Differences Between BRCA1 and BRCA2 Tumors

Dr. Monty Pal and Dr. Matteo Lambertini discuss a compelling global study on the clinical behavior of breast cancer in young BRCA1 and BRCA2 carriers, the association of pre-diagnostic awareness of BRCA status with prognosis, and the importance of identifying healthy people who are at risk of carrying the BRCA1/2 pathogenic variants.

TRANSCRIPT

Dr. Monty Pal: Well, hello everyone, and welcome to the ASCO Daily News Podcast. I'm your host, Dr. Monty Pal. I'm a medical oncologist, professor, and vice chair of medical oncology at the City of Hope Comprehensive Cancer Center in Los Angeles.

Now, when we think about genetic testing, whether for patients diagnosed with breast cancer or for other family members of them, it seems to be widely underutilized. Today, we're going to be discussing a recently published study in the Journal of Clinical Oncology that reported on the clinical behavior of breast cancer and specifically young BRCA1 and BRCA2 carriers, and the association of pre-diagnostic awareness of BRCA status with prognosis. I thought this was just a fascinating piece, and I honestly couldn't wait to have this conversation. It's a really compelling paper that highlights the importance of identifying healthy people who are at risk of carrying the BRCA1/2 pathogenic variants, and really the need for genetic counseling and testing to inform people about early detection that could lead to a better prognosis.

I'm really delighted to welcome the study's lead author, Dr. Matteo Lambertini. He really needs no introduction. He's very well known in the breast cancer world for his amazing contributions to fertility in the context of breast cancer, to pregnancy in the context of breast cancer, and genetic testing. He's an associate professor at the University of Genova, and a breast cancer medical oncologist at the San Martino Polyclinic Hospital in Genova, Italy.

Dr. Lambertini, thank you so much for joining us today.

Dr. Matteo Lambertini: Thank you very much, Dr. Pal. It's a great pleasure.

Dr. Monty Pal: Oh, thanks. And just FYI, if you're listening in and you want to hear our disclosures, they're all listed at the transcript of this podcast.

So, I poured through this paper [Clinical Behavior of Breast Cancer in Young BRCA Carriers and Prediagnostic Awareness of Germline BRCA Status] yesterday, Dr. Lambertini, and first of all, congratulations on this study. This was a huge international multicenter effort, 4,752 patients. How did you pool all these patients with young breast cancer?

Dr. Matteo Lambertini: Thanks a lot for the question. Yes, this was an effort made by several centers all over the world. The main idea behind the creation of this network that we have named as BRCA BCY Collaboration, was to get as many data as possible in a sort of niche patient population in the breast cancer field, meaning women diagnosed with breast cancer at the age of 40 years or younger, and all of them being BRCA carriers. We know that around, in the Western world, around 5% of breast cancer cases are being diagnosed under the age of 40 years, and among them around 10-15% are BRCA carriers. So, I would say it's a relatively rare patient population where we did not have a lot of evidence to support our choices in terms of counseling on treatment, prevention, and oncofertility as well. That was the idea behind the creation of this network that includes many centers.

Dr. Monty Pal: Yeah. You know, what's so interesting about this is that you sort of draw this line between patients who have BRCA testing at the time of diagnosis and then BRCA testing earlier in their course and then leading to a diagnosis perhaps. And I think that's where really sort of the dichotomy in outcome sits. Can you maybe elaborate on this and tell us about timing of genetic testing in this study and what that meant ultimately in terms of prognosis?

Dr. Matteo Lambertini: In this specific analysis from this large network, including almost 5,000 women with breast cancer diagnosed at the age of 40 years or younger and being a BRCA carrier, we looked specifically into the timing of genetic testing because this is a retrospective study and the criteria for inclusion are those that I have just mentioned, so diagnosis at a young age plus carrying germline BRCA pathogenic or likely pathogenic variant. In this analysis, we have looked into the time the patient has got the genetic testing and particular we focused on two populations: those that were diagnosed, knowing already to be a BRCA carrier, and those that got tested after being diagnosed with breast cancer.

And the main findings from this analysis have been that knowing to be a BRCA carrier was associated with a lower stage at the time of diagnosis, meaning more T1 tumors, so a tumor less than 2 cm, more node-negative disease, and this translated into less aggressive treatment, so less often axillary dissection, less often use of chemotherapy and anthracycline-based chemotherapy. And even more importantly, we have seen a better overall survival for those patients that were diagnosed already knowing to be BRCA carriers as compared to those tested after breast cancer diagnosis. These results after adjusting for all the confounding, stage, treatment and so on, there was not significant anymore, meaning that it's not the timing of test per se that is probably leading to a better survival, but it is the fact that knowing to be a BRCA carrier would likely translate into having access to all the preventive measures that we have in this setting and this will translate into an overall survival benefit, so in terms of saving more lives in young BRCA carriers.

