Spinal Tumours

Primary non-lymphoproliferative tumours of the spine are uncommon and make up less than 5% of bone neoplasms. Metastatic disease of the spine is much more common. Approximately 40-80% of patients who die from cancer have bony metastases at the time of death, with the spine being the most common metastatic skeletal location. Problems can be caused by direct compression on the spinal cord, vascular obstruction and invasive infiltration.
In children the common benign tumours include osteoid, osteomas and osteoblastoma.

The most common tumors that metastasize to the spine are as follows:

• Prostate
• Breast adenocarcinoma
• Lung adenocarcinoma
• Renal cell carcinoma
• Gastric carcinoma

Tatsui et al found that patients with prostate cancer had the highest rate of metastases to the spine. ²They also found that lung cancer was the most common primary lesion in patients whose spinal metastases were detected before the diagnosis of primary lesions.
The time from diagnosis of the primary lesion to the time the spinal metastasis was detected has demonstrated to be shortest in patients with lung cancer. It was longest in patients with breast cancer. Patients with metastases from breast cancer or prostate cancer had the highest 1-year survival rate, whereas patients with metastases from lung or gastric cancer had the lowest 1-year survival rates.

Symptoms

• Back pain is the most frequent symptom for patients with either benign or malignant neoplasms of the spine.
• Neurological deficits secondary to compression of the spinal cord or nerve roots also can be part of the presentation. The degree of neurological compromise can vary from slight weakness or an abnormal reflex to complete paraplegia, depending on the degree of encroachment. The loss of bowel or bladder continence can occur from neurologic compression or can be secondary to a local mass effect from a tumor in the sacrococcygeal region of the spine, as occurs in chordomas. Systemic or constitutional symptoms tend to be more common with malignant or metastatic disease than in benign lesions.
• Symptoms usually develop slowly.
• With extradural lesions pain is typically aggravated by coughing or straining.
• It may be radicular, localised to the back or felt generally in an extremity.
• May also be motor deficits, paraesthesia, numbness in legs, loss of sphincter control.

Signs

• Local spinal tenderness
• Motor deficits
• Sensory changes

For these patients workup should include:

• A full blood count and differential
• Serum chemistry profile
• Erythrocyte sedimentation rate, or C-reactive protein to help distinguish between neoplastic and infectious processes.
• Elevations in serum calcium or alkaline phosphatase also can provide evidence for neoplastic bone processes. Specific studies such as serum electrophoresis or urine electrophoresis also can be performed to evaluate the likelihood of multiple myeloma or plasmacytoma.
• Plain X-ray, CT or MRI
• Myelography

Confirmation of diagnosis and ascertaining the specific tumour type is by biopsy of the spine lesion after all radiographic studies have been completed. Biopsy can be performed with open or by percutaneous image-guided technique. Percutaneous needle biopsies may not supply adequate tissue for the diagnosis of a primary tumour of the spine.

Decompression and excision where possible. ^4,5 Radiotherapy and chemotherapy where indicated.

• Osteoid osteomas: Symptoms respond to nonsteroidal anti-inflammatory drugs (NSAIDs) or salicylates.Treatment is resection of the nidus by open surgical approach or by percutaneous CT scan-guided resection.
• Osteoblastomas: Wide local resection is the treatment of choice whenever possible. This sometimes is limited by the proximity of vital vessels or neural tissue in the spine. A 10-20% recurrence rate exists for conventional osteoblastomas. Aggressive osteoblastomas have a recurrence rate of approximately 50% if wide margins are not attained. These tumours are not radiosensitive.
• Giant cell tumour: Although most are benign, the lesions are locally aggressive, and their size and location may not allow complete resection. Those that cannot be excised should be curetted. Radiation is reserved for surgically inaccessible tumours. The recurrence rates can be as high as 40-60%.
• Osteochondroma: Complete surgical resection is usually curative. Clinical symptoms improve in 89% of patients following removal of the exostosis. Incomplete resection can lead to recurrence of the lesion.
• Chondrosarcoma: Surgical resection by vertebral corpectomy and strut bone grafting sometimes may be necessary for complete excision. Cure is possible when complete resection can be achieved; this is possible 25% of the time. If wide marginal resection cannot be achieved, the tumor recurrence results in death in 74% of cases. Chemotherapy is used sometimes to help decrease the size of the mass. Metastases of chondrosarcoma depend on the grade of the primary chondrosarcoma. The lungs are the most frequent sites of metastasis.
• Ewing sarcoma: Before the advent of chemotherapy, the survival rate for patients was low due. This was due to the difficulty of resecting these lesions. Radiation and chemotherapy are the current mainstays of treatment of Ewing sarcoma in the spine. There is almost 100% local control and 86% long-term survival rate in patients with nonsacral sarcomas. Sacral tumours have a 62% local control rate and only 25% long-term survival rate. This is secondary to their tendency for delayed presentation and therefore larger size. The most important prognostic indicator for survival is response to chemotherapy.
• Osteosarcoma: Surgical resection is the rule. However, resection of spine lesions is often incomplete due to the size and location of the tumour at the time of presentation. Adjuvant chemotherapy and radiation therapy often are employed with varying degrees of utility. Spinal osteosarcomas have a dismal prognosis, with deaths usually occurring within the first year of diagnosis. Only a few patients have been reported to survive longer than 2 years.
• Chordomas: Surgical resection is the rule. The prognosis depends on whether the tumour can be resected completely. The location and size at presentation often mean that incomplete resection only is possible. Patients with sacrococcygeal tumours often have improved survival because the surrounding structures are more expendable and allow better resection. These patients usually have 8-10 years survival as opposed to 4-5 years survival for other spinal sites. Death usually is related to local recurrence and invasion rather than metastatic disease. Chordomas can metastasize. The most common sites of metastases are the liver, lungs, regional lymph nodes, peritoneum, skin, and heart.
• Multiple myeloma: These are generally sensitive to radiation and chemotherapy. Surgery for stabilisation is indicated in myelomas of the spine when destruction of the vertebral body exists to such an extent that collapse and possible kyphosis with canal compromise could result. Adjuvant radiation therapy may be used postoperatively once healing of the surgical site has been obtained.

Complications associated with spine tumours can be divided into the following:

• Complications associated with the tumour, its recurrences, or its metastases: Neurological complications include radicular pain or focal weakness from impingement on a nerve root and complete or incomplete paraplegia from direct pressure on the spinal cord.
• Complications associated with the surgical, radiation, or chemotherapeutic treatment of the tumours: Complications that result from the treatment modality employed may be related to structures sacrificed during the surgical resection to obtain clear margins, structures in the path of radiation therapy, or the systemic effects of chemotherapy.