Metastatic breast cancer is an urgent priority for BCRF researchers as the leading cause of breast cancer deaths. While it can be treated—with more therapies and drugs available now than ever before—metastatic breast cancer remains incurable.
In the U.S. today, there are an estimated 200,000 women living with metastatic breast cancer, also called stage 4 breast cancer or advanced breast cancer. In addition, about one in three breast cancer survivors will be diagnosed with a recurrence (cancer that has come back after a diagnosis and treatment), which can metastasize (spread) to other organs of the body. Keep in mind, the rate of recurrence is variable based on many factors including subtype, age, treatment availability and adherence, among others. Alarmingly, in recent years, there has been a rise in metastatic breast cancer diagnoses in young women.
Developing strategies to treat metastatic breast cancer patients and advancing our understanding of the disease is a major focus for breast cancer researchers. Read more about the signs that breast cancer has spread and how BCRF-supported researchers are making progress against it.
Key Takeaways
Metastatic breast cancer is when cancer that initially started in the breast spreads to other areas of the body. Metastasis occurs when breast cancer cells break away from the original tumor or nearby lymph nodes (found under the arm, inside the breast, and near the collarbone). The breast tumor cells then enter the bloodstream or lymphatic system, travel to other organs, and begin to grow. Doctors most commonly find breast cancer metastases in the bones, lungs, liver, and/or brain.
Only 6 to 10 percent of women are first diagnosed with stage 4 breast cancer, called de novo metastatic breast cancer. However, nearly 30 percent of women diagnosed with early-stage breast cancer (stages 1-3) will see their disease metastasize.
The early signs of metastatic breast cancer may vary depending on how far the breast cancer has spread and what area/type of tissue the cancer has invaded. Non-specific symptoms of stage 4 breast cancer can include fatigue, weight loss, and poor appetite, but these may also be caused by medication, depression, and other conditions.
The most common metastatic breast cancer symptoms are listed below.
If you are currently undergoing treatment for breast cancer and experience any of these signs of stage 4 breast cancer, talk to your doctor right away. Early detection is important to ensure you’re getting the best treatment for metastatic breast cancer. If you are a breast cancer survivor or if members of your immediate family have been impacted by the disease and you begin experiencing any of the above symptoms, be sure your doctor knows your personal or family history of breast cancer.
If your doctor has reason to suspect your disease has metastasized (or that you may have de novo metastatic breast cancer) and you have any of the above signs that your breast cancer has spread, he or she may perform follow-up tests. These include imaging tests, blood tests, and biopsies of the suspected metastatic lesion.
For metastatic breast cancer symptoms that point to possible brain involvement, doctors will perform a brain MRI and, in rare cases, when possible, a brain biopsy. If your doctor suspects potential bone, lung, or liver involvement, he or she may use several types of imaging tests, including MRI, CT, or PET, and then perform a biopsy. For suspected lung or liver metastases, doctors will order bronchoscopy or a mucous exam and liver function tests or an ultrasound, respectively. There are also additional imaging tests (i.e., bone scans or X-rays) and blood tests to specifically diagnose metastatic breast cancer in bones.
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While there is no cure for metastatic breast cancer, there are a variety of treatment options that prolong lives.
After a metastatic breast cancer diagnosis, doctors may use several treatment approaches depending on where the cancer has spread, its characteristics (such as hormone receptor or HER2 status), and prior treatments.
The most common treatments for stage 4 breast cancer are:
There are also other therapies that target specific characteristics of cancer cells, such as proteins that allow cancer to grow unchecked. While chemotherapy does not distinguish between cancerous and non-cancerous cells and therefore can harm both, these targeted therapies are generally less likely to harm normal cells. There are more than a dozen such FDA-approved targeted therapies for metastatic breast cancer, including:
These therapies can be used alone or in combination with chemotherapy to treat specific breast cancer subtypes:
While surgery may be an option, it may not be the best one because it is unlikely to remove all cancer cells. However, some doctors recommend targeted surgery and/or radiation to alleviate pain or other specific symptoms. In addition, although doctors don’t commonly use other localized therapies (such as radiation therapy or ablation) to treat metastatic breast cancer, they may use them in certain circumstances, particularly when:
BCRF is the largest private funder of metastatic breast cancer research in the world. This year, the Foundation is dedicating almost $25 million across 96 projects to this area of study.
