Stereotactic Body Radiotherapy May Have Edge in Curbing Pain of Spinal Metastases

NEW YORK (Reuters Health) – Pain from spinal metastases, a frequent manifestation of systemic cancer, appears to be better relieved by stereotactic body radiotherapy than conventional external beam radiotherapy, according to findings from a multinational study.

“This is the first phase-III randomized trial specific to painful spinal metastases that has shown an improvement in the complete-response rate for pain in patients using dose-escalated stereotactic radiation,” said lead author Dr. Arjun Sahgal of the University of Toronto, in Canada.

“Using a higher radiation dose (24 Gy in 2 fractions) has only been possible over the past decade using stereotactic body radiotherapy techniques,” he told Reuters Health by email.

To take part in the study, patients could have no more than three consecutive vertebral segments to be included in the treatment volume and no neurologically symptomatic spinal cord or cauda equina compression. Among the most common primary cancer types were breast and lung cancer.

The researchers randomized 229 patients to receive external beam radiotherapy (at a dose of 20 Gy in five daily fractions) or stereotactic body radiotherapy (at a dose of 24 Gy in two daily fractions). Median follow-up was 6.7 months, the team reports in the Lancet Oncology.

At three months, in intention-to-treat analysis, complete response for pain was seen in 35% of the stereotactic body radiotherapy group, significantly more than the 14% complete response seen in the external beam radiotherapy group. This significant difference was maintained in multivariable analysis (odds ratio, 3.47).

At six months, significantly more patients achieved a complete response for pain with stereotactic body radiotherapy.

“Finding a treatment that can eliminate the pain from spinal metastases is a major step forward in palliative care,” continued Dr. Sahgal, “and demonstrates that we can continue to test in randomized trials new advanced radiotherapy techniques and their role in helping patients with advanced cancer improve symptom control.”

“What we have determined,” he concluded, “is that patients with painful spinal metastases, who meet the eligibility criteria, should be offered this treatment, allowing them to live their life with less pain.”

The co-author of an accompanying editorial, Dr. Joanne M. van der Velden of University Medical Center Utrecht in the Netherlands, told Reuters Health by email that the researchers made a commendable effort.

However, she said, “We cannot directly implement this in our clinics and treat every patient with bone metastases with stereotactic radiotherapy, as we are not (yet) informed about the overall pain response (that is a reduction of 2 points in pain score), which is more clinically relevant than a complete response for pain alone.”

“In addition,” she said, “this is the first randomized trial with positive results while there are 4 negative trials. We think that it is very well possible that a subgroup of patients with bone metastases will benefit from this type of radiotherapy, and that efforts should focus on identifying those subgroups.”

SOURCE: https://bit.ly/3zPd01u and https://bit.ly/3xJ8q2W The Lancet Oncology, online June 11, 2021.

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