Symptoms of Metastatic Breast Cancer

These symptoms shouldn't be ignored

This article was medically reviewed by Steffini Stalos, DO, who is board-certified in Pathology and Lab Medicine, on June 27, 2022.

Breast cancer is the most second common cancer among American women, according to the American Cancer Society (ACS). There is a one in eight chance a woman will develop breast cancer.

For the most part, breast cancer, in general, is very treatable if detected early. But sometimes, that cancer can spread to distant parts of the body—places beyond the breast and nearby lymph nodes—and become too advanced to treat with the intent of a cure. This is known as metastatic breast cancer, or stage 4 breast cancer, and it's the most advanced stage of the disease.

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The most common places for breast cancer to spread are the bones, liver, lungs, and brain; and less commonly, to the abdomen and skin, Nancy Lin, MD, an oncologist who specializes in breast cancer at Dana-Farber Cancer Institute in Boston, told Health. Experts aren't entirely sure why or how breast cancer spreads in this way, but per the National Cancer Institute (NCI), metastasis occurs when cancer cells find their way into the bloodstream and lymphatic system and thus are able to move throughout the body.

The signs of metastatic breast cancer can vary significantly depending on where it has spread and how far it has progressed. Here, experts break down the many metastatic breast cancer symptoms, and what to know if you or a loved one are experiencing them.

What Are the Generalized Symptoms of Metastatic Breast Cancer?

There are some generalized symptoms attributed to metastatic breast cancer. A healthcare provider will best address any symptoms that could overlap with breast cancer or any other health condition.

Generalized symptoms result from your cancer cells starving your body of nutrients. "When you have metastatic disease, the body is really competing with the cancer for survival, nutrition, and energy," Evelyn Toyin Taiwo, MD, hematologist and oncologist at Weill Cornell Medicine and NewYork-Presbyterian Brooklyn Methodist Hospital, told Health. "The body has to work a little bit harder than it normally does (to function)."

Here are some of the more common generalized symptoms of metastatic breast cancer:

Fatigue

This is a common cancer symptom in general, and can be a sign that a person's cancer has metastasized. According to the American Cancer Society, cancer can change normal protein and hormone levels that are linked to inflammatory processes which can cause or worsen fatigue. In addition, cancer forms toxic substances in the body that change the way normal cells work. Cancer can also cause anemia, a condition in which a person lacks enough healthy red blood cells, said Dr. Taiwo, which can also affect energy levels.

Lack of Appetite

According to Dr. Taiwo, anorexia (which in this case means lack of appetite) is a common symptom of metastatic cancer. Naturally, if a person is experiencing symptoms like nausea and vomiting, a person is less likely to eat. Per the ACS, certain types of cancers might also release hormones that impact a person's natural hunger signals.

Extreme Weight Loss

This again goes back to the fact that cancer is starving your healthy cells of nutrients. When cancer has progressed to the point of metastasis, a person can start losing weight without intending to. Additionally, a person who doesn't eat due to a lack of appetite will eventually start to lose weight.

What Are the Other Symptoms?

Metastatic breast cancer most often spreads to the bones, lungs, liver, and brain. It doesn't spread exclusively to those locations, but these are the most common sites of metastasis.

Most metastatic breast cancer patients don't experience symptoms in their breasts, said Dr. Taiwo. That's because, in the majority of cases of metastatic breast cancer, a person was previously diagnosed with an earlier-stage breast cancer and received localized treatment to their breasts. Only a minority of metastatic breast cancer patients are initially diagnosed with stage 4 cancer; if they have a breast mass, it likely isn't painful, said Dr. Taiwo. Very rarely does a breast cancer mass grow to the point where it becomes ulcerous and painful.

Thus, most symptoms of metastatic breast cancer vary depending on where the cancer has spread. Someone who has cancerous lesions in their bone will have a different set of symptoms than someone whose cancer has metastasized to their brain or liver. Here's an overview of the different symptoms of these common sites.

In the Bones

The bone is one of the most common places for breast cancer to metastasize—60% of metastatic breast cancer patients experience bone or lung metastasis, according to research published in the journal Cancer. The most common symptom is bone or joint pain that progressively gets worse, Dean Tsarwhas, MD, the medical director of cancer services for Northwestern Medicine Lake Forest Hospital, told Health. Dr. Tsarwhas added that the most common areas for the bone to be affected are in the hip and lower back.

Identifying bone pain can be challenging for patients who have arthritis or other chronic pain issues, said Dr. Taiwo. "Patients who have arthritis...aren't that concerned about the pain that they're having. They think it's part of the arthritis." Dr. Taiwo added that any new pain that feels different than other chronic pain a patient may have experienced is a red flag that their breast cancer may have spread.

In rare cases, said Dr. Taiwo, patients find out they have metastatic breast cancer in their bones after breaking their bone (say from a fall or other injury). "In the process, images are done and we find that they have other [bone] lesions in the area." This is known as a pathologic fracture.

In the Liver

This can be a bit trickier to identify because the symptoms can be similar to other stomach and gastrointestinal issues, said Dr. Taiwo. Often a person will have abdominal pain, nausea, vomiting, or even jaundice (where the skin and whites of the eyes turn yellow), depending on how much the cancer has spread in the liver. By the time that a patient tends to present with symptoms, they already have a fairly significant burden of disease, explained Dr. Taiwo—meaning that their cancer has already progressed to make them very sick.

