Tumours of the Spine

 
Condition

There are many different tumours which can develop in the spine. ‘Tumour’ in medical terms means ‘swelling’ and is usually used to describe a growth. Some tumours are found incidentally and do not require any treatment, others can be very serious and fatal if not treated. The term tumour does not necessarily mean cancer as there are many benign tumours. In order to understand treatment options for tumours it is important to know about some terminology and principles. It will not be possible to discuss all tumours of the spine and the page focuses on the most common lesions. Management of any tumour, aggressive or not, should always be supervised by an oncologist or spine surgeon with a specialist interest in spinal tumours. In my practice, any tumour is discussed in a multidisciplinary team meeting (MDT). This team consists of spine surgeons, oncologists, radiologists and a pathologist to draw up the best possible management plan for the patient. This co-ordination is essential, as many patients will need more than one type of treatment, for example surgery followed by radiotherapy. The National Institute for Clinical Excellence in the UK (NICE) issued guidelines for the management of spinal metastasis. The MDT forms the central part.

Classifications of tumours

There are many different ways to classify tumours. Classifications are important in order to understand their origin, clinical and biological behaviour and treatment options.

Primary and secondary tumours 

All tumours derive from a single cell which for reasons we often do not fully understand start to multiply. The normal control mechanisms for cell growths and multiplications do not work and the tumour starts growing. In principle, any tissue in the body can grow a tumour. A tumour which grows locally from a tissue in this area is called a primary tumour (for example a liver tumour in the liver or a brain tumour in the brain). Sometimes tumours can spread via the blood stream, lymphatic system or cerebrospinal fluid (in the brain and spine) and settle in different tissues or areas. This is called a secondary tumour or metastasis (for example a lung tumour which has spread from a bowel tumour). It is very important to know whether a tumour in the spine (or anywhere else in the body) is a primary or secondary tumour because it can significantly alter the management.

Benign and cancerous tumours

A benign tumour grows locally but usually does not spread to other parts of the body (there are very rare exceptions) and does not invade surrounding other tissues. It can, however, damage the surrounding tissue and organs by causing pressure. In the spine, a benign tumour can cause pressure on the spinal cord leading to gradual paralysis (myelopathy).

Cancerous tumours often destroy the surrounding tissues and can spread to other parts of the body. Destruction of the vertebral bodies in the spine can lead to collapse and instability.

Other classifications

Another classification commonly used for spinal tumours uses the relationship between the tumour and spinal cord. This classification does not take the nature of the tumour into account but is important for the understanding of surgical treatment.

Extradural tumours     This means outside the dura, which is the sac containing the spinal cord. The vast majority of these tumours arise from the vertebral bodies. The most common tumour in this group is a metastasis. These often present with pain, vertebral collapse or compression of the spinal cord.

Intradural – extramedullary tumours      These tumours lie within the sac containing the spinal cord (dura) but are outside the spinal cord itself. They most frequently arise from the sac or nerve roots within it. Examples are meningiomas or neurofibromas. The most common symptom is pressure on the spinal cord (myelopathy).

Intradural – intramedullary tumours    The tumour is located within the spinal cord. The most common symptom is myelopathy. In general, these are rare tumours. Examples are astrocytomas and ependymomas.

Making the diagnosis

There are important steps to make the correct diagnosis.

History   Important information comes from an accurate history of the patient’s symptoms and signs: duration and progression of symptoms, associated symptoms like weight loss, known other tumours or risk factors (for example smoking, which can cause a lung cancer that can spread to the spine)

Examination   A thorough clinical examination is important to pick up signs of other involved organs in suspected metastatic disease and reveals the extent of the neurological deficit.

Investigations   Imaging the tumour and spine is an important step. Most tumours will require MRI scan and might need an additional CT scan or other x-rays. Some patients will require blood or urine tests. The only definite ways of making the diagnosis is taking a piece of tissue and analyze it (biopsy).

Sometimes, a biopsy is taken before any further treatment is planned. In cases where surgery is required anyway in order to deal with the complications (for example spinal cord compression) the tissue sample is taken at the time of the operation. In some cases, it might not be necessary to take a biopsy if the scan is very suggestive of a benign tumour which was found incidentally (for example a haemangioma). If a metastasis is suspected, patients will often undergo a series of test trying to find the primary tumour. An isotope bone scan can detect other metastases in the skeleton.

