The term “metastatic” means that cancer cells have broken away from their original tumor and traveled to other organs. Cancer cells spread by moving through your bloodstream or lymphatic system (a network of lymph nodes and vessels). In the case of metastatic breast cancer, cancer cells commonly spread from the breast to the:
BonesBrainLiverLungs
Even when the cancer spreads to a new organ, it’s still named after its original location. For example, doctors may find cancer in your lungs, but if the cancer started in your breast, it’s considered metastatic breast cancer (not lung cancer). Though there’s currently no cure for metastatic breast cancer, newer treatments are extending survival and improving quality of life for many people with the disease.
De novo This means the cancer has already spread to another area of the body at the time of diagnosis. About 6 percent of women and 9 percent of men have metastatic disease when their breast cancer is initially diagnosed, according to the Cleveland Clinic.Metastatic or distant recurrence A metastatic or distant recurrence refers to breast cancer that was not considered metastatic at the time of diagnosis, but has come back in another area of the body after initial treatment. A metastatic recurrence is more common than a de novo diagnosis, according to the Cleveland Clinic.
Symptoms of breast cancer that has spread to the bones include:
Bone painSwellingBone fractures
Symptoms of breast cancer that has spread to the brain include:
HeadachesPressure in the headSeizuresVision problemsNausea and vomitingLoss of balanceProblems with speech or memoryPersonality changes
Symptoms of breast cancer that has spread to the liver include:
Jaundice (yellowing of the skin or whites of the eyes)Itchy skinRashStomach painLoss of appetiteNausea or vomitingHigh liver enzymes in the blood
Symptoms of breast cancer that has spread to the lungs include:
Difficulty breathingA cough that doesn’t go awayChest pain
Blood tests These usually include a complete blood count and a comprehensive metabolic panel.Imaging Common imaging tests include magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), ultrasound, X-ray, or a bone scan.Biopsy In a biopsy, doctors remove a sample of tissue from a suspicious area to analyze it for the presence of cancer cells.Bronchoscopy This procedure involves using a scope to look inside the lungs if doctors suspect cancer has spread there.A tap procedure A tap may be performed to remove fluid from the spinal cord or lung area. The fluid is then checked under a microscope for signs of cancer.
Testing a Metastatic Tumor
Once a diagnosis of metastatic breast cancer is confirmed, your doctor may perform other tests to identify the traits of the tumor. This information is important for determining which treatment options will be most successful. Your doctor may test a tumor’s biology for:
Hormone receptor status If a tumor is hormone receptor-positive, it means the tumor can respond to hormonal therapies.HER2 status HER2 is a protein that is overexpressed in certain breast cancer cells. If a cancer is HER2-positive, doctors may recommend treatments that specifically target the HER2 protein.A PIK3CA gene mutation Certain treatments are available to target tumors with a PIK3CA gene mutation.PD-L1 status The presence of PD-L1 proteins on tumor cells suggests that a cancer may be responsive to some forms of immunotherapy.
If the breast cancer is a recurrence, patients may recall having some of these tests done before, when first diagnosed. Doctors will recommend that they be repeated if the disease recurs, because HER2 status and hormone receptor status can change, according to Breastcancer.org. Researchers are studying why metastatic breast cancer occurs in some, but not all, cases of breast cancer. Any type of breast cancer can metastasize, and you can’t do anything to prevent it from happening, according to the Cleveland Clinic.
Risk Factors for Metastatic Breast Cancer
While any breast cancer can spread, some risk factors for metastasis may include:
The type of breast cancer Certain aggressive types of breast cancer, such as HER2-positive and triple-negative breast cancers, are more aggressive, difficult to treat, and more likely to spread.How the cancer grows Fast-growing cancers are more apt to metastasize.The stage at diagnosis Cancers that have already spread to the lymph nodes or are very large may be more likely to metastasize to other areas of the body.
According to the Cleveland Clinic, possible complications related to the site of metastasis include:
Bone metastasis can cause pain, fractures, spinal cord compression, or hypercalcemia (too much calcium in the blood).Lung metastasis can cause shortness of breath, chest pain, pneumonia, pleural effusion (fluid buildup in the membranes that line the lung), bleeding in the lungs, or obstruction of the airways.Liver metastasis can cause jaundice, abdominal pain, shoulder pain, confusion, itching, or bleeding.Brain metastasis can cause seizures, balance issues, weakness, numbness, vision problems, headaches, personality changes, or loss of consciousness.
Where the cancer has spread in your bodyThe tumor’s hormone receptor and HER2 statusThe tumor’s gene mutationsSymptomsThe treatments received in the pastGenderMenopausal statusOverall health
While treatment for metastatic breast cancer is not expected to cure the disease, it can extend survival and improve quality of life.
