Biomarkers for Adjuvant Endocrine and Chemotherapy in Early-Stage Breast Cancer Guideline Update

An interview with Dr. Fabrice André from Institute Gustave Roussy in Paris, France, and Dr. Komal Jhaveri from Memorial Sloan Kettering Cancer Center in New York, NY, authors on "Biomarkers for Adjuvant Endocrine and Chemotherapy in Early-Stage Breast Cancer: ASCO Guideline Update." This updated guideline provides precise guidelines on previously endorsed genomic assays and recommendations on the use of new biomarkers to guide endocrine therapy and chemotherapy in patients with ER-positive HER2-negative tumors, and for those with HER2-positive or triple-negative breast cancer. Read the full guideline at www.asco.org/breast-cancer-guidelines.

TRANSCRIPT

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 asco.org/podcasts.

My name is Brittany Harvey, and today I'm interviewing Dr. Fabrice André from Institut Gustave Roussy in Paris, France, and Dr. Komal Jhaveri from Memorial Sloan Kettering Cancer Center in New York, NY, authors on "Biomarkers for Adjuvant Endocrine and Chemotherapy in Early-Stage Breast Cancer: ASCO Guideline Update." Thank you for being here Dr. André and Dr. Jhaveri.

Dr. Fabrice André and Dr. Komal Jhaveri: Thank you.

Brittany Harvey: First, I'd like to note that ASCO takes great care in the development of guidelines and ensuring that the ASCO conflict of interest policies follow each guideline. The full conflict of interest information for this guideline panel is available online with the publication of the guideline in the Journal of Clinical Oncology. Dr. André, do you have any relevant disclosures that are directly related to this guideline.

Dr. Fabrice André: No.

Brittany Harvey: Thank you. And Dr. Jhaveri, do you have any relevant disclosures that are related to this guideline topic?

Dr. Komal Jhaveri: No.

Brittany Harvey: Great, then let's talk about the content of this guideline update. So, Dr. Jhaveri, what prompted the update to the biomarkers for adjuvant endocrine therapy and chemotherapy in early-stage breast cancer, and what is the scope of this guideline update?

Dr. Komal Jhaveri: So, since the biomarker guideline published in 2016, there were several new publications that came out between January 2016 and October 2021 that provided perspectives on the use of some of the genomic assays broadly, or specifically in women based on menopausal status, age or number of lymph nodes.

Additionally, new biomarkers such as programmed cell death receptor ligand 1 or PD-L1, stromal TILs, circulating tumor DNA, or circulating tumor cells, or new applications, like extended endocrine therapy have also been developed.

So, this updated guideline provides precise guidelines on previously endorsed genomic assays and also provides recommendations on the use of new biomarkers to guide endocrine therapy and chemotherapy in ER-positive HER2-negative, HER2-positive, and triple negative breast cancer.

Brittany Harvey: Great. Thank you for setting the stage for this guideline. So, then Dr. André, I'd like to review the key recommendations of the guideline for our listeners. So, starting with, which biomarkers should be used to guide decisions on adjuvant endocrine and chemotherapy for patients with newly diagnosed ER-positive HER2-negative breast cancer?

Dr. Fabrice André: Thank you. So, when we are focusing on a newly diagnosed patient with ER-positivity HER-2 negative in the context of the question about deciding on chemotherapy. First, the 21 gene recurrence score should be used in patients with node-negative and in patients with 1-3 node positive who are postmenopausal.

In premenopausal, this test will be used only in patients with node-negative. The second test that is recommended is the MammaPrint 70-gene signature. And here the recommendation is to use this test if the patient is older than 50 and is node-negative or 1-3 node-positive.

If the patient is 50 years or younger, the clinician should not use this test. Then also a recommendation is that the clinician could use the 12 gene risk score EndoPredict if the patient is postmenopausal and has breast cancer node negative or 1-3 positive-node.

And finally, for the genomic test for the patient, the doctor could use PAM50. If the patient is postmenopausal and has breast cancer that is node-negative. Something new in this recommendation is the recommendation that the clinician could use Ki67. If the patient is postmenopausal and has stage I-II breast cancer with very specific recommendations on the cut off for positivity.

