Metastatic Epidural Spinal Cord Compression and Decompression Surgery Multicenter Study Results
Commentary by Senior Author Michael G. Fehlings, MD, PhD
Spinal cord decompression surgery, when used as an adjunct to radiation and chemotherapy, provided immediate and sustained improvement in pain, neurological, functional, and health-related quality of life (HRQoL) outcomes in patients with metastatic epidural spinal cord compression (MESCC) who have at least 3 months survival prognosis, according to findings from the prospective multicenter AOSpine North America study.
“MESCC patients suffer from a systemic disease for which there is virtually no life-saving treatment,” said senior author and principal investigator of the study Michael G. Fehlings MD, PhD, Professor of Neurosurgery at the University of Toronto, in Ontario. “There is no such thing as a trivial surgery and there are more risks associated with surgery in frail patients, such as MESCC patients.”
“However, this study highlights that for selected patients suffering from a single symptomatic MESCC lesion deemed candidates for surgical treatment, spinal decompression with or without reconstruction or stabilization is associated with improved neurological, functional, and overall quality of life outcomes,” said coauthor Anick Nater, MD, a neurosurgery resident at University of Toronto, Ontario. “These findings support the growing body of evidence that all patients with symptomatic spinal metastasis should be evaluated to determine whether surgery could help maintain or enhance the quality of their remaining life.”
Prospective Multicenter Study Design
As reported in the January 20 issue of the Journal of Clinical Oncology, the authors examined the survival and clinical outcomes in 142 patients (mean age 59 years; 59% female) with a single MESCC lesion who were treated with surgery for intractable pain (38.7%), neurological deficits (40.2%), or imminent/overt spinal stability (16.2%) at 10 North American centers. The patients had an estimated life expectancy of at least 3 months at baseline, and 32.4% had received nonsurgical oncologic treatment, most commonly radiation therapy. Outcomes data were collected preoperatively and at least at 6 weeks and 3, 6, 9, and 12 months postoperatively. Most of the patients (85.2%) were given radiation therapy postoperatively as well.
Compared with preoperative status, pain severity and pain interference scores on the Brief Pain Inventory as well as ODI and EQ-5D scores showed significant improvement at 6 weeks, and 3, 6, and 12 months postoperatively (Table). Of the 8 scales on the SF-36 Short Form Health Survey, significant improvements were found at all time points for the bodily pain scale; at 3, 6, and 12 months for the emotional well-being scale and the social functioning scale; and 6-month follow-up for both the mental component score and the role limitations as a result of emotional problems scale.
At 6 months, the patients showed significant improvements in ambulatory status (ability to walk 4 steps independently; P<0.001) and bladder dysfunction (P=0.019). The improvement in ambulatory status, but not bladder dysfunction remained significant at 12 months.
Nearly 30% of the patients (42 of 96) experienced complications within 30 days of surgery. The most common of these was infection, which occurred in 20 patients (25%) with urinary tract infections and wound infections accounting for 10 patients each (10.4%). The rate of wound infections was not altered by use of preoperative radiation therapy to the MESCC lesion. In addition, 2 patients required a second spinal surgery because of progressive neurologic deficits resulting from spinal hematoma in 1 patients and screw malposition in 1 patient.
Indications for Surgery in Patients With MESCC
“Common surgical indications for MESCC lesions are pain, imminent, or actual mechanical instability and/or compression of neurological elements, which can lead to temporary or permanent neurological deficits.” Dr. Nater said. “Surgery is recommended in MESCC patients who meet one of the above surgical indications and for whom the potential benefits outweigh the risks. Clinical decision-making typically involves a multidisciplinary team composed of medical oncologists, radiation oncologists, radiologists, internists, palliative care specialists, and spinal surgeons.”
“Health budget constraints are an undeniable reality and scarce resources should be allocated judiciously,” Dr. Nater said. “The AOSpine MESCC study was rigorously performed and gathered high-quality prospective, multicenter data which allowed for assessment of whether MESCC patients demonstrated higher scores on various validated outcome metrics postoperatively compared to their preoperative measures.”
Gandhivarma Subramaniam, MD
Center for Spine Health
Symptomatic metastatic epidural spinal cord compression (MESCC) is among the most debilitating complications of metastatic spine cancer. MESCC is defined as an epidural mass indenting the dural sac of spinal cord, cauda equina, or nerve roots and can lead to severe pain, weakness in limbs, walking difficulty, and dysfunction of bower or bladder.
Even though the treatment for MESCC is palliative, the major goal of treatment is to improve quality of life by alleviating pain, preserving neurologic function, and achieving mechanical spinal stability. In a selected group of patients who have at least 3 months of survival and good preoperative Karnofsky Performance Status Scale (KPS), surgery plays a major role in achieving that goal.
Preoperative functional status of the patients measured by KPS, histological subtype of the tumor, response to other treatment modalities like radiation or spine radiosurgery, and medical comorbidities play a major role in outcome. Spinal instability neoplastic score (SINS) is useful to accurately and reliably predict spinal instability in patients with spinal tumors. SINS considers six different aspects to assess spinal stability and the score varies from 0-18: 0-6 is stable, 7-11 is potentially unstable, and 11-18 is unstable.
Decompression, separation, or stabilization surgery has the conceptual benefit of providing direct spinal cord decompression, reduction of local tumor burden, and the opportunity for mechanical stabilization of the unstable spine. In addition, surgical decompression provides cytoreduction and a margin around neural elements, that is, separation surgery, allowing subsequent adjuvant therapy, which is associated with improved local tumor control.
In this study by Fehlings et al, meta-analyses concluded that decompressive surgery followed by radiation was associated with improved ambulatory status and survival than with radiation alone in selected patients with MESCC. Patient with radioresistant tumor may benefit from spine radiosurgery after decompression or separation surgery.
This was a well-designed prospective, multicenter, cohort study designed to evaluate surgical outcomes in patients with MESCC. This study used both clinicians as well as patient-centered HRQoL outcome analysis, strict inclusion and exclusion criteria, followed a well-known standard indications for surgery.
Limitations of the study included a small number of patients and lack of a control group. Considering the relatively low incidence of MESCC and poor survival, statistical research of appropriate power has been challenging to achieve. In addition, this is an observational study of patient population those with a single MESCC; thus, generalization of these findings to patient populations with multiple spine metastases requires caution. Also, as mentioned in the study, the population censoring was high as a result of significant mortality. Furthermore, the study excluded patients with radioresistant tumors, who may also benefit from decompression and stabilization followed by a possible option of spine radiosurgery.