Leptomeningeal Disease

Leptomeningeal disease is metastatic breast cancer that has spread to the leptomeninges and cerebrospinal fluid — the membranes and fluid that surround your brain and spinal cord. Leptomeningeal disease also may be called leptomeningeal metastases, carcinomatous meningitis, lepto, LMD cancer, LMD or just LM. Any type of cancer can metastasize into leptomeningeal disease.

Leptomeningeal disease is rare, but it’s most common in breast cancer. Up to 8% of people diagnosed with metastatic breast cancer will develop leptomeningeal disease. Triple-negative breast cancer, HER2-positive breast cancer, and lobular breast cancer are the types of breast cancer most likely to develop leptomeningeal metastases.

Brain metastasis happens when breast cancer cells spread to the brain and form tumors there. Leptomeningeal disease happens when breast cancer cells spread to the membranes and fluid that surround the spinal cord and the brain, but not the brain itself. Someone with metastatic breast cancer could have both brain metastases and leptomeningeal disease, or one and not the other.

Because leptomeningeal tumors are in the fluid around the brain and spinal cord, the symptoms they cause are usually neurological, meaning they involve the brain and the central nervous system. Headaches, nausea/vomiting, weakness or numbness in the arms and legs, vision and hearing changes, and problems walking or balancing are the most common. Other symptoms can include mood or behavior changes, dizziness, problems thinking or remembering, difficulty controlling your bladder or bowel movement, and confusion or hallucinations.

The fluid surrounding the brain and spinal cord usually isn’t the first place breast cancer spreads. So people with breast cancer who develop leptomeningeal metastases usually have other symptoms of metastatic breast cancer. This can make leptomeningeal disease challenging to diagnose.

There are three tests your doctor can use to diagnose leptomeningeal disease: a neurological exam, an MRI, and a lumbar puncture. Usually, an MRI or lumbar puncture are used to make the final diagnosis.

Neurological exam

Leptomeningeal disease commonly affects the nerves in your brain and spine, which can cause many different symptoms. During a neurological exam, your doctor will check your cognition (your ability to understand, think clearly, and remember), vision, eye movement, facial muscle strength, arm and leg strength, arm and leg reflexes, fine motor skills (moving your fingers in a coordinated way), and your balance and gait.

MRI scan

An MRI of the brain and spine, with and without contrast, can be used to diagnose leptomeningeal disease. The MRI can show small spots of cancer in the membranes around the brain and spinal cord. 

Lumbar puncture

Also called a spinal tap, a lumbar puncture removes a sample of cerebrospinal fluid to test it for cancer cells. The procedure takes about 15 to 30 minutes.

During a lumbar puncture, your doctor gives you an injection of numbing medicine in the area where the fluid sample will be removed, usually in the lower back. Then the doctor puts a needle through your skin between the bones of the spine, below the level of the spinal cord and removes the sample — usually about one or two teaspoons of fluid — which is sent to a lab for testing.

Some people find that certain symptoms, like headaches, vomiting, and dizziness, get better after a lumbar puncture. It’s important to tell your doctor if you feel better or worse after the procedure. Other people may have what’s called a spinal headache after a lumbar puncture. This is pain in your head when you sit or stand. If this happens, you can ask your doctor about taking over-the-counter pain medicine. Staying hydrated also helps. A spinal headache usually gets better in a few hours, or at most a couple days.

Right now, there isn’t a standard of care for leptomeningeal disease. The treatments your doctor recommends are based on your symptoms, whether or not you have other areas of metastatic disease, and your test results.

The goal of treatment is to ease symptoms, improve quality of life, and kill the cancer cells in the cerebrospinal fluid. In addition to the treatments below, your doctor may suggest anti-seizure medicines, steroids for pain relief, or a brain shunt to redirect cerebrospinal fluid that’s built up in your brain and causing pressure.

Radiation 

Radiation therapy can be used to treat areas where groups of cancer cells are causing symptoms. Your doctor may recommend whole brain radiation, spinal cord radiation, or both.

Intrathecal chemotherapy

A special type of chemotherapy, called intrathecal chemotherapy, delivers chemotherapy directly into the cerebrospinal fluid. This allows the chemotherapy medicine to bypass the blood-brain barrier and reach the cancer cells in the fluid.

You may receive intrathecal chemotherapy through a lumbar puncture or through an Ommaya reservoir. An Ommaya reservoir is a plastic, dome-shaped device that’s placed underneath the skin of your scalp during a short surgery. The reservoir has a small tube coming out of it that connects it to the areas of your brain where cerebrospinal fluid is made. After the scalp area over the reservoir has healed, your doctor uses a needle to inject chemotherapy medicine into the reservoir so it can go directly to the cerebrospinal fluid.

There are several schedules for intrathecal chemotherapy, but you typically receive it once a week at the beginning. After that, you may receive it less often if it’s effective.

Other treatments

Depending on the characteristics of the primary cancer in the breast, your doctor may recommend targeted therapy, immunotherapy, or hormonal therapy as additional treatments.

For people with HER2-positive metastatic breast cancer and leptomeningeal disease, a small 2026 study found that the combination of the targeted therapies Tukysa (chemical name: tucatinib) and Herceptin (chemical name: trastuzumab), and the chemotherapy Xeloda (chemical name: capecitabine) improved survival from a historical average of 4.4 months to 10 months. After 18 months of follow-up, 41% of the people were still alive. The combination of the three medicines also slowed the leptomeningeal tumors’ growth. More than half of the 12 people in the study also saw any neurologic problems improve.

Another small study in people with breast or lung leptomeningeal cancer found that proton radiation therapy offered better outcomes than traditional X-ray radiation therapy. Central nervous system progression-free survival — how long people lived without the cancer around the brain and spinal cord growing — was about eight months for people who received proton therapy and about two months for people who received X-ray radiation therapy. Preliminary results from the study also suggest that proton therap ymay improve overall survival — how long people live whether or not the cancer grows. In addition, people who received proton therapy said their ability to do daily tasks was slightly better than people who received X-ray radiation therapy.

Leptomeningeal disease is a serious complication of metastatic breast cancer. In general, people who receive treatment for leptomeningeal disease live for several months after being diagnosed. But there are people who live longer, so it’s important to remember that each person is unique and these statistics don’t capture all the variables for each individual. People with breast cancer leptomeningeal metastases have lived beyond what the statistics show. 

As leptomeningeal disease progresses, any symptoms it’s causing often get worse, especially symptoms affecting thinking and speaking. Toward the end of life, many caregivers say that people become extremely confused and disoriented and sleep most of the time. They usually also eat very little and have problems swallowing.

If treatments aren’t helping or if someone no longer wants active cancer treatment, hospice care is an option. The goal of hospice care is to offer physical, emotional, and spiritual support to both the person with cancer and their family, as well as treatments that ease symptoms and make a person as comfortable as possible. It’s important to know that if new treatment options become available, a person can leave hospice care and go back into active cancer treatment.

Having leptomeningeal disease can be overwhelming, but you don’t have to go through it alone. Mental health and other support options can help you navigate when you have LMD breast cancer.

The Leptomeningeal Cancer Foundation has a list of organizations that offer education, financial assistance, and  support for both patients and caregivers.