Single radiation treatment may be as effective as a full week of radiation in patients with metastatic spinal canal compression.
CHICAGO-A phase III clinical trial is now suggesting that a single radiation treatment is as effective as a full week of radiation. Investigators looked at patients with metastatic cancer and spinal canal compression and found that it may be possible to shorten treatment events. Investigators in England and Australia reported at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 2–6, that these findings help establish a new standard of care (abstract LBA10004). Currently, no standard of care exists and schedules range from a single dose of 8 Gy to 40 Gy in 20 fractions.
“Our findings establish single-dose radiotherapy as the standard of care for metastatic spinal canal compression, at least for patients with a short life expectancy,” said lead study author Peter Hoskin, MD, an oncologist at the Mount Vernon Cancer Centre in Middlesex, United Kingdom. “For patients, this means fewer hospital visits and more time with family.”
Hoskin and colleagues conducted a study of 688 patients with metastatic prostate (44%), lung (18%), breast (11%), and gastrointestinal cancers (11%). The patients were treated at 43 UK sites and 4 Australian sites. The median age of the patients was 70 years, and 73% were men. All of the patients had spinal cord or cauda equina (C1-S2) compression confirmed by MRI/CT scan, treatable within a single radiation field. These patients also had a life expectancy > 8 weeks and no previous radiotherapy to the same area.
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 5 doses over 5 days. The primary endpoint of the study was 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). At study entry, 66% of patients had an ambulatory status of 1 to 2.
At 8 weeks, 69.5% of patients who received single-dose radiation therapy and 73.3% of those who received 5 doses had an ambulatory status of 1 to 2, showing that both shorter- and longer-course radiation treatments helped patients stay mobile. The median overall survival was similar in the two groups (12.4 weeks with single dose vs 13.7 weeks with 5 doses). The proportion of patients with severe side effects was similar in the two groups (20.6% vs 20.4%). However, mild side effects were less common in the single-dose group (51% vs 56.9%).
The authors now recommend using single-dose radiation therapy in this setting, with the major benefit of requiring only a single hospital visit instead of multiple hospital visits, which is important when considering the short survival time in these patients.
Hoskin noted that a longer course of radiation may still be better for patients with a longer life expectancy. However, more research is needed to confirm this. He noted that the study had limitations and patients with metastatic breast cancer were under-represented in this trial, as were younger patients.