Zosia Chustecka

June 02, 2017

CHICAGO — For patients with advanced, metastatic cancer who develop spinal cord compression, one dose of radiotherapy is as effective as several doses delivered over multiple hospital visits, said British researchers here at the annual meeting of the American Society of Clinical Oncology (ASCO).

The results come from a phase 3 trial (SCORAD III) conducted in 688 patients, which compared a single 8 Gy dose with 20Gy delivered in five fractions over 5 days, and show that the primary endpoint of ambulatory status at 8 weeks was similar in both groups.   

For patients with a shortened life expectancy, such as the participants in this trial (who had a median overall survival of 13 weeks), a single dose of radiotherapy should now become the standard of care, commented lead investigator Peter Hoskin, MD, from the Mount Vernon Cancer Centre in Middlesex, United Kingdom. "For patients, this means fewer hospital visits and more time with family," he added.

"This is a case where less is more," agreed Joshua Jones, MD, from the University of Pennsylvania in Philadelphia, who was speaking as an ASCO expert.

These are results from a large phase 3 study, and are practice-changing, he said. But there is one caveat: the patients in this study had a short life expectancy, he emphasized. For patients who are expected to live longer such as metastatic prostate cancer patients, it may still be better to use several doses of radiotherapy, he told Medscape Medical News.

Dr Hoskin agreed. "Longer radiation may be more effective for preventing regrowth of metastases in the spine," he noted, and therefore "may still be better for patients with a longer life expectancy, but we need more research to confirm this."

The patients taking part in this study had metastatic cancer of the prostate (44%), lung (18%), breast (11%), and gastrointestinal tract (11%). The majority (73%) were male, and the median age was 70 years. 

Once cancer spreads to the bones, it commonly affects the spine, the experts explained. Metastatic spinal cord compression develops in about 10% of patients with advanced cancer, and tumors pressing on the spine can cause back pain, numbness, and difficulties with walking. In more severe cases, spinal cord compression can lead to incontinence and paralysis, which obviously have "a devastating impact on quality of life," Dr Jones commented.

At enrollment, 66% of patients had ambulatory state 1 (able to walk normally) or 2 (able to walk with an aid such as a cane or a walker).

Results at 8 weeks after radiotherapy showed that 69.5% of patients (114/164) treated with a single dose and 73.3% of patients (129/176) treated with several doses had ambulatory status 1 or 2 (risk difference -3.78%).

The overall survival was very similar between the two groups, Dr Hoskins noted: the median was 12.4 weeks after single dose and 13.7 after several doses (hazard ratio 1.02; P = .81).

The proportion of patients experiencing grade 3 or 4 adverse events was similar in the two groups (20.6% with single dose vs 20.4% with several doses), but there were fewer patients with grade 1 or 2 adverse events in the single-dose group (51.0% vs 56.9%), he noted.

"We now recommend using a single dose of radiotherapy in this setting, with the major benefit of requiring only a single instead of multiple hospital visits, important when considering the short survival of these patients," Dr Hoskin concluded.

2017 annual meeting of the American Society of Clinical Oncology (ASCO). Abstract LBA10004 was presented June 2, 2017.

Dr Hoskins reports receiving research funding (institutional) from Varian Medical Systems, and several coauthors also report industry associations, as listed in the abstract.

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