SCORAD III study reveals: one radiation treatment is sufficient to relieve spinal cord compression symptoms

Spinal cord compression is a common complication in patients with metastatic cancer, and represents a major detriment to quality of life. Radiation treatment is widely used to relieve pain and other symptoms, but currently there is no standard recommended schedule. Findings from a phase III clinical trial demonstrated that a single radiation treatment is as effective as a full week of radiation. This is an important finding, especially taking into account the short life expectancy of these patients. In fact, this means fewer hospital visits and more family time in the final stage of their life.

Bone metastases commonly affect the spine, leading to pressure on the spinal canal and causing back pain, numbness, tingling, and difficulty walking. Approximately one out of ten patients with metastatic solid tumors experience metastatic spinal cord compression. The SCORAD III study enrolled 688 patients with metastatic prostate (44%), lung (18%), breast (11%), and gastrointestinal cancer (11%). The median age of the subjects in the study was 70 years and 73% was male. Eligible patients had spinal cord or cauda equina (C1-S2) compression confirmed by MRI/CT imaging, treatable within a single radiation field and had a life expectancy of more than 8 weeks. Previous radiotherapy of the same area was not allowed. The researchers randomly assigned patients to receive external beam spinal canal radiation therapy either as a single dose of 8 Gy or as 20 Gy split in five doses over five days. The primary endpoint of the study consisted of the ambulatory status, measured on a four-point scale:

• Grade 1: Able to walk normally
• Grade 2: Able to walk with walking aid (such as cane or walker)
• Grade 3: Has difficulty walking even with walking aids
• Grade 4: Dependent on wheelchair

Of note, at study entry, 66% of patients had an ambulatory status of 1 to 2.

After eight weeks, 69.5% of patients who received single-dose radiation therapy and 73.3% of those who received five doses had an ambulatory status 1 to 2. This shows that both shorter- and longer-course radiation treatments helped patients to stay mobile. The median overall survival was similar in the two groups at 12.4 weeks for patients who received the single dose as compared to 13.7 weeks for those treated with five doses (HR[95%CI]:1.02[0.86-1.21], p= 0.81). Also the proportion of patients with severe side effects was similar in the two groups (20.6% vs. 20.4%), although the incidence of mild side effects was lower in the single-dose group (51% vs. 56.9%).

In summary, this study shows that a single dose of 8 Gy in patients with metastatic spinal cord compression was as effective as multiple fractions looking at the ambulatory status at 8 weeks and also the survival appeared similar with both approaches. As such, the investigators now recommend to use a single dose of radiotherapy in this setting, with the major benefit of requiring only a single, instead of multiple, hospital visits. The latter is of particular importance considering the short survival in these patients. On a critical note, it could be that longer radiation may be more effective for preventing regrowth of metastases in the spine than single-dose radiation. Therefore, a longer course of radiation may still be better for patients with a longer life expectancy. However, more research is needed to confirm this. In addition, patients with metastatic breast cancer were underrepresented in this clinical trial, as were younger patients. For certain patients with spinal cord compression, surgery instead of, or in addition to radiation therapy, may be recommended.

Reference

Hoskin P, Misra V, Hopkins K, et al. SCORAD III: Randomised non-inferiority phase III trial of single dose radiotherapy (RT) compared to multifraction RT in patients (pts) with metastatic spinal canal compression (SCC). Presented at ASCO 2017; Abstract LBA10004.