Metastatic Brain Tumor

Definition

Brain metastasis, or brain met, is defined as cancer that spreads to the brain. Brain mets are the most common type of malignant brain tumor in adult patients. Most of the time, cancer cells spread to the brain by entering the bloodstream. The brain receives 20% of the entire cardiac output, and therefore, it’s a common site for metastases

Causes

Some of the most common types of cancer that spread to the brain include:

• Lung cancer
• Breast cancer
• Melanoma
• Renal/urothelial cancer
• Thyroid cancer
• Colorectal cancer

Prostate cancer often spreads to the bone (skull) and does not typically metastasize to the brain.

Symptoms of brain metastases

Warning signs include:

• Headaches
• Seizures
• Neurologic deficits (visual problems, language or speech issues or weakness/numbness

These tumors can be asymptomatic, particularly in early stages or if they’re small.

Diagnosis

Brain mets are best diagnosed with a brain MRI performed with and without contrast. Many patients discover their brain met through routine screening with a brain MRI. A head CT scan can show large lesions but may miss smaller tumors. PET scans are good at finding cancer outside of the brain.

Treatment options

Treatment of brain mets at UF Health is tailored to each patient based on the number of brain mets, their location, the type of cancer and molecular or genomic markers observed in the patient’s cancer. Treatment includes:

Surgery

Different forms of surgery may be recommended for some metastatic brain tumors. Oftentimes, the goal is to relieve pressure on the brain and help guide further cancer treatment.

Biopsy

This surgery requires the precise placement of a very small burr hole through which a biopsy needle is guided into the tumor. Once the needle is in place, we collect a small tissue sample and send it to pathology for evaluation. Patients typically undergo this procedure under anesthesia. It is minimally invasive, and most patients can go home the same day.

Surgical removal (craniotomy)

Craniotomies are performed routinely at UF Health to remove large symptomatic brain mets. They’re done under general anesthesia unless the tumor is close to eloquent brain areas controlling motor or language function. If eloquent brain is involved, surgery can be performed with awake brain mapping.

Computer guidance is utilized to assist tumor resection. Intraoperative MRI and fluorescence-guided surgery are also tools used at UF Health to help with tumor removal. Most patients stay in the hospital for 1-2 days after surgery.

Laser Interstitial Thermotherapy (LITT) or MRI-Guided Laser Ablation

This technique uses a thin laser probe that is placed into the tumor to heat and destroy cancer cells. In addition to killing cancer cells, LITT also has the potential benefit of opening the natural blood-brain barrier, or BBB. Because of this effect, cancer treatments given about 2-4 weeks after LITT can potentially reach the brain met more effectively.

Additionally, LITT can also be used to treat radiation necrosis. This is a condition that may develop in brain met patients previously treated with radiation. Surgery involves placing a stereotactic head ring in the preoperative area to ensure accurate placement of the laser. The patient is then brought to the operating room and given general anesthesia. A burr hole is created, and a biopsy is performed. Then, a laser is placed into the tumor with MRI guidance used to direct its heat. Most patients go home the next day.

UF Health: pioneering laser treatment for brain tumors

At UF Health, researchers and clinicians have played a leading role in developing and applying LITT for the treatment of brain tumors. Our academic publications include the use of LITT in combination with other therapies for malignant brain tumors, as well as the development of LITT for preclinical studies of brain tumors.

Radiation

Radiation therapy is a common treatment for metastatic brain tumors. It uses targeted energy to shrink tumors, relieve symptoms and control the cancer in the brain.

Stereotactic Radiosurgery (SRS)

SRS is radiation delivered with computer guidance that allows brain metastases to receive a high dose of radiation with minimal exposure of the normal brain. SRS was pioneered at the University of Florida by Dr. William A. Friedman and Dr. Frank Bova. Together, they’ve treated over 5,000 patients with the technology they’ve developed while publishing hundreds of manuscripts.

SRS can be delivered to multiple brain metastases. Because the normal brain is not affected, SRS is a safe way to deliver high doses of radiation while avoiding cognitive side effects that can occur after whole brain radiotherapy, or WBRT. At UF Health, SRS is usually delivered in a single session. Other practices may deliver SRS in five fractions. In most cases, the use of SRS is limited by the tumor size: it must be 3 cm or less for SRS to be effective.

Fractionated Radiotherapy (RT)

If brain mets are too large for SRS, radiotherapy can be delivered in multiple fractions.

Whole Brain Radiotherapy (WBRT)

If there are numerous brain mets, WBRT is a treatment option. This modality is often delivered over 10 fractions. A long-term side effect may be cognitive decline. However, certain medications — such as amantadine — may reduce the likelihood of developing cognitive decline after WBRT.

Here is some of our research involving radiosurgery and LITT to treat brain tumors:

Medical treatment options

Some immunotherapy drugs (PD-1 inhibitors, CTLA inhibitors) and targeted therapies (tyrosine kinase inhibitors, antibody-drug conjugates and others) do cross the BBB and may be effective for small brain mets.

At UF Health, an interdisciplinary team is assembled for each patient with brain mets. This group of experts includes:

• Neurosurgery
• Radiation oncology
• Medical oncology
• Pathology
• Neuro-oncology
• Radiology
• Social work
• Other relevant services (nutrition, physical medicine and rehab, integrative medicine and others)

This team assesses the patient and determines the best treatment, which may require combinations of the approaches described above.

Outlook (prognosis)

With a multidisciplinary approach and combinatorial strategies, overall survival for patients is improving significantly.

When to contact a medical professional

If you have a brain met, contact UF Health Neurosurgery for an evaluation.