Dr. Monty Pal: I think it's such an important point, and it's one that I think might sound implicit, right, but it needs to be proven, I think, through a study like this. You know, the fact that finding this early, identifying the mutation, doing enhanced screening, and so forth, is really going to lead to superior clinical outcomes. One of the things that I think many people puzzle over, including myself, is what to do? I personally occasionally will see BRCA altered patients in the context of prostate cancer. But that's a very different population of individuals, right? Typically older men. In young females with BRCA mutation, I guess there's a specific set of considerations around reproductive health. You'd already highlighted preventive strategies, but what sorts of things should we be talking about in the clinics once a patient's diagnosed and once perhaps their breast cancer diagnosis is established?

Dr. Matteo Lambertini: Yes, exactly. Knowing to be a BRCA carrier has a lot of implications from prevention to treatment to survivorship issues including reproductive counseling. And this is important not only for the patient that has been diagnosed with breast cancer but also for all the family members that will get tested and maybe identify with this sort of genetic alteration before diagnosis of cancer. Why this is important is because we have access to very effective preventive measures, a few examples: MRI screening, which starts at a very young age and normally young women don't have an effective screening strategy outside the BRCA field.

Also, primary preventive measures, for example, risk-reducing surgery. These women are known to have a high risk of breast cancer and high risk of ovarian cancer. So the guidelines are suggesting to undergo risk-reducing salpingo-oophorectomy at a young age, so 35 to 40 years in BRCA1 carrier, 40 to 45 years in BRCA2 carrier. And also risk-reducing mastectomy should be discussed because it is a very effective way to prevent the occurrence of breast cancer. And in some situations, including the setting that we are talking about, so young women with breast cancer, BRCA carrier, also risk-reducing mastectomy has shown to improve overall survival.

On the other side, once diagnosed with breast cancer, nowadays knowing to be or not a BRCA carrier can make a difference in terms of treatment. We have PARP inhibitors in the early setting, in the adjuvant setting as well as in the metastatic setting. And in terms of survivorship implication, one of the critical aspects for young women is the oncofertility care which is even more complicated when we talk about BRCA carriers that are women candidates for gynecological surgery at a very young age. So this sort of counseling is even more complicated.

Dr. Monty Pal: One of the other things, and this is subtle in your paper and I hope you don't mind me bringing it up, is the difference between BRCA1 and BRCA2. It really got me thinking about that because there are differences in phenotype and manifestation. Do you mind just expanding on that a little bit for the audience because I think that's a really important reminder that you brought up in the discussion?

Dr. Matteo Lambertini: The difference between BRCA1 and BRCA2 carriers has been known that there are different phenotypes of breast cancer that are more often diagnosed in these two different populations. Normally BRCA1 carriers have a higher likelihood to develop a triple negative breast cancer as compared to BRCA2 carriers, more likely to develop a hormone receptor-positive HER2-negative disease. In this study, again, a specific population of young women with breast cancer, we have seen the same findings, mostly triple negative disease in BRCA1 carrier, mostly luminal-like disease in BRCA2 carrier. But what's novel or interesting from this study is to look also at the age at the time of diagnosis of this disease. And particularly in BRCA1 carriers, we should be sort of more careful about diagnosis of breast cancer and also other primary tumors including ovarian cancer because the risk of developing these malignancies is higher even at a younger age as compared to BRCA2 carriers. And this has implications also in the primary and secondary prevention that we were talking about earlier.

Dr. Monty Pal: Oh, interesting. I guess the fundamental question then from your paper becomes, how do we get at the right patients for screening for BRCA1 and BRCA2? And I realize our audience here is largely oncologists who are going to be listening to this podcast, oncology providers, MDs, nurses, etc. But maybe speak for a moment to the general practitioner. Are there things that, for instance, a general practitioner should be looking for to say, "Wait a minute, this patient's high risk, we should consider BRCA1, BRCA2 testing or germline screening"?

Dr. Matteo Lambertini: Yes, it's a very important question for the breast cancer community. After the updated ASCO guideline, the counseling is way easier because right now the age cutoff goes up to 65 years, meaning that all the patients diagnosed with breast cancer below the age of 65 years should be tested these days. And then above the age of 65, there are different criteria like triple-negative disease or family history. From a general practitioner standpoint, it's of course a bit more difficult, but knowing particularly the family history of the person that they have in front will be crucial to know if there are cases of breast cancer diagnosed at a young age, maybe triple-negative cases, knowing cases of ovarian cancer in first-degree relatives or pancreatic cancer in first-degree relatives, and of course cases of prostate cancer as well. So, I would say probably mostly the family side will be important from a general practitioner perspective.

