Exploring Treatment Outcomes for Lobular Breast Cancer With Jason Mouabbi, MD

At the recent American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Dr. Jason Mouabbi of MD Anderson Cancer Center presented a poster focused on survival outcomes of patients with invasive lobular carcinoma treated with endocrine therapy plus a CDK4/6 inhibitor, mammalian target of rapamycin (mTOR) inhibitor, or a PI3K inhibitor, in comparison to those with metastatic hormone receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative invasive ductal carcinoma. Afterwards, he sat down with Oncology Data Advisor to explain the implication of the study’s results and the need for additional research in the field of lobular breast cancer to improve patient outcomes. 

This podcast episode was recorded live at the 2022 ASCO Annual Meeting in Chicago by Oncology Data Advisor and ConveyMed.  

Oncology Data Advisor: Welcome to Oncology Data Advisor, I’m Keira Smith. Today, I’m here at the ASCO Annual Meeting in Chicago speaking with Jason Mouabbi from MD Anderson Cancer Center. Thank you so much for joining us today.

Jason Mouabbi, MD: Thank you, happy to be here.

Oncology Data Advisor: Would you like to tell us a little bit about your poster here?

Dr. Mouabbi: Yes, sure. At MD Anderson, I’m responsible for lobular breast cancer. I’m an expert in that field. Recently, we have shown in one of our review papers that lobular breast cancer, which is the second most common histology of breast cancer after ductal, does not respond as well to chemotherapy. A question that is raised by a lot of my patients who have lobular breast cancer in the metastatic setting is, “Well, how can you tell that I will respond to endocrine therapy plus targeted therapy?” This is the most common line of therapy we use for hormone-positive breast cancer, of which lobular breast cancer is 95%. Because 95% of lobular breast cancers are hormone-positive, a big proportion will get this type of therapy.

Our patients are very excited that all histologies seem to benefit in a similar magnitude from the addition of targeted therapy to endocrine therapy. Finally, if a patient asks, “Do we respond in a similar fashion to the more common ductal?” We can tell them, “Yes, and we have the data to back it.”

For the longest time, we didn’t have these data because all those studies did not discriminate between lobular and ductal, and they were studied as one, but most of those studies were driven by the ductal histology. They had more than 90% ductal accrual on those studies. It was important to do a study using our own numbers at MD Anderson, where we have a big database, to see whether or not the patients with different histologies respond in a similar fashion to endocrine therapy plus a targeted therapy— mainly a CDK4/6 inhibitor; an mTOR inhibitor, everolimus; and a PI3 kinase inhibitor, alpelisib.

So that’s what we did. We conducted the study, and our patients are very excited that all histologies seem to benefit in a similar magnitude from the addition of targeted therapy to endocrine therapy. Finally, if a patient asks, “Do we respond in a similar fashion to the more common ductal?” We can tell them, “Yes, and we have the data to back it.” So, this is an important abstract, and now we’re driving the manuscript to be published, to show that we looked at those patients. Although this is retrospective, it’s important data and can be used for prospective studies.

Oncology Data Advisor. Great, that’s very exciting. Anything else you’d like to share about your experience at ASCO and the research being presented here?

Dr. Mouabbi. A lot of great research is being presented. Unfortunately, lobular is still underrepresented; we need to do better. Lobular has to be studied on its own. I’m hoping that I and other colleagues who are vested in lobular cancer will get there one day, but we definitely need more research dedicated for lobular breast cancer.

Oncology Data Advisor: Absolutely. Well, thank you so much for joining us and explaining this.

Dr. Mouabbi: Thank you.

Thank you for listening to this podcast recorded live at the 2022 ASCO annual meeting by Oncology Data Advisor and ConveyMed. For more expert perspectives on the latest in cancer research and treatment, be sure to subscribe to the podcast at conveymed.io, and oncdata.com. Don’t forget to follow us on social media for news, exclusive interviews, and more.

About Dr. Mouabbi

Jason Mouabbi, MD, is in Assistant Professor in the Department of General Oncology and the Department of Breast Medical Oncology at The University of Texas MD Anderson Cancer Center, where he specializes in lobular breast cancers. His research focuses on the management of breast cancer subtypes and their impact on treatment. Dr. Mouabbi has been the recipient of multiple honors and awards, including the Guiding Researchers and Advocates to Scientific Partnerships (GRASP) Advocate Choice Award in 2022 and the Lester & Sue Smith Breast Cancer Award of Excellence in 2021.

For More Information

Mouabbi JA, Raghavendra AS, Bassett RL, et al (2022). Survival outcomes in metastatic HR-positive, HER2-negative invasive ductal carcinoma compared to invasive lobular carcinoma and mixed ductal/lobular treated with endocrine therapy in combination with CDK4/6 inhibitors, mTOR inhibitor, or PI3K inhibitor. J Clin Oncol (ASCO Annual Meeting Abstracts), 40(suppl_16). Abstract 1067. DOI:10.1200/JCO.2022.40.16_suppl.1067

Mouabbi JA, Hassan A, Lim B, et al (2022). Invasive lobular carcinoma: an understudied emergent subtype of breast cancer. Breast Cancer Res Treat, 193(2):253-264. DOI:10.1007/s10549-022-06572-w

Transcript edited for clarity. Any views expressed above are the speaker’s own and do not necessarily reflect those of Oncology Data Advisor. 

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