“Virtually all deaths from cancer are from metastases—we lose about 43,000 people in the U.S. alone to metastatic breast cancer each year,” says Dr. Dorraya El-Ashry, BCRF Chief Scientific Officer. “That’s why metastatic breast cancer research remains a high priority at BCRF. These projects will help us understand the full spectrum of metastatic disease in order to both effectively treat it and ultimately prevent it altogether.”
BCRF investigators are examining all aspects of stage 4 breast cancer, including:
In addition, BCRF supports several large initiatives through our flagship Evelyn H. Lauder Founder’s Fund for Metastatic Breast Cancer Research. To date, BCRF has invested over $48 million in this initiative.
Founder’s Fund-supported studies led to the development of an experimental model system that precisely mimics human breast metastases as well as an open-access online database of metastases models. Both tools are readily available to the research community to further metastatic breast cancer research.
The Founder’s Fund also supports the largest global effort to study metastatic breast cancer across Europe (AURORA EU) and the U.S. (AURORA US). These projects are designed to gain a deeper understanding of the molecular differences between primary and metastatic breast cancer.
AURORA EU is a large research initiative sponsored by the Breast International Group (BIG) that analyzes tumor and blood samples from metastatic breast cancer patients to better understand the disease, including how it progresses over time and why it responds well or not to specific treatments. It published its first findings in 2019.
AURORA US harnesses the extensive clinical trial infrastructure of the Translational Breast Cancer Research Consortium, a model clinical trials program accelerating advances in breast cancer care. It has two components: a retrospective analysis of primary and metastatic tumors, plus a prospective clinical study. It published its first findings in 2019.
While metastatic breast cancer has defied more simple solutions and is not yet curable, there is much to be hopeful about—especially recently. At the 2022 American Society of Clinical Oncology meeting, researchers, clinicians, and others heralded astonishing results from the DESTINY-Breast04 trial with a standing ovation: Researchers found that the drug Enhertu® significantly improved progression-free survival for patients with HER2-low metastatic cancer. Soon after, the FDA approved Enhertu for advanced HER2-low breast cancer. BCRF researchers and others continue working to more precisely define HER2-low so that more people can benefit from treatment with this drug. “This is an important study,” lead investigator Dr. Shanu Modi told BCRF in an interview. “We’ve opened up a new targetable population of patients within breast cancer. This is more than just about this drug and more than just about breast cancer. It’s about a huge advancement in cancer therapy in general.”
The pace of research in MBC has been accelerating. Since 2015, the FDA has approved 17 new drugs for this disease based on the clinical findings of BCRF investigators and other researchers. These include:
In addition, research is revealing that in certain patients—those with HER2-positive breast cancer—some metastases can be prevented. Research is the reason we are finally seeing real momentum in metastatic breast cancer research. We are on the cusp of groundbreaking developments in stage 4 breast cancer research, and BCRF is committed to leading the way.
Metastatic breast cancer is treatable but not yet curable. Thanks to research funded by organizations like BCRF, new therapies are helping many people live longer while maintaining quality of life.
Yes. While outcomes vary, some people live 10 years or more with metastatic breast cancer. Advances made possible through BCRF-funded research are extending survival and improving day-to-day care for many patients.
Life expectancy differs for each person, but research is steadily improving outcomes. With BCRF investing more in metastatic breast cancer than any other private funder in the U.S., survival rates are improving, offering more hope and time to patients.
Chemotherapy is often part of the treatment for metastatic breast cancer. Effectiveness depends on the individual case, but new targeted therapies and combinations are expanding options. BCRF-funded investigators are at the forefront of developing and testing these treatments.
Information and articles in BCRF’s “About Breast Cancer” resources section are for educational purposes only and are not intended as medical advice. Content in this section should never replace conversations with your medical team about your personal risk, diagnosis, treatment, and prognosis. Always speak to your doctor about your individual situation.
BCRF’s “About Breast Cancer” resources and articles are developed and produced by a team of experts. Chief Scientific Officer Dorraya El-Ashry, PhD provides scientific and medical review. Scientific Program Managers Priya Malhotra, PhD, Marisa Rubio, PhD, and Diana Schlamadinger, PhD research and write content with some additional support. Director of Content Elizabeth Sile serves as editor.
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