When “metastasis” and “vertebral body” stand next to each other in a report, two questions arise at once: the one about the cancer — and the one about the spine. This page answers the second. It explains how a vertebra is weakened by a metastasis, how one tells whether the spine is stable and whether the spinal cord is under pressure, which treatments there are, and which signs allow no delay.
Most spinal metastases are not operated on but treated with radiotherapy and medicines. Surgery is performed when the spine is unstable or the spinal cord is under pressure — and then every day counts.
What is it?
A metastasis is a deposit from a cancer that arose elsewhere in the body. After the liver and the lungs, bone is the third most common site in which solid tumours settle, and with 40 per cent of all bone metastases the spine is the most common site in the skeleton — in descending frequency the lumbar, thoracic and cervical spine, because that is where the red bone marrow lies in which tumour cells settle. Most often the deposits come from breast, prostate and lung cancer, and from kidney and thyroid cancer; multiple myeloma, a disease of the bone marrow itself, involves the vertebrae in a similar way. Sometimes a spinal metastasis is the first sign of a cancer that is not yet known about.
Within the vertebra, the metastasis can dissolve the bone (osteolytic) or condense it (osteoblastic, typical of prostate cancer); condensed bone, too, will not bear load. The consequences are pain, a collapse of the hollowed-out vertebral body — the pathological fracture — and growth of the tumour into the spinal canal, where it constricts nerve roots or the spinal cord. This spinal cord compression is the dreaded complication: it is rare, but an emergency, because lost spinal cord function does not reliably come back.
What symptoms occur?
The pain of a spinal metastasis differs from ordinary back pain — and it is these differences that matter. The British NICE guideline names as suspicious: a severe, unremitting back pain; a pain that steadily increases over weeks; a pain that grows worse on standing, sitting and moving and points to a mechanical weakening of the vertebra; a pain that increases on coughing, sneezing and straining; a pain at night that disturbs sleep and does not get better when lying down; a localised tenderness to tapping over one vertebra. In people with a known or past cancer, any new back pain with one of these features counts as needing assessment.
If a nerve root is constricted, the pain runs like a belt along a rib or into the arm or the leg. If the spinal cord is under pressure, other signs are added, which are often quiet at first: heavy or stiff legs, an unsteady gait, tripping over one’s own feet, numbness or tingling rising from the feet, weakness in the arms or legs, a new problem passing water or opening the bowels. These signs are not a matter for the next appointment but for the same day.
Causes
Tumour cells reach the vertebral bodies through the blood; a network of veins along the spine connects the pelvic and chest organs directly with the vertebrae, which explains why prostate and breast cancer settle there so often. Whether and when metastases arise depends on the type of tumour, its stage and the treatment. They can appear in the first years after the diagnosis and, with some tumours — breast, kidney and thyroid cancer, for instance — also many years later as a single late metastasis. Osteoporosis is not a cause, but with a fracture it can raise the question of whether a tumour lies behind it; the MRI scan distinguishes the two.
How is it diagnosed?
The decisive examination is an MRI scan of the whole spine — not only of the painful section, because metastases often sit at several sites. It shows the involvement of the bone, the growth into the spinal canal and the extent to which the spinal cord or the nerve roots are under pressure. On timing there are clear requirements: with neurological deficits and suspected spinal cord compression, the MRI scan should take place early enough for treatment to begin within 24 hours; with suspected spinal metastases without such deficits, within a week. The CT scan complements it, because it shows the destruction of the bone, the back edge and the stability most precisely and is the basis of any planning for an operation or for radiotherapy. A bone scan or PET-CT captures involvement of the rest of the skeleton. If the tumour of origin is unknown, tissue is taken from the vertebra, provided the result influences the treatment and no immediate treatment is necessary.
