MSCC & Brain Metastases

Metastatic Spinal Cord Compression (MSCC)

Epidural spinal cord compression secondary to metastases is an oncologic emergency and one of the most feared complications of malignancy. If acute cord compression is suspected, workup and management must not be delayed. The most common cancers associated with spinal cord compression are:

• prostate cancer

• lung cancer

• breast cancer

• less-common cancers, including lymphoma, melanoma, renal cancer, sarcoma, and multiple myeloma

An axial view (Panel A) shows a thoracic vertebral body infiltrated by a metastatic tumor. The tumor extends from the bone and narrows the spinal canal, causing distortion and compression of the spinal cord (see the interactive graphic, available at NEJM.org). A parasagittal view of a T2-weighted MRI (Panel B) shows metastasis of renal cancer to the T10 vertebral body and pedicle, causing severe narrowing of the spinal canal. (Source: Acute Spinal Cord Compression, N Engl J Med 2017.)

Symptoms

Pain is typically the first symptom. It may be referred or radicular in nature. Pain from cord compression can be confused with degenerative joint disease (DJD), but the following factors help distinguish the two conditions:

• Pain from metastatic epidural compression can occur at any vertebral level; DJD pain is usually cervical or lumbar.

• Pain from metastatic cord compression is usually new or different from prior pains.

• Lying supine usually alleviates pain from DJD but often aggravates pain from metastatic cord compression.

Other symptoms that typically follow onset of pain from metastatic cord compression include:

• weakness

• sensory loss

• incontinence

• lower-extremity weakness, saddle anesthesia, and urinary retention/overflow incontinence (all of which indicate compression at the level of the cauda equina [cauda equina syndrome])

Review the examination technique for spinal cord compression in an interactive graphic here.

The following table provides an overview of the clinical features, investigations, and management plan for differential diagnoses of acute spinal cord compression:

(Source: Acute Spinal Cord Compression. N Engl J Med 2017.)

Diagnosis & Management

• Review recent imaging for spinal metastases.

• Perform full neurological examination, including the following key components:

  • Palpation over the spinous processes

  • Assessment for a sensory level

  • Motor strength in the extremities

  • Reflexes and tone (including a rectal exam for rectal tone as long as the patient is not neutropenic)

  • Babinski sign

• If there is high suspicion of cord compression, administer intravenous (IV) dexamethasone immediately (a single dose of 10 mg, followed by 4 mg every 6 hours), without waiting for confirmational imaging.

• MRI with and without contrast is the test of choice; CT-based myelography is an alternative when there are contraindications or delays in obtaining an MRI.

• Decision making often involves a multidisciplinary approach, including radiation oncology, spine surgery, and medical oncology. These teams should be consulted immediately upon confirmation of cord compression. Radiotherapy alone used to be the standard of care for cord compression treatment, but a 2005 randomized, controlled trial showed better outcomes with surgical decompression plus radiotherapy.

• Pretreatment neurologic function and duration of deficit are the best indicators of potential for neurologic recovery.

  • Evidence is weak to guide the decision of whether to recommend bed rest or mobilization following a diagnosis of metastatic spinal cord compression. A Cochrane review found insufficient evidence to support bed rest, mobilization, or use of a spinal brace in the management of metastatic spinal cord compression.

Brain Metastases

Brain metastases are an important cause of morbidity and mortality among cancer patients and are more common than primary brain tumors.

The most common cancers that metastasize to the brain include:

• lung

• renal cell cancer

• melanoma

• colorectal cancer

Presentation

Patients can present acutely with symptoms of raised intracranial pressure resulting from brain metastases. Other presenting symptoms associated with brain metastases include:

• nausea and vomiting

• headache

• syncope

• seizures

• visual symptoms (e.g., visual field cuts or diplopia)

• other neurological symptoms (weakness, changes in sensation, etc.)

Many of these symptoms can also be related to vasogenic edema adjacent to the metastatic focus.

Management

Management of patients who present with acute symptoms of brain metastases includes:

• steroid treatment (evidence of efficacy is strongest when symptoms are present)

• antiseizure medications for patients with seizures but not as prophylactic treatment

Management with surgery, radiotherapy (stereotactic vs. whole-brain radiotherapy), systemic therapies, or palliative care will depend on:

• location of the lesions

• number of metastatic brain lesions

• histological diagnosis (i.e., type of cancer)

• performance status (using ECOG/WHO or Karnofsky measures)

• control and presence of extracranial metastases

• the type of cancer and available systemic therapies with CNS penetration

  • Patients presenting with CNS disease from non-small-cell lung cancer with driver mutations involving EGFR or ALK, or melanoma with BRAF alterations, have systemic therapy options with very high CNS penetration and efficacy and can potentially avoid upfront radiation therapy.

  • In the era of immune checkpoint inhibitor therapy, small and asymptomatic brain metastases from certain malignancies (NSCLC and melanoma without actionable drivers) can also be treated with systemic therapy and defer the need for radiation.

Whole brain radiation therapy (WBRT) is associated with more acute and chronic toxicity than stereotactic beam radiation therapy (SBRT), including fatigue, nausea, and alopecia in the short term and cognitive slowing and memory loss over the long term. Memantine can be used concurrently with WBRT to prevent neurocognitive decline.