Compression of the spinal cord and nerve roots is the second most frequent neurologic complication of cancer (brain metastases are the most frequent neurologic complication). Each year in the United States, approximately 20,000 persons with cancer develop SCC; this group represents 5% to 10% of the general cancer population. Because of improved treatments and prolonged survival in various cancers, the incidence of SCC may be increasing.
Cancers most likely to spread to the spine are lung, breast, and prostate cancer; kidney cancer and lymphoma tend to spread to the spinal cord as well. Patients with melanoma, renal cell carcinoma, multiple myeloma, or certain sarcomas are also at risk for SCC. Sarcomas and neuroblastoma cause more than 80% of cases of metastatic SCC in children.
Malignant SCC is defined as compressive indentation, displacement, or encasement of the spinal cord's thecal sac by metastatic or locally advanced cancer. Spinal cord compression produces edema, inflammation, and mechanical compression, which causes direct neural injury to the cord, as well as vascular damage and impairment of oxygenation.
Malignancies of the breast, prostate, lung, and kidney have a propensity to metastasize to bony structures, but any invasive cancer capable of hematogenous spread can produce SCC. Cancers that spread to the spine move to the bone marrow of the vertebral column by way of blood vessels. Spinal cord compression can also occur through direct tumor extension, which is frequently seen in non-Hodgkin's lymphoma. In such cases, there is direct extension of a paraspinal mass through the epidural foramen, and this extension produces the compression. Finally, metastasis results when tumor cells in the cerebrospinal fluid deposit tumor cells in the epidural space.This scenario most often occurs in leukemia.
Spinal cord compression results when a metastatic tumor grows into the epidural space and impinges on the dura (the tough membrane that covers the spinal cord), thereby producing pressure on neurologic tissue. As the mass grows, it destroys the bony structure of the vertebrae and weakens them to the point of collapse. The spinal column may then become weak and destabilized.
 | Figure 1. Spinal cord compression. |
Spinal cord compression constitutes a true emergency because the initial injury to the spinal cord will lead to permanent loss of neurologic function if the pressure of the tumor on the cord is not relieved quickly. Prognosis depends greatly on the length of time of the cord impingement, the location of the mass in the spinal column, and the tissue type of the mass.
Prognosis of SCC also depends on the functional status and length of survival after treatment. Spinal cord compression is fatal only if it occurs in the cervical region of the spinal cord (C4 and above) and if it results in respiratory paralysis that is uncompensated by mechanical ventilation. Tumor tissue type must be considered when the treatment plan is being determined. Some tumors, such as Hodgkin's lymphoma and small cell lung cancer, are very sensitive to chemotherapeutic agents, whereas lymphoma and myeloma are more radiosensitive, and breast and prostate cancers may respond to hormonal agents.
The presenting signs and symptoms depend on the location and level of the metastatic tumor. The thoracic spine is the site most often involved (70% of cases), followed by the lumbosacral spine (20%) and the cervical spine (10%). Other variables include the degree of cord impingement and the duration of tumor involvement. The cardinal initial symptom of SCC is back pain, reported by 90% to 95% of patients. The pain can be localized, radicular, or both and usually precedes other symptoms by 2-4 months. Local pain occurs over the area of the tumor and is caused by vertebral destruction or stretching of the bone by an enlarging tumor mass. Radicular pain is caused by compression of nerve roots and is found in the dermatomes affected by the nerve roots. Radicular pain may travel down the extremity associated with the area of compression and may be aggravated by the Valsalva maneuver. Often the pain is described as a soreness or vague discomfort, which progresses to more severe symptoms such as weakness in one or both limbs, loss of sensation, and then autonomic dysfunction and paralysis. This pain often begins as a nonspecific soreness, which could be attributed to any number of other conditions, such as arthritis, muscle strain, or old injury to the vertebrae. Physical examination findings correspond to the location of the tumor, degree of cord impingement, and duration of involvement. Tenderness is an early sign of SCC and thus may indicate beginning neurologic injury, the prompt treatment of which will result in complete recovery of function. Often the patient will complain of soreness or tenderness over the vertebral body with tumor involvement. Having the patient walk heel to toe will establish whether there are any gait problems. Checking the patient's ability to move specific muscles in response to resistance by the examiner can rule out muscle weakness and paresis. Pain that progresses down the patient's asymptomatic (or less symptomatic) leg when the leg is raised straight may suggest SCC. If cord compression is left untreated, weakness often develops, preceded or accompanied by sensory loss. In a patient with a history of cancer, bilateral leg weakness that is noticeable with stair climbing, paresthesias in the legs, and bowel or bladder dysfunction are all red flags for SCC. Sensory function -- specifically, the ability to distinguish temperatures and feel vibration -- is evaluated using hot and cold tuning forks.Pain recognition is assessed using dull and sharp tools. A rectal examination should be performed to assess sphincter tone. Weak rectal sphincter tone is a late sign of SCC, signaling worsening injury to the nerve roots affected by the increasing compression of the spinal cord. If the patient has urinary complaints, the bladder is catheterized for postvoiding residual urine. Urinary volumes > 200 mL may suggest a neurogenic bladder. Once such autonomic symptoms appear, SCC usually progresses rapidly, and it may result in irreversible paralysis in hours to days if untreated. Laboratory tests include a complete blood cell count with