. LARISSA KORDE: So maybe we can divide this up a little. Let's start with the triple negatives. For triple negative breast cancer patients who are embarking on neoadjuvant chemotherapy, and that would be patients with clinically node positive disease, and/or at least T1C disease, and again, with the thought that the goal is really to think about whether adjuvant therapy recommendations would be altered based on PAP CR. But in that setting, we recommended that patients be offered an anthracyclines and taxane containing regimen.

We also found data supporting the use of carboplatin with neoadjuvant therapy for the purpose of increasing the likelihood of PCR. So we noted that while there is good data showing that PCRs increase with carboplatin, there is more conflicting data regarding the effect of carboplatin on long-term outcomes. Although, hopefully, new clinical trials that are ongoing now or that are in follow up may clarify this question a little bit more.

We felt at the time that we wrote the guideline, and certainly, this is potentially an evolving topic. But at this point, we felt that there was insufficient evidence to recommend routinely adding immune checkpoint inhibitors to neoadjuvant chemotherapy in patients with early stage breast cancer. And again, there may be more data on this upcoming in the next few years. So maybe Dawn can take the next category, the HER2-negative hormone receptor positive patients.

BRITTANY HARVEY: Yeah, that would be great.

DR. DAWN HERSHMAN: Absolutely. So we felt for this population of patients that neoadjuvant chemotherapy could be used instead of adjuvant chemotherapy in any patient where the chemotherapy decision could be made without the benefit of having the results from the surgical pathology data, or any results from the specific genomic testing. So if the decision was made that the patient was going to need chemotherapy regardless, that would be a patient that could get it neoadjuvantly.

We felt that for postmenopausal patients with hormone receptor positive HER2 negative breast cancer that neoadjuvant endocrine therapy with an aromatase inhibitor could be offered to either increase local regional treatment options, if there was no intent for surgery, endocrine therapy could be used for Disease Control. So in a patient where they really were not a good surgical candidate, we could offer this therapy to try to control their disease. For premenopausal patients with hormone receptor positive HER2-negative disease, we did really not feel that neoadjuvant endocrine therapy should be routinely offered outside of a clinical trial. Because in this scenario, there really wasn't enough evidence to offer this approach.

BRITTANY HARVEY: And then Dr. Korde, do want to finally address those patients with HER2-positive disease?

DR. LARISSA KORDE: Absolutely. So in patients with HER2-positive disease that is either node positive or high risk node negative, we felt it would be appropriate to offer neoadjuvant therapy with either an anthracycline and taxane containing regimen, or a non-anthracycline-based regimen in combination with targeted therapy. And we did feel that targeted therapy should include trastuzumab and may also include pertuzumab. For patients with smaller tumors, really those in whom it's unclear whether the more aggressive for on-chemotherapy regimens or even any chemotherapy at all is needed, for example, those with very small tumors, T1A and T1B, we did not feel that neoadjuvant should be routinely offered. And we did note that in those patients with smaller tumors, an alternative regimen, the APT regimen of paclitaxel and Trastuzumab is something that has been studied in the adjuvant setting. But again those patients with these very small node negative tumors, in general, would not be routinely offered neoadjuvant chemotherapy.

BRITTANY HARVEY: Great, thank you both for reviewing those neoadjuvant systemic therapy approaches for those specific patient populations. So Dr. Hershman, in your view, what is the importance of this guideline? And how will it impact clinical practice?

DR. DAWN HERSHMAN: Yeah, that's an excellent question. I think as our data has shown more and more studies where there's a benefit to giving adjuvant treatment based on the response of patients in the neoadjuvant setting to get additional benefit long-term amongst patients with residual disease, I think that these guidelines really can help clinicians to understand those scenarios where we know we can maximize treatment.

I think ultimately the goal of neoadjuvant therapy is that it gives us opportunities to both escalate treatment in patients that are at high risk that don't have great responses, and de-escalate therapy in patients that have outstanding responses. And so I think this will help clinicians understand what those benefits are.

BRITTANY HARVEY: Definitely. It seems like it will provide some clarity for those scenarios. So finally, Dr. Korde, how do you envision that these guideline recommendations will affect patients with non-metastatic breast cancer?

DR. LARISSA KORDE: Well, I think building on Dr. Hershman's answer to the previous question, really, the key here is to be able to personalize or tailor the therapy for individual patients. So in those patients whose disease is very high risk, or did not respond to initial therapy, patients can be given appropriate escalation of treatment. And for patients who have an excellent response to treatment in the neoadjuvant setting can potentially be spared other treatments. And so I think that the main use of neoadjuvant treatment and the use of this guideline in terms of how it affects patients is being able to offer the most appropriate therapy for each patient.

BRITTANY HARVEY: Great, well, thank you both for your work on this guideline on neoadjuvant chemotherapy, endocrine therapy, and targeted therapy for breast cancer. Appreciate your leadership on this guideline. And I want to thank you also for taking the time to speak with me today, Dr. Korde and Dr. Hershman.

DR. DAWN HERSHMAN: Thank you.

DR. LARISSA KORDE: Happy to be here. Thanks so much.

BRITTANY HARVEY: And thank you to all of our listeners for tuning in to the ASCO Guidelines podcast series. To read the full guideline, go to www.asco.org/breast-cancer-guidelines. You can also find many of our guidelines and interactive resources in the free ASCO guidelines app available in iTunes or the Google Play store. If you have enjoyed what you've heard today, please rate and review the podcast and be sure to subscribe so you never miss an episode.