Published on August 13, 2020
New PET Tracer Imaging for Breast Cancer
Metastatic breast cancer patient advocate Kelly Shanahan talks to Dr. Daniel Stover of the Ohio State University Comprehensive Cancer Center about his research on novel PET tracers. Watch as they discuss how this would help target subsets of breast cancer and advance immunotherapy options.
This is part one of a two-part series. Part 2: New Liquid Biopsy Tests for Breast Cancer.
Transcript | New PET Tracers for Breast Cancer
Welcome today. We have with us today Dr. Daniel Stover of the Ohio State University Comprehensive Cancer Center also known as The James and Dr. Stover did his training at a place that's actually kind of near and dear to me, did medical school and residency at Vanderbilt University. I lost my spleen at Vanderbilt. And then did his oncology fellowship at Dana-Farber up in Boston. So he's started off in the East and has kind of moved to the Midwest now.
Dr. Stover works with the translational therapeutics program at The James. And I'm really excited for you guys to hear about some of the work he's doing. I am lucky enough to be a research advocate for Dr. Stover, so I'm aware of some of his amazing, amazing work. And what I'd love to start off with is some of the work you're doing on novel tracers, especially with PETs. We all know about the glucose tagged PET, the FDG-PET that probably most of us with metastatic disease have had at one point. But there are other tracers that can help find different cancer subtypes in different places. And I'd love for you to start off telling us a little bit about the work you're doing in that area.
Well, thanks, Kelly. Thanks for having me. Excited to be on and thinking about some of these important issues. So you're exactly right. When we think about imaging for metastatic breast cancer, the standard is to use a contrast-enhanced CT scan with a bone scan or a standard FDG or glucose, as you said, a PET scan, but there are these novel tracers. So a PET scan can be done with a tracer that targets many different possible molecules. Historically, glucose is the most well studied and most widely implemented because cancer cells take up glucose. But there are several new tracers that are targeting different aspects of advanced breast and other cancers.
One of those that you and I have worked on developing a study around is sodium fluoride, which is a very sensitive tracer related to bone uptake. And so there's interest to see whether we can build on some existing work with sodium fluoride PET to see if it can be a more sensitive marker for bone metastases. Sodium fluoride PET scans have been studied for some time. And there are some questions about whether there are too many false positives and expense, which is always a challenge with scans. But the question of whether this could be used to help the patients, particularly those with only bone metastases, potentially even enroll in clinical trials is of great interest.
Let me interrupt for a second. Do you need anything special other than the tracer itself, which it seems like, as you know, I live at Lake Tahoe, so not exactly the hotbed of medical research and or medical facilities, but is that something where a tracer could be sent? Do you need a special type of PET machine, like latest-generation PET, or could it be done on just the type of PET scanner that's available in most communities?
That's a great question and I'm a medical oncologist, so not a PET imaging expert. But you're exactly right that the tracer itself is one of the key things that it has to be made in a specialized facility and it has to be able to be accessed where those PET scanners are so that the patient can be delivered the tracer. So I think that that is one major hurdle. I think that the other, without strong evidence for exactly how to use it, that has sort of limited its widespread adoption. And then there's also the reading, so the radiologists have to be comfortable with that. So I think that there are definitely still some, as you said, just general logistical hurdles, but I think that the core thing is to really first understand if we could do better for patients with advanced breast cancer, then we really need to think about how we can get over those logistical hurdles.
And I think that there's a lot of exciting new tracers that could be used with PET scans. One that we have studied is FLT, which is a marker of how fast cells are dividing. So that can be studied. There can be specific targets. You mentioned the estrogen receptor targeting PETs or HER-2. And then there's also a lot of excitement about using sort of immune PETs, so tracers that might tell us something more about what's going on in the immune microenvironment or among the immune cells that are within individual tumors.
And this is very exciting in the immuno-oncology space, where they're looking at medications that activate the body's own immune system. So can these immune PETs help us both tell whether a patient's responding or not and also guide therapy? So I think that there's a lot that is sort of ongoing in that research. But the core challenge with these novel imaging is to show that it's at least as good or better than standard and it can be delivered broadly. And that there's always the cost question. If these are a lot more expensive, does that cost-benefit work? And so I think that those three areas are always a challenge with imaging.
So that's a challenge with everything...
... that we face in oncology.