How Is Lobular Breast Cancer Detected?

This Q&A is adapted from The Breastcancer.org Podcast episode transcript.

Detecting lobular breast cancer is more difficult than finding ductal breast cancer because lobular breast cancer cells can grow in lines rather than masses. This means there may not be a mass that you can feel or that your doctor can see on a mammogram. Dr. Maxine Jochelson, director of mammography for Breastlink in Beverly Hills/Radnet, provided further information on this topic.

Q: In many cases, lobular breast cancer doesn't cause a lump. Is this why it's harder to see on a mammogram?

Dr. Maxine Jochelson: This is why it's harder to see on a mammogram, and why, by the time the patient does have a symptom, it's often later.

Q: When you're reading a mammogram and you see a suspicious area, do you automatically recommend another type of imaging, or does it depend on what you see?

Dr. Maxine Jochelson: So, first of all, there are two kinds of mammograms. There are screening mammograms – those are mammograms that are done in women who have no symptoms at all – and then there are diagnostic mammograms, where a woman may come in with a symptom. And we approach them slightly differently.

If the patient has a lump, the technologist (the person who performs the mammogram) has marked its location on the mammograms. I look at the mammogram. If I don't see anything on the mammogram that goes with the lump, I will then do an ultrasound. We read diagnostic mammograms while the patient is in the building.

Screening mammograms, the ones done in women with no symptoms, we read in batches. The patient gets the results by the next business day. If I do see something abnormal, I will do additional mammographic imaging and often ultrasound.

Q: If you're looking at a diagnostic mammogram and lobular breast cancer is a possibility, how do you approach that?

Dr. Maxine Jochelson: When I read any mammogram, I'm just looking for a cancer.

I don't really think, “Oh, I'm looking for invasive lobular,” but there are patterns that you do see when you have lobular cancer. Sometimes  there is an asymmetry — an area of tissue that doesn’t fit into the pattern of the normal breast; the breast looks a little different than the other breast, for example. Or there's a well-known syndrome when it's fairly advanced, is that you have a shrinking breast. So, if you see old films and you see, all of a sudden, one breast is getting smaller, those are the kinds of things that can tip you off, but no finding is so distinctive that you can make a diagnosis. A biopsy is required..

But by the time you're seeing those things, the tumor's been there for a while, but those are the things that makes your brain go lobular versus ductal cancer.

Q: Is it possible to find lobular breast cancer early?

Dr. Maxine Jochelson: Yes, sometimes. Because it does disrupt the architecture of the breast and it may just be a small area early on, and one of the things that tomosynthesis [3D mammograms] is very good for is looking at what we call asymmetries or architectural distortion, because since you're looking at such thin slices through the breast.

In the old days, mammography only provided a two-dimensional image and you see everything on top of everything so subtle changes could be missed. Whereas, with tomosynthesis, you are going in thin sections through the breast, and so, a subtle area of change can be detected more easily than you could on the old type of mammograms. So, you can find them early. Sometimes they present with microcalcifications.

Q: There are different types of PET scans, which are used to look for metastatic disease — cancer in parts of the body away from the breast — after someone has been diagnosed with lobular breast cancer. What's the difference between a FES-PET scan versus an FDG-PET scan?

Dr. Maxine Jochelson: The tools that we use have changed over time. We used to use just CAT scans and bone scans to look for metastatic disease. Once we started doing PET scans, we found that PET scans were more sensitive and more accurate.

In an FDG-PET scan, FDG, which stands for fluorodeoxyglusose, is a sugar labelled with a radioactive tracer that is injected intravenously into a patient who has been fasting for four to six hours. The patient lies still for an hour after they've done this and while they're resting, the FDG will go to areas of cancer. It can also go to areas that are not cancer. For example, the heart — because the heart's beating. FDG isn’t great at showing cancers in the brain, but very accurate in most other places in the body. What we've learned, over a period of time, FDG is fantastic for invasive ductal cancers.

We began to realize that women with invasive lobular cancers don't necessarily take up the FDG at all or to the same extent as women with invasive ductal cancers, and over a period of time, we have looked at other tracers.

