Cord Compression in the oncology patient
Cord compression occurs in about 5% of all children with cancer at some stage during the disease process. In children, epidural disease is the most common cause of cord compression.
Causes
Cord compression occurs in about 5% of all children with cancer at some stage during the disease process. In children, epidural disease is the most common cause of cord compression. This is most likely due to dumbbell extension of tumour through the intervertebral foramina from an extra-spinal site.
Other causes include:
intradural metastases of CNS tumours
vertebral compression secondary to bony metastases or crush fractures from prolonged steroid use
direct invasion of intraspinal tumours.
Neuroblastoma is the most common cause of spinal cord compression at diagnosis, followed by soft tissue sarcomas and lymphoma. Overall, soft tissue sarcomas are the most common tumours in children over five years, while neuroblastoma is the most common in under five year olds.
With quick, appropriate management, 50% of children who are unable to walk at presentation regain independent ambulation.
Investigations
The investigation of choice for spinal imaging is MRI. Indications for MRI include:
any neurological deficit suggestive of cord compression
urinary retention/leakage
constipation, overflow, or lack of anal sensation
weakness, numbness or parathesia of limbs
decreased sensation with a sensory level on the torso
decreased reflexes
paravertebral neuroblastoma
unexplained localized backache. Backache in children is more common than appreciated. However, backache that is persistent or worsening, wakes a child from sleep, or pain that breaks through non-steroidal therapy requires further investigation. Imaging may be appropriate after full physical and neurological exam.
Management
Cord compression is an oncological emergency. Contact the paediatric oncologist on call urgently.
Keep nil by mouth.
Send urgent spot urine for catecholamines for new patients (discuss with specialist biochemistry lab).
start dexamethasone 1 mg/kg IV followed by 0.25 mg/kg/dose q6h. The dose is controversial but the usual dose is a maximum of 20mg as an initial bolus and a maximum of 12mg q8h. Please discuss with the paediatric oncologist or paediatric neurosurgeon on call.
If lymphoma is part of the differential diagnosis, biopsy should be obtained within 24 hours of starting therapy.
Cord compression at diagnosis
It has been shown for neuroblastoma and Ewings/PNET that chemotherapy is as good as surgery in relieving cord compression. Rhabdomyosarcoma may also invade the intervertebral foramen - it rarely produces cord compression, but is chemosensitive. Therefore, the principles of management should apply to this tumour as well.
First line treatment for most tumour types is steroidsfollowed by chemotherapy. Surgery, particularly multilevel laminectomy should be avoided in a child if possible because this can lead to orthopaedic instability later in life. Urgent external beam radiotherapy should also be considered, depending on the clinical scenario.
Dumbbell tumours
Biopsy extraspinal component only. This can occasionally cause swelling of the intraspinal component and further neurological deterioration.
Tumours with intraspinal component only
Discuss with neurosurgeons. Plan for surgical decompression.
Neuroblastoma chemotherapy
The important principle here is to avoid drugs that require hyperhydration which has been known to cause tumour swelling and neurological deterioration. Therefore, cisplatin and higher doses of cyclophosphamide should not be given initially.
The chemotherapy combination may be dictated by the study on which the child is entered.
Cord compression presenting in previously diagnosed patients
Therapy depends on the child's current progress and expected prognosis.
Chemotherapy is likely to be less effective initially than in newly diagnosed patients. Radiotherapy, surgery, chemotherapy or no treatment may be appropriate depending on the clinical circumstances. Follow the initial steps above and discuss with the on call oncologist urgently.