Investigations
1st investigations to order
gadolinium-enhanced MRI spine
Test
Imaging of choice for suspected MSCC.
MRI allows for assessment of the soft tissue structures, degree of cord compression, and details about leptomeningeal involvement. It is important that MRI of the whole spine is carried out, as multiple sites of metastasis are common. Post contrast fat-suppressed images allow differentiation of metastases from bone marrow.[7][19][42][43][44][45][46]
Result
visualisation of extradural tumour, extent of epidural disease, extent of cord compression, spinal cord oedema; possible visualisation of leptomeningeal and intramedullary tumours; visualisation of tumour involvement/compression of spinal nerve roots, meninges, spinal musculature
MRI spine
CT myelography
Test
Should be used for diagnosis only in patients with contraindications for MRI (e.g., those with an implanted pacemaker or claustrophobia).
Myelography allows imaging of the degree of cord compression in flexion and extension.[7][19][33]
Result
visualisation of compressed structures (classical hourglass constriction shape of the dye column)
Investigations to consider
CT spine
x-ray
Test
Plain radiographs can be useful in the assessment for pathological 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]
Result
visualisation of spinal fractures and skeletal metastases
bone scintigraphy
Test
Useful if primary imaging is not available, and in selected cases for staging purposes and planning of systemic treatment.
An osteotropic radioisotope (an agent that accumulates at the site of active bone production), most commonly technetium-99-labelled methylene diphosphonate (99mTc-MDP), is injected into the bloodstream.[49] Images are captured on film using a gamma camera.
Result
visualisation of skeletal metastases; identifies areas of osteoblastic activity
positron emission tomography (PET)
Test
PET is superior to conventional bone scanning in terms of spatial resolution. 18F-Fluorodeoxyglucose is used to detect the presence of a tumour based on metabolic activity. PET may also be used as part of hybrid imaging techniques such as PET/CT and PET/MR.[42][49]
Result
identifies areas of osteoblastic activity or hypermetabolism
tumour biopsy and histopathology
Test
CT-guided biopsy and histopathology confirm the diagnosis of primary or metastatic spinal cord tumour.[7]
Genotyping of tumours has become a standard to aid in therapy and prognosis. The MSK-IMPACT data revealed crucial roles of the TP53, KRAS, PIK3CA, and BRAF genes in metastatic tumours. A whole-exome sequencing analysis of approximately 500 patients with metastatic tumours reported that TP53, CDKN2A, PTEN, PIK3CA, and RB1 were the most prevalent genes altered somatically in metastatic cancer.[25]
Result
tissue diagnosis of malignancy
serum calcium
Test
Hypercalcaemia is the most common metabolic derangement seen in cancer patients.
Result
may be elevated in cancer patients
serum alkaline phosphatase
cancer-specific laboratory testing
Test
Testing such as prostate specific antigen, breast cancer genes 1 and 2 (BRCA1 and 2), carcinoembryonic antigen, and serum and urine protein electrophoresis should be included based on clinical suspicion.[18]
Result
helps to identify primary tumour
cancer stem cell markers
Test
Cancer stem cells (a small sub-population of cells within tumours capable of self-renewal, differentiation, and tumorigenicity) have been identified in solid tumours by a variety of markers, including CD133, ALDH, OCT3/4, SOX2, PROCR, CD24, CD29, CD44, and NESTIN.[52][53] Identifying markers helps to guide treatment, including predicting whether aggressive treatment is needed.
Result
positive for markers depending on tumour type
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