FES, which stands for Fluoroestradiol F18, is a relatively newly U.S. Food and Drug Administration-approved tracer attached to an estradiol, a type of estrogen. With this tracer, you don’t have to lie still after the injection. What we've learned is that in breast cancers that are less aggressive, or slower growing – so, that includes invasive lobulars – FES is often better than FDG.

FES has one flaw: It normally goes to the liver and the liver takes up so much FES that your ability  to detect liver metastases is  reduced.

Otherwise, FES shows you the rest of the body beautifully, and in fact, we have certainly seen patients in whom the FDG is negative or not so much going on, and the FES is very avid, so you see the tumor well.

Because FES is still relatively new, in most women, we start with the FDG-PET scan, because that still is the standard of care.

The other thing that's very interesting is that the FDG and FES scans can also tell you which drugs are more likely to work in your tumor. So, if you don't see a lot of uptake on the PET scan in an ER-positive tumor, those women are less likely to get a benefit from certain hormone therapies than women where there's more uptake. Therefore, the different tracers help you predict response to treatment by certain drugs.

If the patient has more FDG uptake, it's a more aggressive tumor. So, [FDG-PET and FES-PET] don’t just help you find the cancer. They also tell you how it should be treated and how it will behave.

Q: If somebody had been diagnosed with lobular breast cancer and it was suspected that the cancer had metastasized, it's likely the person would probably get the FDG-PET scan first, and then, if that didn't show anything, they would get the FES-PET scan? Is that correct?

Dr. Maxine Jochelson: At this point in time, yes.

Q: If someone were diagnosed with metastatic lobular breast cancer, is PET scan the primary type of imaging somebody would have to monitor how treatment was working?

Dr. Maxine Jochelson: Yes, and it's a PET/CT, so you are getting a CT scan along with this. It's not just pure PET. So, you're seeing the bones. You're seeing all the structures, and then you're seeing the PET scan on top.

There are still places that aren't using PET. There are issues in terms of insurers reimbursing for it, although it has finally made it all the way to the top in the NCCN guidelines, which is how the insurers take their cues [If a treatment is in the NCCN guidelines, it’s usually covered by insurance. If a treatment isn’t in the guidelines, some insurers won’t cover it]. So some are still doing CT and bone scans, but most research says that PET/CT is a better tool.

If a patient comes in and we're suspecting metastases, we'll do the PET or the FES, and then we'll treat the patient, and then, depending on the individual and her tumor, in two to three to four months, reimage. It also depends on what drugs you're using and how the patient is. You know, if she's not responding well to the drug or if it's making her ill, they may rescan her and see what's going on.

Q: Are the PET/CT scan done all at one time?

Dr. Maxine Jochelson: The patient gets a CT, which only takes minutes, followed by the PET imaging, which takes around 20-30 minutes.

So you read the CT with that, and then it fuses them, and so, you can then look at them, the PET on top of the CT alone and then the PET is fused with the CT. The machines are getting faster and faster.

Q: When lobular breast cancer metastasizes, it tends to go to some different areas than ductal breast cancer, including the gastrointestinal tract, the abdominal lining, and the tissue around the eyes or kidneys. Are the same imaging tests used on those areas?

Dr. Maxine Jochelson: Yes. The issue is just recognizing where these metastases occur and paying attention to those areas. For example,  the lining of the stomach is just a very thin layer of cells. So, you have to look in a different way. I mean, you know, we look for everything, but you have to have, in your brain, well, in this particular patient, I really need to make sure that I take a really good look there.

Q: If somebody suspected that they had lobular breast cancer rather than ductal breast cancer, should they go to their doctor and ask for specific tests, or is the doctor going to know and order them?

Dr. Maxine Jochelson: When a patient has a breast symptom, they go to the doctor, and the doctor examines them and you start with the routine test.

There's no reason to start with anything but your basic mammogram and ultrasound. And then, if there is still further concern, then your doctor can do additional testing, and many people will think about doing a breast MRI. We also have a test that we do at Memorial Sloan Kettering called contrast-enhanced mammography, and both of these are similar, in that you give women dye.

Cancer vessels are leaky, and when you give people the dye, it leaks out, and it will show you something's going on in that area, even if you can't see a discreet mass, and so, if you're highly suspicious that something like that is going on with the patient and you're not finding it on the mammogram or the ultrasound, then move to to MRI or contrasted-enhanced mammography to try to get a better look at what's going on.