Hormone Therapy
Hormone therapy may be a treatment option for tumors that test positive for estrogen or progesterone receptors. The treatment works by lowering levels of these hormones in your body or blocking them from reaching cancer cells. This prevents the tumors from using the hormones to fuel their growth. There are many hormone therapies available. Doctors commonly recommend tamoxifen, an aromatase inhibitor, or fulvestrant (Faslodex) for breast cancer that has come back or spread, according to the American Cancer Society.
Chemotherapy
Chemotherapy involves using drugs to kill cancer cells. Most of the time, chemotherapy drugs are given one at a time for advanced cancer, instead of in combination with each other, as they are in earlier-stage disease. The American Cancer Society lists the following chemo medicines as possible treatments for metastatic breast cancer:
Taxanes, such as paclitaxel (Taxol), docetaxel (Taxotere), and albumin-bound paclitaxel (Abraxane)Anthracyclines, such as doxorubicin (Adriamycin), liposomal doxorubicin (Doxil), and epirubicin (Ellence)Platinum agents (Cisplatin, carboplatin)Ixabepilone (Ixempra)Eribulin (Halaven)Vinorelbine (Navelbine)Capecitabine (Xeloda)Gemcitabine (Gemzar)Antibody drug conjugates (ado-trastuzumab emtansine [Kadcyla], fam-trastuzumab deruxtecan [Enhertu], sacituzumab govitecan [Trodelvy])
Targeted Therapy
Targeted therapies focus on blocking specific proteins on breast cancer cells that help them grow and spread. Different tumors have different targets. That’s why doctors perform tests to identify the gene mutations or proteins in your tumor. The type of targeted therapy your doctor recommends will depend on your tumor’s biology. For instance, if your tumor tests positive for HER2, targeted treatments may be used to block the HER2 protein that promotes breast cancer cell growth. There are many types of targeted therapies. According to Memorial Sloan Kettering Cancer Center, some newer targeted medicines commonly used in breast cancer are:
Trastuzumab (Herceptin)Pertuzumab (Perjeta)Ado-trastuzumab-emtansine (T-DM1, Kadcyla)Everolimus (Afinitor)Lapatinib (Tykerb)Palbociclib (Ibrance)
Immunotherapy
Immunotherapy involves using the body’s own immune system to fight cancer. The following immunotherapies are used to treat metastatic breast cancer, according to the American Society of Clinical Oncology:
Pembrolizumab (Keytruda)Dostarlimab (Jemperli)
Surgery
Surgery isn’t commonly used to treat metastatic breast cancer, but it can be an option in certain cases. For example, doctors may remove a tumor that’s causing discomfort or other problems. Or, if breast cancer has spread to the brain, surgery may be used to shrink the cancer.
Radiation
Radiation involves using high-energy X-rays or other particles to kill cancer cells. The treatment may help shrink tumors or improve symptoms. It may also be used for breast cancer that has spread to the brain.
Clinical Trials
Clinical trials are research studies that look for new ways to treat or prevent different diseases. People with metastatic breast cancer may benefit from participating in a clinical trial by receiving certain therapies that aren’t available otherwise. Talk to your doctor about the pros and cons of joining a clinical trial. Additionally, the Centers for Disease Control and Prevention (CDC) says you can reduce your risk of developing breast cancer by:
Maintaining a healthy weightBeing physically activeAvoiding alcohol or drinking in moderationBreastfeedingAvoiding taking combined hormone replacement therapy (HRT)
Research also shows postmenopausal women with hormone receptor positive breast cancers who take estrogen-blocking medicines, such as tamoxifen, may reduce their risk of recurrence by 40 percent to 50 percent. Metastatic breast cancer can also affect men, but male breast cancer is rare. According to Breastcancer.org, less than 1 percent of all breast cancers occur in men. In 2022, about 2,700 men will develop the disease compared with 287,000 women. The American Cancer Society says that about 530 men will die of breast cancer. Black women are also more likely to have breast cancer at a younger age, have more aggressive forms of the disease, and have a higher death rate. Black women have a 41 percent higher death rate from breast cancer than white women, according to the American Cancer Society. The death rate among young Black women is about double that of young white women, according to the Breast Cancer Research Foundation. Researchers are conducting studies to better understand why this disparity exists. According to the Breast Cancer Research Foundation, some possible reasons include:
Social and economic factorsUnequal access to medical careBiological differences in breast tumorsLifestyle habits
The American Cancer Society says that Black men with breast cancer also tend to have a worse prognosis.
Breast cancerInvasive ductal carcinoma (IDC)Invasive lobular carcinomaTriple-negative breast cancerInflammatory breast cancerDuctal carcinoma in situ (DCIS)
Breastcancer.org Metastatic Breast Cancer Network Metastatic Breast Cancer Alliance MBCBrainMets.org METAvivor Metastasis Research Society Twisted Pink Susan G. Komen Living Beyond Breast Cancer CancerCare National Breast Cancer Coalition Tigerlily Foundation Inflammatory Breast Cancer Research Foundation Cancer.Net