differential, an erythrocyte sedimentation rate determination, urinalysis, and a chemistry profile including calcium and liver function studies. The complete blood cell count and erythrocyte sedimentation rate may be useful in differentiating SCC from infection, whereas the chemistry profile may indicate the primary cancer or the patient's general condition. Imaging studies include plain radiography and magnetic resonance imaging (MRI) with contrast of the spine. Plain films of the spine frequently demonstrate associated vertebral blastic or lytic lesions. However, gadolinium-enhanced MRI provides the best definition of spinal lesions. Magnetic resonance imaging not only shows cord compression caused by extra dural masses but also shows paravertebral masses, intramedullary disease, and bone metastasis. Magnetic resonance imaging of the entire spine should be ordered, because approximately 10% to 30% of patients with clinical symptoms of SCC have multiple lesions. Lumbar puncture is contraindicated because removal of cerebrospinal fluid may worsen the SCC. Treatment is palliative in most cases, but goals are relief of pain and maintenance or restoration of neurologic function. Other goals include spinal column stabilization and local tumor control. Choice of therapy depends on the tumor type and location, the speed of onset, and the degree of function before onset of symptoms. The patient is admitted to the hospital, usually by the medical oncologist, who has typically consulted with the radiation oncologist and the neurosurgeon. A course of treatment with the corticosteroid dexamethasone is started to reduce the edema and cord compression caused by the tumor mass and to thereby relieve the pain. Dexamethasone has lympholytic activity against lymphomas involving the epidural space. Some controversy exists regarding the optimal dose of dexamethasone; adult doses ordered range from 4 to 100 mg, given every 6 hours. However, many physicians administer a 4- to 100-mg intravenous (IV) bolus followed by 16-96 mg/d in divided doses over several days. The dose of dexamethasone, like any corticosteroid, must be tapered gradually. A common schedule for tapering calls for decreasing the dose by one third every 3-4 days. If tapering is not tolerated and neurologic deterioration occurs, a trial of an escalated dose may be attempted, followed by tapering. Patients who take dexamethasone must be monitored carefully for side effects of corticosteroids, such as immunosuppression, gastrointestinal irritation, fluid retention, euphoria, depression, and hyperglycemia. Blood glucose levels are a particular concern in diabetic patients and must be monitored closely. The diabetic patient's diet and insulin dose may need to be changed. If the patient has been treated with an oral hypoglycemic drug, insulin may need to be temporarily substituted to manage the higher glucose levels. Bolus injections of dexamethasone must be given slowly to avoid rectal or vaginal burning. Radiation therapy is the standard of care for SCC caused by tumor involvement. Radiation therapy resolves pain by reducing the tumor mass and relieving the SCC. There are different regimens of radiation therapy for SCC. The commonly prescribed regimen is 2-3 Gy per fraction to a total dose not exceeding 30-40 Gy, directed to the spinal cord over 2-4 weeks. Indicators of a response to radiation therapy include pain relief and a return to baseline function or improved function. Patients may experience some relief of symptoms within a few days after starting radiation therapy, and pain sometimes is relieved within hours. However, return to baseline function after radiation therapy can be delayed for months. In a small number of patients, particularly those with spinal instability or a rapidly progressing loss of neurologic function, surgery may be indicated. Often these oncology patients are severely compromised by their underlying cancer and numerous treatment regimens. Wound healing and recovery from surgery can be difficult in this population, so patients must be selected carefully for any surgical procedure. They may have failed to respond to radiation therapy, the site of the primary tumor may be unknown, they may have local tumor that recurs at a previously irradiated site, or they may have pathologic fracture with spinal instability or compression of the cord by bone. Chemotherapy is indicated in adults with chemosensitive tumors such as lymphoma or Hodgkin's disease. Chemotherapy can also be used as an adjuvant therapy with irradiation or surgery in patients with breast cancer, prostate cancer, or multiple myeloma. The choice of chemotherapeutic agents depends on the primary tumor type and the chemotherapy history of the patient. Hormone therapy is another option for patients with prostate or breast cancer. Patients who have failed to respond to chemotherapy and conventional radiation therapy (external beam radiotherapy) and are not candidates for standard surgical procedures (laminectomy) have few options. Palliative care consisting of analgesic administration, nerve blocks, corticosteroid therapy, and side effect management, best performed by hospice care workers, is indicated in these patients. Optimal nursing management after treatment for SCC is paramount for success.Clinical Presentation
Physical Examination
Diagnostic Tests
Treatment
Corticosteroid Therapy
Radiation Therapy
Surgery
Chemotherapy
Palliative Care
Palliative care goals include prevention of further injury, good pain control, restoration and maintenance of bowel and bladder function, and provision of emotional support for both the patient and caregivers. The response to treatment depends in general on the level of function at the time of diagnosis. If a patient presents with bladder and bowel symptoms and paresthesias, it is less likely that he or she will recover bladder and bowel function or the ability to walk.
So, Hospice referral is appropriate for the patient with SCC whose cancer has progressed to end-stage disease. The members of the hospice team are experts in pain control and provision of emotional support to the patient and his or her family in the face of a steady progression of losses, ultimately leading to death.
Source :
Maryjo Osowski, RN, MSN, AOCN
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