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How Does Biomarker Testing Impact Metastatic Breast Cancer Treatment Options?

How Does Biomarker Testing Impact Metastatic Breast Cancer Treatment Options? from Patient Empowerment Network on Vimeo.

How are metastatic breast cancer treatment options impacted by biomarker testing results? Dr. Jane Lowe Meisel explains germline testing versus somatic testing – and how results may be used to help determine optimal treatment.

Jane Lowe Meisel, MD is an Associate Professor of Hematology and Medical Oncology at Winship Cancer Institute at Emory University. Learn more about Dr. Meisel here.

See More From INSIST! Metastatic Breast Cancer

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Essential Testing Following a Metastatic Breast Cancer Diagnosis

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Transcript:

Katherine:

What is biomarker testing, and how do results impact treatment options?

Dr. Meisel:

Great question. So, I think people often confuse germline mutations and somatic mutations. So, I’ll talk about that a little bit as we talk ab out biomarkers. So, I think biomarkers in general are factors within the tumor that allow us to make treatment decisions. So, if a biomarker in the tumor can predict response to a certain type off treatment, we want to know what that biomarker is so we can better treat the patient and more elegantly design a regimen. So, for example, having an estrogen-positive tumor, estrogen positivity is a biomarker suggestive of response to anti-estrogen treatments, which is why we give anti-estrogen therapy to ER-positive breast cancers.

But more recently, we’ve been able to move a little bit beyond estrogen, HER2 and triple-negative as our subtypes and think a little bit more in some patients about more sophisticated biomarkers. And that’s where somatic mutation testing comes in. So, there are germline mutations, which are inherited mutations that’re present in every cell in your body. So, for example, if your mother was a BRCA mutation carrier and based that BRCA mutation down to you, you would have a germline BRCA mutation. So, your cancer would carry a BRCA mutation, but so would every other cell you have.

And that’s a biomarker. That would make you a candidate for something like a PARP inhibitor. But in cancers, which the genes in the cancer have gone awry by definition, there are often other biomarkers within that tumor that may make you a candidate for certain treatments. And so, those mutations that arise in the cancer itself are called, somatic mutations. Those are mutations in the tumor, can’t be passed down to your offspring or anything like that and were not inherited by your parents. But mutations that’ve accumulated over time as these cancer cells have gone awry.

And so, genomic testing, or biomarker testing can be done often on a metastatic specimen. So, to be specific about it, say you had a metastatic breast cancer to the liver. You could have a liver biopsy done and that tissue from the liver biopsy could be sent for genomic testing. There are a lot of companies that do this and there are also some larger cancer centers that actually do in house testing for genomics. So, this testing can be done and what it does then is, it helps you determine, do you have a biomarker that predisposes you to a certain treatment.

So, if that metastatic liver tissues, for example contained high levels of PBL1 expression for example and you were triple-negative, that would say to your doctor ooh, this is a great candidate for immunotherapy along with chemotherapy. Or if you’re estrogen-positive for example and your tumor contains a mutation in the gene called PIK3CA and that might make you a candidate for a drug called, Alpelisib. So, these mutations could often be paired to a drug or treatment options, or sometimes to a clinical trial to allow patients to come take advantage of more targeted therapies. That sometimes, because they’re targeted, have fewer side effects than drugs that are a little more discriminate.

Katherine:

Marie sent in this question prior to the program, “Are there some genetic tests that’re more accurate than others?”

Dr. Meisel:

That’s a good question. I would say most genetic testing platforms have been heavily vetted and approved by national organizations and laboratories that’ve been tested multiple times before they’re allowed to be marketed. So, I wouldn’t say that one genetic testing program is necessarily better than another. I think that any of the commercially available platforms that’re used are probably pretty accurate.

I was just going to add one thing to that, if that’s okay. I was going to say that I think it’s important when you’re using genetic testing platforms though to know what you’re testing for. So, there are some platforms that will just test for say, the three most common mutations in BRCA1 and BRCA2 that Ashkenazi Jews have.