From an oncology one, the other point that I think is important to stress also based on the data that we have shown in this publication is that having a case of breast cancer known to carry a BRCA pathogenic or likely pathogenic variant. It means that all the people around this case should get tested and if found to be BRCA carrier and healthy carrier, these people should also undergo the primary and secondary prevention strategies because this is very critical also to improve their outcomes and try to avoid the developing of breast or ovarian cancer, but also in the case of diagnosis of this disease, a diagnosis at an earlier stage, as we have seen in this paper.

Dr. Monty Pal: Brilliant. I'm going to diverge from our list of questions here and close by asking a question that I have at the top of my mind. You're very young. I know our podcast listeners can't see you, but you're very, very young.

Dr. Matteo Lambertini: Thank you. Thank you for that. Not so young but yeah.

Dr. Monty Pal: You have nearly 300 papers. Your H-index is 67. You've already made these seminal contributions, as I outlined it from the outset, regarding fertility, regarding use of GnRH analogs, regarding pregnancy and breast cancer. What are you studying now? What are you really excited about right now that you're doing that you think might potentially be practice changing? Give us a little teaser.

Dr. Matteo Lambertini: Yeah. Thanks a lot, Dr. Pal. Receiving this compliment from you is fantastic. So, thanks a lot for that. From my side, in terms of my research, I've been interested in the field of breast cancer in young women since the start of my training. I've had very good mentors from Italy, from Europe, from the U.S. I'm still interested in this field, so I think we still have a lot to learn to try to improve the care of young women with breast cancer. For example, the oncofertility care, which is something I worked a lot over the past years. Now with all the new treatment options, there's a sort of new chapter of oncofertility counseling. So, what's the impact of immunotherapy? What's the impact of the new targeted agents?

More on the genetic aspects, now we know that there's not only BRCA1 or BRCA2. There are a lot of other different genes that may increase the risk of breast cancer and other malignancies. And also for these genes, we really don't have a lot of evidence to counsel women on prognosis, treatment, prevention strategy. So we need to learn way more for this special patient population that are quite rare, and so we really need a multicenter academic effort to try to give some evidence in this field.

Dr. Monty Pal: Yeah. It's tough because these are rare circumstances, but, you know, I think that you've done really well to sort of define some collective experiences that I think really define therapy. I mean, I just remember when I was in training 25 years ago, just reading through textbooks where all the experience around breast cancer and pregnancy was really just very sort of anecdotal almost, you know? And so it's great to see that the state of the science has moved forward.

Well, gosh, I really enjoyed our conversation today. I think your study really reminds us how powerful genetic information is in terms of improving outcomes. And, you know, hopefully this will lead some individuals to perhaps test more broadly in appropriate settings. So, thank you so much, Matteo, for joining us today with your fantastic insights on the ASCO Daily News Podcast.

Dr. Matteo Lambertini: Thank you very much, Dr. Pal. It's a real pleasure.

Dr. Monty Pal: And thanks to our listeners too. You'll find a link to Dr. Lambertini's study in the transcript of this episode. Finally, if you value the insights that you heard today on the ASCO Daily News Podcast, please rate, review, and subscribe wherever you get your podcasts. Thanks a ton.

Disclaimer:

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, service, organization, activity, or therapy should not be construed as an ASCO endorsement.

Find out more about today's speakers:

Dr. Sumanta (Monty) Pal

@montypal

Dr. Matteo Lambertini

@matteolambe

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Disclosures:

Dr. Monty Pal:

Speakers' Bureau: MJH Life Sciences, IntrisiQ, Peerview

Research Funding (Inst.): Exelixis, Merck, Osel, Genentech, Crispr Therapeutics, Adicet Bio, ArsenalBio, Xencor, Miyarsian Pharmaceutical

Travel, Accommodations, Expenses: Crispr Therapeutics, Ipsen, Exelixis

Dr. Matteo Lambertini:

Consulting or Advisory Role: Roche, Novartis, Lilly, AstraZeneca, Pfizer, MSD, Exact Sciences, Gilead Sciences, Seagen, Menarini, Nordic Pharma

Speakers' Bureau: Takeda, Roche, Lilly, Novartis, Pfizer, Sandoz, Ipsen, Knight Therapeutics, Libbs, Daiichi Sankyo, Gilead Sciences, AstraZeneca, Menarini, AstraZeneca, Menarini

Research Funding (Inst.): Gilead Sciences

Travel, Accommodations, Expenses: Gilead Sciences, Daiichi Sankyo Europe GmbH, Roche