Am I Feeling Symptoms of Breast Cancer Spreading to My Brain — or Something Else?

When breast cancer spreads to the brain, if it spreads beyond the breast and nearby lymph nodes at all, a brain metastasis diagnosis can be complicated by symptoms that resemble various noncancerous conditions, such as stroke and severe forms of long-COVID.

• Changes in mental function (ability to think, process information, understand, and use words correctly)
• Changes in smell or hearing
• Headaches
• Loss of balance
• Nausea or vomiting
• Personality changes
• Seizures
• Vision changes (seeing double, lights or flashes, or a narrowed visual field)
• Weakness or numbness on one side of the body

But these symptoms are also similar to those of many other conditions that aren't cancer.

“It’s unfortunate because with metastatic breast cancer, we want people to be vigilant, but we don’t want them living in fear of every headache, brain fog, or muscle spasm,” says Sara A. Hurvitz, MD, the senior vice president and the director of the Clinical Research Division at Fred Hutchinson Cancer Center in Seattle.

Given that the brain is the command-control center for so many bodily functions, a cancer affecting it is “unusually scary,” says Azka Ali, MD, a breast medical oncologist at Cleveland Clinic in Ohio. “People envision the many ways in which it might cause them to lose bodily control.”

How, then, can people with breast cancer appropriately identify the signs and symptoms of brain metastasis? Here’s what Drs. Hurvitz and Ali advise.

Know What’s Normal for You

And make sure that your healthcare team knows it, too.

“If you regularly experience headaches, for example, recognize when they’re more frequent, more severe, or have additional associated symptoms, and when your usual meds or therapies aren’t working,” Ali says.

The same is true if you have age-related macular degeneration or diabetic macular edema and it worsens, further impairing your vision. Or perhaps your severe COVID-19 infection brought on a persistent brain fog, dizziness, and loss of smell or taste.

It’s also important to know the possible side effects of your breast cancer treatments.

Some side effects may mimic symptoms of brain metastasis. “Tell your healthcare team right away,” Ali says, “so that together you can consider different treatments that are better tolerated.”

Use the 2-Week Rule

Give yourself two weeks, Hurvitz says, to determine whether any changes you’re experiencing dissipate (with or without medication). If they remain the same or intensify, they may need to be assessed by a doctor.

While you should speak with your oncologist sooner if symptoms worry you, Hurvitz says, “Two weeks gives people a rough measure of whether they’re underreacting and perhaps denying that something’s out-of-the-ordinary, or overreacting to something that, within a reasonable period, goes away.”

There are exceptions, however.

Run, Don’t Walk, to the Oncologist With These Symptoms

Call the oncologist immediately if you have any of the following:

• A debilitating headache
• A seizure
• What feels like a stroke, such as sudden numbness or drooping of one side of the face or body, slurring of words or trouble speaking, or severe headache with no known cause
• New muscle weakness
• Mental confusion, excessive drowsiness, inability to think

Sometimes these can be misleading, Hurvitz says. “Only brain imaging and tests can tell us for sure.”

Understand Your Specific Risk Factors

The risk of brain metastasis has a lot to do with your tumor’s biology, or your breast cancer subtype.

• Human epidermal growth factor receptor 2–positive (HER2-positive) breast cancer, which means your cancer cells have high levels of the HER2 protein, and which accounts for about 15 to 20 percent of breast tumors

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• Triple-negative breast cancer, which is defined by the absence of estrogen-, progesterone-, and HER2 receptors, and describes 10 to 15 percent of breast cancers

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“We do see that Black Americans — women and men — are affected by more aggressive types of breast cancer and tend to have more advanced disease and higher death rates,” Ali says. “That’s why people need to speak with their healthcare teams about whether they’re in a high-risk group or at increased risk in other ways.”

Ask Early and Often About Clinical Trials

Participation in clinical trials can help people feel that they are actively pursuing better healthcare. “That sense of taking action on their own behalf,” Hurvitz says, “can change the tinted glasses through which people regard living with cancer and the fear of its spread.”

Joining a clinical trial may alleviate some fears of metastasis because it provides access to comprehensive checkups, continual surveillance, and state-of-the-art care, plus the latest thinking in risk assessment, diagnosis, and treatments.

“Black Americans and others who are underrepresented in clinical trials need to strongly advocate for themselves,” Hurvitz says, “and if their healthcare providers aren’t discussing how to join clinical trials, they or their advocate should bring up the subject.”

Though eligibility requirements, inconvenient locations, and other barriers can make clinical trial enrollment difficult, there are workarounds and good places to start, including ClinicalTrials.gov (U.S. National Library of Medicine) and BreastCancerTrials.org's clinical trial matching tool for people with metastatic breast cancer, Metastatic Trial Search.

Bring Someone With You to Healthcare Appointments

When speaking with healthcare providers about symptoms you’re experiencing, Hurvitz says, having another set of ears — an advocate — will help ensure that your questions and concerns are fully addressed, and not dismissed.

Find a Doctor You Can Trust

Don’t self-diagnose with Dr. Google. Talk with your breast oncologist and healthcare team members about any unsettling symptoms: They know you best, and that’s part of their job, Ali says.

You shouldn’t be embarrassed to discuss treatment side effects and other quality of life issues, Ali says, “or to ask about a second opinion.”

Hurvitz adds: “Everyone diagnosed with breast cancer should look for a healthcare provider, preferably a breast oncologist, who continues asking over the years, ‘How are you feeling?’ Someone who really listens and thoroughly explores the likelihood of metastasis when there are concerning signs or symptoms.”

The Bottom Line

Breast cancer spreading to the brain is a possibility for some people, but it doesn't mean you have to live in fear. Because the symptoms of brain metastasis overlap with symptoms from many other causes, it's important to know your body's normal and understand your risk factors to help you stay vigilant while still enjoying your life.

Above all, find a doctor whom you can trust to carefully listen to all your concerns and address any potential signs of metastasis.