Brittany Harvey: Great. Thank you for reviewing those recommendations, Dr. André, and highlighting the new Ki67. So, then, in your introduction, Dr. Jhaveri, you discuss the application of assays for extended endocrine therapy. So, which biomarkers should be used to guide decisions regarding extended endocrine therapy for patients with ER-positive HER2-negative breast cancer?

Dr. Komal Jhaveri: Thank you. So, a quick word about extended endocrine therapy. I think extended adjuvant endocrine therapy, which is beyond five years of primary endocrine therapy, has certainly demonstrated improved outcomes, however, with modest absolute benefit and added toxicity and tolerability issues. Furthermore, while extended endocrine therapy is endorsed by clinical practice guidelines, clear guidance on individualized approaches to optimize patient selection for prolonged endocrine regimens, also remains limited. And this really underscores the need for prognostic and predictive information from genomic assays that can help guide this important clinical question we face.

One such example that has now borne out has been the breast cancer index and really collected evidence from now five studies supports the prognostic and predictive utility of this assay, such that if a patient has node-negative or one to three positive nodes, and has been treated with five years of primary endocrine therapy, to guide decisions about extended endocrine therapy, the clinician may offer Breast Cancer Index with either tamoxifen or aromatase inhibitors or tamoxifen, followed by an aromatase inhibitor.

Brittany Harvey: Great, thank you, Dr. Jhaveri. So, then, Dr. André, which biomarkers should be used to guide decisions on adjuvant therapy for early-stage HER2-positive breast cancer or triple-negative breast cancer?

Dr. Fabrice André: Well, first, we have to be sure that we are good at defining HER2-positive breast cancer and triple-negative breast cancer. So, it's always good to remind colleagues to have quality control assessment in place for HER2, estrogen receptor, and progesterone receptor stainings.

So far, when it's about predicting the benefit of adjuvant chemo or trastuzumab, there is no genomic test that is recommended in patients with HER2-positive or triple-negative breast cancer.

Brittany Harvey: Great, thank you. So, then, Dr. Jhaveri, what recommendations did the expert panel make regarding emerging biomarkers?

Dr. Komal Jhaveri: When we're talking about emerging biomarkers, we're referring to stromal TILs, we're referring to PD-L1, circulating tumor cells, and circulating tumor DNA. And while there is a lot of emerging data, currently, clinicians should not be utilizing these new biomarkers to guide decisions about adjuvant endocrine therapy or chemotherapy, as we do not have sufficient evidence to support their use.

Brittany Harvey: Great and that's important for clinicians to know. So, then finally, Dr. André, in your view, how will these updated guideline recommendations impact both clinicians and patients?

Dr. Fabrice André: So, we know Komal mentioned this at the beginning that now there is a very large amount of new publications, new data coming every day in the field of cancer. So, the only way for clinicians to deliver the best treatments for patients is to have the right guidelines with the right methodology, and ASCO is really putting in place a very rigorous methodology to deliver guidelines.

And this is the best way to be sure that all patients will have access to the best decision by the doctor. So guidelines are also here to decrease the disparities in terms of the expert decision, and any patient in the world can have access to the best decision, thanks to guidelines delivered by ASCO and all the colleagues of the panel that worked very hard to deliver these guidelines.

Brittany Harvey: Excellent! Well, thank you both so much, and the entire expert panel for your work to update these guidelines, and for taking the time to speak with me today, Dr. André and Dr. Jhaveri.

Dr. Komal Jhaveri: Thank you.

Dr. Fabrice André: Thank you, Brittany.

Brittany Harvey: 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 in interactive resources in the free ASCO guidelines app available in iTunes or Google Play Store. If you've enjoyed what you've heard today, please rate and review the podcast and be sure to subscribe so you never miss an episode.

The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. Guest statements on the podcast do not express the opinions of ASCO the mention of any product or service organization activity or therapy should not be construed as an ASCO endorsement.