Abstract
Background
Corticosteroids
Dexamethasone is the most tested steroid in clinical trials. Studies have shown that steroids provide analgesia and reduce vasogenic edema, which may lead to better neurological outcomes. Treatment should be started as soon as diagnosis is made; studies in acute spinal cord injury suggest significant neurological improvement when used within 8 hours of injury. Historically, debate existed between using high-dose dexamethasone (100 mg loading, then 96 mg daily) versus moderate dose (10 mg loading, then 16 mg daily). A randomized controlled trial comparing the two doses found no differences in efficacy and thus most give the lower dose. 1 Many studies give the steroids divided 4 times a day (total 16 mg daily), tapered over 10 to 14 days. Most generally start intravenously (IV) and then switch to oral administration (PO) when patients are “clinically stable” and more definitive therapy (radiation or surgery) has been initiated. Steroids should be tapered as soon as possible to prevent long-term toxicities. 2 Common short-term side effects include hyperglycemia, insomnia, and gastric distress. Serious acute adverse effects such as gastrointestinal perforation or bleeding, psychosis, risk of infections, and death are associated with high doses only (17%). 3
Radiotherapy (RT)
In the absence of bony instability, RT has historically been the treatment of choice, preferably started within 24 hours of diagnosis. Dose schedule for RT ranges from single fraction 8 Gy to 20 fractions of 40 Gy. One or two fractions of 8 Gy may be preferable in patients with short prognoses and, in one study, had a similar outcome to more prolonged treatment. 4 RT results in pain relief in 40% to 80% of patients and sphincter control in 45% to 90% of cases3,4 when instituted in time. About 90% of ambulatory patients retain ambulation with RT alone, but less than 30% of patients who have lost the ability to walk by the time RT is initiated regain ambulation. 3
Surgery
Until recently, surgery was reserved for cases with SCC in a previously irradiated area, neurological deterioration during RT, spinal instability, or bony compression. However, a recent meta-analysis 5 and a randomized controlled trial 6 found better functional outcomes with surgery plus postoperative RT as compared with RT alone. This trial used a newer surgical technique (circumferential decompression, reconstruction, and immediate stabilization). Of the patients in the surgery group, 84% were ambulatory and retained ambulation for a longer time (a median of 122 days) after treatment compared with 57% in the RT group (median 13 days). Of the nonambulatory patients, 62% regained the ability to walk after the surgery compared with 19% in the RT groups. The surgery group also maintained continence for a significantly longer time (median 156 days vs. 17 days). A more recent retrospective matched pair analysis of cancer patients with SCC comparing RT alone with surgery plus RT did not find any significant differences in outcome between the two treatments. 7 Prompt, interdisciplinary evaluation by radiation oncologists and spine surgeons is indicated to identify the best treatment course.
Other treatments
Spinal Stereotactic Radiosurgery (SRS) has an investigational role in adult nonsurgical patients with radio-resistant tumor or those with previously irradiated areas. Studies suggest more than 80% improvement in overall neurological function. 8 Transarterial embolization is another novel investigational treatment. It is generally used preoperatively for hypervascular spinal tumors causing compression, is safe and effective, and can make radical tumor resection possible at times. 9 In adults, chemotherapy has no role in acute management even in chemosensitive cancers because of its slow effect. Although bisphosphonates reduce the incidence of skeletal complications of cancer, there are no data to suggest a benefit in treating SCC.
Prognosis
Median survival after developing SCC is between 3 and 6 months in adults. Poor prognostic factors for survival include nonambulatory status, SCC within 15 months of original cancer diagnosis, presence of visceral or other bone metastases, cancer type (survival is worse for lung cancer and better for myeloma/lymphoma), and rapidity of developing motor symptom (worst if <7 days and better if >2 weeks after the onset of symptoms).
Conclusion
A loading dose of dexamethasone 10 mg IV should be given as soon as possible after diagnosis, followed by maintenance dose of 4 to 6 mg every 6 to 8 hours, and referral made for primary surgery (if feasible) with adjuvant RT. If surgery is contraindicated, palliative RT alone is indicated.