Whether the spine is stable is assessed with the SINS score (Spinal Instability Neoplastic Score). It rates six features: the position of the affected vertebra, whether the pain depends on movement, whether the bone is dissolved or condensed, whether the alignment of the spine is altered, how far the vertebral body has collapsed, and whether the posterior parts of the vertebra are involved. Values of 0 to 6 count as stable, 7 to 12 as possibly unstable, 13 to 18 as unstable. From the middle range upwards the assessment should be made by a spinal surgeon. Added to this are assessments of the overall prognosis, which feed into the choice of treatment. What the terms in your report mean is explained on the page Understanding your MRI report.
Warning signs
With a known or past cancer, a new weakness in the legs or arms, an unsteady gait, rising numbness, a problem passing water or opening the bowels, and numbness in the area of the buttocks and the perineum belong in an emergency department on the same day — at night and at the weekend as well. The guidelines then require an MRI scan and the start of treatment within 24 hours; in hospital a high-dose cortisone preparation is usually given straight away to reduce the swelling around the spinal cord until radiotherapy or surgery begins. You should have assessed within a few days a new back pain with the features named above — above all pain at night that does not get better when lying down. Everything else on the page Warning signs.
Treatment without an operation
Spinal metastases are never treated by one discipline alone. The decision is made in a tumour board, in which oncology, radiotherapy, spinal surgery, radiology and pain medicine assess the findings together. With a stable metastasis without pressure on the spinal cord, the S3 guideline says that treatment without an operation should be preferred.
- Radiotherapy — the most important local treatment: against pain, against restricted movement, where there is a risk of fracture, after a surgical stabilisation, and where there is threatened or established pressure on the spinal cord. In a summary of 25 studies with over 5,600 patients, the pain responded to radiotherapy in about 60 in 100; often a single session is enough. The effect sets in over days to weeks.
- Treatment of the cancer — chemotherapy, anti-hormonal or targeted treatment, immunotherapy, according to the type of tumour. It also acts on the metastases in the bone.
- Bone-protecting medicines — bisphosphonates or the antibody denosumab slow the breakdown of bone by the metastasis and lower the risk of fractures and of further skeletal complications.
- Pain treatment — following the stepwise scheme up to opioids, supplemented by medicines for nerve pain. The aim is that you can move; pain that cannot be controlled is itself a reason to think about radiotherapy or a procedure.
- Cortisone — where the spinal cord is under pressure, as an immediate measure until the actual treatment begins; after the operation or with the start of radiotherapy it is tapered off again.
- Brace — a supporting corset can ease pain; that it prevents a fracture is not established, which is why the guideline advises restraint.
When an operation is considered
The S3 guideline names as reasons for a procedure: pressure on the spinal cord with neurological deficits, a fracture that has occurred or is threatening — assessed with the SINS score —, a single late metastasis, progression of the destruction of bone despite radiotherapy, and pain that cannot be controlled in any other way. The most important evidence for the value of surgery in spinal cord compression comes from a randomised study of 2005: of 101 participants, 84 in 100 could walk after surgery followed by radiotherapy, and 57 in 100 after radiotherapy alone; the ability to walk was preserved for a median of 122 days after surgery, compared with 13 days. Of those who could already no longer walk, 62 in 100 regained the ability to walk after surgery, and 19 in 100 after radiotherapy alone.
The NICE guideline concludes from this: an operation intended to halt or reverse the loss of nerve function should take place as early as possible after the deficits begin; the speed at which the deficits develop determines the urgency; and a complete paralysis that has already occurred is not in itself a reason to forgo the procedure. A stabilisation should also be offered where the deficit is severe, if the spine is unstable and the movement-dependent pain cannot be controlled. Into the decision go: the prognosis of the cancer, the general condition, the tumour’s sensitivity to radiation — some, such as lymphomas and myeloma, respond so well to radiotherapy that an operation is usually not necessary —, the extent of the involvement, and stability. Against a procedure speaks a condition in which recovery from the operation would use up the time remaining.
Surgical options
The aim of any operation on a spinal metastasis is, according to the S3 guideline, that you can get up and walk without a brace — largely free of pain and without new nerve deficits. A cure of the cancer is as a rule not part of it; the operation creates stability and room for the spinal cord, and the radiotherapy afterwards treats the tumour. Which of the following options comes into consideration is agreed in the tumour board; such procedures take place in a hospital with an intensive care unit and oncology support.
