The vast majority of patients have a preexisting cancer diagnosis. Even without one, MESCC should be suspected in anyone who initially seen with progressively worsening back pain, incontinence, or paraplegia, especially in the high-risk population such as long-time smokers or women with a strong family history of breast cancer. In a review by Fuller et al. (5) of more than 1,000 patients with MESCC reported in the literature, the most common tumor type is breast cancer (29%), followed by lung cancer (17%) and prostate cancer (14%), which reflects the high natural incidence of these tumors. New-onset back pain in cancer patients must be taken very seriously, and a proper workup must be performed.

The osseous vertebral column is affected in 85% of cases, paravertebral sites in 10% to 15%, and rare cases exist of isolated epidural or intramedullary metastasis (6). Back pain is the most common presenting symptom (88% to 96%), followed by weakness (76% to 86%), sensory deficits (51% to 80%), and autonomic dysfunction (40% to 64%) (7,8,9,10). The most common level of the MESCC involvement is in the thoracic spine (59% to 78%), followed by lumbar (16% to 33%) and cervical spine (4% to 15%), whereas multiple levels are involved in up to half of the patients (5,7,11).

Magnetic resonance imaging (MRI) is the standard modality for imaging of the central nervous system in cancer patients. It has a very high sensitivity (93%), specificity (97%), and accuracy (95%) in diagnosing MESCC (12). Because patients can have synchronous, multifocal MESCC, an MRI of the entire spine with and without contrast should be promptly performed in anyone suspected of having MESCC (13). High-resolution computed tomography (CT) scan or CT myelogram of the spine should be performed for those with contraindications to MRI.

Prognostic factors predicting survival are generally similar to those of patients with brain metastasis. In terms of predicting ambulatory outcome, one of the most important factors is the rapidity of symptom onset. Other important prognostic factors include radiosensitive histology (e.g., multiple myeloma, germ-cell tumors, lymphomas, and small cell carcinoma) and pretherapy ambulatory function. In a prospective study of 98 patients with MESCC reported by Rades et al. (14), the single strongest predictor for ambulatory status after therapy on multivariate (p < 0.001) analysis was time to development of motor deficits before radiation from the start of any symptoms. This cohort was separated into three groups according to the time to motor deficits before radiation therapy: 1 to 7 days (group I), 8 to 14 days (group II), and more than 14 days (group III). The ambulatory rates for groups I, II, and III were 35%, 55%, and 86% (p < 0.001), respectively. The symptom-improvement rates for groups I, II, and III were 10%, 29%, and 86% (p = 0.026), respectively. The other factor significant on the multivariate analysis for posttherapy ambulatory status was favorable histology (p = 0.005), and a trend was found regarding pretherapy ambulatory status (p = 0.076). Only 10% of the patients in group I had symptom improvement. Acute, rapid deterioration is predictive of irreversible spinal cord infarction; therefore recognition, prompt diagnosis, and treatment of MESCC are crucial.

Although multiple retrospective studies have demonstrated its clinical efficacy, Sorensen et al. (15) reported the only randomized controlled study on the utility of high-dose corticosteroids before definitive radiotherapy in MESCC from solid tumors. The treatment arm consisted of 96 mg of intravenous (i.v.) bolus of dexamethasone followed by 96 mg oral (p.o.) per day for 3 days and a 10-day taper, versus no corticosteroids before radiotherapy. This study demonstrated 3-month and 6-month ambulatory rates of 81% versus 63% and 59% versus 33% (p < 0.05), respectively, in favor of dexamethasone.
Corticosteroids must be started as soon as possible in anyone suspected of having MESCC even before radiographic diagnosis, because this can be rapidly discontinued with a negative diagnosis. Corticosteroids effectively decrease cord edema, and they serve as an effective bridge to definitive treatment.

Although a small randomized trial argued for a lower dexamethasone dose (4 mg per day) in patients with brain metastasis (16), the optimal maintenance dose of corticosteroids in patients with MESCC is unknown. With regard to i.v. loading dose for MESCC, Vecht et al. (17) reported the only randomized study comparing i.v. dexamethasone loading dose of 10 mg versus 100 mg, followed in both arms by the same p.o. regimen of 16 mg per day. Both arms demonstrated significant reductions in pain from baseline (p < 0.001); however, no difference was noted between the two arms with respect to pain reduction, ambulation, or bladder function.

Very high doses of corticosteroids are associated with significant side effects, mainly gastrointestinal (GI). The Sorensen phase III study reported an 11% frequency of serious side effects for patients in the treatment arm, whereas Heimdal et al. (15,18) reported a 14.3% frequency of serious GI side effects (one fatal ulcer, one rectal bleeding, and two bowel perforations) in 28 consecutive patients treated with 96 mg of i.v. dexamethasone per day. When the dexamethasone dose was decreased to 16 mg per day for the next 38 consecutive patients, no instances of serious side effects occurred in either group, with no difference in ambulatory rates between the groups.

Based on these data, a loading of 10 mg of i.v. dexamethasone and followed by a maintenance dose of 4 to 6 mg (i.v. or p.o.) every 6 to 8 hours should be sufficient for most patients. Furthermore, patients should be started on a proton-pump inhibitor for GI prophylaxis (19).