Treatment  

The treatment depends on many factors including type, biological behavior and location of the tumour. It would not be possible to discuss all treatment options for all tumours here. The list below is a guide for common spinal tumours. Specific cases should always be discussed individually with a specialist (oncologist and spine surgeon).

Specific tumours

Tumours of the vertebra (Extradural tumours)    Spinal metastases occur in around 10% of all cancers (see picture below). The most common tumours, which cause metastases, are cancers of the lung, breast, prostate, gut, melanoma (skin) and lymphoma. The most important part of the treatment is usually controlling the underlying cancer. The National Institute for Clinical Excellence in the UK (NICE) has issued guidelines regarding the management of these cases. (www.nice.org.uk/nicemedia/pdf/CG75FullGuideline.pdf) The role for surgery is usually restricted to decompression and stabilization of the spine. It is important to remember that surgery cannot cure the disease and usually only deals with its complications of spinal cord compression and instability due to erosion of the vertebra. Surgery is usually done in combination with other forms of treatment, for example radiotherapy. Complication rates are usually higher, if surgery is done after rather than before radiotherapy. The decision to treat should be made in consultation with a multidisciplinary team. The overall prognosis for the patient usually depends on the behaviour of the underlying cancer and not the spine operation. However, quality of life can be significantly improved by preventing paralysis, incontinence and reduction in pain (see also metastatic spinal cord compression)

Myeleoma/Plasmocytoma is a tumour from the blood producing cells in the vertebra. Treatment should be supervised by a specialist (Haemoncologist). Surgery is rarely necessary and restricts itself to cases of compression of the spinal cord and instability causing progressive deformity. Vertebroplasty or kyphoplasty can be a very good way of controlling the pain and adding some stability.

Haemangiomas are benign lesions of the spine. The majority of these tumours are found incidentally on MRI scan. The appearance is usually typical and biopsies are not necessary. They rarely require any treatment. In case of symptomatic tumours, surgery can consist of decompression, stabilization or vertebroplasty.

Intradural – extramedullary tumours    Meningiomas arise from the sac containing the spinal cord (dura). The cause is usually unknown apart from very rare cases (for example many years following radiotherapy to the spine for other conditions or genetic defects in patients with type 2 neurofibromatosis). Meningiomas are more common in women and usually occur in middle-aged patients. The most common site is in the thoracic spine and is almost never seen in the sacral area. They usually present with signs of slowly progressive myelopathy, which might develop over months or years. The tumour is usually benign. The diagnosis can be made in the majority of cases with a contrast enhanced MRI scan although they can look like neurofibromas. Treatment of choice is surgery, which usually cures it. There is a small chance of recurrence even many years after surgery.

Neurofibromas are tumours from the sheath of nerve roots (see picture below). In most cases they are single tumours but can occur in large numbers in a condition called neurofibromatosis type 2. They can cause sensory disturbance or pain along the nerve it arises from but also compression of the spinal cord. Small tumours can be completely asymptomatic. Like in meningiomas, the diagnosis can be mad with a contrast enhanced MRI scan although neurofibromas and meningiomas can look very similar.

Intradural – intramedullary tumours   Astrocytomas occur in the brain and spinal cord (see picture below). They are classified in grade 1-4 depending on certain histological features. Some are diffusely infiltrating the spinal cord (grade 2-4) and therefore cannot be resected surgically. However, the pilocytic astrocytoma has often a clear margin between tumour and spinal cord and can be resected. High grade tumours (grade 3&4) might need radiotherapy in addition to surgery.

Ependymomas also arise from cells within the spinal cord (see picture below). Like in astrocytomas an MRI scan with contrast is necessary and sometimes a biopsy is indicated before definite treatment. If the diagnosis is certain on MRI, the best treatment is surgical resection. In the case of incomplete resection or recurrence radiotherapy might be indicated. Unfortunately, these tumours can spread via the cerebrospinal fluid (CSF) to other parts of the spine and brain. Therefore, all patients should have an MRI scan of the entire spine and brain before and after any treatment.

Cervical neurofibroma before and after surgery

Cervical neurofibroma before and after surgery

Thoracic metastasis before and after surgery (3-D reconstruction)

Thoracic metastasis before and after surgery (3-D reconstruction)

ependymoma before and after surgery

ependymoma before and after surgery

Cervical pilocytic astrocytoma before and after surgery

Cervical pilocytic astrocytoma before and after surgery