- Decompression and stabilisationWhere the spinal cord is under pressure, the tumour is removed from the spinal canal and the spinal cord is freed; the weakened segment is stabilised in the same procedure from behind with screws and rods, in tumour-weakened bone often anchored with cement. If the vertebral body is destroyed, it can be replaced with a spacer. After recovery from the operation, radiotherapy follows.
- Cement stabilisationWhere one or more vertebral bodies of the thoracic or lumbar spine have collapsed painfully without tumour in the spinal canal, bone cement can be introduced into the vertebra (vertebroplasty or kyphoplasty) in order to ease the pain quickly. In a randomised study with 134 cancer patients, kyphoplasty improved back function after one month by 8.3 points on a 24-point scale, and treatment without a procedure by 0.1 points. The procedure does not replace radiotherapy.
- Complete removalWith a single metastasis — most likely with kidney and breast cancer — the affected vertebra can be removed whole and replaced, in order to prevent a recurrence at that site. This is a major procedure that comes into consideration only in selected situations.
The risks are those of any spinal operation — infection, bleeding, injury to the membrane around the nerves, loosening of screws — and they are higher with a cancer, a previous operation, previous radiotherapy and a weakened general condition; wound healing can be delayed. Against this stand the consequences of doing nothing: lasting paralysis, uncontrollable pain, being bedbound. With us you can have such a finding put in context: we assess the images and the stability with you, explain what the tumour board proposes, and give a second opinion if you are facing the decision for or against a procedure.
Alternatives
With a stable spine and without pressure on the spinal cord, radiotherapy with treatment by medicines is not an alternative to an operation but the standard. With radiation-sensitive tumours it can also treat a beginning spinal cord compression. If an operation is not possible because the general condition does not allow it, a supporting corset can ease the movement-dependent pain. And at every stage palliative medicine belongs with it — not as giving up, but as the speciality for pain, mobility and quality of life. If you have been advised to have a procedure and you are unsure, a second opinion is your right with a cancer too.
What to expect
The further course depends on the cancer, not on the spine. As far as the spine is concerned: after radiotherapy or surgery the affected section is checked at intervals with an MRI scan, the bone-protecting medication continues, and physiotherapy helps to preserve gait and strength. Watch for new pain elsewhere in the back, for changes in your walking and for numbness — and get in touch early, not only at the next scheduled appointment. The experience from the studies is unambiguous: those who are still walking when treatment begins are, with high probability, still walking afterwards.
Frequently asked questions
Does a spinal metastasis mean that I will be paralysed?
No. Most spinal metastases do not press on the spinal cord and are treated with radiotherapy and medicines. What matters is that you know the signs of beginning pressure — unsteady walking, weakness, rising numbness, bladder problems — and then act on the same day.
Does a spinal metastasis have to be operated on?
Only if the spine is unstable, the spinal cord is under pressure, or the pain cannot be controlled in any other way. With a stable spine, treatment without an operation is preferred. The decision is made in a tumour board, in which all the specialities involved assess the findings.
Can an affected vertebra be stabilised with cement?
With a painful collapse without tumour in the spinal canal, a vertebroplasty or kyphoplasty comes into consideration in order to ease the pain quickly. It replaces neither the radiotherapy nor the treatment of the cancer, and it is not suitable once the tumour has grown into the spinal canal.
How quickly does it have to happen?
With neurological deficits, within hours: an MRI scan and the start of treatment within 24 hours are what the guidelines require. With pain but no deficits, within days: the MRI scan should take place within a week. Back pain with a known cancer is not a case for waiting.
What should I bring to my first appointment?
All images of the spine on CD together with the reports, the letters from oncology and radiotherapy, the record of the tumour board if you have it, and your list of medicines. Come with someone if you can — there is a great deal to discuss. Everything else is on the page Your first appointment.