And so, if you get that testing back and you’re negative, you might think, “Oh, I don’t have a mutation in those genes.” Well, we know from that testing, just as an example, is that you don’t have a mutation in those three alleles of that gene. But if you haven’t had full gene sequencing, you could have a mutation somewhere else in that gene. So, I would say all genetic testing that’s commercially available is probably pretty accurate. But it is important when you get testing done to know what you’re testing for and what you’re not testing for so you can interpret your results accurately. And genetic counselors, as well as your doctors can help you do that. 

Have You Had These Essential Myelofibrosis Tests?

Have You Had These Essential Myelofibrosis Tests? from Patient Empowerment Network on Vimeo.

What are the essential tests that should follow a myelofibrosis diagnosis? Dr. Joseph Scandura reviews the necessary laboratory testing, along with a discussion of next generation sequencing, and explains how often bone marrow biopsies should take place.

Dr. Joseph Scandura is Associate Professor of Medicine and Scientific Director of the Silver MPN Center at Weill Cornell Medicine. Learn more about Dr. Scandura, here.

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Transcript

Katherine Banwell: 

What testing should take place following a myelofibrosis diagnosis? 

Dr. Scandura:  

So, a diagnosis of myelofibrosis always comes after a bone marrow exam and a physical examination. Often, patients have an enlarged spleen and blood count testing and a variety of other laboratory tests. So, after that and a diagnosis is made of myelofibrosis and, sort of, coincident with the diagnosis, we often look for molecular markers of myelofibrosis. So, these are malignancies of the bone marrow, cancers, if you will, on the bone marrow, although the term is scarier than or is different than what we think of for many malignancies in how it acts. But the myelofibrosis, this is a disease that’s characterized by, really, mutations in the malignant cells, the abnormal cells. 

They’re really just one of three genes. And so, JAK2 being one of the genes, calreticulin or CALR being another one, and MPL one.  

And more than 90 percent are people having mutation in just one of those three genes. And so, often at the time of diagnosis, tests for those mutations are done, and they help eliminate the possibilities of other causes of myelofibrosis – infections, rheumatological diseases. Sometimes, you can have marrow fibrosis but they don’t go along with mutations and the same clinical situation. And so, at the time of diagnosis, we usually know something about a mutation in JAK2, CALR, or MPL.    

More commonly now, and it’s increasingly common over the past 10 years in, I would say, in New York City and many places across the country, we also look more broadly for other common mutations in the MPN cells. And these are what we refer in the batch as next generation sequencing or NGS panels, and we use the term panels because we’re looking at from a few tens to even 100 or a couple hundred genes for mutations that occur far less frequently than in JAK2 or MPL or CALR.  

But they occur often enough that some of them we use to help guide treatment decision-making or approach to therapy. The reality of it is that that the technology to sequence and identify mutations has really outstripped our knowledge of what to do with all of that information. 

And, for the vast majority of people, it comes down to do you have a marker, a genetic marker that tends to go along with higher risk, meaning a higher likelihood of something that we don’t want to have happen. And in that instance, although it may be looking at a hundred or so genes, it comes down to a binary thing – either you have or you don’t have. 

Katherine Banwell:

Is there any other testing that you usually want to do? 

Dr. Scandura:

Laboratory testing, for sure and, as I mentioned before, a bone marrow exam. But physical examination, some people might do imaging of the spleen size. Honestly, I don’t routinely do that outside of the setting of the clinical trial. I don’t really think it dictates therapy very often. 

And if the spleen is so small that you can’t feel it on physical exam, it probably isn’t clinically meaningful anyway in terms of something to treat. It might be there, but it doesn’t really change things too much.   

Katherine Banwell:

How often should patients have a bone marrow biopsy? 

Dr. Scandura:

So, I’ll answer there is no standard in terms of monitoring for myelofibrosis with the marrow or otherwise. My personal approach is I do a marrow when I think it’s going to help medical decision-making. And so, for a patient who’s got early myelofibrosis, who’s been very stable, responding well to therapy, that could be three, five years between marrow exams. 

For somebody who’s being considered for a clinical trial, oftentimes, a marrow exam is required before they start on the clinical trial and at various intervals afterwards. If there’s somebody who had been stable and something is changing, like the blood counts are changing or his symptoms are changing, or any of a number of clinical features, then I might look in the marrow to see what’s happening there, to see if explains and can help guide a treatment approach to help people feel better. So, there is no single standard, but my personal approach is to do a bone marrow exam when I think it’s going to help make a decision.