Approach

Diagnosis of MSCC is based on clinical history and findings on imaging. Other serious causes of loss of sensory, motor, or autonomic function should be excluded when making the diagnosis.

Investigation of suspected MSCC may not be warranted under certain circumstances (e.g., in patients with paralysis of more than 1 week's duration, poor baseline performance status, and short life expectancy [days to weeks] due to underlying disease).[7] However, establishing a diagnosis may aid in managing subsequent pain and spinal stability issues. Any decision not to investigate and treat must be reached in collaboration with the patient.[7]

History

The patient should be asked about smoking history, environmental or occupational exposures to carcinogens, travel history, recent screening examinations, and any family history of cancer.

Malignancy

The clinical history of any malignancy should be established, including diagnosis and treatments.

The most common tumors metastasizing to the spine include prostate cancer, lung cancer, breast cancer, renal cancer, and thyroid cancer.[7] Other cancers associated with MSCC include myeloma, non-Hodgkin lymphoma, neuroblastoma, soft-tissue sarcoma, and high-grade meningioma.[12][13][14] However, any systemic cancer can metastasize to the spine.

Symptoms and signs

Back pain is the most common and usually the first symptom of MSCC. It may be present for several weeks before neurologic symptoms appear. Three classic pain types are seen with spinal lesions: localized, radicular, and mechanical pain.

  • Localized back pain (in and around the spinal column) is often referred to as biologic pain or tumor pain. This pain is thought to be an early symptom of bone metastases, representing tumor infiltration into the vertebral body. It is nagging or aching in nature, prominent at night, and typically responds well to anti-inflammatory medications.[28] Pain often becomes more severe over time, and may be worse when the patient is lying down (preventing sleep or causing waking), or coughing or straining.​[7][9]​​[19]

  • Radicular pain is described as sharp, shooting pain that radiates into an extremity with cervical or lumbar spine involvement, or around the chest in the thoracic spine. Radicular pain may indicate epidural disease affecting local nerve roots.[29]

  • Mechanical pain is movement-based pain that worsens with position changes and activity, and indicates spinal instability. This type of pain often requires surgical intervention.[29]

Other common symptoms of MSCC include:

  • Limb weakness or paralysis. Symptoms may be present for days or weeks before MSCC diagnosis. An unsteady gait or increased difficulty in walking, standing, or transferring that has worsened over days or a few weeks is typical.[7]

  • Sensory symptoms, such as numbness, paresthesias, or sensory loss (e.g., loss of pinprick, temperature, position, and vibratory sensation). Sensory symptoms are less common than motor symptoms in patients with MSCC. They may be present for days or weeks before diagnosis.[7]

  • Bladder and/or bowel dysfunction. This is often a late consequence of MSCC, and may present as urinary retention, urinary or fecal incontinence, or constipation.[7] It is rarely the only symptom or sign of MSCC.

Neurologic impairments should correlate with the location of the lesion.

Exam

Physical exam includes assessment of motor function, reflexes, sensation, and sphincter function. Spinal stability may also be assessed to inform treatment decisions.

Changes in motor function can be tested using the Medical Research Council manual muscle motor test scoring system of 0 to 5.[30]

  • Grade 5: patient can hold the position against maximum resistance and through complete range of motion (ROM).

  • Grade 4: patient can hold the position against strong to moderate resistance and has full ROM.

  • Grade 3: patient can tolerate no resistance but can perform the movement through the full ROM.

  • Grade 2: patient has all or partial ROM in the gravity eliminated position.

  • Grade 1: the muscle/muscles can be palpated while the patient is performing the action in the gravity eliminated position.

  • Grade 0: no contractile activity can be felt in the gravity eliminated position.

The International Standards for Neurological Classification of Spinal Cord Injury is recommended as a guide for this population, although it is not validated.[29][31]

Reflexes should be tested.[32] Hyperreflexia and Babinski sign (an abnormal plantar reflex consisting of extension [upward motion] of the great toe on stimulation of the lateral side of the sole, starting from the heel to the base of the toes) are early signs of MSCC.[33] For patients who have sensitivity to tickle, the Oppenheimer (stroking of the anterior tibia) or Chaddock (stroking the lateral malleolus) signs are equally useful.

A digital rectal exam may be carried out to assess for tone/presence of voluntary anal contraction. Evidence from traumatic injury suggests that this information is helpful in determining the severity of injury, and to help guide bowel and bladder programs.[34] Clinicians must assess for contraindications, such as an immunocompromised state and recent anal surgical intervention, before performing the exam.[35]

Spinal stability may be assessed using the Spinal Instability Neoplastic Score (SINS), which can be used by nonspecialist physicians as well as specialists.[20][36][37][38][39] Six variables are scored using SINS: lesion location, pain characteristics, bone lesion type, radiographic spinal alignment, degree of vertebral body destruction, and involvement of posterolateral spinal elements. Scores range from 0 to 18. Scores of 7 to 12 are associated with potential spinal instability, whereas scores of 13 to 18 denote instability. The Spine Oncology Study Group recommends surgical evaluation for all patients with a SINS score above 7.[36]

Imaging

Magnetic resonance imaging (MRI), ideally with gadolinium enhancement, is the preferred imaging investigation for patients with suspected MSCC.[7][40][41][42]​​​ Sensitivity and specificity are both above 90%. The whole spine should be imaged, since multiple lesions are frequently observed.[7][19][43][44][45][46]​ The UK National Institute for Health and Care Excellence recommends that MRI is performed as soon as possible, and always within 24 hours, for people with suspected MSCC.[47]​​

Computerized tomography (CT) scans can provide highly detailed imaging of the osseous anatomy of the spine and degree of tumor involvement. The addition of myelography allows for assessment of spaces occupied by neural elements and identification of compressed structures.[18][28][41][42]​​[48] This may be useful for patients who cannot tolerate MRI, and for some surgical or radiation therapy treatment planning. Patients with suspected metastatic disease should have CT imaging of the chest, abdomen, and pelvis to establish the extent of disease or identify the primary tumor.[18]

Plain radiographs can be useful in assessment for pathologic spinal fractures.[39] They can also help to determine whether spinal lesions are osteolytic, osteoblastic, or mixed. However, plain films should not be used to diagnose MSCC.[7]

Other imaging techniques that may be used include the following:

  • Positron emission tomography, which uses fluorodeoxyglucose to detect the presence of a tumor based on metabolic activity, can assist in differentiating tumors from benign lesions.[41]

  • Bone scintigraphy can be used to evaluate skeletal metastases.[49]

Laboratory tests

The following should be measured:

  • Calcium levels: hypercalcemia is the most common metabolic derangement seen in cancer patients.

  • Alkaline phosphatase (ALP): a serum marker of bone turnover and mineralization, and a diagnostic marker for the presence of bone metastases. Elevated serum ALP is correlated with poor prognosis in the setting of bone metastasis.[50][51]

  • Cancer-specific laboratory testing, such as prostate specific antigen (PSA), breast cancer genes 1 and 2 (BRCA1 and 2), carcinoembryonic antigen (CEA), and serum and urine protein electrophoresis, should be included based on clinical suspicion.[18]

If not already established, definitive diagnosis of the primary or metastatic spinal tumor by CT-guided biopsy and histopathology should be done, ideally before radiation therapy or surgery.[7] This can be done at the same time as vertebroplasty or kyphoplasty if such treatment is being carried out.

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