Though invasive lobular carcinoma (ILC) is the second most common form of invasive breast cancer—accounting for 10 to 15 percent of invasive breast cancer diagnoses and affecting nearly 40,000 people each year—it has unfortunately been understudied and misunderstood.
ILC, also known as lobular breast cancer, originates in the milk-producing glands of the breast and presents differently than other invasive breast cancers, making it more difficult to detect by traditional screening and self-exam. Recent research has not only shown that ILC is its own distinct subtype of breast cancer, but also that it may not respond as well to standard treatments, recur later, and metastasize in unusual ways.
But thanks to the tireless work of researchers and patient advocates, awareness of ILC is growing and the disease is being more rigorously studied as the unique breast cancer that it is.
BCRF’s Margaret Flowers, PhD spoke with investigator Steffi Oesterreich, PhD and patient advocate Leigh Pate, founder of the Lobular Breast Cancer Alliance, about the second-annual International Invasive Lobular Breast Cancer Symposium—and how research is improving our understanding of ILC. Watch the full video above or read an edited version of the conversation below.
I’m a professor at the University of Pittsburgh, and I’m the co-director of the Woman’s Cancer Research Center, which is a collaboration between UPMC Hillman Cancer Center and Magee-Womens Research Institute. For many years I’ve been interested in hormone response and response to endocrine treatment in patients with estrogen receptor–positive breast cancer. And as part of these studies, I became very interested in invasive lobular breast cancer, which is mostly estrogen receptor–positive and characterized by loss of a molecule that keeps cells glued together called E-cadherin. It has become obvious now that there are many molecular and clinical features that are different between ductal and lobular cancer. We need to study it more to really understand them and find ways to personalize medicine for patients was ILC.
I was diagnosed with early-stage lobular breast cancer in 2011, and when I started researching the disease, I realized that there was very little information out there and that lobular breast cancer wasn’t really talked about. As I became more and more interested in patience advocacy, I started asking, why is this? As a patient going through treatment, it’s clear that treatments that are equally applied [to all people with hormone receptor–positive breast cancer], are not always as well received in patients with lobular. Surgeries and screening and imaging is different. Being a patient with lobular breast cancer is like being the square peg as it’s pounded into the round hole. Sometimes it works if you pound on it hard enough, and then sometimes it doesn’t work at all.
I got some patient advocate training and then learned about the first Invasive Lobular Breast Cancer Symposium in Pittsburgh, which BCRF sponsored, and Steffi was one of the chairs. I was super excited, and about 30 of us from all over the country flew into Pittsburgh. We had advocate meetings and learned a lot, and then after that meeting, we continued to talk, eventually forming what became the Lobular Breast Cancer Alliance. Since that meeting, Steffi and I have worked very closely together on research and building advocacy for lobular breast cancer.
The meeting was great. We had more than 700 participants from 35 countries. A lot of progress has been made in the last five years since the first symposium. More investigators have started to include lobular models in their research, which has really propelled discoveries. Much of what we have learned is in ILC’s basic biology. That had resulted in a couple of clinical trials specifically for patients was ILC, which is exciting and which the advocacy community has pushed a lot.
There’s been a lot of progress in pathology. We can’t just use old methodologies, which very often are quite biased and subjective, to diagnose lobular breast cancer. We’re investigating using molecular signatures and artificial intelligence to diagnose ILC. Imaging remains a big problem for lobular tumors, both in the primary cancer setting as well as in the metastatic setting. It is clearly not picked up by traditional imaging approaches. We had a couple of great presentations on novel methodologies of imaging.
And I want to mention that for the longest time, we couldn’t make progress because we didn’t have models. All the models were for ductal cancer. So even if you had an idea, you couldn’t test it because you didn’t have the model. But again, we have made tremendous progress on this. And there are now multiple models where people can really study the disease more faithfully.
I also want to say that now we are seeing the next generation of lobular researchers. At the symposium, we had new investigators who are at the start of their career presenting, and they’re saying, ‘I’m going to start my lab studying lobular breast cancer.’
For me, it’s night and day almost between being diagnosed when there was no information available to the first symposium where lobular breast cancer had just begun to be understood as a different disease and was being discussed that way. There was opportunity there to really come together and advance interest in research. And at the same time, patients came together online and started talking to each other through Facebook groups, and this ignited a catalyst to start organizing as patients to move forward. We’ve seen great progress on that front as well. The Lobular Breast Cancer Alliance is probably still the flagship organization, but there are new organizations and movements in Europe, and we have advocates in Canada, Australia, and all over the world. We understand that it’s very important to collaborate and to all pull in the same direction. Now we need to keep identifying priorities for research and collaborating internationally as advocates and as researchers and clinicians to move forward.
What I’m most excited about is the increased awareness among researchers, physicians, and patients. People are now asking, what histology is it? That’s different from even 10 years ago. That’s exciting because it results in everybody asking, ‘Well, what does it mean? What is different?’ The second thing is that improvements have happened on the clinical end as well. There are clinical trials now running specifically for patients with ILC, which came out of benchwork that said, ‘OK, there is this overexpression of genes X, Y, and Z,’ and we need to test this in a clinical trial. Leigh mentioned this already, but different groups have come together in the U.S. and abroad. People know we need to work on this together. The symposium this year was co-run by investigators here and in Europe. We have an ILC symposium planned next year in Europe. The international collaboration we’ve developed has really opened a lot of new avenues of research.
In my lab, we have a pretty big group, so we try to tackle a couple of questions. Metastasis in ILC is a very big topic for us. There are clearly unique features of the metastasis. It recurs later. And it goes to different sites in the body—unusual sites, like the peritoneal metastasis that goes to the ovary. We don’t understand it yet, but we hope that we can set up models and work with patient advocates. Like many others, we have high hopes for immunotherapy. In general, the current dogma is that immune infiltration is low in estrogen receptor–positive disease, and it is high and much more tolerable in triple-negative breast cancer. But we do think there is a subset of patients with ILC whose tumors are immune infiltrated. And if not, can we try to get the immune cells into the tumor? We have an active program to try to see if there are specific biomarkers in ILC patients to determine whose tumors might actually respond to immunotherapy.
I should also say that we collaborate with many other groups on model development, and we make them available to other investigators. We are currently finishing a large comprehensive characterization of these models that will all go online, so everybody can access it.
Dr. Oesterreich: I’m grateful to BCRF for funding ILC research and the symposia. Everything the Foundation does is so important.
Leigh: We’re excited about the future and what can happen with lobular breast cancer. It feels like we’re on the brink of being able to have enriched clinical trials with lobular patients to understand the disease, and patients are only going to benefit from having personalized therapy moving forward.
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