In the Lungs

As with the liver, there aren't often symptoms of metastatic breast cancer in the lungs until the disease has progressed fairly significantly, said Dr. Taiwo. Sometimes a person has a dry cough, or fluid builds up in the lungs to cause shortness of breath.

In the Brain

Metastatic breast cancer doesn't often spread to the brain, although it is more common with triple-negative breast cancer, said Dr. Tsarwhas. When it does, symptoms can include headaches, nausea, vomiting, dizziness, or trouble standing or walking, explained Dr. Taiwo. In rarer cases, a patient can experience seizures. These symptoms result from the increased intracranial pressure caused by the addition of cancer to the brain cavity—which is a pretty tight space to begin with, said Dr. Taiwo.

What Are Other Complications?

If a person's cancer has progressed significantly without treatment (or without response to treatment), it can cause more serious complications that can be life-threatening. Here are some of the most common:

Bone Fractures

These are a common complication from metastatic breast cancer that has spread to the bones, Alberto Montero, MD, director of the breast cancer program at University Hospitals Seidman Cancer Center in Cleveland, Ohio, told Health. "Cancer in the bone can erode the integrity of the bone, causing a fracture," said Dr. Montero.

Spinal Cord Compression

This can happen if cancer metastasizes into the spinal column, said Dr. Taiwo. The cancer can press into the spinal cord and surrounding nerves (which are protected by the spinal column), causing weakness or numbness in the limbs—particularly the lower extremities, Dr. Taiwo explained. If not addressed, a person can lose function of their bladder, bowels, or limbs. According to the journal Clinical Medicine, this is a less common complication affecting an estimated 3%–5% of cancer patients. Although it's more likely to happen in patients with breast, prostate, and lung cancer.

Hypercalcemia

This is where a person has too much calcium in their blood. It can be a complication of metastatic breast cancer (although it can happen in earlier-stage breast cancers). "Whenever there's cancer in the bone, calcium can leach out," said Dr. Montero. Cancer cells release cytokines and proteins that disrupt the bone regrowth process, making the bone break down faster than it can regenerate itself—releasing calcium into the blood. "Really high calcium levels can cause heart abnormalities," said Dr. Montero, as well as confusion, excessive thirst, confusion, and lethargy. Hypercalcemia is often a sign that the cancer has advanced significantly, and is associated with a poorer prognosis despite newer advancements in treatment, according to data in the Journal of Clinical Oncology.

Malignant Pleural Effusion

This is a complication of metastatic breast cancer in the lungs. It is caused by the buildup of cancer cells and excess fluid in the pleura (defined by the National Library of Medicine as the tissues that cover and protect the lungs). Normally these tissues have a small amount of fluid for lubrication, explained Dr. Montero, which gets reabsorbed by your lymphatic system. "When there's metastatic cancer, it can clog up the lymphatic system in your chest," said Dr. Montero, leading to a buildup of fluid that causes coughing, shortness of breath, and chest pain.

How Is Metastatic Breast Cancer Diagnosed?

Usually, an earlier-stage breast cancer diagnosis happens by mammogram, said Dr. Lin. Often there's a follow-up with an ultrasound or MRI, then a biopsy, to confirm that it is breast cancer and not a benign mass. But with metastatic breast cancer, a patient usually has already been diagnosed with and treated for breast cancer. So diagnosis typically comes in response to new symptoms.

"Our antennae are always up," said Dr. Taiwo, if a patient with a history of breast cancer starts experiencing symptoms such as new bone pain or unexplained nausea, or weight loss. "We have a low threshold to investigate further to see if the patient is now metastatic."

For example: If a patient who was initially diagnosed with stage 2 breast cancer later complains of hip pain and trouble walking, said Dr. Lin, she'll typically do an X-ray and a bone scan to see if there's any evidence of cancer in the bone. Similarly, if a person with a history of breast cancer starts experiencing headaches and dizziness, a healthcare provider may perform an MRI to see whether the cancer has spread to the brain.

In the future, said Dr. Tsarwhas, there may be more proactive ways to diagnose metastatic breast cancer, such as blood tests that can detect metastatic breast cancer cells in the bloodstream. For instance, the development of liquid biopsies that detect cell-free DNA as an indicator of minimum residual disease (MRD) is currently underway. The National Cancer Institute defines MRD as a term describing when a very small number of cancer cells remain in the body during or after treatment. According to a 2021 study published in the journal Cancers, the field is constantly advancing and could add to the detection capabilities for breast cancer.

Dr. Lin said that these kinds of tests could help providers begin treatment and potentially even eradicate the cancer before it progresses to stage 4. Treatments are also improving to help drastically increase a patient's lifespan, added Dr. Tsarwhas.

If you have a history of breast cancer and are experiencing new, troubling symptoms, be sure to talk to your healthcare provider as soon as possible. "There are times for optimism given all of the research and developments that have happened in the treatment of breast cancer," said Dr. Tsarwhas. By being proactive about any metastatic breast cancer symptoms you have, you can help ensure that you are getting the best possible care—and improving your odds for living a longer life with the disease.

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