Radiation Therapy Alone for Spinal Cord Compression: Time to Improve Upon a Relatively Ineffective Status Quo

Abstract

Metastatic spinal cord compression (MSCC) is a common problem afflicting cancer patients. It affects 5% to 14% of all patients with cancer, and more than 20,000 cases are diagnosed annually in the United States. Once diagnosed, it is considered to be a medical emergency, and immediate intervention is required with high-dose corticosteroids and radiotherapy, with or without decompressive surgery. Without therapy, MSCC is a source of significant morbidity and mortality, causing pain, paralysis, incontinence, and an overall decline in quality of life. Even with aggressive therapy, results can often be unsatisfactory. Although most patients will die as a result of their underlying cancer within the first year of the diagnosis of MSCC, up to one third will survive beyond 1 year. Therefore, optimal therapy is required to maintain quality of life. Palliative radiotherapy has long been standard in the management of patients with MSCC, but the radiation oncologist is often faced with multiple competing and complex issues. The need to deliver a meaningful radiation dose to the tumor for adequate palliation must be balanced with the necessity of avoiding undue toxicity, the most serious of which is radiation myelopathy. Furthermore, the fractionation scheme must be weighed against the performance status and expected survival of the patient. These issues may explain the wide range of fractionation schemes reported in multiple retrospective analyses, with a total of 30 Gy in 3-Gy daily fractions for 10 days most frequently prescribed. In this issue of the Journal of Clinical Oncology, Maranzano et al report on a phase III, randomized, multicenter trial of two hypofractionation schemes, short course compared with split course, for patients with MSCC. Although there are multiple randomized trials on fractionation schemes for brain and bone metastases, to our knowledge this report is the first such trial for MSCC. The authors should be commended for completing such a difficult trial. Unfortunately, multiple problems are inherent in this study, and readers should be cautious before implementing the results in clinical practice. The explanation of the selection criteria for short life expectancy ( 6 months) of the study patients is incomplete. One can form the interpretation that the main criterion for inclusion was unfavorable histology alone, or favorable histology with neurologic dysfunction or poor performance status. However, this study has included groups of patients who might be anticipated to live significantly longer than 6 months. For example, one of the most significant predictors of short survival for patients with metastatic cancer is poor performance status; yet, 17% of patients in this study had Karnofsky performance status of 80 to 100. Furthermore, patients with radiosensitive tumors (such as lymphoma, seminoma, and myeloma) were included, as were those with histologies that have relatively long survivals after development of metastasis (such as breast and prostate cancer). Although patients with these favorable factors may have been equally distributed between the two treatments, the inclusion of such patients needs to be taken into account to estimate the true efficacy of radiation in the trial. Although only five patients experienced in-field recurrence, 18 patients (10%) lost the ability to walk after therapy. Is it possible that the inclusion of patients with favorable histology and good Karnofsky performance status allowed for longer survivals, and offered just enough time for the late toxicities of hypofractionated radiotherapy to occur? One of the most controversial aspects of this study was the choice of the two treatment arms. The most common JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 23 NUMBER 15 MAY 2