Common Metastatic Breast Cancer Questions Answered by Oncologists

When told they have metastatic breast cancer, some individuals might be overflowing with questions about what it means for them, while others may not know what to ask their doctors. So, having a list of frequently asked questions about metastatic breast cancer may be helpful.

Dr. Jennifer M. Matro and Dr. Rebecca A. Shatsky answered several frequently asked questions about leptomeningeal disease, clinical trials and treatment options, following the Educated Patient® Metastatic Breast Cancer Summit.

Matro and Shatsky are breast medical oncologists at the University of California San Diego Health.

LEARN MORE: Answers to 10 Frequently Asked Questions About Metastatic Breast Cancer

If a person has brain metastases, do you order a biopsy of the lumbar spine (lower back) to rule out central nervous system or leptomeningeal diseases?

Matro and Shatsky: Generally, we can see leptomeningeal disease on brain magnetic resonance imaging (MRI; noninvasive imaging to see organs, bones and muscles) or spine MRI. The way to detect abnormal cells in the cerebral spinal fluid is by what’s called a lumbar puncture where they take fluid from your spine. We do not do this in all patients with brain metastases, because the rate of leptomeningeal disease even in patients with brain metastases is very low, especially if the MRI does not suggest there is leptomeningeal disease.

What trials are available for patients with metastatic lobular breast cancer?

There are very, very few trials for metastatic lobular breast cancer because many patients with metastatic lobular breast cancer do not have measurable disease by certain criteria. My good friend Dr. Jason Mouabbi is starting a trial at The University of Texas MD Anderson Cancer Center for metastatic lobular [breast cancer], but that is the only one I currently know of. I am currently trying to get funding for a registry trial, but it is not a treatment trial.

READ MORE: Oncologist Debunks Clinical Trial Myths

What percentage of the study trials mentioned having patients who are African American, and are there any noted differences in treatment responses compared with patients who are White?

The National Cancer Institute and the American Society of Clinical Trials have a specific initiative to increase the enrollment of participants who identify as minorities. However, historically enrollment of African American participants has been low for a variety of reasons. Most modern trials do have African American participants, but the levels are still lower than we would like.

What is known about the prognosis of bone-only disease? It sounds like not much is known if it’s typically not allowed in clinical trials.

The prognosis of bone-only disease is actually better! Patients with bone-only HR-positive metastatic breast cancer tend to have the best prognosis. It’s just hard to follow cancer in the bone on scans, which is why it can be hard to get on a study, where they need clear/hard evidence of growth or shrinkage of tumors.

Does research with immunotherapy lag behind other tumor types?

So there is extensive research ongoing on breast cancer with immunotherapy, but unfortunately, immunotherapy does not have the benefits in breast cancer that it does in certain other tumor types, like melanoma or kidney cancer. It is beneficial in certain breast cancer cases (usually triple-negative breast cancer cases), but not in most cases of the most common type of breast cancer, such as estrogen-positive, HER2-negative disease.

What is the longest time patients with estrogen-receptor (ER)-positive should be on hormone-blocking therapy? Should it be 10 years or longer?

For early-stage breast cancer, five to 10 years is standard and the exact duration is decided between the patient and their provider.

For metastatic breast cancer, there is no "longest" time. If you can stay on hormone therapy for more than 10 years, that's great! That means a much longer time until chemotherapy might be needed.

How often do doctors retest the tumor for HER2-low metastatic breast cancer, especially because Enhertu (fam-trastuzumab deruxtecan-nxki) seems very effective?

We'll retest until we have a "positive" result, meaning if you have a prior biopsy of HER2 1+ or 2+, you don't need a new biopsy just for HER2 testing. Going forward, many pathologists may be commenting on HER2 "ultralow", which, until now, was usually classified as HER2 0.

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